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Document and Entity Information	12 Months Ended
Document and Entity Information	Dec. 31, 2019 shares
Document Type	20-F
Document Period End Date	Dec. 31, 2019
Document Registration Statement	false
Document Annual Report	true
Document Transition Report	false
Document Shell Company Report	false
Entity Registrant Name	Niu Technologies
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Central Index Key	0001744781
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Amendment Flag	false
Class A Ordinary Shares
Entity Common Stock, Shares Outstanding	130,174,878
Class B Ordinary Shares
Entity Common Stock, Shares Outstanding	19,242,020

CONSOLIDATED BALANCE SHEETS	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)
Current assets
Cash	$ 40,211,719	¥ 279,945,942	¥ 569,059,591
Term deposits	25,051,647	174,404,554	27,452,663
Restricted cash	31,838,902	221,656,071	179,262,714
Short-term investments	44,591,818	310,439,321	120,241,425
Accounts receivable, net	16,551,567	115,228,700	54,424,845
Inventories	25,659,068	178,633,299	142,382,205
Prepayments and other current assets	4,450,305	30,982,131	26,919,954
Total current assets	188,355,026	1,311,290,018	1,119,743,397
Non-current assets
Property, plant and equipment, net	21,674,185	150,891,344	40,985,174
Intangible assets, net	1,117,491	7,779,749	7,717,754
Land use right, net	4,934,921	34,355,936
Other non-current assets	936,907	6,522,561	16,805,474
Total non-current assets	28,663,504	199,549,590	65,508,402
Total assets	217,018,530	1,510,839,608	1,185,251,799
Current liabilities
Short-term bank borrowings (including short term bank borrowings of VIE without recourse to the Company of RMB179,978,003 and RMB217,394,132 as of December 31, 2018 and 2019, respectively)	31,226,713	217,394,132	179,978,003
Accounts payable (including accounts payable of VIE without recourse to the Company of RMB249,665,890 and RMB258,934,264 as of December 31, 2018 and 2019, respectively)	37,201,336	258,988,264	249,665,890
Advance from customers (including advance from customers of VIE without recourse to the Company of RMB20,505,861 and RMB7,478,309 as of December 31, 2018 and 2019, respectively)	1,074,192	7,478,309	20,505,861
Deferred revenue - current (including deferred revenue-current of VIE without recourse to the Company of RMB12,666,330 and RMB31,105,700 as of December 31, 2018 and 2019, respectively)	4,468,054	31,105,700	12,666,330
Accrued expenses and other current liabilities (including accrued expenses and other current liabilities of VIE without recourse to the Company of RMB119,242,975 and RMB164,442,316 as of December 31, 2018 and 2019, respectively)	25,213,795	175,533,397	134,184,026
Income taxes payable (including income taxes payable of VIE without recourse to the Company of nil and RMB3,013,805 as of December 31, 2018 and 2019, respectively)	432,906	3,013,805
Total current liabilities	99,616,996	693,513,607	597,000,110
Non-current liabilities
Deferred revenue - non-current (including deferred revenue-non current of VIE without recourse to the Company of RMB234,801 and RMB2,171,033 as of December 31, 2018 and 2019, respectively)	311,849	2,171,033	234,801
Deferred income tax liability (including deferred income taxes of VIE without recourse to the Company of nil and RMB1,265,780 as of December 31, 2018 and 2019, respectively)	181,818	1,265,780
Other non-current liabilities (including other non-current liabilities of VIE without recourse to the Company of RMB17,609,842 and RMB22,358,968 as of December 31, 2018 and 2019, respectively)	3,211,665	22,358,968	17,609,842
Total non-current liabilities	3,705,332	25,795,781	17,844,643
Total liabilities	103,322,328	719,309,388	614,844,753
SHAREHOLDERS' EQUITY:
Additional paid-in capital	249,662,837	1,738,102,741	1,717,483,548
Accumulated other comprehensive loss	(1,776,584)	(12,368,224)	(22,786,922)
Accumulated deficit	(134,203,908)	(934,300,768)	(1,124,385,539)
Total shareholders' equity	113,696,202	791,530,220	570,407,046
Total liabilities and shareholders' equity	217,018,530	1,510,839,608	1,185,251,799
Class A Ordinary Shares
SHAREHOLDERS' EQUITY:
Ordinary Shares	12,137	84,494	83,120
Class B Ordinary Shares
SHAREHOLDERS' EQUITY:
Ordinary Shares	$ 1,720	¥ 11,977	¥ 12,839

CONSOLIDATED BALANCE SHEETS (Parenthetical)	12 Months Ended
CONSOLIDATED BALANCE SHEETS (Parenthetical)	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 $ / shares shares	Dec. 31, 2019 CNY (¥) shares	Dec. 31, 2018 CNY (¥) shares
Short-term bank borrowings	$ 31,226,713		¥ 217,394,132	¥ 179,978,003
Accounts payable	37,201,336		258,988,264	249,665,890
Advances from customers	1,074,192		7,478,309	20,505,861
Deferred revenue - current	4,468,054		31,105,700	12,666,330
Accrued expenses and other current liabilities	25,213,795		175,533,397	134,184,026
Income taxes payable	432,906		3,013,805
Deferred revenue - non current	311,849		2,171,033	234,801
Deferred income tax liability	181,818		1,265,780
Other non-current liabilities	$ 3,211,665		¥ 22,358,968	¥ 17,609,842
Class A Ordinary Shares
Ordinary shares, par value (in dollars per share) \| $ / shares	$ 0.0001	$ 0.0001
Ordinary shares, authorized \| shares	4,900,000,000		4,900,000,000	4,900,000,000
Ordinary shares, issued \| shares	130,174,878		130,174,878	128,032,038
Ordinary shares, outstanding \| shares	130,174,878		130,174,878	128,032,038
Class B Ordinary Shares
Ordinary shares, par value (in dollars per share) \| $ / shares	$ 0.0001	$ 0.0001
Ordinary shares, authorized \| shares	50,000,000		50,000,000	50,000,000
Ordinary shares, issued \| shares	19,242,020		19,242,020	20,642,020
Ordinary shares, outstanding \| shares	19,242,020		19,242,020	20,642,020
Class A shares issued upon conversion of each share \| shares	1	1
VIE
Short-term bank borrowings			¥ 217,394,132	¥ 179,978,003
Accounts payable			258,988,264	249,665,890
Advances from customers			7,478,309	20,505,861
Deferred revenue - current			31,105,700	12,666,330
Accrued expenses and other current liabilities			164,442,316	119,242,975
Income taxes payable			3,013,805	0
Deferred revenue - non current			2,171,033	234,801
Deferred income tax liability			1,265,780	0
Other non-current liabilities			¥ 22,358,968	¥ 17,609,842

CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) /INCOME	12 Months Ended
CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) /INCOME	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2019 CNY (¥) ¥ / shares shares	Dec. 31, 2018 CNY (¥) ¥ / shares shares	Dec. 31, 2017 CNY (¥) ¥ / shares shares
CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) /INCOME
Revenues	$ 298,240,268	¥ 2,076,289,101	¥ 1,477,781,304	¥ 769,368,001
Cost of revenues	(228,351,654)	(1,589,738,548)	(1,279,155,847)	(714,669,718)
Gross profit	69,888,614	486,550,553	198,625,457	54,698,283
Operating expenses:
Selling and marketing expenses	(26,267,993)	(182,872,514)	(150,150,872)	(83,064,894)
Research and development expenses	(9,650,859)	(67,187,348)	(91,811,892)	(39,492,743)
General and administrative expenses	(11,436,060)	(79,615,561)	(272,464,481)	(74,799,105)
Total operating expenses	(47,354,912)	(329,675,423)	(514,427,245)	(197,356,742)
Government grants	4,285,353	29,833,770	1,395,200	833,000
Operating (loss) / income	26,819,055	186,708,900	(314,406,588)	(141,825,459)
Changes in fair value of a convertible loan \| ¥			(34,499,858)	(43,006,399)
Interest expenses	(1,637,076)	(11,396,998)	(7,721,675)	(3,153,521)
Interest income	2,427,359	16,898,785	2,998,796	1,006,972
Investment income	874,548	6,088,425	4,601,849	2,315,536
(Loss) / income before income taxes	28,483,886	198,299,112	(349,027,476)	(184,662,871)
Income tax expenses	(1,179,916)	(8,214,341)	0	0
Net (loss) / income	27,303,970	190,084,771	(349,027,476)	(184,662,871)
Other comprehensive income / (loss)
Foreign currency translation adjustment, net of nil income taxes	1,275,931	8,882,775	(28,436,867)	9,994,461
Unrealized gain on available for sale securities, net income taxes of nil, nil and RMB2,034,081 for the year 2017, 2018 and 2019, respectively	876,532	6,102,242	4,655,556	2,415,901
Less: reclassification adjustment for gain on available for sale securities realized in net income, net income taxes of nil, nil and RMB1,522,106 for the year 2017, 2018 and 2019, respectively	(655,911)	(4,566,319)	(4,601,849)	(2,315,536)
Comprehensive (loss) / income	$ 28,800,522	¥ 200,503,469	¥ (377,410,636)	¥ (174,568,045)
Net (loss) / income per ordinary share
Basic (In dollars per share) \| (per share)	$ 0.18	¥ 1.28	¥ (5.30)	¥ (7.02)
Diluted (In dollars per share) \| (per share)	$ 0.18	¥ 1.24	¥ (5.30)	¥ (7.02)
Weighted average number of ordinary shares and ordinary shares equivalents outstanding used in computing net (loss) / income per ordinary share
Basic	149,025,166	149,025,166	65,834,876	26,295,181
Diluted	153,248,188	153,248,188	65,834,876	26,295,181

CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) /INCOME (Parenthetical) - CNY (¥)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) /INCOME
Foreign currency translation adjustment, income tax	¥ 0	¥ 0	¥ 0
Unrealized gain on available for sale securities, income tax	2,034,081	0	0
Reclassification adjustment for gain on available for sale securities realized in net income, income tax	¥ 1,522,106	¥ 0	¥ 0

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' (DEFICIT) / EQUITY	Ordinary shares Series Seed Preferred Shares CNY (¥) shares	Ordinary shares Class A Ordinary Shares CNY (¥) shares	Ordinary shares Class B Ordinary Shares CNY (¥) shares	Ordinary shares USD ($) shares	Ordinary shares CNY (¥) shares	Series Seed Preferred Shares Series Seed Preferred Shares CNY (¥) shares	Series Seed Preferred Shares CNY (¥) shares	Additional paid-in capital Class A Ordinary Shares CNY (¥)	Additional paid-in capital Class B Ordinary Shares CNY (¥)	Additional paid-in capital USD ($)	Additional paid-in capital CNY (¥)	Accumulated other comprehensive (loss) / income USD ($)	Accumulated other comprehensive (loss) / income CNY (¥)	Accumulated deficit USD ($)	Accumulated deficit CNY (¥)	Class A Ordinary Shares CNY (¥)	Class B Ordinary Shares CNY (¥)	USD ($)	CNY (¥)
Beginning balance at Dec. 31, 2016					¥ 39,948		¥ 18,436				¥ 377,738,798		¥ (4,498,588)		¥ (586,493,123)				¥ (213,194,529)
Beginning balance (in shares) at Dec. 31, 2016 \| shares				64,570,520	64,570,520		30,000,000
Increase (decrease) in shareholders' deficit
Share-based compensation											62,527,098								62,527,098
Net (loss) / income															(184,662,871)				(184,662,871)
Foreign currency translation adjustment, net of nil income taxes													9,994,461						9,994,461
Unrealized holding gains on available-for-sale security, net of income taxes													2,415,901						2,415,901
Reclassification adjustment for gain on available for sale securities realized in net income, net of income taxes													(2,315,536)						(2,315,536)
Ending balance at Dec. 31, 2017					¥ 39,948		¥ 18,436				440,265,896		5,596,238		(771,155,994)				(325,235,476)
Ending balance (in shares) at Dec. 31, 2017 \| shares				64,570,520	64,570,520		30,000,000
Increase (decrease) in shareholders' deficit
Share-based compensation											265,874,927								265,874,927
Issuance of ordinary shares					¥ 9,714						383,308,578								383,318,292
Issuance of ordinary shares (in shares) \| shares				14,000,000	14,000,000
Repurchase and retirement of ordinary shares					¥ (266)										(4,202,069)				(4,202,335)
Repurchase and retirement of ordinary shares (in shares) \| shares				(432,000)	(432,000)
Conversion of preferred shares into ordinary shares	¥ 18,436	¥ 24,562	¥ 3,565			¥ (18,436)		¥ 451,100,862	¥ 176,933,285							¥ 451,125,424	¥ 176,936,850
Conversion of preferred shares into ordinary shares (in shares) \| shares	30,000,000	35,397,679	5,137,859			(30,000,000)
Net (loss) / income															(349,027,476)				(349,027,476)
Foreign currency translation adjustment, net of nil income taxes													(28,436,867)						(28,436,867)
Unrealized holding gains on available-for-sale security, net of income taxes													4,655,556						4,655,556
Reclassification adjustment for gain on available for sale securities realized in net income, net of income taxes													(4,601,849)						(4,601,849)
Ending balance at Dec. 31, 2018					¥ 95,959						1,717,483,548		(22,786,922)		(1,124,385,539)				570,407,046
Ending balance (in shares) at Dec. 31, 2018 \| shares				148,674,058	148,674,058
Beginning balance at Dec. 31, 2017					¥ 39,948		¥ 18,436				440,265,896		5,596,238		(771,155,994)				(325,235,476)
Beginning balance (in shares) at Dec. 31, 2017 \| shares				64,570,520	64,570,520		30,000,000
Increase (decrease) in shareholders' deficit
Conversion of preferred shares into ordinary shares																			628,062,274
Ending balance at Dec. 31, 2019				$ 13,857	¥ 96,471					$ 249,662,837	1,738,102,741	$ (1,776,584)	(12,368,224)	$ (134,203,908)	(934,300,768)			$ 113,696,202	791,530,220
Ending balance (in shares) at Dec. 31, 2019 \| shares				149,416,898	149,416,898
Beginning balance at Dec. 31, 2018					¥ 95,959						1,717,483,548		(22,786,922)		(1,124,385,539)				570,407,046
Beginning balance (in shares) at Dec. 31, 2018 \| shares				148,674,058	148,674,058
Increase (decrease) in shareholders' deficit
Share-based compensation											19,622,779								19,622,779
Exercise of share-based awards					¥ 512						996,414								996,926
Exercise of share-based awards (in shares) \| shares				742,840	742,840
Net (loss) / income															190,084,771			27,303,970	190,084,771
Foreign currency translation adjustment, net of nil income taxes													8,882,775					1,275,931	8,882,775
Unrealized holding gains on available-for-sale security, net of income taxes													6,102,242					876,532	6,102,242
Reclassification adjustment for gain on available for sale securities realized in net income, net of income taxes													(4,566,319)					(655,911)	(4,566,319)
Ending balance at Dec. 31, 2019				$ 13,857	¥ 96,471					$ 249,662,837	¥ 1,738,102,741	$ (1,776,584)	¥ (12,368,224)	$ (134,203,908)	¥ (934,300,768)			$ 113,696,202	¥ 791,530,220
Ending balance (in shares) at Dec. 31, 2019 \| shares				149,416,898	149,416,898

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' (DEFICIT) / EQUITY (Parenthetical) - CNY (¥)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' (DEFICIT) / EQUITY
Foreign currency translation adjustment, income tax	¥ 0	¥ 0	¥ 0
Unrealized holding gains on available-for-sale security, income tax	2,034,081	0	0
Reclassification adjustment for gains on available-for-sale securities realized in net income, income tax	¥ 1,522,106	¥ 0	¥ 0

CONSOLIDATED STATEMENTS OF CASH FLOWS	12 Months Ended
CONSOLIDATED STATEMENTS OF CASH FLOWS	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2017 CNY (¥)
Operating activities:
Net (loss) / income	$ 27,303,970	¥ 190,084,771	¥ (349,027,476)	¥ (184,662,871)
Adjustments to reconcile net (loss) / income to net cash provided by operating activities
Allowance / (reversals) for doubtful accounts	439,597	3,060,389	(1,215,464)	1,908,399
Share-based compensation	2,818,636	19,622,779	265,874,927	62,527,098
Change in fair value of a convertible loan			34,499,858	43,006,399
Depreciation and amortization	4,658,047	32,428,391	18,881,376	9,746,569
Investment income	(874,548)	(6,088,425)	(4,601,849)	(2,315,536)
Unrealized foreign exchange loss / (gain)	(101,513)	(706,712)	108,528	219,885
Loss on disposal of property, plant and equipment	6,705	46,679	227,720	4,697
Write-down of inventories	1,506,958	10,491,137	18,254,406
Changes in operating assets and liabilities:
Accounts receivable	(9,173,525)	(63,864,244)	(42,827,269)	8,307,152
Inventories	(6,713,684)	(46,739,327)	(72,410,646)	(21,444,209)
Prepayments and other current assets	(566,480)	(3,943,720)	(19,570,371)	24,498,743
Other non-current assets	(347,525)	(2,419,398)	(130,199)
Accounts payable	1,338,986	9,321,752	124,728,425	53,119,693
Advances from customers	(1,871,291)	(13,027,552)	(27,997,528)	35,169,999
Deferred revenue	2,926,772	20,375,602	2,903,070	5,143,914
Other non-current liabilities	76,483	532,460	5,231,091	5,682,222
Deferred income tax liability	108,277	753,805
Income taxes payable	432,906	3,013,805
Accrued expenses and other current liabilities	3,697,067	25,738,243	55,640,518	39,151,124
Net cash provided by operating activities	25,665,838	178,680,435	8,569,117	80,063,278
Investing activities:
Cash paid for purchase of property, plant and equipment	(16,408,721)	(114,234,236)	(32,017,882)	(23,244,485)
Purchase of land use right	(3,556,866)	(24,762,190)	(12,329,652)
Purchase of intangible assets	(289,817)	(2,017,645)	(8,941,893)
Purchase of term deposits	(24,763,288)	(172,397,059)	(95,540,873)
Cash received from redemption of term deposits	3,962,116	27,583,462	75,638,800
Cash paid for purchase of short-term investments	(259,769,475)	(1,808,463,130)	(1,308,000,000)	(412,000,000)
Cash received from sale of short-term investments	233,617,966	1,626,401,557	1,277,601,849	379,315,536
Net cash used in investing activities	(67,208,085)	(467,889,241)	(103,589,651)	(55,928,949)
Financing activities:
Proceeds from issuance of Class A Ordinary Shares upon IPO, net of underwriting commissions and discounts of RMB30,599,667			406,538,433
Payment of issuance cost of Class A Ordinary Shares in connection with IPO	(449,688)	(3,130,639)	(20,089,502)
Issuance of Series B Redeemable Convertible Preferred Shares			161,392,196
Cash received from exercise of employee stock option	143,199	996,926
Cash paid for repurchase of Ordinary Shares			(4,202,335)
Proceeds from short-term bank borrowings	38,248,763	266,280,240	199,978,003	118,701,147
Repayment for short-term bank borrowings	(32,874,273)	(228,864,111)	(188,234,207)	(49,997,837)
Net cash provided by financing activities	5,068,001	35,282,416	555,382,588	68,703,310
Effect of foreign currency exchange rate changes on cash and restricted cash	1,035,094	7,206,098	6,074,726	(13,064,824)
Net increase / (decrease) in cash and restricted cash	(35,439,152)	(246,720,292)	466,436,780	79,772,815
Cash and restricted cash at the beginning of the year	107,489,773	748,322,305	281,885,525	202,112,710
Cash and restricted cash at the end of the year	72,050,621	501,602,013	748,322,305	281,885,525
Supplemental information
Interest paid	1,394,094	9,705,406	7,656,695	¥ 3,117,410
Income tax paid	638,733	4,446,731
Payable for issuance cost of Class A Ordinary Shares in connection with IPO			¥ (3,130,639)
Payable for the construction of building	$ 3,301,233	¥ 22,982,521

CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical)	12 Months Ended
CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical)	Dec. 31, 2019 CNY (¥)
CONSOLIDATED STATEMENTS OF CASH FLOWS
Underwriting commissions and discounts for issuance of Class A Ordinary Shares upon IPO	¥ 30,599,667

DESCRIPTION OF ORGANIZATION AND PRINCIPAL ACTIVITIES

12 Months Ended

Dec. 31, 2019

DESCRIPTION OF ORGANIZATION AND PRINCIPAL ACTIVITIES

DESCRIPTION OF ORGANIZATION AND PRINCIPAL ACTIVITIES

1. DESCRIPTION OF ORGANIZATION AND PRINCIPAL ACTIVITIES

Organization and principal activities

Niu Technologies (“the Company”), through its wholly-owned subsidiaries, consolidated variable interest entity (“VIE”) and VIE’s subsidiaries (collectively referred to as “the Group”), is principally engaged in designing, manufacturing and selling of smart electric scooters and its accessories under the brand name of “NIU”. The Group’s principal operations and geographic markets are mainly in the People’s Republic of China (“PRC”).

The accompanying consolidated financial statements include the financial statements of the Company, its wholly-owned subsidiaries, consolidated VIE and VIE’s subsidiaries.

The VIE arrangements

The Group operates its online business in the PRC through Beijing Niudian Technologies Co., Ltd. ("Beijing Niudian", or the "VIE"), a limited liability company established under the laws of the PRC on September 18, 2014. Beijing Niudian holds the necessary PRC operating licenses for the online business. The equity interests of Beijing Niudian are legally held by individuals who act as nominee equity holders of the VIE on behalf of Beijing Niudian Information Technology Co., Ltd. ("Niudian Information"), the Company’s wholly owned subsidiary. A series of contractual agreements, including Powers of Attorney, Exclusive Business Cooperation Agreement, Equity Pledge Agreement, Exclusive Option Agreement and Spousal Consent Letters (collectively, the "VIE Agreements"), were entered among the Company, Niudian Information, Beijing Niudian and its nominee equity holders on May 27, 2015 and were subsequently amended to include registration of the Equity Pledge Agreement with the relevant registration authority on June 11, 2018, amended when an equity holder transferred certain equity interests to another equity holder on July 20, 2018 .

The contractual agreements were further amended when two equity holders transferred certain equity interests to another equity holder on March 10, 2020.

Pursuant to the VIE Agreements, the Company is able to exercise effective control over, bears the risks of, enjoys substantially all of the economic benefits of the VIE, and has an exclusive option to purchase all or part of the equity interests in the VIE when and to the extent permitted by PRC law at the lowest price possible. The Company’s management concluded that Beijing Niudian is a VIE and the Company is its primary beneficiary. As such, the consolidated financial statements of the VIE are included in the consolidated financial statements of the Company.

The principal terms of the VIE Agreements are further described below.

1) Powers of Attorney

The Company and each of the equity holders of Beijing Niudian entered into Powers of Attorney. Pursuant to the Powers of Attorney, the equity holders of Beijing Niudian irrevocably appointed the Company as their attorney-in-fact to exercise all equity holder rights, including, but not limited to, convening and attending in the equity holders’ meeting, appointing or removing directors, executive officers and senior management, disposing of all or part of the equity holder’s interests in Beijing Niudian, casting equity holder’s vote on matters requiring equity holders’ approval and doing all other acts in the capacity of equity holder as permitted by Beijing Niudian’s Memorandum and Articles of Association. In addition, the Company has a right to assign its rights and benefits under the Powers of Attorney to any other parties without an advance notice to the equity holders of Beijing Niudian. The Powers of Attorney shall continue in force and be irrevocable as long as the equity holders of Beijing Niudian remain as the equity holders of Beijing Niudian.

2) Exclusive Business Cooperation Agreement

Niudian Information and Beijing Niudian entered into an Exclusive Business Cooperation Agreement, whereby Niudian Information is appointed as the exclusive service provider for the provision of business support, technology and consulting services to Beijing Niudian. Unless a written consent is given by Niudian Information, Beijing Niudian is not allowed to engage a third party to provide such services, while Niudian Information is able to designate another party to render such services to Beijing Niudian. Beijing Niudian shall pay Niudian Information on a monthly basis a service fee, which shall equal to 100% of the monthly net profits of Beijing Niudian, and Niudian Information has the sole discretion to adjust the basis of calculation of the service fee amount according to service provided to Beijing Niudian. Niudian Information owns the exclusive intellectual property rights, whether created by Niudian Information or Beijing Niudian, as a result of the performance of the Exclusive Business Cooperation Agreement unless terminated in writing by Niudian Information. The Exclusive Business Cooperation Agreement will be in effect until September 17, 2044 which represents the end of operation term of Beijing Niudian.

3) Equity Pledge Agreement

An Equity Pledge Agreement was entered into by and among Niudian Information, Beijing Niudian and equity holders of Beijing Niudian. To guarantee payment from Beijing Niudian, including but not limited to the service fee pursuant to the Exclusive Business Cooperation Agreement, and the performance of Beijing Niudian and the nominee equity holders’ obligations under the contractual arrangements including the Exclusive Business Cooperation Agreement, Exclusive Option Agreement and Powers of Attorney, the equity holders of Beijing Niudian pledged their respective equity in Niudian Information under the Equity Pledge Agreement to Niudian Information as collateral. In the event Beijing Niudian fails to pay Niudian Information its service fee, Niudian Information will have the right to sell the pledged equity and apply the proceeds received to pay any outstanding service fees due by Beijing Niudian to Niudian Information. The equity holders of Beijing Niudian agree that, during the term of the Equity Pledge Agreement, they will not dispose of the pledged equity or create or allow any encumbrance on the pledged equity, and they also agree that Niudian Information’s rights relating to the equity pledges shall not be prejudiced by any legal actions of the equity holders of Beijing Niudian, their successors or their designees. The equity pledges have been registered with the relevant registration authority and became effective and enforceable since registration. The Equity Pledge Agreement may only be terminated upon the fulfillment of all contractual obligations under the Exclusive Business Cooperation Agreement, Exclusive Option Agreement and Powers of Attorney. During the term of the Equity Pledge Agreement, Niudian Information is entitled to receive dividends attributable to the pledged Beijing Niudian equity.

4) Exclusive Option Agreement

Each of the equity holders of Beijing Niudian entered into an Exclusive Option Agreement with the Company, Niudian Information, and Beijing Niudian, pursuant to which the equity holders of Beijing Niudian granted the Company, and Niudian Information or other person upon the designation by the Company, an irrevocable and exclusive option to purchase, at its discretion and to the extent permitted under the PRC law, all or part of the equity holders’ interests in Beijing Niudian at RMB100 or the lowest price that the PRC law permits at the time unless a valuation of the equity is required by the PRC law. The equity holders of Beijing Niudian commit that without the prior written consent of the Company, the equity holders of Beijing Niudian will not, among other things, (i) create any pledge or encumbrance on their equity interests in Beijing Niudian, (ii) transfer or otherwise dispose of their equity interests in Beijing Niudian, (iii) change Beijing Niudian’s registered capital, (iv) amend Beijing Niudian’s articles of association, (v) dispose of Beijing Niudian’s material assets or enter into any material contract with a value of over RMB100,000 (except in the ordinary course of business), or (vi) merge Beijing Niudian with any other entity. In addition, Beijing Niudian undertakes that, without the Company’s prior written consent, it will not, among other things, create any pledge or encumbrance on any of its assets, or transfer or otherwise dispose of its material assets (except in the ordinary course of business). Beijing Niudian and its equity holders shall appoint those individuals recommended by the Company as directors of Beijing Niudian. Beijing Niudian shall provide operating and financial information to the Company at the request of the Company and ensure the continuance of the business. The Exclusive Option Agreement will remain effective until all equity interests in Beijing Niudian held by its equity holders are transferred or assigned to the Company or its designee. Beijing Niudian and its equity holders shall not have any right to terminate the Exclusive Option Agreement.

5) Spousal Consent Letters

The spouses of each of nominee equity holders signed Spousal Consent Letters to consent that the equity interests in Beijing Niudian held by and registered in the name of the respective nominee equity holders will be disposed of pursuant to the VIE Agreements. These spouses agreed not to assert any rights over the equity interest in Beijing Niudian held by their spouses. In addition, in the event that the spouses obtain any equity interests in Beijing Niudian held by their spouses for any reason, they agreed to be bound by the VIE Agreements.

Risks in relation to the VIE structure

In the opinion of the Company’s management, the VIE Agreements have resulted in the Company having the power to direct activities that most significantly impact the VIE, including appointing key management, setting up operating policies, exerting financial controls and transferring profit or assets out of the VIE at its discretion. The Company considers that it has the right to receive all the benefits and assets of the VIE. As the VIE was established as a limited liability company under the PRC law, its creditors do not have recourse to the general credit of the Company for the liabilities of the VIE, and the Company does not have the obligation to assume the liabilities of the VIE.

The Company has determined that the VIE Agreements are in compliance with PRC laws and are legally enforceable. However, uncertainties in the PRC legal system could limit the Company’s ability to enforce the VIE Agreements; and if the equity holders of the VIE were to reduce their interest in the Company, their interests may diverge from that of the Company and that may potentially increase the risk that they would seek to act contrary to the contractual terms.

The Company’s ability to control the VIE also depends on the rights provided to the Company under the Powers of Attorney to vote on all matters requiring equity holders’ approval in the respective VIE. As noted above, the Company believes these Powers of Attorney are legally enforceable but yet they may not be as effective as direct equity ownership. In addition, if the corporate structure of the Group or the contractual arrangements between the Company, Niudian Information, the VIE and its respective equity holders were found to be in violation of any existing PRC laws and regulations, the relevant PRC regulatory authorities could:

revoke the business license and/or operating licenses of such entities;

discontinue or place restrictions or onerous conditions on the Group’s operations;

impose fines, confiscate the income from our VIE, or impose other requirements with which the Group may not be able to comply;

require the Group to restructure its ownership structure or operations, including terminating the contractual arrangements with the VIE and deregistering the equity pledges of the VIE, which in turn would affect the Company’s ability to consolidate, derive economic interests from, or exert effective control over the VIE; or

restrict or prohibit our use of the proceeds of this offering to finance our business and operations in China.

The imposition of any of the above restrictions or actions may result in a material and adverse effect on the Group’s ability to conduct its business. In addition, if the imposition of any of these restrictions causes the Company to lose the right to direct the activities of the VIE or the right to receive its economic benefits, the Company would no longer be able to consolidate the VIE. The Company’s management believes that the likelihood to lose the Company’s current ownership structure or the contractual arrangements with the VIE is remote based on the current facts and circumstances.

There is no VIE in which the Company has a variable interest but is not the primary beneficiary. Currently there is no contractual arrangement that could require the Company to provide additional financial support to the VIE.

The following consolidated assets and liabilities information of the Group’s VIE as of December 31, 2018 and 2019, and consolidated revenues, net (loss) / income and cash flow information for the years ended December 31, 2017, 2018 and 2019, have been included in the accompanying consolidated financial statements. All intercompany transactions and balances with the Company and its wholly-owned subsidiaries have been eliminated upon consolidation.


	As of December 31,
	2018	2019
	RMB	RMB
Cash	90,723,253	93,548,349
Short-term investments	120,241,425	310,439,321
Accounts receivable, net	54,424,845	115,228,700
Inventories	142,155,411	178,476,473
Prepayments and other current assets	22,711,514	18,613,814
Amounts due from intercompany	4,262,270	4,303,778
Total current assets	434,518,718	720,610,435

Property, plant and equipment, net	40,580,352	148,937,701
Intangible assets, net	580,667	1,962,530
Land use right, net	—	34,355,936
Other non-current assets	16,805,475	5,961,241
Total assets	492,485,212	911,827,843

Short-term bank borrowings	179,978,003	217,394,132
Accounts payable	249,665,890	258,988,264
Amounts due to intercompany	211,250,230	306,137,760
Advances from customers	20,505,861	7,478,309
Deferred revenue—current	12,666,330	31,105,700
Accrued expenses and other current liabilities	119,242,975	164,442,316
Income taxes payable	—	3,013,805
Total current liabilities	793,309,289	988,560,286
Deferred revenue—non current	234,801	2,171,033
Deferred income tax liability	—	1,265,780
Other non-current liabilities	17,609,842	22,358,968
Total liabilities	811,153,932	1,014,356,067


	For the Year Ended December 31,
	2017	2018	2019
	RMB	RMB	RMB
Revenues	769,368,001	1,477,593,628	2,115,501,618
Net (loss) / income	(145,154,084)	(294,156,973)	196,473,033
Net cash (used in) / provided by operating activities	(2,423,156)	14,379,166	284,907,333
Net cash used in investing activities	(55,928,949)	(74,333,070)	(319,696,832)
Net cash provided by financing activities	68,703,310	78,199,492	37,416,129
Effect of foreign currency exchange rate changes on cash	(813,270)	684,791	198,466
Net increase in cash	9,537,935	18,930,379	2,825,096
Cash at the beginning of the year	62,254,939	71,792,874	90,723,253
Cash at the end of the year	71,792,874	90,723,253	93,548,349

The unrecognized revenue-producing assets that are held by the VIE primarily consist of ICP License, Production License for National Industrial Products, trademarks, patents, know-how and customer relationships. None of the assets of the VIE can be used only to settle obligations of VIE. None of the assets of the VIE has been pledged or collateralized. The creditors of the VIE do not have recourse to the general credit of the Company or its consolidated subsidiaries.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

12 Months Ended

Dec. 31, 2019

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

(a) Basis of presentation

The accompanying consolidated financial statements of the Group have been prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP").

(b) Principles of consolidation

The consolidated financial statements of the Group have been prepared in accordance with U.S. GAAP. The consolidated financial statements include the financial statements of the Company, its subsidiaries, the VIE for which the Company or its subsidiary is the primary beneficiary, and the VIE’s subsidiaries.

Subsidiaries are those entities in which the Company, directly or indirectly, controls more than one half of the voting power or has the power to govern the financial and operating policies, to appoint or remove the majority of the members of the board of directors, or to cast a majority of votes at the meeting of directors. A VIE is an entity in which the Company, or its subsidiary, through contractual arrangements, exercises effective control over the activities that most impact the economic performance, bears the risks of, and enjoys the rewards normally associated with ownership of the entity, and therefore the Company or its subsidiary is the primary beneficiary of the entity.

All intercompany transactions and balances among the Company, its subsidiaries, the VIE and the VIE’s subsidiaries have been eliminated upon consolidation.

The preparation of the consolidated financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, related disclosures of contingent assets and liabilities at the balance sheet date, and the reported revenues and expenses during the reported period in the consolidated financial statements and accompanying notes. Significant accounting estimates include, but not limited to, the stand-alone selling price ("SSP") of distinct performance obligations, the allowance for doubtful accounts receivable, write downs for excess and obsolete inventories, depreciable lives of property , plant and equipment, intangible assets and land use right, the realization of deferred income tax assets, future warranty expenses, the fair value of share-based compensation awards and convertible loans, and the fair value of the ordinary shares to determine the existence of beneficial conversion feature of the convertible redeemable preferred shares prior to IPO. Changes in facts and circumstances may result in revised estimates. Actual results could differ from those estimates, and as such, differences may be material to the consolidated financial statements.

(d) Convenience translation

Translations of balances in the consolidated financial statements from RMB into US$ as of and for the year ended December 31, 2019 are solely for the convenience of the readers and were calculated at the rate of US$1.00=RMB6.9618, representing the noon buying rate in The City of New York for cable transfers of RMB as certified for customs purposes by the Federal Reserve Bank of New York on December 31, 2019. No representation is made that the RMB amounts could have been, or could be, converted, realized or settled into US$ at that rate on December 31, 2019, or at any other rate. The US$ convenience translation is not required under U.S. GAAP.

(e) Commitments and contingencies

In the normal course of business, the Group is subject to loss contingencies, such as legal proceedings and claims arising out of its business, that cover a wide range of matters, including, among others, government investigations, shareholder lawsuits, and non-income tax matters. An accrual for a loss contingency is recognized when it is probable that a liability has been incurred and the amount of loss can be reasonably estimated. If a potential material loss contingency is not probable but is reasonably possible, or is probable but cannot be estimated, then the nature of the contingent liability, together with an estimate of the range of possible loss if determinable and material, is disclosed.

(f) Cash

Cash consist of cash on hand, cash at bank and term deposits, which have original maturities of three months or less and are readily convertible to known amounts of cash. Cash at bank and term deposits are deposited in financial institutions at below locations:


	As of December 31,
	2018	2019
	RMB	RMB
Financial institutions in the mainland of the PRC
—Denominated in RMB	145,529,365	90,078,714
—Denominated in USD	155,583,394	178,359,872
Total cash balances held at mainland PRC financial institutions	301,112,759	268,438,586

Financial institutions in the United States
—Denominated in USD	4,038,742	3,523,116
Total cash balances held at the United States financial institutions	4,038,742	3,523,116

Financial institutions in the Hong Kong S.A.R.
—Denominated in USD	263,588,286	6,015,191

Total cash balances held at Hong Kong S.A.R. financial institutions	263,588,286	6,015,191

Financial institutions in Indonesia
—Denominated in USD	—	1,765,448
Total cash balances held at the Indonesia financial institutions	—	1,765,448
Total cash balances held at financial institutions	568,739,787	279,742,341

(g) Term deposits

Term deposits represent deposits placed with bank with original maturities of more than three months but less than one year. The Group's term deposits are denominated in USD and are deposited at a financial institution in the mainland of the PRC.

(h) Restricted cash

Restricted cash is an amount of cash deposited with banks in conjunction with borrowings from the banks. Restriction on the use of such cash and the interest earned thereon is imposed by the banks and remains effective throughout the terms of the bank borrowings. Restricted cash is classified as current asset on the Company’s consolidated balance sheets , as all the balance will be released to cash within the next 12 months. The Group’s restricted cash are denominated in RMB and USD and are deposited at financial institutions in the mainland of the PRC.

In November 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2016-18, Statement of Cash Flows: Restricted Cash ("ASU 2016-18"). ASU 2016-18 requires that the statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. Entities are also required to reconcile such total to amounts on the balance sheet and disclose the nature of the restrictions. ASU 2016-18 became effective for the Company as of January 1, 2019. Adoption of ASU 2016-18 resulted in the Group including changes in cash and restricted cash in its consolidated statements of cash flows. The Group adopted this ASU on January 1, 2019 on a retrospective basis. The adoption of this guidance impacted the presentation and classification of changes in restricted cash in the Group's consolidated statements of cash flows.

The impact of adoption on the consolidated statements of cash flows for the years ended December 31, 2017 and 2018 was as follows:


	For the Year Ended December 31,
	2017	2018
	RMB	RMB
Net cash provided by operating activities	—	789,751
Net cash provided by financing activities	66,288,600	—
Effect of foreign currency exchange rate changes on restricted cash	(7,391,400)	8,583,763
Net increase in cash and restricted cash	58,897,200	9,373,514

For the year ended December 31, 2017, the changes in restricted cash amounting to RMB66,288,600 previously reported in financing activities was reclassified to total cash and restricted cash in the consolidated statements of cash flows. For the year ended December 31, 2018, the changes in restricted cash amounting to RMB789,751 previously reported in operating activities was related to interest income on restricted cash and reclassified to total cash and restricted cash in the consolidated statements of cash flows.

The following table provides a reconciliation of cash and restricted cash reported within the consolidated balance sheets that sum to the total of the same such amounts shown in the consolidated statements of cash flows.


	As of December 31,
	2018	2019
	RMB	RMB
Cash	569,059,591	279,945,942
Restricted cash, current	179,262,714	221,656,071
Restricted cash, non-current	—	—
Total cash and restricted cash	748,322,305	501,602,013

(i) Short-term investments

The Group’s short-term investments represent the Group’s investments in financial products managed by financial institutions in the PRC which are redeemable at the option of the Group on any working day, which are classified as available-for-sale securities. Short-term investments are reported at fair value, with unrealized holding gains or losses, net of the related tax effect, excluded from earnings and recorded as a separate component of accumulated other comprehensive income / (loss) until realized. Realized gains or losses from the sale of short-term investments are determined on a specific identification basis and are recorded as investment income when earned.

(j) Inventories

Inventories, consisting of raw materials, work in progress and products available for sale, are stated at the lower of cost or net realizable value. The cost of inventory is determined using the weighted average cost method. Cost of work-in-process and finished goods comprise direct materials, direct production costs and an allocation of production overheads based on normal operating capacity. The Group takes ownership, risks and rewards of the products purchased. Inventory is written down for damaged and slow-moving goods, which is dependent upon factors such as historical and forecasted consumer demand. When appropriate, write downs to inventory are recorded to write down the cost of inventories to their net realizable value.

(k) Property, plant and equipment, net

Property, plant and equipment are stated at cost less accumulated depreciation and any recorded impairment.

The estimated useful lives are as follows:


Building		50 years
Machinery and equipment		3 ~ 10 years
Furniture		3 years
Leasehold improvements		3 years
Office and electronic equipment		2 ~ 5 years
Motor vehicles		4 years

Depreciation on property, plant and equipment is calculated on the straight-line method over the estimated useful lives of the assets.

Depreciation and amortization of property, plant and equipment attributable to manufacturing activities is capitalized as part of inventories, and recognized as cost of revenues when the inventory is sold.

When items are retired or otherwise disposed of, income is charged or credited for the difference between net book value and the proceeds received thereon. Ordinary maintenance and repairs are charged to expense as incurred, and replacements and betterments are capitalized and amortized over the remaining useful life.

(l) Intangible assets

Intangible assets acquired separately are measured on initial recognition at cost. Following initial recognition, intangible assets with finite lives are carried at cost less any accumulated amortization and any accumulated impairment losses.

Intangible assets with finite lives are amortized over the useful economic life on straight-line basis and assessed for impairment whenever there is an indication that the intangible assets may be impaired.

(m) Land use right, net

Land use right is recorded at cost less accumulated amortization and any accumulated impairment losses. Amortization is provided on a straight-line basis over the estimated useful lives, which is 50 years and represents the shorter of the estimated usage years or the terms of the land use right certificate.

(n) Impairment of long-lived assets

Long-lived assets such as property, plant and equipment, intangible assets and land use right with finite lives are evaluated for impairment whenever events or changes in circumstances indicate that the carrying value of an asset may not be fully recoverable or that the useful life is shorter than the Group had originally estimated. When these events occur, the Group evaluates the impairment for the long-lived assets by comparing the carrying value of the assets to an estimate of future undiscounted cash flows expected to be generated from the use of the assets and their eventual disposition. If the sum of the expected future undiscounted cash flows is less than the carrying value of the assets, the Group recognizes an impairment loss based on the excess of the carrying value of the assets over the fair value of the assets. No impairment of long-lived assets was recognized for the years ended December 31, 2017, 2018 and 2019.

(o) Value added taxes

The Company’s PRC subsidiaries are subject to value added tax ("VAT"). Revenues from sales of products are generally subject to VAT at the rate of 17% prior to May 1, 2018, which was adjusted to 16% after May 1, 2018, then to 13% after April 1, 2019. Revenues from services are generally subject to VAT at the rate of 6%. VAT are subsequently paid to PRC tax authorities after netting input VAT on purchases and VAT export rebates. The excess of output VAT over input VAT and VAT export rebates is reflected in Accrued expenses and other current liabilities, and the excess of input VAT and VAT export rebates over output VAT is reflected in Prepayments and other current assets in the consolidated balance sheets.

(p) Fair value measurements

Fair value represents the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability.

Accounting guidance defines fair value, establishes a framework for measuring fair value and expands disclosures about fair value measurements. Accounting guidance establishes a three-level fair value hierarchy and requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. A financial instrument’s categorization within the fair value hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The three levels of inputs are:

Level 1—Observable inputs that reflect quoted prices (unadjusted) for identical assets or liabilities in active markets.

Level 2—Include other inputs that are directly or indirectly observable in the marketplace.

Level 3—Unobservable inputs which are supported by little or no market activity.

Accounting guidance also describes three main approaches to measuring the fair value of assets and liabilities: (1) market approach; (2) income approach and (3) cost approach. The market approach uses prices and other relevant information generated from market transactions involving identical or comparable assets or liabilities. The income approach uses valuation techniques to convert future amounts to a single present value amount. The measurement is based on the value indicated by current market expectations about those future amounts. The cost approach is based on the amount that would currently be required to replace an asset.

Financial assets and liabilities of the Group primarily consist of cash, term deposits, restricted cash, short-term investments, accounts receivable, short term bank borrowings, convertible loan and accounts payable. The Group measures short-term investments and convertible loan at fair value on a recurring basis. Short-term investments include financial products issued by financial institutions, which are valued based on prices per units quoted by issuers. They are categorized in Level 2 of the fair value hierarchy. Convertible loan being recognized in its entirety at fair value were measured at fair value using unobservable inputs. They are categorized in Level 3 of the fair value hierarchy. As of December 31, 2018 and 2019, the carrying values of other financial instruments approximated to their fair values due to the short term maturity of these instruments.

The Group’s non-financial assets, such as land use right, intangible assets and property, plant and equipment, would be measured at fair value only if they were determined to be impaired.

(q) Revenue recognition

The Group generates substantially all of its revenues from sales of smart electric scooters, accessories and spare parts to the Group’s PRC domestic offline distributors and overseas offline distributors or directly to individual customers online. The Group also generates its revenues from its subscription-based mobile application services, as well as insurance service as an agent.

Periods prior to January 1, 2019

Prior to January 1, 2019, the Group recognizes revenue when persuasive evidence of an arrangement exists, delivery has occurred and the services have been rendered, the sales price is fixed or determinable, and collection is reasonably assured.

When the Group sells its smart electric scooters to its customers, it also provides mobile application services for free for one to two years (the “free service period”). Customers are able to locate their smart electric scooters, as well as obtain the operating status (e.g. battery status), and claim online repair and maintenance requests of their smart electric scooters, upon their registration of their smart electric scooters on the Group’s mobile application. Customers may subscribe to such service after the free service period if they want to continue using aforementioned functions.

The Group allocates revenue to all deliverables based on their relative selling prices. The Group uses a hierarchy to determine the selling price to be used for allocating revenue to the deliverables: (i) vendor-specific objective evidence ("VSOE") of fair value, (ii) third-party evidence ("TPE"), and (iii) best estimate of the selling price ("BESP"). The Group uses the SSP as the fair value of VSOE for advanced mobile application services. The allocated revenue to mobile application services is deferred and recognized over the free service period. The deferred revenue that will be recognized in the next twelve months is classified as current portion, and the remaining balance of deferred revenue is classified as non-current portion.

Revenue from sales of products is recognized when the products is accepted by the domestic offline distributors, overseas offline distributors or individual customers. When the Group sells its products to its domestic offline distributors for domestic sales in PRC, acceptance of the products by the domestic offline distributors is evidenced by goods receipt notes signed by the domestic offline distributors, which is generally at the Group’s warehouse. The Group has no remaining obligations upon the domestic offline distributors acceptance of the products. The risks and rewards of ownership of the products is transferred to the domestic offline distributors upon the signing of the goods receipt notes and the domestic offline distributors have no rights to return the products. When the Group sells its products to distributors for oversea sales, risks and rewards of ownership are transferred to the distributors upon the products are delivered to and accepted by distributors at the named port of shipment. When the Group sells its products to individual customers through its own online store and third-party e-commerce platform, the Group is responsible for the delivery to individual customers. Acceptance of the products is evidenced by goods receipt notes signed by individual customers, which represents the risks and rewards of ownership are transferred to individual customers. The Group offers 7-day return-and-refund policy to individual customers who purchase products online.

Revenue is recognized net of sales volume rebate, return allowances and VAT. The Group provides sales volume rebate to qualified distributors based on the volume sold by such distributors in a certain period. Sales volume rebates are accrued, when the products are sold to distributors. Return allowances, which reduce net revenues, are estimated based on historical experiences.

The Group also sells insurance plan for electric scooters (“NIU Cover”) to individual customers at their option. The insurance is provided by third party insurance companies. The Group earns the service fee on net basis. The Group recognizes revenue when the insurance agreement is signed, since the Group bears no further obligation upon the agreements are entered into between individual customers and insurance providers.

For some sales, the Group collects cash before delivery. Cash collected before product delivery is recognized as advances from customers.

Period commencing January 1, 2019

The Group adopted Accounting Standards Codification Topic 606, Revenue from Contracts with Customers ("ASC 606") on January 1, 2019. The Group applied ASC 606 using the modified retrospective method for contracts which were not completed at the date of initial adoption. Results for reporting periods beginning after January 1, 2019 are presented under the new revenue recognition, while prior periods amounts are not adjusted and continue to be reported in accordance with ASC 605, Revenue Recognition.

Since the adoption of ASC 606 starting from January 1, 2019, the Group recognizes revenues upon the satisfaction of its performance obligation (upon transfer of control of promised goods or services to customers) in an amount that reflects the consideration to which the Group expects to be entitled to in exchange for those goods or services, excluding amounts collected on behalf of third parties (for example, value added taxes). For each performance obligation satisfied over time, the Group recognizes revenue over time by measuring the progress toward complete satisfaction of that performance obligation. If the Group does not satisfy a performance obligation over time, the performance obligation is satisfied at a point in time.

The adoption of new revenue standard did not impact accumulated deficit as of January 1, 2019. The Group has updated significant accounting policies and relevant disclosures hereinafter.

To achieve that core principle, the Group applies the five steps defined under Topic 606: (i) identify the contract(s) with a customer, (ii) identify the performance obligations in the contract, (iii) determine the transaction price, (iv) allocate the transaction price to the performance obligations in the contract, and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Group assesses its revenue arrangements against specific criteria in order to determine if it is acting as principal or agent. Revenue arrangements with multiple performance obligations are divided into separate distinct goods or services. A performance obligation is considered distinct from other obligations in a contract when it (a) provides a benefit to the customer either on its own or together with other resources that are readily available to the customer and (b) is separately identified in the contract. The Group allocates the transaction price to each performance obligation based on the relative SSP of the goods or services provided. Revenue is recognized upon the transfer of control of promised goods or services to a customer.

Products

The Group identified one performance obligation which is to sell products, such as smart electric scooters, accessories and spare parts, to the Group’s PRC domestic offline distributors and overseas offline distributors or directly to individual customers online. For all sales of products, the Group requires a signed contract or purchase order, which specifies pricing, quantity and product specifications. Revenue of product sales is recognized on a gross basis upon the satisfaction of its performance obligation, which is to transfer the control of the promised products to customers.

The transfer of control of the products is satisfied at a point in time, which occurs when the products are accepted by the domestic offline distributors, overseas offline distributors or individual customers. When the Group sells its products to its domestic offline distributors for domestic sales in PRC, acceptance of the products by the domestic offline distributors is evidenced by goods receipt notes signed by the domestic offline distributors, which is generally at the Group’s warehouse. When the Group sells its products to distributors for oversea sales, acceptance of the products by overseas offline distributors is evidenced upon the products are delivered to and accepted by distributors at the named port of shipment. When the Group sells its products to individual customers through its own online store and third-party e-commerce platform, the Group is responsible for the delivery to individual customers. Acceptance of the products is evidenced by goods receipt notes signed by individual customers.

The Group provides sales volume rebate to qualified distributors based on the volume sold to such distributors in a certain period and grants online individual customers unconditional right to return the products within 7 days after their acceptance.

Revenues are measured as the amount of consideration the Group expects to receive in exchange for transferring products to domestic offline distributors, overseas offline distributors or individual customers. Consideration is recorded net of sales volume rebate, sales returns and VAT. Sales returns is estimated based on historical experiences, which were insignificant for the years ended December 31, 2017, 2018 and 2019.

The Group utilizes delivery service providers to deliver products to overseas offline distributors and individual customers ("shipping activities"), but the delivery service is not considered as a separate obligation as the shipping activities are performed before the overseas offline distributors and individual customers obtain control of the products. Therefore, shipping activities are not considered a separate promised service to them but rather are activities to fulfill the Group's promise to transfer the products. Outbound shipping charges to overseas offline distributors and individual customers are included as a part of the revenues, and outbound shipping-related costs are recorded as cost of revenues. Shipping costs incurred for sales of products and recognized as cost of revenues were RMB8,917,910, RMB16,752,785 and RMB31,912,258 for the years ended December 31, 2017, 2018 and 2019, respectively.

For some sales, the Group collects cash before delivery. Cash collected before product delivery is recognized as advances from customers.

Service

When the Group sells its smart electric scooters to its customers, it also provides mobile application services for free for one to two years (the "free service period"). Customers are able to locate their smart electric scooters, as well as obtain the operating status (e.g. battery status), and claim online repair and maintenance requests of their smart electric scooters, upon their registration of their smart electric scooters on the Group's mobile application. Customers may subscribe to such service after the free service period if they want to continue using aforementioned functions.

Such revenue arrangements are divided into separate distinct performance obligations, including electric scooters and mobile application services. SSP for electric scooters is not directly observable, as the Group does not sell the electric scooters without mobile application service for certain free service period. The Group determines the SSP for electric scooters using the residual approach and subtracting the observable SSP of the mobile application services from the total transaction price.

The allocated revenue to mobile application services of free service period and subscribed mobile application service revenue is deferred and recognized on a straight-line basis over the service period, as the Group determines that the customer simultaneously receives and consumes benefits provided by the Group as the Group performs during the free service period or the subscription period.

The Group entered into an agreement with a customer in 2019 and provides design, testing and producing prototype of a product for the customer. The Group identifies each deliverable specified in the agreement as a distinct performance obligation at contract inception. The Group determines the SSP for each performance obligation in the agreement using the expected cost plus a margin approach and allocates the transaction price to each distinct performance obligation based on the relative estimated SSP of each performance obligation. The Group recognizes revenue for each performance obligation when the specified deliverable is accepted by the customer.

The deferred revenue that will be recognized in the next twelve months is classified as current portion, and the remaining balance of deferred revenue is classified as non-current portion.

The Group also sells insurance plan for electric scooters ("NIU Cover") to individual customers at their option. The insurance is provided by third party insurance companies. The Group determines that it acts as an agent for the NIU Cover service because it does not obtain control of the service before the service is transferred to the customers. The Group recognizes revenue on net basis when the insurance agreement is entered into between individual customers and insurance providers.

Remaining performance obligations

The remaining performance obligation disclosure provides the aggregate amount of the transaction price yet to be recognized as of the end of the reporting period and an explanation as to when the Group expects to recognize these amounts in revenue. Additionally, as a practical expedient, the Group does not include contracts that have an original duration of one year or less.

As of December 31, 2019, the aggregate amount of the transaction price allocated to remaining performance obligations that are unsatisfied or partially unsatisfied was RMB47,461,086. Given the profile of contract terms, RMB45,290,053 of the remaining performance obligation is expected to be recognized as revenue within the next 12 months and RMB2,171,033 is expected to be recognized as revenue between next 12 to 24 months.

(r) Contract Balances

Timing of revenue recognition may differ from the timing of invoicing to customers. Accounts receivable are recorded at the invoiced amount and do not bear interest. Amounts collected on trade accounts receivable are included in net cash provided by operating activities in the consolidated statements of cash flows. Management considers the following factors when determining the collectability of specific accounts: historical experience, credit worthiness of the clients, aging of the receivables and other specific circumstances related to the accounts. An allowance for doubtful accounts is made and recorded into general and administrative expenses based on aging of accounts receivable and on any specifically identified accounts receivable that may become uncollectible. Accounts receivable which are deemed to be uncollectible are charged off against the allowance after all means of collection have been exhausted and the potential for recovery is considered remote. There is a time lag between when the Group estimates a portion of or the entire account balances to be uncollectible and when a write off of the account balances is taken. The Group does not have any off-balance sheet credit exposure related to its customers.

A contract liability is recognized when the Group has an obligation to transfer products or services to a customer for which the Group has received consideration from the customer, or for which an amount of consideration is due from the customer. Contract liabilities are included in advances from customers and deferred revenue on the consolidated balance sheets.

In accordance with the new revenue standard requirements, the Company reclassified VAT payable from advances from customers to accrued expenses and other current liabilities. The disclosure of the impact of adoption on the consolidated balance sheets was as follows:


			Amounts
			without
	As of		adoption of
	December 31, 2019	Adjustments	ASC 606
Advances from customers	7,478,309	497,004	7,975,313
Accrued expenses and other current liabilities	175,533,397	(497,004)	175,036,393

Changes in the Group's contract liabilities (advances from customers and deferred revenue) are presented in the following table for the year ended December 31, 2019:


		For the Year Ended
		December 31, 2019
Contract liabilities as of January 1, 2019 prior to adoption of ASC 606		33,406,992
Reclassification of VAT payable to Accrued expenses and other liabilities as of January 1, 2019 as a result of adoption of ASC 606		(2,348,375)
Cash received in advance, excluding VAT		1,967,468,291
Revenue recognized from opening balance of contract liabilities		(30,823,816)
Revenue recognized from contract liabilities arising during current year		(1,926,948,050)
Contract liabilities as of December 31, 2019		40,755,042

(s) Warranties

The Group provides for the estimated costs of warranties at the time when revenue is recognized. The specific terms and conditions of those warranties vary among different parts of electric scooters. Factors that affect the Group’s warranty obligation include product defect rates and costs of repair or replacement. These factors are estimates that may change based on new information that becomes available each period. The portion of the warranty reserve expected to be incurred within the next 12 months is included within accrued expenses and other current liabilities while the remaining balance is included within other non-current liabilities on the consolidated balance sheets.

(t) Cost of Revenues

Cost of revenues mainly consists of the cost of products sold, write-downs of inventories, logistics costs and warranty costs.

(u) Selling and Marketing Expenses

Selling and marketing expenses mainly consist of advertising costs, promotion expenses and payroll and related expenses for personnel engaged in selling and marketing activities. Advertising expenses, which consist primarily of online and offline advertisements, are expensed when the services are received. The advertising expenses were RMB28,345,034, RMB76,791,991 and RMB79,533,394 for the years ended December 31, 2017, 2018 and 2019, respectively.

(v) General and Administrative Expenses

General and administrative expenses mainly consist of payroll and related costs for employees involved in general corporate functions, professional fees, foreign currency exchange gain/(losses) and other general corporate expenses, as well as expenses associated with the use by these functions of facilities and equipment, such as rental and depreciation expenses.

(w) Research and Development Expenses

Research and development expenses mainly consist of payroll and related costs for employees involved in researching and developing new products and technologies, and outsourced design expenses as well as expenses associated with the use by these functions of facilities and equipment, such as rental and depreciation expenses. Research and development expenses are expensed as incurred.

(x) Government Grants

Government grant is recognized when there is reasonable assurance that the Group will comply with the conditions attach to it and the grant will be received. Government grant for the purpose of giving immediate financial support to the Group with no future related costs or obligation is recognized in the Group’s consolidated statements of comprehensive (loss) / income when the grant becomes receivable.

(y) Share-based Compensation

The Company periodically grants share-based awards, including but not limited to, restricted ordinary shares, restricted share units and share options to eligible employees and directors.

Share-based awards granted to employees and directors are measured at the grant date fair value of the awards, and are recognized as compensation expense using the straight-line method over the requisite service period, which is generally the vesting period. For the year ended December 31, 2017, the Company estimated forfeitures at the time of grant and revised in the subsequent periods if actual forfeitures differ from those estimates. Effective from January 1, 2018, forfeitures are accounted when they occur.

A change in any of the terms or conditions of share-based awards is accounted for as a modification of the awards. The Group calculates incremental compensation cost of a modification as the excess of the fair value of the modified awards over the fair value of the original awards immediately before its terms are modified at the modification date. For vested awards, the Group recognizes incremental compensation cost in the period the modification occurs. For awards not being fully vested, the Group recognizes the sum of the incremental compensation cost and the remaining unrecognized compensation cost for the original awards over the remaining requisite service period after modification.

Share-based compensation in relation to the restricted ordinary shares and restricted share units is measured based on the fair value of the Company's ordinary shares at the grant date of the award. Prior to the IPO, the fair value was estimated using the income approach and equity allocation method. Estimation of the fair value of the Company's ordinary shares involves significant assumptions that might not be observable in the market, and a number of complex and subjective variables, including the expected share price volatility (approximated by the volatility of comparable companies), discount rate, risk-free interest rate and subjective judgments regarding the Company's projected financial and operating results, its unique business risks, the liquidity of its ordinary shares and its operating history and prospects at the time the grants are made. After the IPO, the fair value is the closing prices of the Company’s stock traded in the open market as of the grant date. Share-based compensation in relation to the share options is estimated using the Binominal Option Pricing Model. The determination of the fair value of share options is affected by the share price of the Company's ordinary shares as well as the assumptions regarding a number of complex and subjective variables, including the expected share price volatility, risk-free interest rate, exercise multiple and expected dividend yield. The fair value of these awards was determined with the assistance from a valuation report prepared by an independent valuation firm using management's estimates and assumptions.

(z) Employee Benefits

The Company’s subsidiaries and the VIE and VIE’s subsidiaries in PRC participate in a government mandated, multiemployer, defined contribution plan, pursuant to which certain retirement, medical, housing and other welfare benefits are provided to employees. PRC labor laws require the entities incorporated in China to pay to the local labor bureau a monthly contribution calculated at a stated contribution rate on the monthly basic compensation of qualified employees. The Group has no further commitments beyond its monthly contribution. Employee social benefits included as cost of products and expenses in the accompanying consolidated statements of comprehensive (loss) / income amounted to RMB13,705,669, RMB15,544,106 and RMB20,729,717 for the years ended December 31, 2017, 2018 and 2019, respectively.

(aa) Income Taxes

Current income taxes are provided on the basis of net income / (loss) for financial reporting purposes, and adjusted for income and expense items which are not assessable or deductible for income tax purposes, in accordance with the regulations of the relevant tax jurisdictions. Deferred income taxes are provided using the liability method. Under this method, deferred income tax assets and liabilities are recognized for the tax effects of temporary differences and are determined by applying enacted statutory tax rates that will be in effect in the period in which the temporary differences are expected to reverse to the temporary differences between the financial statements’ carrying amounts and the tax bases of assets and liabilities. Deferred tax assets and liabilities are offset if there is a legally enforceable right to offset deferred tax liabilities and assets, and they relate to income taxes levied by the same tax authority on the same taxable entity, or on different tax entities, but they intend to settle deferred tax liabilities and assets on a net basis or their deferred tax assets and liabilities will be realized simultaneously.

A valuation allowance is provided to reduce the amount of deferred income tax assets if based on the weight of available evidence, it is more-likely-than-not that some portion, or all, of the deferred income tax assets will not be realized. The effect on deferred income taxes arising from a change in tax rates is recognized in the consolidated statements of comprehensive (loss) / income in the period of change.

The Group applies a "more likely than not" recognition threshold in the evaluation of uncertain tax positions. The Group recognizes the benefit of a tax position in its consolidated financial statements if the tax position is "more likely than not" to prevail based on the facts and technical merits of the position. Tax positions that meet the "more likely than not" recognition threshold are measured at the largest amount of tax benefit that has a greater than fifty percent likelihood of being realized upon settlement. Unrecognized tax benefits may be affected by changes in interpretation of laws, rulings of tax authorities, tax audits, and expiry of statutory limitations. In addition, changes in facts, circumstances and new information may require the Group to adjust the recognition and measurement estimates with regard to individual tax positions. Accordingly, unrecognized tax benefits are periodically reviewed and re-assessed. Adjustments, if required, are recorded in the Group’s consolidated financial statements in the period in which the change that necessities the adjustments occur. The ultimate outcome for a particular tax position may not be determined with certainty prior to the conclusion of a tax audit and, in certain circumstances, a tax appeal or litigation process. The Group records interest and penalties related to unrecognized tax benefits (if any) in interest expenses and general and administrative expenses, respectively. As of December 31, 2018 and 2019, the Group did not have any significant unrecognized uncertain tax positions.

(bb) Operating leases

The Group leases premises for offices and production lines under non-cancellable operating leases. Leases with escalated rent provisions are recognized on a straight-line basis commencing with the beginning of the lease term.

(cc) Foreign currency translation and foreign currency risks

The Company’s reporting currency is Renminbi ("RMB"). The functional currency of the Company and its subsidiary incorporated at Hong Kong S.A.R. are the United States dollars ("US$").The functional currency of the Company's subsidiary incorporated in Indonesia is Indonesia Rupiah. The functional currency of the Company’s PRC subsidiaries, VIE and VIE’s subsidiaries is RMB.

Transactions denominated in currencies other than the functional currency are remeasured into the functional currency at the exchange rates prevailing at the dates of the transactions. Monetary assets and liabilities denominated in a foreign currency are remeasured into the functional currency using the applicable exchange rate at the balance sheet date. The resulted exchange differences are recorded as foreign currency exchange gain or losses in the consolidated statements of comprehensive (loss) / income.

The financial statements of the Company, its subsidiaries incorporated at Hong Kong S.A.R and Indonesia. are translated from the functional currency into RMB. Assets and liabilities are translated into RMB using the applicable exchange rates at the balance sheet date. Equity accounts other than earnings / (deficits) generated in the current period are translated into RMB using the appropriate historical rates. Revenues, expenses, gains and losses are translated into RMB using the average exchange rates for the relevant period. The resulted foreign currency translation adjustments are recorded as a component of other comprehensive (loss) / income in the consolidated statements of comprehensive (loss) / income, and the accumulated foreign currency translation adjustments are recorded as a component of accumulated other comprehensive loss in the consolidated statements of changes in shareholders’ (deficit) / equity.

The RMB is not a freely convertible currency. The PRC State Administration for Foreign Exchange, under the authority of the PRC government, controls the conversion of RMB to foreign currencies. The value of the RMB is subject to changes of central government policies and international economic and political developments affecting supply and demand in the China foreign exchange trading system market.

(dd) Concentration and risk

Concentration of customers and suppliers

No customers individually represent greater than 10% of total revenues of the Group for the years ended December 31, 2017, 2018 and 2019.

Suppliers from whom individually represent greater than 10% of total purchases of the Group for the years ended December 31, 2017, 2018 and 2019, are as follows:


	For the Year ended December 31,
	2017			2018			2019
	RMB	%		RMB	%		RMB	%
Supplier F	*	*		193,555,999	15	%	225,527,597	15	%
Supplier A	187,065,077	21	%	150,385,652	12	%	173,723,118	11	%
Supplier B	152,966,930	18	%	*	*		*	*

Customers accounting for 10% or more of accounts receivable, net are as follows:


	As of December 31,
	2018			2019
	RMB	%		RMB	%
Customer Y	45,980,177	84	%	*	*
Customer R	*	*		46,263,295	40	%

Customers accounting for 10% or more of advances from customers are as follows:


	As of December 31,
	2018		2019
	RMB	%	RMB	%
Customer U	*	*	1,090,262	15	%
Customer W	*	*	767,993	10	%

Suppliers accounting for 10% or more of accounts payable are as follows:


	As of December 31,
	2018			2019
	RMB	%		RMB	%
Supplier E	26,483,893	11	%	*	*
Supplier F	25,702,037	10	%	26,134,706	10	%

The amount was less than 10% of total balance.

Concentration of credit risk

Financial instruments that potentially expose the Group to concentrations of credit risk consist principally of cash, term deposits, restricted cash, short-term investments and accounts receivable, net.

The Group's investment policy requires cash, term deposits, restricted cash and short-term investments to be placed with high-quality financial institutions and to limit the amount of credit risk from any one issuer. The Group regularly evaluates the credit standing of the counterparties or financial institutions.

The Group conducts credit evaluations on its customers prior to delivery of goods or services. The assessment of customer creditworthiness is primarily based on historical collection records, research of publicly available information and customer on-site visits by senior management. Based on this analysis, the Group determines what credit terms, if any, to offer to each customer individually. If the assessment indicates a likelihood of collection risk, the Company will not deliver the services or sell the products to the customer or require the customer to pay cash, post letters of credit to secure payment or to make significant down payments.

Interest rate risk

The Group’s short-term bank borrowing bears interests at fixed rates. If the Group were to renew these loans, the Group might be subject to interest rate risk.

(ee) Earnings / (Loss) per Share

Basic earnings/(loss) per share is computed by dividing net income / (loss) attributable to holders of ordinary shares, considering the accretions to redemption value of the preferred shares (if any), by the weighted average number of ordinary shares or ordinary share equivalents outstanding during the year using the two-class method. Vested share options, which are exercisable for nominal consideration, and vested restricted share units are included in the calculation of the weighted-average number of shares of ordinary shares as ordinary share equivalents. Under the two-class method, any net income is allocated between ordinary shares and other participating securities based on their participating rights. A net loss is not allocated to participating securities when the participating securities does not have contractual obligation to share losses.

The Company's preferred shares and restricted ordinary shares are participating securities. The preferred shares are participating securities as they participate in undistributed earnings on an as-if-converted basis and the restricted ordinary shares are participating securities as the holders of the restricted ordinary shares have a non-forfeitable right to receive dividends with all ordinary shares. Neither the preferred shares nor the restricted ordinary shares have a contractual obligation to fund or otherwise absorb the Group's losses. Accordingly, any undistributed net income is allocated on a pro rata basis to ordinary shares, preferred shares and restricted ordinary shares; whereas any undistributed net loss is allocated to ordinary shares only.

Restricted ordinary shares were excluded from the weighted average number of ordinary shares outstanding because the restricted ordinary shareholders must return the restricted ordinary shares to the Company, if the specified condition are not met.

Diluted earnings / (loss) per share is calculated by dividing net income / (loss) attributable to ordinary shareholders, as adjusted for the accretion and allocation of net income related to the preferred shares, if any, by the weighted average number of ordinary shares used in calculating basic net earnings / (loss) per ordinary share and dilutive ordinary equivalent shares outstanding during the period. Ordinary equivalent shares consist of shares issuable upon the conversion of the preferred shares and convertible loan using the if-converted method, restricted ordinary shares and ordinary shares issuable upon the exercise of outstanding share option with the exception of vested share options with nominal exercise consideration and unvested restricted share units (using the treasury stock method). Ordinary equivalent shares are calculated based on the most advantageous conversion rate or exercise price from the standpoint of the security holder. Ordinary equivalent shares are not included in the denominator of the diluted earnings per share calculation when inclusion of such shares would be anti-dilutive.

(ff) Segment Reporting

The Company’s chief operating decision maker has been identified as the Chief Executive Officer, who reviews consolidated results when making decisions about allocating resources and assessing performance of the Group. For the purpose of internal reporting and management’s operation review, the Company’s Chief Executive Officer and management personnel do not segregate the Group’s business by product. All products and services are viewed as in one and the only operating segment.

(gg) Statutory Reserves

In accordance with the PRC Company Laws, the Group’s PRC subsidiaries, VIE and VIE’s subsidiaries must make appropriations from their after-tax profits as determined under the Generally Accepted Accounting Principles in the PRC ("PRC GAAP") to non-distributable reserve funds including statutory surplus fund and discretionary surplus fund. The appropriation to the statutory surplus fund must be 10% of the after-tax profits as determined under PRC GAAP. Appropriation is not required if the statutory surplus fund has reached 50% of the registered capital of the PRC companies. Appropriation to the discretionary surplus fund is made at the discretion of the PRC companies.

The statutory surplus fund and discretionary surplus fund are restricted for use. They may only be applied to offset losses or increase the registered capital of the respective companies. These reserves are not allowed to be transferred to the Company by way of cash dividends, loans or advances, nor can they be distributed except for liquidation.

For the years ended December 31, 2017, 2018 and 2019, the Group's PRC subsidiaries made appropriations to the statutory reserves of nil, nil and RMB3,316,650 respectively.

(hh) Recent Accounting Pronouncements

In February 2016, the FASB established Topic 842, Leases, by issuing ASU No. 2016-02, which requires lessees to recognize leases on-balance sheet and disclose key information about leasing arrangements. Topic 842 was subsequently amended by ASU No. 2018-01, Land Easement Practical Expedient for Transition to Topic 842, ASU No. 2018-10, Codification Improvements to Topic 842, Leases, ASU No. 2018-11, Targeted Improvements, ASU No. 2019-01, Leases (Topic 842): Codification Improvements, and ASU No. 2019-10, Financial Instruments – Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842), Effective Dates. The new standard establishes a right-of-use model (ROU) that requires a lessee to recognize a ROU asset and lease liability on the balance sheet for all leases with a term longer than 12 months. Leases will be classified as finance or operating, with classification affecting the pattern and classification of expense recognition in the income statement. The new standard is effective for public business entities for annual periods beginning after December 15, 2018, and interim periods therein. For all other entities, the standard is effective for fiscal years beginning after December 15, 2020, and interim periods within fiscal years beginning after December 15, 2021. Early adoption is permitted. A modified retrospective transition approach is required, applying the new standard to all leases existing at the date of initial application. The Group will adopt the new standard on January 1, 2021 and plan to use the effective date as the date of initial application. Consequently, financial information will not be updated and the disclosures required under the new standard will not be provided for dates and periods before January 1, 2021. The new standard provides a number of optional practical expedients in transition. The Group plans to elect the 'package of practical expedients', which permits the Group not to reassess under the new standard its prior conclusions about lease identification, lease classification and initial direct costs. The Company is currently evaluating the impact of adopting this standard on its consolidated financial statements.

In June 2018, the FASB issued ASU No. 2018-07, Compensation—Stock Compensation (Topic 718), which simplifies the accounting for share-based payments granted to nonemployees for goods and services. Under the ASU, most of the guidance on such payments to nonemployees would be aligned with the requirements for share-based payments granted to employees. For public entities, this standard will be effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. For all other entities, this standard is effective for annual periods beginning after December 15, 2019, and interim periods within annual periods beginning after December 15, 2020. Early adoption is permitted, but no earlier than an entity’s adoption date of Topic 606. Management is currently evaluating the impact of this amendment and does not expect the impact to be material.

In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement. ASU 2018-13 modifies certain disclosure requirements on fair value measurements, including (i) clarifying narrative disclosure regarding measurement uncertainty from the use of unobservable inputs, if those inputs reasonably could have been different as of the reporting date, (ii) adding certain quantitative disclosures, including (a) changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period and (b) the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements, and (iii) removing certain fair value measurement disclosure requirements, including (a) the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, (b) the policy for timing of transfers between levels of the fair value hierarchy and (c) the valuation processes for Level 3 fair value measurements. The amendments in ASU 2018-13 are effective for all entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. The Company is permitted to early adopt any removed or modified disclosures and delay adoption of the additional disclosures until their effective date. The Company is currently evaluating the effect of the disclosure requirements of ASU 2018-13 will have on its consolidated financial statements and does not expect the impact to be material.

In June 2016, the FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments (Topic 326), which significantly changes the way entities recognize impairment of many financial assets by requiring immediate recognition of estimated credit losses expected to occur over their remaining life, instead of when incurred. In November 2018, the FASB issued ASU No. 2018-19, Codification Improvements to Topic 326, Financial Instruments–Credit Losses, which amends Subtopic 326-20 (created by ASU No.2016-13) to explicitly state that operating lease receivables are not in the scope of Subtopic 326-20. Additionally, in April 2019, the FASB issued ASU No.2019-04, Codification Improvements to Topic 326, Financial Instruments—Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments, in May 2019, the FASB issued ASU No. 2019-05, Financial Instruments—Credit Losses (Topic 326): Targeted Transition Relief, and in November 2019, the FASB issued ASU No. 2019-10, Financial Instruments—Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842): Effective Dates, and ASU No. 2019-11, Codification Improvements to Topic 326, Financial Instruments—Credit Losses, to provide further clarifications on certain aspects of ASU No. 2016-13 and to extend the nonpublic entity effective date of ASU No. 2016-13. The changes (as amended) are effective for the Group for annual and interim periods in fiscal years beginning after December 15, 2022. While the Group expects its allowance for credit losses to increase upon adoption of ASU No. 2016-13, the Group does not expect the adoption of ASU No. 2016-13 to have a material effect on its consolidated financial statements.

SHORT-TERM INVESTMENTS

12 Months Ended

Dec. 31, 2019

SHORT-TERM INVESTMENTS

SHORT-TERM INVESTMENTS

3. SHORT-TERM INVESTMENTS

Short-term investments consisted of the following:


	As of December 31,
	2018	2019
	RMB	RMB
Aggregate cost basis	120,000,000	308,150,000
Gross unrealized holding gain	241,425	2,289,321
Aggregate fair value	120,241,425	310,439,321

The Group’s short-term investments represent wealth management products issued by commercial banks in the PRC which are redeemed upon demand of the Group. The wealth management products are invested in debt securities issued by the PRC government, corporate debt securities, bank deposits, central bank bills and other securities issued by other financial institutions. As of December 31, 2018 and 2019, there were no gross unrealized holding losses.

ACCOUNTS RECEIVABLES, NET

12 Months Ended

Dec. 31, 2019

ACCOUNTS RECEIVABLES, NET

ACCOUNTS RECEIVABLES, NET

4. ACCOUNTS RECEIVABLES, NET

Accounts receivables, net consisted of the following:


	As of December 31,
	2018	2019
	RMB	RMB
Accounts receivable	54,652,991	118,517,235
Allowance for doubtful accounts	(228,146)	(3,288,535)
Accounts receivable, net	54,424,845	115,228,700

The movement of the allowance for doubtful accounts is as follows:


	For the Year Ended
	December 31,
	2017	2018	2019
	RMB	RMB	RMB
Balance at the beginning of the year	47,846	1,956,245	228,146
Additions / (reversals) charged to bad debt expense	1,908,399	(1,215,464)	3,060,389
Write-off of bad debt allowance	—	(512,635)	—
Balance at the end of the year	1,956,245	228,146	3,288,535

INVENTORIES

12 Months Ended

Dec. 31, 2019

INVENTORIES

INVENTORIES

5. INVENTORIES

Inventories consisted of the following:


	As of December 31,
	2018	2019
	RMB	RMB
Raw materials	120,290,456	151,975,367
Works in progress	1,948,838	1,481,938
Finished goods	20,142,911	25,175,994
Inventories	142,382,205	178,633,299

On April 5, 2018, there was a fire accident incurred at the warehouse in the Group’s rented plant facility in Jiangsu Province of PRC. RMB18,254,406 inventories damage loss was recognized in general and administrative expenses for the year ended December 31, 2018. In addition, write-downs of inventories from the carrying amount to its estimated net realizable value amounted to RMB10,491,137 for the year ended December 31, 2019, and was recorded as cost of revenues. No such write-downs was made for the years ended December 31, 2017 and 2018.

PREPAYMENTS AND OTHER CURRENT ASSETS

12 Months Ended

Dec. 31, 2019

PREPAYMENTS AND OTHER CURRENT ASSETS

PREPAYMENTS AND OTHER CURRENT ASSETS

6. PREPAYMENTS AND OTHER CURRENT ASSETS

Prepayments and other current assets consisted of the following:


	As of December 31,
	2018	2019
	RMB	RMB
Advances to suppliers	15,507,866	11,124,716
Deductible input VAT and VAT rebates receivable	7,855,998	8,678,443
Staff advances	447,791	514,328
Interest receivable	659,194	5,369,826
Others*	2,449,105	5,294,818
Prepayments and other current assets	26,919,954	30,982,131

Others mainly include deposits receivable.

PROPERTY, PLANT AND EQUIPMENT, NET

12 Months Ended

Dec. 31, 2019

PROPERTY, PLANT AND EQUIPMENT, NET

PROPERTY, PLANT AND EQUIPMENT, NET

7. PROPERTY, PLANT AND EQUIPMENT, NET

Property, plant and equipment consisted of the following:


	As of December 31,
	2018	2019
	RMB	RMB
Machinery and equipment	22,615,657	47,307,840
Furniture	36,630,720	76,258,884
Office and electronic equipment	9,071,471	16,909,504
Leasehold improvement	2,116,266	4,081,766
Motor vehicles	802,251	1,173,634
Building and building improvements	—	64,887,245
Property, plant and equipment	71,236,365	210,618,873
Less: Accumulated depreciation	(30,251,191)	(59,727,529)
Property, plant and equipment, net	40,985,174	150,891,344

Depreciation expense was RMB9,049,769, RMB16,808,987 and RMB29,501,123 for the years ended December 31, 2017, 2018 and 2019, respectively.

Depreciation expense on property, plant and equipment was allocated to the following expense items:


	For the Year ended December 31,
	2017	2018	2019
	RMB	RMB	RMB
Cost of revenues	4,217,126	4,638,662	6,109,583
General and administrative expenses	1,873,711	2,261,620	3,403,502
Selling and marketing expenses	2,646,204	9,438,501	19,025,624
Research and development expenses	312,728	470,204	962,414
Total depreciation expense	9,049,769	16,808,987	29,501,123

INTANGIBLE ASSETS, NET

12 Months Ended

Dec. 31, 2019

INTANGIBLE ASSETS, NET

INTANGIBLE ASSETS, NET

8. INTANGIBLE ASSETS, NET

Intangible assets consisted of the following:


	As of December 31, 2018
		Gross		Net
	Amortization	carrying	Accumulated	carrying
RMB	period	amount	amortization	amount
Trademarks	5 years	8,564,505	(1,427,418)	7,137,087
Domain name	5 years	3,484,000	(2,903,333)	580,667
Total		12,048,505	(4,330,751)	7,717,754


	As of December 31, 2019
		Gross		Net
	Amortization	carrying	Accumulated	carrying
RMB	period	amount	amortization	amount
Trademarks	5-10 years	8,911,271	(3,193,738)	5,717,533
Domain name	5-10 years	3,821,474	(3,517,748)	303,726
License	10 years	1,943,396	(184,906)	1,758,490
Total		14,676,141	(6,896,392)	7,779,749

Amortization expense on intangible assets was allocated to the following expense items:


	For the Year ended December 31,
	2017	2018	2019
	RMB	RMB	RMB
Cost of revenues	—	—	184,906
General and administrative expenses	696,800	2,072,389	2,336,803

Total amortization expense	696,800	2,072,389	2,521,709

As of December 31, 2019, estimated amortization expense of the existing intangible assets for each of the next five years is RMB1,969,336, RMB1,969,336, RMB1,969,336, RMB535,118 and RMB248,274, respectively.

LAND USE RIGHT, NET

12 Months Ended

Dec. 31, 2019

LAND USE RIGHT, NET

LAND USE RIGHT, NET

9.LAND USE RIGHT, NET

Land use right, net consisted of the following:


	As of December 31,
	2018	2019
	RMB	RMB
Gross carrying amount	—	34,761,487
Less: Accumulated amortization	—	(405,551)

Land use right, net	—	34,355,936

Amortization expense of RMB405,551 was recognized in general and administrative expenses for the year ended December 31, 2019.

OTHER NON-CURRENT ASSETS

12 Months Ended

Dec. 31, 2019

OTHER NON-CURRENT ASSETS

OTHER NON-CURRENT ASSETS

10.OTHER NON-CURRENT ASSETS

Other non-current assets consisted of the following:


	As of December 31,
	2018	2019
	RMB	RMB
Prepayments for land use right	10,000,000	—
Others*	6,805,474	6,522,561

Other non-current assets	16,805,474	6,522,561

Others mainly include deposits and prepayments for equipment and intangible assets.

SHORT-TERM BANK BORROWINGS AND RESTRICTED CASH

12 Months Ended

Dec. 31, 2019

SHORT-TERM BANK BORROWINGS AND RESTRICTED CASH

SHORT-TERM BANK BORROWINGS AND RESTRICTED CASH

11. SHORT-TERM BANK BORROWINGS AND RESTRICTED CASH


	As of December 31,
	2018	2019
	RMB	RMB
East West Bank loan	99,978,003	48,910,799
Bank of China loan	20,000,000	20,000,000
SPD Silicon Valley Bank loan	60,000,000	120,000,000
Bank of Ningbo loan	—	28,483,333
Short-term bank borrowings	179,978,003	217,394,132

In December 2015 and March 2016, Jiangsu Xiaoniu Diandong Technology Co., Ltd. (“Jiangsu Xiaoniu”), a subsidiary of Beijing Niudian, entered into two line-of-credit agreements with East West Bank that provided a one-year term revolving credit facility up to RMB100,000,000, in aggregate with interest rate of 2.8% per annum. All drawdowns are due within one year from the drawdown date. To collateralize these lines of credits, the Company and Niu Technologies Group Limited, a subsidiary of the Company incorporated in Hong Kong S.A.R., made deposits of US$16,000,000 (equivalent to RMB103,674,877) in aggregate at East West Bank. The Group can apply for withdrawing the restricted cash when borrowing drawdowns are repaid. As of December 31, 2018, the line-of-credit agreements were subsequently amended several times, related to 1) increase the interest rate to 4.75% per annum and 2) extend the maturity date to April 15, 2020. In October and November 2019, RMB35,930,480 and RMB52,933,631 of the loans were repaid, respectively, and the relative restricted cash was released. In November 2019, Jiangsu Xiaoniu applied a new drawdown of RMB37,796,907 with an interest rate of 4.2% per annum. As of December 31, 2018 and 2019, total outstanding balances of these loans were RMB99,978,003 and RMB48,910,799, respectively. Total outstanding balances of restricted cash were equivalent to RMB109,811,200 and RMB56,525,358, respectively. On April 15, 2020, Jiangsu Xiaoniu repaid all the loans and the restricted cash was released accordingly.

In August 2017, Jiangsu Xiaoniu entered into a short-term bank borrowing agreement with Bank of China (the "2017 BOC Loan") that provides a six‑month RMB10,000,000 loan bearing interest at 4.5675% per annum. Mr. Yi’nan Li, the founder and a board member of the Company until June 8, 2018, Mr. Changlong Sheng, a shareholder of the Company, Beijing Niudian and its subsidiary Shanghai Niudian Trading Co., Ltd., and Jiangsu Xiaoniu’s subsidiary Changzhou Niudian International Trading Co., Ltd. (“Changzhou Niudian”) provided joint liability guaranties for the loan. On February 5, 2018, Jiangsu Xiaoniu fully repaid the 2017 BOC Loan. On February 8, 2018, Jiangsu Xiaoniu obtained a new one-year short-term bank borrowing of RMB20,000,000, which bears interest rate at 4.5675% per annum, from Bank of China (the "2018 BOC Loan"). The guaranties for this loan are as same as the 2017 BOC Loan. The loan was fully repaid by Jiangsu Xiaoniu in December 2018. In December 2018, Jiangsu Xiaoniu obtained a new one-year short-term bank borrowing of RMB20,000,000, which bears interest at a rate of 4.5675% per annum, from Bank of China (the "2019 BOC Loan"). The guarantees for this loan are the same as for the previous loan in February 2018. The 2019 BOC Loan was fully repaid by Jiangsu Xiaoniu in December 2019. On December 12, 2019, Jiangsu Xiaoniu obtained a new one-year short-term bank borrowing of RMB20,000,000, which bears interest at a rate of 4.5675% per annum, from Bank of China (the “2020 BOC Loan”). Beijing Niudian and Changzhou Niudian provided joint liability guaranties for the 2020 BOC Loan. As of December 31, 2019, the outstanding balance of the 2020 BOC Loan was RMB20,000,000.

In November 2017, Jiangsu Xiaoniu entered into a line-of-credit agreement with SPD Silicon Valley Bank that provides a one-year term credit facility of up to RMB60,000,000. The interest rate of the loan is at standard rate published by People’s Bank of China. To collateralize this line of credit, the Company made deposits of US$10,000,000 (equivalent to RMB66,288,600) at the bank which remained restricted until February 7, 2019. In November 2018, the line-of-credit agreement was amended to extend the maturity date to March 15, 2019. In March 2019, the maturity date of the line-of-credit agreement was extended to June 12, 2019, as well as the corresponding restricted cash. On June 12, 2019, Jiangsu Xiaoniu repaid the loan and the restricted cash was released.

On June 12, 2019, Jiangsu Xiaoniu, Beijing Niudian and Changzhou Niudian jointly entered into a line-of-credit agreement with SPD Silicon Valley Bank that provides a one-year term credit facility of up to RMB120,000,000. The interest rate of the drawn down funds was at 4.35% per annum. To collateralize this line of credit, the Company made deposits of US$19,149,307 (equivalent to RMB132,000,000) at the bank which remained restricted until September 11, 2020. On June 12, 2019, Jiangsu Xiaoniu and Changzhou Niudian obtained loans from SPD Silicon Valley Bank in amounts of RMB60,000,000 and RMB60,000,000, respectively, with a one-year term to June 12, 2020. As of December 31, 2019, the balance of the drawdown to under this line of credit was RMB120,000,000.

On January 23, 2019, Beijing Niudian entered into an agreement with Bank of Ningbo who provided a one- year short-term bank borrowing of RMB28,483,333 bearing interest at 5.32% per annum. To collateralize this borrowing, Niudian Information deposited RMB30,000,000 in Bank of Ningbo as collateral. As of December 31, 2019, outstanding balances of the borrowing and the restricted cash were RMB28,483,333 and RMB30,000,000, respectively. On January 22, 2020, Beijing Niudian repaid the borrowing and the restricted cash was released.

CONVERTIBLE LOAN	12 Months Ended
CONVERTIBLE LOAN	Dec. 31, 2019
CONVERTIBLE LOAN
CONVERTIBLE LOAN	12. CONVERTIBLE LOAN On December 16, 2016, the Company entered a convertible loan agreement (the "2016 Convertible Loan") with Glory Achievement Fund Limited, GGV Capital V L.P., GGV Capital V Entrepreneurs Fund L.P., Hyperfinite Galaxy Holding Limited, Plum Angel Investment Co., Ltd., and Future Capital Discovery Fund I, L.P. (collectively "2016 Convertible Loan Holders") to obtain a loan of US$16,827,000 (equivalent to RMB115,808,672) in aggregate with one-year term. 2016 Convertible Loan Holders were entitled to an option to convert all or part of the outstanding principal of the 2016 Convertible Loan to the Company’s preferred shares upon next round of financing. The interest rate of 2016 convertible loan was 5% per annum provided that no interest should be accrued on the outstanding principal amount, if the entire or any portion of the principal amount was converted to the Company’s preferred shares. The conversion price should be the per share price based on valuation of the Company at 80% of lower of US$260,400,000 or the pre-money valuation in the next round financing. If the conversion price was based on a valuation equal to 80% of US$260,400,000, the 2016 convertible loan should be converted to Series A‑3 Preferred Shares. If the conversion price was based on a valuation lower than 80% of US$260,400,000, the 2016 Convertible Loan should be converted to preferred shares with the same terms and the same rights and obligation as the preferred shares any new investors might have in the next round of financing. As the conversion price was not determinable at the issuance date, there was no noncontingent beneficial conversion feature. As such, the 2016 Convertible Loan was not in whole or in part classified as a component of equity. The Company elected to measure the 2016 Convertible Loan in its entirety at fair value with amount of changes in fair value recognized in earnings in consolidated statements of comprehensive (loss) / income. The Company adopted a scenario-weighted average method to estimate the fair value of the convertible loan as of December 31, 2017 and the conversion date based on the probability of each scenario and pay-off of convertible loan under each scenario. The scenarios included different timing of next round financing and corresponding conversion price of the convertible loan. The 2016 Convertible Loan was converted to 10,119,329 Series A‑3 Preferred Shares at the price of US$1.66 per share on March 26, 2018 (Note 15).

ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES

12 Months Ended

Dec. 31, 2019

ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES

ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES

13. ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES


	As of December 31,
	2018	2019
	RMB	RMB
Accrued payroll and social insurance	32,008,825	30,780,693
Warranty—current	31,262,442	41,809,564
Sales rebate	34,029,433	40,344,717
Construction payable	—	18,765,855
Deposits	16,360,762	16,293,035
Deferred ADR income	4,250,126	—
Other taxes payable	3,656,732	10,273,637
IPO cost payable	3,130,639	—
Interest payable	318,774	2,010,366
Others*	9,166,293	15,255,530
Accrued expenses and other current liabilities	134,184,026	175,533,397

* Others mainly include employee options payable and accrued marketing expenses.

The Group provides limited warranty to its end customers for terms varying from six months to three years, subject to certain conditions, such as normal use. For the electric motor, the Group provides a 24-month or 30,000‑kilometer warranty. For lithium-ion battery packs, the Group provides 24‑month or 20,000‑kilometer warranty or a 36‑month or 30,000‑kilometer warranty, depending on the model.

For other parts of the Group’s smart electric-scooters, the Group provides quality warranty varying from six months to 24 months depending on the parts. The Group is responsible for replacing or repairing the faulty products during their respective warranty terms.

The Group provides for the estimated costs of warranties at the time revenue is recognized. Factors that affect the Group’s warranty obligation include product defect rates and costs of repair or replacement.

Movement of provision for warranty is as follows:


	For the Year ended December 31,
	2017	2018	2019
Accrued warranty—beginning of year	17,649,411	30,648,678	48,872,284
Accrual for warranties issued during the year	27,395,169	29,346,974	40,271,444
Warranty claims paid	(14,395,902)	(7,923,760)	(22,132,194)
Pre-existing warranty expired	—	(3,199,608)	(7,059,668)
Accrued warranty—end of year	30,648,678	48,872,284	59,951,866

OTHER NON-CURRENT LIABILITIES

12 Months Ended

Dec. 31, 2019

OTHER NON-CURRENT LIABILITIES

OTHER NON-CURRENT LIABILITIES

14.OTHER NON-CURRENT LIABILITIES

Other non-current liabilities consisted of the following:


	As of December 31,
	2018	2019
	RMB	RMB
Warranty—non-current	17,609,842	18,142,302
Deposits for construction of building —non-current	—	4,216,666

Other non-current liabilities	17,609,842	22,358,968

REDEEMABLE CONVERTIBLE PREFERRED SHARES

12 Months Ended

Dec. 31, 2019

REDEEMABLE CONVERTIBLE PREFERRED SHARES

REDEEMABLE CONVERTIBLE PREFERRED SHARES

15. REDEEMABLE CONVERTIBLE PREFERRED SHARES

On March 5, 2015, the Company issued convertible loan of US$3.9 million to GGV Capital V L.P., GGV Capital V Entrepreneurs Fund L.P., IDG China Venture Capital Fund IV L.P., and IDG China IV Investors L.P. in aggregate (the "2015 Convertible Loan"), which carried nil interest and was due by September 5, 2015. On May 27, 2015, the Company issued 16,666,667 Series A‑1 Preferred Shares at US$1.20 per share, of which 3,250,000 Series A‑1 Preferred Shares were issued upon conversion the 2015 Convertible Loan. The total proceeds from the issuance of Series A‑1 Preferred Shares was US$16,100,000 (equivalent to RMB101,208,371).

On May 27, 2015, the Company issued 3,608,247 Series A‑2 redeemable convertible preferred shares ("Series A‑2 Preferred Shares") at US$1.66 per share. The total proceeds from the issuance of Series A‑2 Preferred Shares was US$6,000,000 (equivalent to RMB36,720,422).

On January 29, 2016, the Company issued 5,003,436 Series A‑3 Preferred Shares at US$2.08 per share. The total proceeds from the issuance of Series A‑3 Preferred Shares was US$10,400,000 (equivalent to RMB67,883,227).

On March 26, 2018, the holders of 2016 Convertible Loan converted the entire outstanding principal of the 2016 Convertible Loan of US$16,827,000 to 10,119,329 Series A-3 Preferred Shares at the conversion price of US$1.66 per share. The carrying amount of 2016 Convertible Loan of RMB181,112,874 as of March 26, 2018 was recorded as the initial amount reported in Series A-3 Preferred Shares.

On March 26, 2018, the Company issued 5,137,859 Series B redeemable convertible preferred shares ("Series B Preferred Shares") at the price of US$4.96 per share to Plum Angel Investment Co., Ltd., GGV Capital V L.P., GGV Capital V Entrepreneurs Fund L.P., GGV Capital Select L.P., Phoenix Wealth Investment (Holdings) Limited, Future Capital Discovery Fund I, L.P., IDG China Venture Capital Fund IV L.P. and IDG China IV Investors L.P. in aggregate. The total proceeds from the issuance of Series B Preferred Shares was US$25,500,000 (equivalent to RMB161,392,196).

The Company classified Series A‑1 Preferred Shares, Series A‑2 Preferred Shares, Series A‑3 Preferred Shares (collectively "Series A Preferred Shares"), and Series B Preferred Shares as mezzanine equity in the consolidated balance sheets since they were contingently redeemable at the option of the holders after a specified time period.

The Company evaluated the embedded conversion option in the Series A Preferred Shares and Series B Preferred Shares to determine if the embedded conversion option require bifurcation and accounting for as a derivative. The Company concluded the embedded conversion option did not need to be bifurcated pursuant to ASC 815 Derivatives and Hedging. The Company also determined that there was no beneficial conversion feature attributable to the Series A Preferred Shares and Series B Preferred Shares because the initial effective conversion prices of these shares were higher than the fair value of the Company’s ordinary shares at the relevant commitment dates. The fair value of the Company’s ordinary shares on the commitment date was estimated by management with the assistance of an independent valuation firm. The Company also determined there was no other embedded features to be separated from Series A Preferred Shares or Series B Preferred Shares.

The rights, preferences and privileges of the redeemable convertible preferred shares were as follows:

Redemption Rights

The redemption date of Series A Preferred Shares was at any time:

(i)

after the fifth-year anniversary of May 27, 2015, subject to the applicable laws of the Cayman Islands; or

(ii)

any holder of any other class of shares elects to exercise its redemption right.

The redemption date of Series B Preferred Shares was at any time:

(i)

after the fifth-year anniversary of March 26, 2018, subject to the applicable laws of the Cayman Islands; or

(ii)

any holder of any other class of shares elects to exercise its redemption right.

The Company should redeem, up to all of the outstanding Series A Preferred Shares and Series B Preferred Shares out of funds legally available therefor including capital in accordance with the agreement, provided, however, that no Series A redemption price should be paid until the Series B redemption price with respect to the Series B Preferred Shares requested to be redeemed was paid.

The redemption price for Series A Preferred Shares or Series B Preferred Shares, should be the sum of their issue price, all accrued dividends, and any declared but unpaid dividends thereon up to the date of redemption.

Conversion Rights

Each redeemable convertible preferred share was convertible, at the option of the holder, at any time after the issuance date according to a conversion ratio, subject to adjustments for dilution, including but not limited to stock splits, stock dividends and certain other events. Each redeemable convertible preferred share was convertible into a number of ordinary shares determined by dividing the applicable original issuance price by the conversion price. The conversion price of each redeemable convertible preferred share was the same as its original issuance price and no adjustments to conversion price have occurred. As of December 31, 2017, each redeemable convertible preferred share was convertible into one ordinary share.

Each Series A Preferred Share should automatically be converted into Ordinary Shares at a 1‑to‑1 initial conversion ratio immediately upon the closing of a Qualified Initial Public Offering ("Qualified IPO"), and approved by the holders of more than two-thirds of the Series A Preferred Shares. Each Series B Preferred Share should automatically be converted into Ordinary Shares at a 1-to-1 initial conversion ratio immediately upon the closing of a Qualified IPO, and approved by the holders of more than half of the Series B Preferred Shares.

A "Qualified IPO" was defined as the closing of a firm commitment underwritten public offering of the Ordinary Shares (or depositary receipts or depositary shares therefor) in the United States pursuant to an effective registration statement under the United States Securities Act of 1933, as amended, with an offering price per share (net of underwriting commissions and expenses) that reflected the valuation of the Company immediately prior to such offering of at least US$1,000,000,000 and that resulted in gross proceeds to the Company of at least US$100,000,000, or in a public offering of the Ordinary Shares in the Hong Kong S.A.R. or any other jurisdiction which resulted in the Ordinary Shares trading publicly on a recognized international securities exchange so long as the offering price per share (net of underwriting commissions and expenses) satisfied the foregoing pre-offering valuation and gross proceeds requirements, in each case, unless such requirements were waived by the holders of more than two-thirds of the Series A Preferred Shares.

Voting Rights

Each redeemable convertible preferred share should be entitled to that number of votes corresponding to the number of ordinary shares on an as-converted basis. Redeemable convertible preferred share should vote separately as a class with respect to certain specified matters. Otherwise, the holders of redeemable convertible preferred shares, convertible preferred shares and ordinary shares should vote together as a single class.

Dividend Rights

Prior to the issuance of Series B Preferred Shares in March 2018, each holder of Series A Preferred Shares should be entitled to receive dividends payable only when, as and if declared by the majority of the Board, out of any assets at the time legally available therefor, in preference and priority to any declaration or payment of any dividends on Ordinary Shares, Series Seed convertible preferred shares ("Series Seed Preferred Shares") or any other class or series of shares issued by the Company, and should participate in any subsequent distribution among the Ordinary Shares, Series Seed Preferred Shares and all other classes or series of shares issued by the Company pro rata based on the number of Ordinary Shares held by such holder of Series A Preferred Shares (calculated on an as-converted basis).

Upon the issuance of Series B Preferred Shares and amendment and restatement of Memorandum of Association thereupon in March 2018, each holder of a Series A Preferred Share should be entitled to receive dividends payable only when, as and if declared by the majority of the Board, out of any assets at the time legally available therefor, in preference and priority to any declaration or payment of any dividends on Ordinary Shares, Series Seed Preferred Shares, or any other class or series of shares issued by the Company (other than Series B Preferred Shares), and should participate in any subsequent distribution among the Ordinary Shares, Series Seed Preferred Shares and all other classes or series of shares issued by the Company pro rata based on the number of Ordinary Shares held by such holder of Series A Preferred Shares (calculated on an as-converted basis).

Liquidation Preferences

Prior to the issuance of Series B Preferred Shares in March 2018, in the event of any liquidation including deemed liquidation, dissolution or winding up of the Company, holders of the Series A Preferred Shares should be entitled to receive a per share amount equal to 150% of the original preferred share issue price of the respective series of preferred shares, as adjusted for share dividends, share splits, combinations, recapitalizations or similar events, plus all accrued and declared but unpaid dividends thereon, in the following sequence: Series A Preferred Shares and Series Seed Preferred Shares. After such liquidation amounts have been paid in full, any remaining funds or assets of the Company legally available for distribution to shareholders should be distributed on a pro rata, pari passu basis among the holders of the then outstanding preferred shares (on an as-converted basis), together with the holders of the then outstanding ordinary shares.

Upon the issuance of Series B Preferred Shares and amendment and restatement of Memorandum of Association thereupon in March 2018, in the event of any liquidation including deemed liquidation, dissolution or winding up of the Company, holders of the Series A and Series B Preferred Shares should be entitled to receive a per share amount equal to 150% of the original preferred share issue price of the respective series of preferred shares, as adjusted for share dividends, share splits, combinations, recapitalizations or similar events, plus all accrued and declared but unpaid dividends thereon, in the following sequence: Series B Preferred Shares, Series A Preferred Shares and Series Seed Preferred Shares. After such liquidation amounts had been paid in full, any remaining funds or assets of the Company legally available for distribution to shareholders should be distributed on a pro rata, pari passu basis among the holders of the then outstanding preferred shares (on an as-converted basis), together with the holders of the then outstanding ordinary shares.

With approval from the holders of Series A Preferred Shares and Series B Preferred Shares and waiver of the Qualified IPO from the holders of Series A Preferred Shares, all of the redeemable convertible preferred shares were converted to Class A ordinary shares immediately prior to the completion of the Company’s initial public offering on October 19, 2018.

The Company's redeemable convertible preferred shares activities consisted of the following:


			Series A-2	Series A-3	Series B
			Preferred	Preferred	Preferred
	Series A-1 Preferred Shares		Shares	Shares	Shares
	Carrying	Subscription	Carrying	Carrying	Carrying
RMB	amount	receivable	amount	amount	amount	Total
Balance as of January 1, 2017	138,740,003	—	41,621,992	72,144,418	—	252,506,413
Foreign currency translation adjustment	(8,056,000)	—	(2,416,800)	(4,189,098)	—	(14,661,898)
Balance as of December 31, 2017	130,684,003	—	39,205,192	67,955,320	—	237,844,515
Issuance of preferred shares	—	—	—	181,112,874	161,392,196	342,505,070
Foreign currency translation adjustment	8,090,000	—	2,427,000	21,651,035	15,544,654	47,712,689
Conversion to Ordinary Shares	(138,774,003)	—	(41,632,192)	(270,719,229)	(176,936,850)	(628,062,274)
Balance as of December 31, 2018 and 2019	—	—	—	—	—	—

ORDINARY SHARES AND SERIES SEED PREFERRED SHARES	12 Months Ended
ORDINARY SHARES AND SERIES SEED PREFERRED SHARES	Dec. 31, 2019
ORDINARY SHARES AND SERIES SEED PREFERRED SHARES
ORDINARY SHARES AND SERIES SEED PREFERRED SHARES	16. ORDINARY SHARES AND SERIES SEED PREFERRED SHARES Ordinary Shares The Company’s Memorandum and Articles of Association authorizes the Company to issue 444,721,650 ordinary shares of US$0.0001 par value as of December 31, 2017. On March 26, 2018, the Company repurchased 432,000 ordinary shares from Niu Holding Inc. beneficially owned by Mr. Token Yilin Hu at total consideration of US$665,000 (equivalent to RMB4,202,335). Such shares were cancelled immediately upon repurchase. In October 2018, the Company completed its initial public offering (“the IPO”) of 14,000,000 newly issued Class A ordinary shares, at a public offering price of US$4.5 per share. The net proceeds after deducting underwriting commissions and discounts were US$58,590,000 (equivalent to RMB406,538,433). Immediately prior to the completion of the IPO, the Company’s authorized share capital was increased to US$500,000 divided into 5,000,000,000 shares comprising of (i) 4,900,000,000 Class A ordinary shares with a par value of US$0.0001 each, (ii) 50,000,000 Class B ordinary shares with a par value of US$0.0001 each and (iii) 50,000,000 shares with a par value of US$0.0001 each of such class or classes (however designated) as the board of directors may determine in accordance with the Company’s post-offering Memorandum and Articles of Association. Immediately prior to the completion of the IPO, all outstanding preferred shares, including (i) 30,000,000 Series Seed Preferred Shares with a par value of US$0.0001 each, (ii) 16,666,667 of Series A-1 Preferred Shares with a par value of US$0.0001 each, (iii) 3,608,247 of Series A-2 Preferred Shares with a par value of US$0.0001 each, (iv) 15,122,765 Series A-3 Preferred Shares with a par value of US$0.0001 each, and (v) 5,137,859 of Series B Preferred Shares with a par value of US$0.0001 each, were converted into Class A ordinary shares on a one-for-one bases. All outstanding ordinary shares were re-designated and re-classified as Class A ordinary shares on a one-for-one basis, except that 6,615,000 ordinary shares held by ELLY Holdings Limited and 14,027,020 ordinary shares held by Niu Holding Inc. were re-classified and re-designated as Class B ordinary shares on a one-for-one basis. Holders of Class A ordinary shares and Class B ordinary shares have the same rights except for voting and conversion rights. Each Class A ordinary share entitles the holder to one vote on all matters subject to vote at general meetings of the Company, and each Class B ordinary share entitles the holder to four votes on all matters subject to vote at general meetings of the Company. Class A ordinary shares are not convertible into Class B ordinary shares under any circumstances. On September 5, 2019, a Class B ordinary shareholder converted 1,400,000 Class B ordinary shares to Class A ordinary shares. As of December 31, 2019, there were 130,174,878 and 19,242,020 Class A and Class B ordinary shares outstanding, respectively. Series Seed Preferred Shares The Company’s Memorandum and Articles of Association authorizes the Company to issue 30,000,000 Series Seed Preferred Shares of US$0.0001 par value as of December 31, 2017. Series Seed Preferred Shares were not redeemable and were convertible to ordinary shares at a one-for-one initial conversion ratio at the option of the holder at any time after the date of issuance. The liquidation preference of Series Seed Preferred Shares was preferable to ordinary shares but subordinated to redeemable convertible preferred shares as disclosed in Note 15. Voting rights and dividend rights of Series Seed Preferred Shares were as same as ordinary shares. Immediately prior to the completion of the IPO, all outstanding Series Seed Preferred Shares were converted into Class A ordinary shares on one-for-one bases.

SHARE-BASED COMPENSATION

12 Months Ended

Dec. 31, 2019

SHARE-BASED COMPENSATION

SHARE-BASED COMPENSATION

17. SHARE-BASED COMPENSATION

Restricted ordinary shares

In May 2015, Mr. Yi’nan Li, Mr. Token Yilin Hu, Ms. Yuqin Zhang and Niu Holding Inc. entered into an arrangement with other investors of the Company, whereby all of their 59,459,020 ordinary shares became restricted and subject to service vesting conditions. The restricted ordinary shares vested equally in four years from the date of imposition of the restriction , which was accelerated in the event of the Company’s IPO. The restricted ordinary shares were subject to repurchase by the Company upon termination of Mr. Yi’nan Li, Mr. Token Yilin Hu and Ms. Yuqin Zhang’s service with the Group. The Company had the right, at its sole discretion, to repurchase restricted ordinary shares at its par value within 60 days after the termination. The restricted ordinary shares were not transferable prior to be vested. Other than the restriction on transfer and service vesting conditions, restricted ordinary shareholders had all other rights and privileges as ordinary shareholders. Compensation cost was measured for the restricted ordinary shares using the estimated fair value of the Company’s ordinary shares of US$0.53 per share at the date of imposition of the restriction in May 2015, and was amortized to consolidated statements of comprehensive (loss)/income on a straight-line basis over the vesting term of four years.

In February 2016, Ms. Yuqin Zhang resigned from the Group and the Company determined not to repurchase restricted ordinary shares held by Ms. Yuqin Zhang. As such, all restricted ordinary shares held by Ms. Yuqin Zhang vested immediately, compensation cost of RMB7,574,133 was recognized immediately when the service condition was waived.

On January 7, 2016, the shareholders of the Company approved a modification of 3,307,500 restricted ordinary shares owned Mr. Yi’nan Li, through Niu Holding Inc.. Such number of restricted ordinary shares vested immediately and became transferable. Unrecognized compensation cost of RMB9,803,035 of 3,307,500 shares was recognized upon modification. Mr. Yi’nan Li transferred 3,307,500 ordinary shares to ELLY Holdings Limited, an entity owned by Dr. Yan Li, the new Chief Operating Officer of the Company who became the Chief Executive Officer of the Company in December 2017. On January 7, 2016, the Company also issued 3,307,500 restricted ordinary shares to ELLY Holdings Limited at par value. As a result of these transactions, ELLY Holdings Limited collectively owned 6,615,000 restricted ordinary shares which vested annually in equal instalments over four years from January 7, 2016.

On January 7, 2016, the Company also issued 1,804,000 restricted ordinary shares to Smart Power Group Limited, an entity owned by Mingming Huang, a new member of Board of Directors of the Company. 25% of the restricted ordinary shares vested on May 27, 2016 and the remaining 75% of the restricted ordinary shares vested annually in equal instalments over the next three years.

On June 8, 2018, Mr. Yi'nan Li and Mr. Mingming Huang resigned from the Company and the Company determined not to repurchase 9,798,125 and 451,000 restricted ordinary shares held by Mr. Yi'nan Li and Mr. Mingming Huang, respectively. It represented a modification to accelerate vesting. Compensation cost of RMB173,156,580 was recognized immediately as general and administrative expenses upon the modification.

On October 19, 2018, the remaining restricted ordinary shares of Mr. Token Yilin Hu and Dr. Yan Li were vested immediately upon the Company’s initial public offering. Compensation cost of RMB8,935,076 and RMB10,535,229 was immediately recognized as research and development expenses and general and administrative expenses, respectively.

The total fair value of shares vested during the years ended December 31, 2017 and 2018 was RMB58,848,966 and RMB264,075,922, respectively . Total compensation expenses recognized for restricted ordinary shares for the years ended December 31, 2017 and 2018 were allocated to the following expense items:


	For the year ended
	December 31,
	2017	2018
	RMB	RMB
Research and development expenses	13,045,853	18,371,203
General and administrative expenses	46,185,090	207,871,076
Total restricted ordinary shares compensation expense	59,230,943	226,242,279

As of December 31, 2018, there was no unrecognized compensation expense related to restricted ordinary shares.

Transfer of ordinary shares

On June 8, 2018, Mr. Token Yilin Hu transferred 2,000,000 ordinary shares beneficially owned through Niu Holdings Inc. to Mr. Carl Chuankai Liu, the vice president of design of the Company at nil consideration. The Company accounted for such transfer as share-based compensation as the ordinary shares were granted to Mr. Carl Chuankai Liu as compensation for his services provided to the Group. As there was no service condition, RMB33,537,572 share-based compensation expenses were recognized in research and development expenses immediately upon transfer.

Share options and restricted share units

2016 Global Incentive Plan

In January 2016, the Company's Shareholders and Board of Directors approved 2016 Global Share Incentive Plan and amended it in March 2018 (the "Amended 2016 Plan"). Under the Amended 2016 Plan, a maximum aggregate number of 5,861,480 ordinary shares may be issued pursuant to all awards granted. Share options or restricted share unites expire 10 years from the grant date.

As of December 31, 2019, the Company has granted under the 2016 Plan: (i) 4,540,000 share options with exercise price of US$0.20 per share and vesting schedule of 40% vesting on the second anniversary of the grant date and the remaining vesting in three equal annual installments; (ii) 705,196 share options with exercise price of nil and vesting in four equal annual installments; (iii) 100,000 restricted share units and vesting in two equal annual installments; and (iv) 428,000 restricted share units with vesting in four equal annual installments.

2018 Share Incentive Plan

In September 2018, the Company’s Shareholders and Board of Directors approved the 2018 Share Incentive Plan (the “2018 Plan”). Under the 2018 Plan, the maximum aggregate number of ordinary shares available for issuance is 6,733,703 ordinary shares, which shall be increased by a number equal to 1.5% of the total number of ordinary shares issued and outstanding on the last day of the immediately preceding fiscal year, each fiscal year during the term of the 2018 Plan, if determined and approved by the board of directors for the relevant fiscal year. In November 2019, the board of directors approved an increase by 2,230,111 ordinary shares, representing 1.5% of total issued and outstanding shares at the end of 2018 pursuant to the 2018 Share Incentive Plan.

As of December 31, 2019, the Company has granted under the 2018 Plan: (i) 4,180,000 share options with exercise price of US$3.425 and vesting in four equal annual installments; and (ii) 1,266,600 restricted share units with vesting in four equal annual installments.

A summary of the share options activities under the Amended 2016 Plan and the 2018 Plan for the year ended December 31, 2019 is presented below:


			Weighted
		Weighted	remaining
	Number of	average exercise	contractual	Aggregate
	share	price	years	intrinsic value
		US$		US$
Outstanding at January 1, 2019	5,314,246	0.17
Granted	4,180,000	3.43
Exercised	(742,840)	0.19
Forfeited	(69,050)	0.20
Outstanding at December 31, 2019	8,682,356	1.74	8.18	21,950,316
Exercisable as of December 31, 2019	2,387,959	0.19	6.44	9,738,313

The fair value of the options granted is estimated on the grant dates using the binomial option pricing model with the following key assumptions used:


Grant Date:	2017	2018	2019
Risk-free rate of return (per annum)	2.25% - 2.48%	2.78%-3.13%	1.90%
Volatility	51.7% - 54.4%	49.9%-50.9%	47.9%
Expected dividend yield	0%	0%	0%
Exercise multiple	2.2	2.2	2.2-2.8
Fair value of underlying ordinary share	US$0.44 - US$1.22	US$2.05 - US$4.10	US$3.425
Expected term (in years)	10	10	10

The expected volatility was estimated based on the historical volatility of the Company and comparable peer public companies with a time horizon close to the expected term of the Company’s options. The risk-free interest rate was estimated based on the yield to maturity of U.S. treasury bonds denominated in USD for a term consistent with the expected term of the Company’s options in effect at the option valuation date. The expected exercise multiple was estimated as the average ratio of the stock price to the exercise price of when employees would decide to voluntarily exercise their vested options. As the Company did not have sufficient information of past employee exercise history, it has considered the statistics on exercise patterns of employees compiled by Huddart and Lang in Huddart, S., and M. Lang. 1996. "Employee Stock Option Exercises: An Empirical Analysis." Journal of Accounting and Economics, vol. 21, no. 1 (February):5‑43, which are widely adopted by valuers as authoritative guidance on expected exercise multiples. Expected dividend yield is zero as the Company has never declared or paid any cash dividends on its shares, and the Company does not anticipate any dividend payments in the foreseeable future. Expected term is the contract life of the option.

The weighted average grant date fair value of the share options granted for the years ended December 31, 2017, 2018 and 2019 was US$0.86, US$2.11 and US$1.62, respectively. Compensation costs recognized for share options for the years ended December 31, 2017, 2018 and 2019 were allocated to the following expense items:


	For the year ended
	December 31,
	2017	2018	2019
	RMB	RMB	RMB
Cost of revenues	253,545	246,947	255,679
Selling and marketing expenses	1,611,160	2,124,728	2,471,725
Research and development expenses	832,782	955,538	3,060,263
General and administrative expenses	598,668	2,392,740	6,232,590
Total share option compensation expense	3,296,155	5,719,953	12,020,257

As of December 31, 2019, RMB56,411,059 of total unrecognized compensation expense related to share options is expected to be recognized over a weighted average period of approximately 3.31 years.

A summary of the restricted share units activities for the year ended December 31, 2019 is presented below:


		Weighted
		average grant
	Number of	date fair
	shares	value
		US$
Unvested as of January 1, 2019	100,000	4.33
Granted	1,694,600	3.62
Vested	(50,000)	4.33
Forfeited	—	—
Unvested as of December 31, 2019	1,744,600	3.64

Compensation costs recognized for restricted share units for the years ended December 31, 2018 and 2019 were allocated to the following expense items:


	For the year ended
	December 31,
	2018	2019
	RMB	RMB
Cost of revenues	—	36,332
Selling and marketing expenses	—	2,185,586
Research and development expenses	—	1,146,846
General and administrative expenses	375,123	4,233,758
Total share option compensation expense	375,123	7,602,522

As of December 31, 2019, RMB37,794,188 of total unrecognized compensation expense related to restricted share units is expected to be recognized over a weighted average period of approximately 3.36 years.

Total share-based compensation expenses recognized for the years ended December 31, 2017, 2018 and 2019 were allocated to the following expense items:


	For the year ended December 31,
	2017	2018	2019
	RMB	RMB	RMB
Cost of revenues	253,545	246,947	292,011
Selling and marketing expenses	1,611,160	2,124,728	4,657,311
Research and development expenses	13,878,635	52,864,313	4,207,109
General and administrative expenses	46,783,758	210,638,939	10,466,348
Total share-based compensation expense	62,527,098	265,874,927	19,622,779

FAIR VALUE MEASUREMENT

12 Months Ended

Dec. 31, 2019

FAIR VALUE MEASUREMENT

FAIR VALUE MEASUREMENT

18. FAIR VALUE MEASUREMENT

The following tables present the fair value hierarchy for those assets and liabilities measured at fair value on a recurring basis as of December 31, 2018 and 2019, respectively:


	December 31, 2019			Total
RMB	Level 1	Level 2	Level 3	Fair Value
Assets
Short-term investments (Note 3)	—	310,439,321	—	310,439,321


	December 31, 2018			Total
RMB	Level 1	Level 2	Level 3	Fair Value
Assets
Short-term investments (Note 3)	—	120,241,425	—	120,241,425

The table below reflects the reconciliation from the opening balances to the closing balances for a convertible loan, a recurring fair value measurement categorized as Level 3 of the fair value hierarchy, for the years ended December 31, 2017 and 2018, respectively:


	For the Year Ended December 31,
	2017	2018
Convertible loan - beginning of year	116,728,899	151,557,796
Change in fair value	43,006,399	34,499,858
Conversion to Series A-3 Preferred Shares	—	(181,112,874)
Foreign currency translation adjustment	(8,177,502)	(4,944,780)
Convertible loan - end of year	151,557,796	—

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

INCOME TAX

12 Months Ended

Dec. 31, 2019

INCOME TAX

INCOME TAX

19. INCOME TAX

a) Income tax

Cayman Islands

Under the current laws of the Cayman Islands, the Company is not subject to tax on income or capital gain. Additionally, the Cayman Islands does not impose a withholding tax on payments of dividends to shareholders.

No stamp duty is payable in respect of the issue of the shares or on an instrument of transfer in respect of a share.

Indonesia

Under the current laws of the Republic of Indonesia, the Company's subsidiaries in Indonesia are subject to 25% income tax on its taxable income generated from operations in Indonesia.

Hong Kong

Under the Hong Kong tax laws, subsidiaries in Hong Kong are subject to the Hong Kong profits tax rate at 16.5% and they are exempted from income tax on their foreign-derived income and there are no withholding taxes in Hong Kong on remittance of dividends. A two-tiered profits tax rates regime was introduced in 2018 where the first HK$2 million of assessable profits earned by a company will be taxed at half of the current tax rate (8.25%) whilst the remaining profits will continue to be taxed at 16.5%. There is an anti-fragmentation measure where each group will have to nominate only one company in the group to benefit from the progressive rates. The Company did not make any provisions for Hong Kong profit tax as there were no assessable profits derived from or earned in Hong Kong for any of the periods presented.

PRC

The Group’s PRC subsidiaries, the VIE, and VIE’s subsidiaries are subject to the PRC Corporate Income Tax Law ("CIT Law") and are taxed at the statutory income tax rate of 25%, unless otherwise specified.

The CIT Law also provides that an enterprise established under the laws of a foreign country or region but whose "de facto management body" is located in the PRC be treated as a resident enterprise for PRC tax purposes and consequently be subject to the PRC income tax at the rate of 25% for its global income. The Implementing Rules of the CIT Law define the location of the "de facto management body" as "the place where the exercising, in substance, of the overall management and control of the production and business operation, personnel, accounting, property, etc., of a non-PRC company is located." Based on a review of surrounding facts and circumstances, the Group does not believe that it is likely that its operations outside the PRC should be considered a resident enterprise for PRC tax purposes.

The components of (loss) / income before income taxes are as follows:


	For the Year Ended
	December 31,
	2017	2018	2019
	RMB	RMB	RMB
Cayman	(39,610,348)	(34,397,077)	6,633,761
Indonesia	—	—	(11,705)
Hong Kong S.A.R.	219,935	(4,507,360)	(3,820,485)
PRC, excluding Hong Kong S.A.R.	(145,272,458)	(310,123,039)	195,497,541
Total	(184,662,871)	(349,027,476)	198,299,112

The Group had current income tax expense of RMB7,460,535 and deferred income tax expense of RMB753,806 for a PRC subsidiary of a VIE for the year ended December 31, 2019 and no current and deferred income tax expense for the years ended December 31, 2017 and 2018.

Withholding tax on undistributed dividends

The CIT law also imposes a withholding income tax of 10% on dividends distributed by a foreign investment enterprise ("FIE") to its immediate holding company outside of China, if such immediate holding company is considered as a non-resident enterprise without any establishment or place within China or if the received dividends have no connection with the establishment or place of such immediate holding company within China, unless such immediate holding company’s jurisdiction of incorporation has a tax treaty with China that provides for a different withholding arrangement. The Cayman Islands, where the Company is incorporated, does not have such tax treaty with China. According to the arrangement between Mainland China and Hong Kong Special Administrative Region on the Avoidance of Double Taxation and Prevention of Fiscal Evasion in August 2006, dividends paid by an FIE in China to its immediate holding company in Hong Kong will be subject to withholding tax at a rate of no more than 5% (if the foreign investor owns directly at least 25% of the shares of the FIE). The Group did not record any dividend withholding tax, as the Group’s PRC entities, have no retained earnings in any of the periods presented.

Reconciliation of the differences between PRC statutory income tax rate and the Group’s effective income tax rate for the years ended December 31, 2017, 2018 and 2019 are as follows:


	For the Year Ended
	December 31,
	2017	2018	2019
	RMB	RMB	RMB
Computed expected income tax expense	(46,165,718)	(87,256,869)	49,574,778
Non-PRC entities not subject to income tax	9,847,603	9,726,109	(700,393)
Research and development expenses bonus deduction	(1,032,177)	(7,528,081)	(10,181,598)
Non-deductible share-based compensation expenses	15,631,775	66,374,951	4,532,885
Other non-deductible expenses	358,759	176,111	32,602
Expiration of loss carry forwards	—	—	304,194
Change in valuation allowance	21,359,758	18,507,779	(35,348,127)
Actual income tax expense	—	—	8,214,341

b) Deferred income tax assets and deferred income tax liabilities


	As of December 31,
	2018	2019
	RMB	RMB
Deferred income tax assets
Net operating loss carry forwards	74,657,570	39,342,952
Accrued warranty	12,218,071	14,987,967
Accrued payroll and social insurance	5,099,295	3,873,748
Deferred revenue	3,225,283	6,363,254
Advertising expense	2,955,152	937,639
Allowance for doubtful accounts	57,037	822,134
Write-downs for inventories	—	2,622,784
Less: Valuation allowance	(98,212,408)	(62,864,281)

Total deferred income tax assets, net	—	6,086,197


Deferred income tax liabilities
Short-term investments	—	511,975
Property, plant and equipment	—	6,840,002

Total deferred income tax liabilities	—	7,351,977
Net deferred income tax assets	—	—
Net deferred income tax liabilities	—	1,265,780

As of December 31, 2019, the Group had net operating loss carry forwards of RMB157,371,809 attributable to the PRC subsidiaries, the VIE and VIE's subsidiaries. Tax losses of RMB22,993,915, RMB39,644,651, RMB35,015,516, RMB50,628,062 and RMB9,089,665 will expire, if unused, by 2020, 2021, 2022, 2023 and 2024, respectively.

A valuation allowance is provided against deferred income tax assets when the Group determines that it is more likely than not that some portion or all of the deferred income tax assets will not be utilized in the foreseeable future. The valuation allowance as of December 31, 2018 and 2019 was primarily provided for the deferred income tax assets of the Group’s PRC subsidiaries, VIE and VIE’s subsidiaries. In making such determination, the Group evaluates a variety of factors including the Group’s operating history, accumulated deficit, existence of taxable temporary differences and reversal periods. The ultimate realization of deferred income tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible or utilizable. Management considers projected future taxable income and tax planning strategies in making this assessment.

Changes in valuation allowance are as follows:


	For the Year Ended
	December 31,
	2017	2018	2019
	RMB	RMB	RMB
Balance at the beginning of the year	58,344,871	79,704,629	98,212,408
Additions / (reversals)	21,359,758	18,507,779	(35,348,127)
Balance at the end of the year	79,704,629	98,212,408	62,864,281

According to the PRC Tax Administration and Collection Law, the statute of limitation is three years if the underpayment of taxes is due to computational errors made by the taxpayer or the withholding agent. The statute of limitation is extended to five years under special circumstances where the underpayment of taxes is more than RMB100,000. In the case of transfer pricing issues, the statute of limitation is 10 years. There is no statute of limitation in the case of tax evasion. The income tax returns of the Company’s PRC subsidiaries, consolidated VIE and VIE’s subsidiaries for the years from 2015 to 2019 are open to examination by the PRC tax authorities.

NET (LOSS)/INCOME PER ORDINARY SHARE

12 Months Ended

Dec. 31, 2019

NET (LOSS)/INCOME PER ORDINARY SHARE

NET (LOSS)/INCOME PER ORDINARY SHARE

20. NET (LOSS) / INCOME PER ORDINARY SHARE

The following table sets forth the basic and diluted net (loss) / income per ordinary share computation and provides a reconciliation of the numerator and denominator for the years presented:


	For the Year Ended
	December 31,
	2017	2018	2019
	RMB	RMB	RMB
Numerator:
Net (loss) / income attributable to ordinary shareholders	(184,662,871)	(349,027,476)	190,084,771

Denominator:
Weighted average number of ordinary shares outstanding	26,295,181	65,834,876	148,896,691
Weighted average number of ordinary shares equivalents outstanding	—	—	128,475

Denominator for basic net (loss) / income per ordinary share	26,295,181	65,834,876	149,025,166
Dilutive effect of outstanding share options	—	—	3,978,477
Dilutive effect of unvested restricted share units	—	—	244,545

Denominator for diluted net (loss) / income per ordinary share	26,295,181	65,834,876	153,248,188

Net (loss) / income per ordinary share
—Basic	(7.02)	(5.30)	1.28
—Diluted	(7.02)	(5.30)	1.24

Securities that could potentially dilute basic net (loss) / income per share in the future that were not included in the computation of diluted net (loss) / income per share because to do so would have been antidilutive for the years ended December 31, 2017, 2018 and 2019 are as follow:


	For the Year Ended
	December 31,
	2017	2018	2019
Share options	4,265,750	5,314,246	4,180,000
Unvested restricted share units	—	100,000	—
Restricted ordinary shares	32,689,010	—	—
Series Seed Preferred Shares	30,000,000	—	—
Series A Preferred Shares	25,278,350	—	—
Convertible loan	10,119,329	—	—

REVENUE INFORMATION

12 Months Ended

Dec. 31, 2019

REVENUE INFORMATION

REVENUE INFORMATION

21. REVENUE INFORMATION

Revenues consist of the following:


	For the Year Ended
	December 31,
	2017	2018	2019
	RMB	RMB	RMB
Electronic scooter sales	709,595,841	1,370,522,269	1,787,274,271
Accessory and spare parts sales	49,159,080	91,373,179	253,799,782
Service revenues	10,613,080	15,885,856	35,215,048
Revenues	769,368,001	1,477,781,304	2,076,289,101

The following summarizes the Group’s revenue from the following geographic areas (based on the location of customers):


	For the Year Ended
	December 31,
	2017	2018	2019
	RMB	RMB	RMB
PRC	731,423,647	1,318,657,227	1,643,221,531
Europe	36,257,165	148,963,330	274,445,360
Others	1,687,189	10,160,747	158,622,210
Revenues	769,368,001	1,477,781,304	2,076,289,101

COMMITMENTS AND CONTINGENCIES

12 Months Ended

Dec. 31, 2019

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES

22. COMMITMENTS AND CONTINGENCIES

The Group leases its offices and facilities under non-cancelable operating lease agreements. Rental expenses were RMB4,896,922, RMB7,306,686 and RMB10,931,713 for the years ended December 31, 2017, 2018 and 2019, respectively.

As of December 31, 2019, future minimum lease commitments, all under office and facilities non-cancelable operating lease agreements, were as follows:


Year ending December 31,		RMB
2020		11,817,396
2021		11,278,557
2022		10,131,766
2023		10,131,766
2024		10,131,766

Except for those disclosed above, the Group did not have any significant capital or other commitments, long-term obligations, or guarantees as of December 31, 2019.

RELATED PARTY TRANSACTIONS	12 Months Ended
RELATED PARTY TRANSACTIONS	Dec. 31, 2019
RELATED PARTY TRANSACTIONS
RELATED PARTY TRANSACTIONS	23. RELATED PARTY TRANSACTIONS Mr. Yi’nan Li, the founder and a board member of the Company until June 8, 2018 and Mr. Changlong Sheng, a shareholder of the Company, provide joint liability guaranty for the 2017 BOC Loan, the 2018 BOC Loan and the 2019 BOC Loan (Note 11) borrowed by Jiangsu Xiaoniu. The 2019 BOC Loan was fully repaid by Jiangsu Xiaoniu in December 2019 and the guaranty was released correspondingly.

SUBSEQUENT EVENTS	12 Months Ended
SUBSEQUENT EVENTS	Dec. 31, 2019
SUBSEQUENT EVENTS
SUBSEQUENT EVENTS	24. SUBSEQUENT EVENTS An outbreak of a new type of severe pneumonia caused by novel coronavirus (COVID-19) was found to be spreading from person to person and spread globally around the beginning of 2020. Chinese government has taken certain hygiene measures, which include restrictive measures that adversely affected and slowed down the economic development during the period. Due to the strict quarantine and avoid massing crowd policies, the Group has to reduce work in February and March in 2020 after the Chinese New Year holiday. The Group also suffered from shrinking market demand both from China and overseas markets as a result of the pandemic. Consequently, the COVID-19 outbreak will likely adversely affect the Group's business operations and its financial condition and operation results for the first quarter of 2020, including but not limited to material negative impact to the Group's total revenues and results of operations. However, given the uncertainty around the extent and timing of the potential future spread or mitigation of the COVID-19 and around the imposition or relaxation of protective measures, the Group cannot reasonably estimate the impact to its future results of operations, cash flows, or financial condition for the remainder of fiscal year 2020.

PARENT COMPANY ONLY CONDENSED FINANCIAL INFORMATION

12 Months Ended

Dec. 31, 2019

PARENT COMPANY ONLY CONDENSED FINANCIAL INFORMATION

PARENT COMPANY ONLY CONDENSED FINANCIAL INFORMATION

25. PARENT COMPANY ONLY CONDENSED FINANCIAL INFORMATION

For the presentation of the parent company only condensed financial information, the Company records its investment in subsidiaries, consolidated VIE and VIE’s subsidiaries, under the equity method of accounting as prescribed in ASC 323, “Investments-Equity Method and Joint Ventures”. Such investments are presented on the condensed balance sheets as “Investment in subsidiaries, consolidated VIE and VIE's subsidiaries” and the subsidiaries, consolidated VIE and VIE’s subsidiaries’ (losses) / income as “Share of (losses) / income from subsidiaries, consolidated VIE and VIE's subsidiaries” on the condensed statements of results of operations. The parent company only condensed financial information should be read in conjunction with the Company’s consolidated financial statements. As of December 31, 2019, there were no material contingencies, significant provisions of long-term obligations, mandatory dividend or redemption requirements of redeemable stocks or guarantees of Niu Technologies, except for those, which have been separately disclosed in the consolidated financial statements.

(a)

Condensed Balance Sheets


	As of December 31,
	2018	2019
	RMB	RMB
Assets
Current assets
Cash	149,901,311	120,548,511
Term deposits	27,452,663	174,404,554
Restricted cash	124,357,114	135,130,713
Prepayments and other current assets	3,707,403	7,705,862
Total current assets	305,418,491	437,789,640
Non-current assets
Investment in and amount due from subsidiaries, consolidated VIE and VIE’s subsidiaries	405,843,735	479,225,101
Total assets	711,262,226	917,014,741

Liabilities
Current liabilities
Amount due to subsidiaries, consolidated VIE and VIE’s subsidiaries	4,262,270	4,262,270
Accrued expenses and other current liabilities	7,593,082	451,354
Total current liabilities and total liabilities	11,855,352	4,713,624

Shareholders’ equity:
Class A ordinary shares	83,120	84,494
Class B ordinary shares	12,839	11,977
Additional paid-in capital	1,717,483,548	1,738,102,741
Accumulated other comprehensive loss	(25,394,429)	(13,895,942)
Accumulated deficit	(992,778,204)	(812,002,153)
Total shareholders’ equity	699,406,874	912,301,117
Total liabilities and shareholders’ equity	711,262,226	917,014,741

(b)

Condensed Statements of Results of Operations


	For the Year Ended December 31,
	2017	2018	2019
	RMB	RMB	RMB
Total operating expenses	3,029,256	(1,908,610)	(3,810,862)
Changes in fair value of a convertible loan	(43,006,399)	(34,499,858)	—
Share of (losses) / income from subsidiaries, consolidated VIE and VIE’s subsidiaries	(62,527,098)	(331,955,300)	174,142,290
Interest income	366,795	2,011,390	10,444,623
(Loss) / income before income taxes	(102,137,446)	(366,352,378)	180,776,051
Income tax expense	—	—	—
Net (loss) / income	(102,137,446)	(366,352,378)	180,776,051

(c)

Condensed Statements of Cash Flows


	For the Year Ended
	December 31,
	2017	2018	2019
	RMB	RMB	RMB
Net cash provided by / (used in) operating activities	79,113,690	(351,432,253)	124,118,382
Net cash used in investing activities	—	(19,902,073)	(144,813,597)
Net cash provided by / (used in) financing activities	—	481,123,035	(2,133,713)
Effect of foreign currency exchange rate changes on cash and restricted cash	(6,058,261)	7,176,014	4,249,727
Net increase in cash and restricted cash	73,055,429	116,964,723	(18,579,201)
Cash and restricted cash at the beginning of the year	84,238,273	157,293,702	274,258,425
Cash and restricted cash at the end of the year	157,293,702	274,258,425	255,679,224

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)

12 Months Ended

Dec. 31, 2019

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Basis of presentation

(a) Basis of presentation

The accompanying consolidated financial statements of the Group have been prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP").

Principles of consolidation

(b) Principles of consolidation

All intercompany transactions and balances among the Company, its subsidiaries, the VIE and the VIE’s subsidiaries have been eliminated upon consolidation.

Use of estimates

Convenience translation

(d) Convenience translation

Commitments and contingencies

(e) Commitments and contingencies

Cash

(f) Cash


	As of December 31,
	2018	2019
	RMB	RMB
Financial institutions in the mainland of the PRC
—Denominated in RMB	145,529,365	90,078,714
—Denominated in USD	155,583,394	178,359,872
Total cash balances held at mainland PRC financial institutions	301,112,759	268,438,586

Financial institutions in the United States
—Denominated in USD	4,038,742	3,523,116
Total cash balances held at the United States financial institutions	4,038,742	3,523,116

Financial institutions in the Hong Kong S.A.R.
—Denominated in USD	263,588,286	6,015,191

Total cash balances held at Hong Kong S.A.R. financial institutions	263,588,286	6,015,191

Financial institutions in Indonesia
—Denominated in USD	—	1,765,448
Total cash balances held at the Indonesia financial institutions	—	1,765,448
Total cash balances held at financial institutions	568,739,787	279,742,341

Term deposits

(g) Term deposits

Restricted cash

(h) Restricted cash

The impact of adoption on the consolidated statements of cash flows for the years ended December 31, 2017 and 2018 was as follows:


	For the Year Ended December 31,
	2017	2018
	RMB	RMB
Net cash provided by operating activities	—	789,751
Net cash provided by financing activities	66,288,600	—
Effect of foreign currency exchange rate changes on restricted cash	(7,391,400)	8,583,763
Net increase in cash and restricted cash	58,897,200	9,373,514


	As of December 31,
	2018	2019
	RMB	RMB
Cash	569,059,591	279,945,942
Restricted cash, current	179,262,714	221,656,071
Restricted cash, non-current	—	—
Total cash and restricted cash	748,322,305	501,602,013

Short-term investments

(i) Short-term investments

Inventories

(j) Inventories

Property, plant and equipment, net

(k) Property, plant and equipment, net

Property, plant and equipment are stated at cost less accumulated depreciation and any recorded impairment.

The estimated useful lives are as follows:


Building		50 years
Machinery and equipment		3 ~ 10 years
Furniture		3 years
Leasehold improvements		3 years
Office and electronic equipment		2 ~ 5 years
Motor vehicles		4 years

Depreciation on property, plant and equipment is calculated on the straight-line method over the estimated useful lives of the assets.

Intangible assets

(l) Intangible assets

Land use right, net

(m) Land use right, net

Impairment of long-lived assets

(n) Impairment of long-lived assets

Value added taxes

(o) Value added taxes

Fair value measurements

(p) Fair value measurements

Level 1—Observable inputs that reflect quoted prices (unadjusted) for identical assets or liabilities in active markets.

Level 2—Include other inputs that are directly or indirectly observable in the marketplace.

Level 3—Unobservable inputs which are supported by little or no market activity.

The Group’s non-financial assets, such as land use right, intangible assets and property, plant and equipment, would be measured at fair value only if they were determined to be impaired.

Revenue recognition

(q) Revenue recognition

Periods prior to January 1, 2019

For some sales, the Group collects cash before delivery. Cash collected before product delivery is recognized as advances from customers.

Period commencing January 1, 2019

The adoption of new revenue standard did not impact accumulated deficit as of January 1, 2019. The Group has updated significant accounting policies and relevant disclosures hereinafter.

Products

For some sales, the Group collects cash before delivery. Cash collected before product delivery is recognized as advances from customers.

Service

The deferred revenue that will be recognized in the next twelve months is classified as current portion, and the remaining balance of deferred revenue is classified as non-current portion.

Remaining performance obligations

Contract Balances

(r) Contract Balances


			Amounts
			without
	As of		adoption of
	December 31, 2019	Adjustments	ASC 606
Advances from customers	7,478,309	497,004	7,975,313
Accrued expenses and other current liabilities	175,533,397	(497,004)	175,036,393

Changes in the Group's contract liabilities (advances from customers and deferred revenue) are presented in the following table for the year ended December 31, 2019:


		For the Year Ended
		December 31, 2019
Contract liabilities as of January 1, 2019 prior to adoption of ASC 606		33,406,992
Reclassification of VAT payable to Accrued expenses and other liabilities as of January 1, 2019 as a result of adoption of ASC 606		(2,348,375)
Cash received in advance, excluding VAT		1,967,468,291
Revenue recognized from opening balance of contract liabilities		(30,823,816)
Revenue recognized from contract liabilities arising during current year		(1,926,948,050)
Contract liabilities as of December 31, 2019		40,755,042

Warranties

(s) Warranties

Cost of Revenues

(t) Cost of Revenues

Cost of revenues mainly consists of the cost of products sold, write-downs of inventories, logistics costs and warranty costs.

Selling and Marketing Expenses

(u) Selling and Marketing Expenses

General and Administrative Expenses

(v) General and Administrative Expenses

Research and Development Expenses

(w) Research and Development Expenses

Government Grants

(x) Government Grants

Share-based Compensation

(y) Share-based Compensation

The Company periodically grants share-based awards, including but not limited to, restricted ordinary shares, restricted share units and share options to eligible employees and directors.

Employee Benefits

(z) Employee Benefits

Income Taxes

(aa) Income Taxes

Operating leases

(bb) Operating leases

Foreign currency translation and foreign currency risks

(cc) Foreign currency translation and foreign currency risks

Concentration and risk

(dd) Concentration and risk

Concentration of customers and suppliers

No customers individually represent greater than 10% of total revenues of the Group for the years ended December 31, 2017, 2018 and 2019.

Suppliers from whom individually represent greater than 10% of total purchases of the Group for the years ended December 31, 2017, 2018 and 2019, are as follows:


	For the Year ended December 31,
	2017			2018			2019
	RMB	%		RMB	%		RMB	%
Supplier F	*	*		193,555,999	15	%	225,527,597	15	%
Supplier A	187,065,077	21	%	150,385,652	12	%	173,723,118	11	%
Supplier B	152,966,930	18	%	*	*		*	*

Customers accounting for 10% or more of accounts receivable, net are as follows:


	As of December 31,
	2018			2019
	RMB	%		RMB	%
Customer Y	45,980,177	84	%	*	*
Customer R	*	*		46,263,295	40	%

Customers accounting for 10% or more of advances from customers are as follows:


	As of December 31,
	2018		2019
	RMB	%	RMB	%
Customer U	*	*	1,090,262	15	%
Customer W	*	*	767,993	10	%

Suppliers accounting for 10% or more of accounts payable are as follows:


	As of December 31,
	2018			2019
	RMB	%		RMB	%
Supplier E	26,483,893	11	%	*	*
Supplier F	25,702,037	10	%	26,134,706	10	%

The amount was less than 10% of total balance.

Concentration of credit risk

Interest rate risk

The Group’s short-term bank borrowing bears interests at fixed rates. If the Group were to renew these loans, the Group might be subject to interest rate risk.

Earnings / (Loss) per Share

(ee) Earnings / (Loss) per Share

Segment Reporting

(ff) Segment Reporting

Statutory Reserves

(gg) Statutory Reserves

For the years ended December 31, 2017, 2018 and 2019, the Group's PRC subsidiaries made appropriations to the statutory reserves of nil, nil and RMB3,316,650 respectively.

Recent Accounting Pronouncements

(hh) Recent Accounting Pronouncements

DESCRIPTION OF ORGANIZATION AND PRINCIPAL ACTIVITIES (Tables)

12 Months Ended

Dec. 31, 2019

DESCRIPTION OF ORGANIZATION AND PRINCIPAL ACTIVITIES

Schedule of Group's VIE information


	As of December 31,
	2018	2019
	RMB	RMB
Cash	90,723,253	93,548,349
Short-term investments	120,241,425	310,439,321
Accounts receivable, net	54,424,845	115,228,700
Inventories	142,155,411	178,476,473
Prepayments and other current assets	22,711,514	18,613,814
Amounts due from intercompany	4,262,270	4,303,778
Total current assets	434,518,718	720,610,435

Property, plant and equipment, net	40,580,352	148,937,701
Intangible assets, net	580,667	1,962,530
Land use right, net	—	34,355,936
Other non-current assets	16,805,475	5,961,241
Total assets	492,485,212	911,827,843

Short-term bank borrowings	179,978,003	217,394,132
Accounts payable	249,665,890	258,988,264
Amounts due to intercompany	211,250,230	306,137,760
Advances from customers	20,505,861	7,478,309
Deferred revenue—current	12,666,330	31,105,700
Accrued expenses and other current liabilities	119,242,975	164,442,316
Income taxes payable	—	3,013,805
Total current liabilities	793,309,289	988,560,286
Deferred revenue—non current	234,801	2,171,033
Deferred income tax liability	—	1,265,780
Other non-current liabilities	17,609,842	22,358,968
Total liabilities	811,153,932	1,014,356,067


	For the Year Ended December 31,
	2017	2018	2019
	RMB	RMB	RMB
Revenues	769,368,001	1,477,593,628	2,115,501,618
Net (loss) / income	(145,154,084)	(294,156,973)	196,473,033
Net cash (used in) / provided by operating activities	(2,423,156)	14,379,166	284,907,333
Net cash used in investing activities	(55,928,949)	(74,333,070)	(319,696,832)
Net cash provided by financing activities	68,703,310	78,199,492	37,416,129
Effect of foreign currency exchange rate changes on cash	(813,270)	684,791	198,466
Net increase in cash	9,537,935	18,930,379	2,825,096
Cash at the beginning of the year	62,254,939	71,792,874	90,723,253
Cash at the end of the year	71,792,874	90,723,253	93,548,349

- Definition

Tabular disclosure of the significant judgments and assumptions made in determining whether a variable interest (as defined) held by the entity requires the variable interest entity (VIE) (as defined) to be consolidated and (or) disclose information about its involvement with the VIE, individually or in aggregate (as applicable); the nature of restrictions, if any, on the consolidated VIE's assets and on the settlement of its liabilities reported by an entity in its statement of financial position, including the carrying amounts of such assets and liabilities; the nature of, and changes in, the risks associated with involvement in the VIE; how involvement with the VIE affects the entity's financial position, financial performance, and cash flows; the lack of recourse if creditors (or beneficial interest holders) of the consolidated VIE have no recourse to the general credit of the primary beneficiary (if applicable); the terms of arrangements, giving consideration to both explicit arrangements and implicit variable interests, if any, that could require the entity to provide financial support to the VIE, including events or circumstances that could expose the entity to a loss; the methodology used by the entity for determining whether or not it is the primary beneficiary of the variable interest entity; the significant factors considered and judgments made in determining that the power to direct the activities of a VIE that most significantly impact the VIE's economic performance are shared (as defined); the carrying amounts and classification of assets and liabilities of the VIE included in the statement of financial position; the entity's maximum exposure to loss, if any, as a result of its involvement with the VIE, including how the maximum exposure is determined and significant sources of the entity's exposure to the VIE; a comparison of the carrying amounts of the assets and liabilities and the entity's maximum exposure to loss; information about any liquidity arrangements, guarantees, and (or) other commitments by third parties that may affect the fair value or risk of the entity's variable interest in the VIE; whether or not the entity has provided financial support or other support (explicitly or implicitly) to the VIE that it was not previously contractually required to provide or whether the entity intends to provide that support, including the type and amount of the support and the primary reasons for providing the support; and supplemental information the entity determines necessary to provide.

+ References + Details

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)

12 Months Ended

Dec. 31, 2019

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

Summary of impact of adoption on the consolidated statements


			Amounts
			without
	As of		adoption of
	December 31, 2019	Adjustments	ASC 606
Advances from customers	7,478,309	497,004	7,975,313
Accrued expenses and other current liabilities	175,533,397	(497,004)	175,036,393

Summary of reconciliation of cash and restricted cash reported within the consolidated balance sheets that sum to the total of the same such amounts shown in the consolidated statements of cash flows


	As of December 31,
	2018	2019
	RMB	RMB
Cash	569,059,591	279,945,942
Restricted cash, current	179,262,714	221,656,071
Restricted cash, non-current	—	—
Total cash and restricted cash	748,322,305	501,602,013

Schedule of cash at bank and term deposits are deposited in financial institutions


	As of December 31,
	2018	2019
	RMB	RMB
Financial institutions in the mainland of the PRC
—Denominated in RMB	145,529,365	90,078,714
—Denominated in USD	155,583,394	178,359,872
Total cash balances held at mainland PRC financial institutions	301,112,759	268,438,586

Financial institutions in the United States
—Denominated in USD	4,038,742	3,523,116
Total cash balances held at the United States financial institutions	4,038,742	3,523,116

Financial institutions in the Hong Kong S.A.R.
—Denominated in USD	263,588,286	6,015,191

Total cash balances held at Hong Kong S.A.R. financial institutions	263,588,286	6,015,191

Financial institutions in Indonesia
—Denominated in USD	—	1,765,448
Total cash balances held at the Indonesia financial institutions	—	1,765,448
Total cash balances held at financial institutions	568,739,787	279,742,341

Schedule of estimated useful lives of property and equipment


Building		50 years
Machinery and equipment		3 ~ 10 years
Furniture		3 years
Leasehold improvements		3 years
Office and electronic equipment		2 ~ 5 years
Motor vehicles		4 years

Summary of changes in the contract liabilities (advances from customers and deferred revenue)


		For the Year Ended
		December 31, 2019
Contract liabilities as of January 1, 2019 prior to adoption of ASC 606		33,406,992
Reclassification of VAT payable to Accrued expenses and other liabilities as of January 1, 2019 as a result of adoption of ASC 606		(2,348,375)
Cash received in advance, excluding VAT		1,967,468,291
Revenue recognized from opening balance of contract liabilities		(30,823,816)
Revenue recognized from contract liabilities arising during current year		(1,926,948,050)
Contract liabilities as of December 31, 2019		40,755,042

Schedule of concentration of customers and suppliers


	For the Year ended December 31,
	2017			2018			2019
	RMB	%		RMB	%		RMB	%
Supplier F	*	*		193,555,999	15	%	225,527,597	15	%
Supplier A	187,065,077	21	%	150,385,652	12	%	173,723,118	11	%
Supplier B	152,966,930	18	%	*	*		*	*

Customers accounting for 10% or more of accounts receivable, net are as follows:


	As of December 31,
	2018			2019
	RMB	%		RMB	%
Customer Y	45,980,177	84	%	*	*
Customer R	*	*		46,263,295	40	%

Customers accounting for 10% or more of advances from customers are as follows:


	As of December 31,
	2018		2019
	RMB	%	RMB	%
Customer U	*	*	1,090,262	15	%
Customer W	*	*	767,993	10	%

Suppliers accounting for 10% or more of accounts payable are as follows:


	As of December 31,
	2018			2019
	RMB	%		RMB	%
Supplier E	26,483,893	11	%	*	*
Supplier F	25,702,037	10	%	26,134,706	10	%

The amount was less than 10% of total balance.

2016-18

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

Summary of impact of adoption on the consolidated statements


	For the Year Ended December 31,
	2017	2018
	RMB	RMB
Net cash provided by operating activities	—	789,751
Net cash provided by financing activities	66,288,600	—
Effect of foreign currency exchange rate changes on restricted cash	(7,391,400)	8,583,763
Net increase in cash and restricted cash	58,897,200	9,373,514

SHORT-TERM INVESTMENTS (Tables)

12 Months Ended

Dec. 31, 2019

SHORT-TERM INVESTMENTS

Schedule of short-term investments


	As of December 31,
	2018	2019
	RMB	RMB
Aggregate cost basis	120,000,000	308,150,000
Gross unrealized holding gain	241,425	2,289,321
Aggregate fair value	120,241,425	310,439,321

ACCOUNTS RECEIVABLES, NET (Tables)

12 Months Ended

Dec. 31, 2019

ACCOUNTS RECEIVABLES, NET

Schedule of accounts receivables, net


	As of December 31,
	2018	2019
	RMB	RMB
Accounts receivable	54,652,991	118,517,235
Allowance for doubtful accounts	(228,146)	(3,288,535)
Accounts receivable, net	54,424,845	115,228,700

Schedule of movement of the allowance for doubtful accounts


	For the Year Ended
	December 31,
	2017	2018	2019
	RMB	RMB	RMB
Balance at the beginning of the year	47,846	1,956,245	228,146
Additions / (reversals) charged to bad debt expense	1,908,399	(1,215,464)	3,060,389
Write-off of bad debt allowance	—	(512,635)	—
Balance at the end of the year	1,956,245	228,146	3,288,535

INVENTORIES (Tables)

12 Months Ended

Dec. 31, 2019

INVENTORIES

Schedule of inventories


	As of December 31,
	2018	2019
	RMB	RMB
Raw materials	120,290,456	151,975,367
Works in progress	1,948,838	1,481,938
Finished goods	20,142,911	25,175,994
Inventories	142,382,205	178,633,299

PREPAYMENTS AND OTHER CURRENT ASSETS (Tables)

12 Months Ended

Dec. 31, 2019

PREPAYMENTS AND OTHER CURRENT ASSETS

Schedule of prepayments and other current assets


	As of December 31,
	2018	2019
	RMB	RMB
Advances to suppliers	15,507,866	11,124,716
Deductible input VAT and VAT rebates receivable	7,855,998	8,678,443
Staff advances	447,791	514,328
Interest receivable	659,194	5,369,826
Others*	2,449,105	5,294,818
Prepayments and other current assets	26,919,954	30,982,131

Others mainly include deposits receivable.

PROPERTY, PLANT AND EQUIPMENT, NET (Tables)

12 Months Ended

Dec. 31, 2019

PROPERTY, PLANT AND EQUIPMENT, NET

Schedule of property and equipment


	As of December 31,
	2018	2019
	RMB	RMB
Machinery and equipment	22,615,657	47,307,840
Furniture	36,630,720	76,258,884
Office and electronic equipment	9,071,471	16,909,504
Leasehold improvement	2,116,266	4,081,766
Motor vehicles	802,251	1,173,634
Building and building improvements	—	64,887,245
Property, plant and equipment	71,236,365	210,618,873
Less: Accumulated depreciation	(30,251,191)	(59,727,529)
Property, plant and equipment, net	40,985,174	150,891,344

Schedule of depreciation expense on property and equipment allocated to expense items


	For the Year ended December 31,
	2017	2018	2019
	RMB	RMB	RMB
Cost of revenues	4,217,126	4,638,662	6,109,583
General and administrative expenses	1,873,711	2,261,620	3,403,502
Selling and marketing expenses	2,646,204	9,438,501	19,025,624
Research and development expenses	312,728	470,204	962,414
Total depreciation expense	9,049,769	16,808,987	29,501,123

INTANGIBLE ASSETS, NET (Tables)

12 Months Ended

Dec. 31, 2019

INTANGIBLE ASSETS, NET

Schedule of intangible assets


	As of December 31, 2018
		Gross		Net
	Amortization	carrying	Accumulated	carrying
RMB	period	amount	amortization	amount
Trademarks	5 years	8,564,505	(1,427,418)	7,137,087
Domain name	5 years	3,484,000	(2,903,333)	580,667
Total		12,048,505	(4,330,751)	7,717,754


	As of December 31, 2019
		Gross		Net
	Amortization	carrying	Accumulated	carrying
RMB	period	amount	amortization	amount
Trademarks	5-10 years	8,911,271	(3,193,738)	5,717,533
Domain name	5-10 years	3,821,474	(3,517,748)	303,726
License	10 years	1,943,396	(184,906)	1,758,490
Total		14,676,141	(6,896,392)	7,779,749

Summary of amortization expenses on intangible assets

Amortization expense on intangible assets was allocated to the following expense items:


	For the Year ended December 31,
	2017	2018	2019
	RMB	RMB	RMB
Cost of revenues	—	—	184,906
General and administrative expenses	696,800	2,072,389	2,336,803

Total amortization expense	696,800	2,072,389	2,521,709

LAND USE RIGHT, NET (Tables)

12 Months Ended

Dec. 31, 2019

LAND USE RIGHT, NET

Summary of land use right, net


	As of December 31,
	2018	2019
	RMB	RMB
Gross carrying amount	—	34,761,487
Less: Accumulated amortization	—	(405,551)

Land use right, net	—	34,355,936

OTHER NON-CURRENT ASSETS (Tables)

12 Months Ended

Dec. 31, 2019

OTHER NON-CURRENT ASSETS

Schedule of other non-current assets


	As of December 31,
	2018	2019
	RMB	RMB
Prepayments for land use right	10,000,000	—
Others*	6,805,474	6,522,561

Other non-current assets	16,805,474	6,522,561

Others mainly include deposits and prepayments for equipment and intangible assets.

SHORT-TERM BANK BORROWINGS AND RESTRICTED CASH (Tables)

12 Months Ended

Dec. 31, 2019

SHORT-TERM BANK BORROWINGS AND RESTRICTED CASH

Schedule of short-term bank borrowings


	As of December 31,
	2018	2019
	RMB	RMB
East West Bank loan	99,978,003	48,910,799
Bank of China loan	20,000,000	20,000,000
SPD Silicon Valley Bank loan	60,000,000	120,000,000
Bank of Ningbo loan	—	28,483,333
Short-term bank borrowings	179,978,003	217,394,132

ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES (Tables)

12 Months Ended

Dec. 31, 2019

ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES

Schedule of accrued expenses and other current liabilities


	As of December 31,
	2018	2019
	RMB	RMB
Accrued payroll and social insurance	32,008,825	30,780,693
Warranty—current	31,262,442	41,809,564
Sales rebate	34,029,433	40,344,717
Construction payable	—	18,765,855
Deposits	16,360,762	16,293,035
Deferred ADR income	4,250,126	—
Other taxes payable	3,656,732	10,273,637
IPO cost payable	3,130,639	—
Interest payable	318,774	2,010,366
Others*	9,166,293	15,255,530
Accrued expenses and other current liabilities	134,184,026	175,533,397

* Others mainly include employee options payable and accrued marketing expenses.

Schedule of movement of provision for warranty


	For the Year ended December 31,
	2017	2018	2019
Accrued warranty—beginning of year	17,649,411	30,648,678	48,872,284
Accrual for warranties issued during the year	27,395,169	29,346,974	40,271,444
Warranty claims paid	(14,395,902)	(7,923,760)	(22,132,194)
Pre-existing warranty expired	—	(3,199,608)	(7,059,668)
Accrued warranty—end of year	30,648,678	48,872,284	59,951,866

OTHER NON-CURRENT LIABILITIES (Tables)

12 Months Ended

Dec. 31, 2019

OTHER NON-CURRENT LIABILITIES

Summary of other non-current liabilities


	As of December 31,
	2018	2019
	RMB	RMB
Warranty—non-current	17,609,842	18,142,302
Deposits for construction of building —non-current	—	4,216,666

Other non-current liabilities	17,609,842	22,358,968

REDEEMABLE CONVERTIBLE PREFERRED SHARES (Tables)

12 Months Ended

Dec. 31, 2019

REDEEMABLE CONVERTIBLE PREFERRED SHARES

Schedule of redeemable convertible preferred shares activities


			Series A-2	Series A-3	Series B
			Preferred	Preferred	Preferred
	Series A-1 Preferred Shares		Shares	Shares	Shares
	Carrying	Subscription	Carrying	Carrying	Carrying
RMB	amount	receivable	amount	amount	amount	Total
Balance as of January 1, 2017	138,740,003	—	41,621,992	72,144,418	—	252,506,413
Foreign currency translation adjustment	(8,056,000)	—	(2,416,800)	(4,189,098)	—	(14,661,898)
Balance as of December 31, 2017	130,684,003	—	39,205,192	67,955,320	—	237,844,515
Issuance of preferred shares	—	—	—	181,112,874	161,392,196	342,505,070
Foreign currency translation adjustment	8,090,000	—	2,427,000	21,651,035	15,544,654	47,712,689
Conversion to Ordinary Shares	(138,774,003)	—	(41,632,192)	(270,719,229)	(176,936,850)	(628,062,274)
Balance as of December 31, 2018 and 2019	—	—	—	—	—	—

SHARE-BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2019

Restricted ordinary shares

SHARE-BASED COMPENSATION

Schedule of share-based compensation expenses recognized


	For the year ended
	December 31,
	2017	2018
	RMB	RMB
Research and development expenses	13,045,853	18,371,203
General and administrative expenses	46,185,090	207,871,076
Total restricted ordinary shares compensation expense	59,230,943	226,242,279

Unvested restricted share units

SHARE-BASED COMPENSATION

Summary of the restricted share units activities


	For the year ended
	December 31,
	2018	2019
	RMB	RMB
Cost of revenues	—	36,332
Selling and marketing expenses	—	2,185,586
Research and development expenses	—	1,146,846
General and administrative expenses	375,123	4,233,758
Total share option compensation expense	375,123	7,602,522

Amended 2016 Plan

SHARE-BASED COMPENSATION

Summary of the share options activities


			Weighted
		Weighted	remaining
	Number of	average exercise	contractual	Aggregate
	share	price	years	intrinsic value
		US$		US$
Outstanding at January 1, 2019	5,314,246	0.17
Granted	4,180,000	3.43
Exercised	(742,840)	0.19
Forfeited	(69,050)	0.20
Outstanding at December 31, 2019	8,682,356	1.74	8.18	21,950,316
Exercisable as of December 31, 2019	2,387,959	0.19	6.44	9,738,313

Schedule of stock option valuation allowance using the binomial option pricing model


Grant Date:	2017	2018	2019
Risk-free rate of return (per annum)	2.25% - 2.48%	2.78%-3.13%	1.90%
Volatility	51.7% - 54.4%	49.9%-50.9%	47.9%
Expected dividend yield	0%	0%	0%
Exercise multiple	2.2	2.2	2.2-2.8
Fair value of underlying ordinary share	US$0.44 - US$1.22	US$2.05 - US$4.10	US$3.425
Expected term (in years)	10	10	10

Schedule of share-based compensation expenses recognized


	For the year ended
	December 31,
	2017	2018	2019
	RMB	RMB	RMB
Cost of revenues	253,545	246,947	255,679
Selling and marketing expenses	1,611,160	2,124,728	2,471,725
Research and development expenses	832,782	955,538	3,060,263
General and administrative expenses	598,668	2,392,740	6,232,590
Total share option compensation expense	3,296,155	5,719,953	12,020,257

Amended 2016 Plan | Restricted ordinary shares

SHARE-BASED COMPENSATION

Summary of the restricted share units activities


		Weighted
		average grant
	Number of	date fair
	shares	value
		US$
Unvested as of January 1, 2019	100,000	4.33
Granted	1,694,600	3.62
Vested	(50,000)	4.33
Forfeited	—	—
Unvested as of December 31, 2019	1,744,600	3.64

2018 Plan

SHARE-BASED COMPENSATION

Schedule of share-based compensation expenses recognized


	For the year ended December 31,
	2017	2018	2019
	RMB	RMB	RMB
Cost of revenues	253,545	246,947	292,011
Selling and marketing expenses	1,611,160	2,124,728	4,657,311
Research and development expenses	13,878,635	52,864,313	4,207,109
General and administrative expenses	46,783,758	210,638,939	10,466,348
Total share-based compensation expense	62,527,098	265,874,927	19,622,779

FAIR VALUE MEASUREMENT (Tables)

12 Months Ended

Dec. 31, 2019

FAIR VALUE MEASUREMENT

Schedule of fair value hierarchy for assets and liabilities measured at fair value on recurring basis


	December 31, 2019			Total
RMB	Level 1	Level 2	Level 3	Fair Value
Assets
Short-term investments (Note 3)	—	310,439,321	—	310,439,321


	December 31, 2018			Total
RMB	Level 1	Level 2	Level 3	Fair Value
Assets
Short-term investments (Note 3)	—	120,241,425	—	120,241,425

Schedule of reconciliation of recurring fair value measurements categorized as Level 3


	For the Year Ended December 31,
	2017	2018
Convertible loan - beginning of year	116,728,899	151,557,796
Change in fair value	43,006,399	34,499,858
Conversion to Series A-3 Preferred Shares	—	(181,112,874)
Foreign currency translation adjustment	(8,177,502)	(4,944,780)
Convertible loan - end of year	151,557,796	—

INCOME TAX (Tables)

12 Months Ended

Dec. 31, 2019

INCOME TAX

Components of (loss)/income before income taxes


	For the Year Ended
	December 31,
	2017	2018	2019
	RMB	RMB	RMB
Cayman	(39,610,348)	(34,397,077)	6,633,761
Indonesia	—	—	(11,705)
Hong Kong S.A.R.	219,935	(4,507,360)	(3,820,485)
PRC, excluding Hong Kong S.A.R.	(145,272,458)	(310,123,039)	195,497,541
Total	(184,662,871)	(349,027,476)	198,299,112

Schedule of reconciliation of statutory income tax rate and effective income tax rate


	For the Year Ended
	December 31,
	2017	2018	2019
	RMB	RMB	RMB
Computed expected income tax expense	(46,165,718)	(87,256,869)	49,574,778
Non-PRC entities not subject to income tax	9,847,603	9,726,109	(700,393)
Research and development expenses bonus deduction	(1,032,177)	(7,528,081)	(10,181,598)
Non-deductible share-based compensation expenses	15,631,775	66,374,951	4,532,885
Other non-deductible expenses	358,759	176,111	32,602
Expiration of loss carry forwards	—	—	304,194
Change in valuation allowance	21,359,758	18,507,779	(35,348,127)
Actual income tax expense	—	—	8,214,341

Schedule of deferred income tax assets and deferred income tax liabilities


	As of December 31,
	2018	2019
	RMB	RMB
Deferred income tax assets
Net operating loss carry forwards	74,657,570	39,342,952
Accrued warranty	12,218,071	14,987,967
Accrued payroll and social insurance	5,099,295	3,873,748
Deferred revenue	3,225,283	6,363,254
Advertising expense	2,955,152	937,639
Allowance for doubtful accounts	57,037	822,134
Write-downs for inventories	—	2,622,784
Less: Valuation allowance	(98,212,408)	(62,864,281)

Total deferred income tax assets, net	—	6,086,197


Deferred income tax liabilities
Short-term investments	—	511,975
Property, plant and equipment	—	6,840,002

Total deferred income tax liabilities	—	7,351,977
Net deferred income tax assets	—	—
Net deferred income tax liabilities	—	1,265,780

Schedule of changes in valuation allowance


	For the Year Ended
	December 31,
	2017	2018	2019
	RMB	RMB	RMB
Balance at the beginning of the year	58,344,871	79,704,629	98,212,408
Additions / (reversals)	21,359,758	18,507,779	(35,348,127)
Balance at the end of the year	79,704,629	98,212,408	62,864,281

NET (LOSS)/INCOME PER ORDINARY SHARE (Tables)

12 Months Ended

Dec. 31, 2019

NET (LOSS)/INCOME PER ORDINARY SHARE

Schedule of basic and diluted net loss per share computation

The following table sets forth the basic and diluted net (loss) / income per ordinary share computation and provides a reconciliation of the numerator and denominator for the years presented:


	For the Year Ended
	December 31,
	2017	2018	2019
	RMB	RMB	RMB
Numerator:
Net (loss) / income attributable to ordinary shareholders	(184,662,871)	(349,027,476)	190,084,771

Denominator:
Weighted average number of ordinary shares outstanding	26,295,181	65,834,876	148,896,691
Weighted average number of ordinary shares equivalents outstanding	—	—	128,475

Denominator for basic net (loss) / income per ordinary share	26,295,181	65,834,876	149,025,166
Dilutive effect of outstanding share options	—	—	3,978,477
Dilutive effect of unvested restricted share units	—	—	244,545

Denominator for diluted net (loss) / income per ordinary share	26,295,181	65,834,876	153,248,188

Net (loss) / income per ordinary share
—Basic	(7.02)	(5.30)	1.28
—Diluted	(7.02)	(5.30)	1.24

Schedule of antidilutive securities


	For the Year Ended
	December 31,
	2017	2018	2019
Share options	4,265,750	5,314,246	4,180,000
Unvested restricted share units	—	100,000	—
Restricted ordinary shares	32,689,010	—	—
Series Seed Preferred Shares	30,000,000	—	—
Series A Preferred Shares	25,278,350	—	—
Convertible loan	10,119,329	—	—

REVENUE INFORMATION (Tables)

12 Months Ended

Dec. 31, 2019

REVENUE INFORMATION

Schedule of net revenues


	For the Year Ended
	December 31,
	2017	2018	2019
	RMB	RMB	RMB
Electronic scooter sales	709,595,841	1,370,522,269	1,787,274,271
Accessory and spare parts sales	49,159,080	91,373,179	253,799,782
Service revenues	10,613,080	15,885,856	35,215,048
Revenues	769,368,001	1,477,781,304	2,076,289,101

Schedule of the Group's revenue based on geographic areas


	For the Year Ended
	December 31,
	2017	2018	2019
	RMB	RMB	RMB
PRC	731,423,647	1,318,657,227	1,643,221,531
Europe	36,257,165	148,963,330	274,445,360
Others	1,687,189	10,160,747	158,622,210
Revenues	769,368,001	1,477,781,304	2,076,289,101

COMMITMENTS AND CONTINGENCIES (Tables)

12 Months Ended

Dec. 31, 2019

COMMITMENTS AND CONTINGENCIES

Schedule of future minimum lease commitments


Year ending December 31,		RMB
2020		11,817,396
2021		11,278,557
2022		10,131,766
2023		10,131,766
2024		10,131,766

PARENT COMPANY ONLY CONDENSED FINANCIAL INFORMATION (Tables)

12 Months Ended

Dec. 31, 2019

PARENT COMPANY ONLY CONDENSED FINANCIAL INFORMATION

Schedule of condensed balance sheets


	As of December 31,
	2018	2019
	RMB	RMB
Assets
Current assets
Cash	149,901,311	120,548,511
Term deposits	27,452,663	174,404,554
Restricted cash	124,357,114	135,130,713
Prepayments and other current assets	3,707,403	7,705,862
Total current assets	305,418,491	437,789,640
Non-current assets
Investment in and amount due from subsidiaries, consolidated VIE and VIE’s subsidiaries	405,843,735	479,225,101
Total assets	711,262,226	917,014,741

Liabilities
Current liabilities
Amount due to subsidiaries, consolidated VIE and VIE’s subsidiaries	4,262,270	4,262,270
Accrued expenses and other current liabilities	7,593,082	451,354
Total current liabilities and total liabilities	11,855,352	4,713,624

Shareholders’ equity:
Class A ordinary shares	83,120	84,494
Class B ordinary shares	12,839	11,977
Additional paid-in capital	1,717,483,548	1,738,102,741
Accumulated other comprehensive loss	(25,394,429)	(13,895,942)
Accumulated deficit	(992,778,204)	(812,002,153)
Total shareholders’ equity	699,406,874	912,301,117
Total liabilities and shareholders’ equity	711,262,226	917,014,741

Schedule of condensed statements of results of operations


	For the Year Ended December 31,
	2017	2018	2019
	RMB	RMB	RMB
Total operating expenses	3,029,256	(1,908,610)	(3,810,862)
Changes in fair value of a convertible loan	(43,006,399)	(34,499,858)	—
Share of (losses) / income from subsidiaries, consolidated VIE and VIE’s subsidiaries	(62,527,098)	(331,955,300)	174,142,290
Interest income	366,795	2,011,390	10,444,623
(Loss) / income before income taxes	(102,137,446)	(366,352,378)	180,776,051
Income tax expense	—	—	—
Net (loss) / income	(102,137,446)	(366,352,378)	180,776,051

Schedule of condensed statements of cash flows


	For the Year Ended
	December 31,
	2017	2018	2019
	RMB	RMB	RMB
Net cash provided by / (used in) operating activities	79,113,690	(351,432,253)	124,118,382
Net cash used in investing activities	—	(19,902,073)	(144,813,597)
Net cash provided by / (used in) financing activities	—	481,123,035	(2,133,713)
Effect of foreign currency exchange rate changes on cash and restricted cash	(6,058,261)	7,176,014	4,249,727
Net increase in cash and restricted cash	73,055,429	116,964,723	(18,579,201)
Cash and restricted cash at the beginning of the year	84,238,273	157,293,702	274,258,425
Cash and restricted cash at the end of the year	157,293,702	274,258,425	255,679,224

DESCRIPTION OF ORGANIZATION AND PRINCIPAL ACTIVITIES - Principal terms of VIE Agreements (Details)	12 Months Ended
	Dec. 31, 2019 CNY (¥)
DESCRIPTION OF ORGANIZATION AND PRINCIPAL ACTIVITIES
Percentage of monthly net profits under Exclusive Business Cooperation Agreement	100.00%
Maximum equity holders' interests permitted under Exclusive Option Agreement	¥ 100
Minimum value of material assets for dispositions under Exclusive Option Agreement	¥ 100,000

DESCRIPTION OF ORGANIZATION AND PRINCIPAL ACTIVITIES - Group's VIE information (Details)	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2019 CNY (¥)
Group's VIE information
Cash	$ 40,211,719		¥ 569,059,591		¥ 279,945,942
Short-term investments	44,591,818		120,241,425		310,439,321
Accounts receivable, net	16,551,567		54,424,845		115,228,700
Inventories	25,659,068		142,382,205		178,633,299
Prepayments and other current assets	4,450,305		26,919,954		30,982,131
Total current assets	188,355,026		1,119,743,397		1,311,290,018
Property, plant and equipment, net	21,674,185		40,985,174		150,891,344
Intangible assets, net	1,117,491		7,717,754		7,779,749
Land use right, net	4,934,921				34,355,936
Other non-current assets	936,907		16,805,474		6,522,561
Total assets	217,018,530		1,185,251,799		1,510,839,608
Short-term bank borrowings	31,226,713		179,978,003		217,394,132
Accounts payable	37,201,336		249,665,890		258,988,264
Advances from customers	1,074,192		20,505,861		7,478,309
Deferred revenue - current	4,468,054		12,666,330		31,105,700
Accrued expenses and other current liabilities	25,213,795		134,184,026		175,533,397
Income taxes payable	432,906				3,013,805
Total current liabilities	99,616,996		597,000,110		693,513,607
Deferred revenue - non current	311,849		234,801		2,171,033
Deferred income tax liability	181,818				1,265,780
Other non-current liabilities	3,211,665		17,609,842		22,358,968
Total liabilities	103,322,328		614,844,753		719,309,388
Revenues	298,240,268	¥ 2,076,289,101	1,477,781,304	¥ 769,368,001
Net (loss) / income	27,303,970	190,084,771	(349,027,476)	(184,662,871)
Net cash (used in) / provided by operating activities	25,665,838	178,680,435	8,569,117	80,063,278
Net cash used in investing activities	(67,208,085)	(467,889,241)	(103,589,651)	(55,928,949)
Net cash provided by financing activities	5,068,001	35,282,416	555,382,588	68,703,310
Effect of foreign currency exchange rate changes on cash	1,035,094	7,206,098	6,074,726	(13,064,824)
Net increase in cash	(35,439,152)	(246,720,292)	466,436,780	79,772,815
Cash and restricted cash at the beginning of the year	107,489,773	748,322,305	281,885,525	202,112,710
Cash and restricted cash at the end of the year	$ 72,050,621	501,602,013	748,322,305	281,885,525
VIE
Group's VIE information
Cash			90,723,253		93,548,349
Short-term investments			120,241,425		310,439,321
Accounts receivable, net			54,424,845		115,228,700
Inventories			142,155,411		178,476,473
Prepayments and other current assets			22,711,514		18,613,814
Amounts due from intercompany			4,262,270		4,303,778
Total current assets			434,518,718		720,610,435
Property, plant and equipment, net			40,580,352		148,937,701
Intangible assets, net			580,667		1,962,530
Land use right, net					34,355,936
Other non-current assets			16,805,475		5,961,241
Total assets			492,485,212		911,827,843
Short-term bank borrowings			179,978,003		217,394,132
Accounts payable			249,665,890		258,988,264
Amounts due to intercompany			211,250,230		306,137,760
Advances from customers			20,505,861		7,478,309
Deferred revenue - current			12,666,330		31,105,700
Accrued expenses and other current liabilities			119,242,975		164,442,316
Income taxes payable			0		3,013,805
Total current liabilities			793,309,289		988,560,286
Deferred revenue - non current			234,801		2,171,033
Deferred income tax liability			0		1,265,780
Other non-current liabilities			17,609,842		22,358,968
Total liabilities			811,153,932		¥ 1,014,356,067
Revenues		2,115,501,618	1,477,593,628	769,368,001
Net (loss) / income		196,473,033	(294,156,973)	(145,154,084)
Net cash (used in) / provided by operating activities		284,907,333	14,379,166	(2,423,156)
Net cash used in investing activities		(319,696,832)	(74,333,070)	(55,928,949)
Net cash provided by financing activities		37,416,129	78,199,492	68,703,310
Effect of foreign currency exchange rate changes on cash		198,466	684,791	(813,270)
Net increase in cash		2,825,096	18,930,379	9,537,935
Cash and restricted cash at the beginning of the year		90,723,253	71,792,874	62,254,939
Cash and restricted cash at the end of the year		¥ 93,548,349	¥ 90,723,253	¥ 71,792,874

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)	Dec. 31, 2019 ¥ / $
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Convenience translation rate (in RMB/USD)	6.9618

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Cash (Details) - CNY (¥)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Cash
Total cash balances held at financial institutions	¥ 279,742,341	¥ 568,739,787
Minimum
Cash
Original maturities of term deposit	3 months
Maximum
Cash
Original maturities of term deposit	1 year
PRC
Cash
Total cash balances held at financial institutions	¥ 268,438,586	301,112,759
PRC \| Denominated in RMB
Cash
Total cash balances held at financial institutions	90,078,714	145,529,365
PRC \| Denominated in USD
Cash
Total cash balances held at financial institutions	178,359,872	155,583,394
United States
Cash
Total cash balances held at financial institutions	3,523,116	4,038,742
United States \| Denominated in USD
Cash
Total cash balances held at financial institutions	3,523,116	4,038,742
Hong Kong SAR
Cash
Total cash balances held at financial institutions	6,015,191	263,588,286
Hong Kong SAR \| Denominated in USD
Cash
Total cash balances held at financial institutions	6,015,191	¥ 263,588,286
Indonesia
Cash
Total cash balances held at financial institutions	1,765,448
Indonesia \| Denominated in USD
Cash
Total cash balances held at financial institutions	¥ 1,765,448

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Restricted cash (Details)	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2016 CNY (¥)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities	$ 25,665,838	¥ 178,680,435	¥ 8,569,117	¥ 80,063,278
Net cash provided by financing activities	5,068,001	35,282,416	555,382,588	68,703,310
Effect of foreign currency exchange rate changes on restricted cash	1,035,094	7,206,098	6,074,726	(13,064,824)
Net increase / (decrease) in cash and restricted cash	(35,439,152)	¥ (246,720,292)	466,436,780	79,772,815
Reconciliation of cash and restricted cash reported within the consolidated balance sheets that sum to the total of the same such amounts shown in the consolidated statements of cash flows
Cash	40,211,719				¥ 279,945,942		¥ 569,059,591
Restricted cash, current	31,838,902				221,656,071		179,262,714
Total cash and restricted cash	$ 72,050,621			281,885,525	¥ 501,602,013	$ 107,489,773	¥ 748,322,305	¥ 202,112,710
2016-18 \| Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities			789,751
Net cash provided by financing activities				66,288,600
Effect of foreign currency exchange rate changes on restricted cash			8,583,763	(7,391,400)
Net increase / (decrease) in cash and restricted cash			¥ 9,373,514	¥ 58,897,200

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Inventories, Property, plant and equipment, net (Details)	12 Months Ended
	Dec. 31, 2019
Building
Estimated useful lives
Property, plant and equipment, useful life	50 years
Machinery and equipment \| Minimum
Estimated useful lives
Property, plant and equipment, useful life	3 years
Machinery and equipment \| Maximum
Estimated useful lives
Property, plant and equipment, useful life	10 years
Furniture
Estimated useful lives
Property, plant and equipment, useful life	3 years
Leasehold improvements
Estimated useful lives
Property, plant and equipment, useful life	3 years
Office and electronic equipment \| Minimum
Estimated useful lives
Property, plant and equipment, useful life	2 years
Office and electronic equipment \| Maximum
Estimated useful lives
Property, plant and equipment, useful life	5 years
Motor vehicles
Estimated useful lives
Property, plant and equipment, useful life	4 years

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Intangible assets, Impairment of Long-lived Assets (Details) - CNY (¥)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Estimated useful life of land use right, net	50 years
Impairment of Long-lived Assets
Impairment of long-lived assets	¥ 0	¥ 0	¥ 0

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Value added taxes, Revenue recognition (Details)	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2017 CNY (¥)	Apr. 01, 2019	May 01, 2018	Apr. 30, 2018
Value added taxes
VAT rate (in percentage)		6.00%			13.00%	16.00%	17.00%
Revenue recognition
Return and refund policy term (in days)	7 days	7 days
Cost of revenues	$ 228,351,654	¥ 1,589,738,548	¥ 1,279,155,847	¥ 714,669,718
Transaction price allocated to remaining performance obligations		47,461,086
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-12-31
Revenue recognition
Transaction price allocated to remaining performance obligations		¥ 45,290,053
Period over which remaining performance obligation is expected to be recognized as revenue		12 months
Shipping costs incurred
Revenue recognition
Cost of revenues		¥ 31,912,258	¥ 16,752,785	¥ 8,917,910
Minimum
Revenue recognition
Free service period	1 year	1 year
Minimum \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-12-31
Revenue recognition
Transaction price allocated to remaining performance obligations		¥ 2,171,033
Period over which remaining performance obligation is expected to be recognized as revenue		12 months
Maximum
Revenue recognition
Free service period	2 years	2 years
Maximum \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-12-31
Revenue recognition
Period over which remaining performance obligation is expected to be recognized as revenue		24 months

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Contract Balances (Details)	12 Months Ended
	Dec. 31, 2019 CNY (¥)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Advances from customers		$ 1,074,192	¥ 7,478,309	¥ 20,505,861
Accrued expenses and other current liabilities		$ 25,213,795	175,533,397	¥ 134,184,026
Changes in the Group's contract liabilities (advances from customers and deferred revenue)
Contract liabilities as of January 1, 2019 prior to adoption of ASC 606	¥ 33,406,992
Reclassification of VAT payable to Accrued expenses and other liabilities as of January 1, 2019 as a result of adoption of ASC 606	(2,348,375)
Cash received in advance, excluding VAT	1,967,468,291
Revenue recognized from opening balance of contract liabilities	(30,823,816)
Revenue recognized from contract liabilities arising during current year	(1,926,948,050)
Contract liabilities as of December 31, 2019	¥ 40,755,042
2016-18
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Advances from customers			7,478,309
Accrued expenses and other current liabilities			175,533,397
2016-18 \| Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Advances from customers			497,004
Accrued expenses and other current liabilities			(497,004)
2016-18 \| Amounts without adoption of ASC 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Advances from customers			7,975,313
Accrued expenses and other current liabilities			¥ 175,036,393

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Selling and Marketing Expenses, Employee Benefits (Details) - CNY (¥)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Advertising expenses	¥ 79,533,394	¥ 76,791,991	¥ 28,345,034
Employee social benefits included as expenses	¥ 20,729,717	¥ 15,544,106	¥ 13,705,669

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Concentration and risk (Details)	12 Months Ended
	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)
Concentration and risk
Accounts receivable		¥ 54,424,845		$ 16,551,567	¥ 115,228,700
Advances from customers		20,505,861		1,074,192	7,478,309
Accounts payable		249,665,890		$ 37,201,336	258,988,264
Total purchases \| Suppliers risk \| Supplier F
Concentration and risk
Total purchases	¥ 225,527,597	¥ 193,555,999
Concentration risk (as a percent)	15.00%	15.00%
Total purchases \| Suppliers risk \| Supplier A
Concentration and risk
Total purchases	¥ 173,723,118	¥ 150,385,652	¥ 187,065,077
Concentration risk (as a percent)	11.00%	12.00%	21.00%
Total purchases \| Suppliers risk \| Supplier B
Concentration and risk
Total purchases			¥ 152,966,930
Concentration risk (as a percent)			18.00%
Accounts receivable \| Customer risk \| Customer Y
Concentration and risk
Accounts receivable		¥ 45,980,177
Concentration risk (as a percent)		84.00%
Accounts receivable \| Customer risk \| Customer Z
Concentration and risk
Accounts receivable					46,263,295
Concentration risk (as a percent)	40.00%
Advances from customers \| Customer risk \| Customer U
Concentration and risk
Advances from customers					1,090,262
Concentration risk (as a percent)	15.00%
Advances from customers \| Customer risk \| Customer W
Concentration and risk
Advances from customers					767,993
Concentration risk (as a percent)	10.00%
Accounts payable \| Suppliers risk \| Supplier F
Concentration and risk
Accounts payable		¥ 25,702,037			¥ 26,134,706
Concentration risk (as a percent)	10.00%	10.00%
Accounts payable \| Suppliers risk \| Supplier E
Concentration and risk
Accounts payable		¥ 26,483,893
Concentration risk (as a percent)		11.00%

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Segment Reporting (Details)	12 Months Ended
	Dec. 31, 2019 segment
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Number of operating segment	1

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Statutory Reserves (Details) - CNY (¥)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Percentage of after tax profit, transferred annually by PRC subsidiaries to statutory surplus fund	10.00%
Maximum percentage criteria for appropriation of after-tax profit of PRC subsidiaries to statutory surplus fund (as a percent)	50.00%
Appropriations to statutory reserves	¥ 3,316,650	¥ 0	¥ 0

SHORT-TERM INVESTMENTS (Details)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)
SHORT-TERM INVESTMENTS
Aggregate cost basis		¥ 308,150,000	¥ 120,000,000
Gross unrealized holding gain		2,289,321	241,425
Aggregate fair value	$ 44,591,818	310,439,321	120,241,425
Gross unrealized holding losses		¥ 0	¥ 0

ACCOUNTS RECEIVABLES, NET (Details)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2016 CNY (¥)
ACCOUNTS RECEIVABLES, NET
Accounts receivable		¥ 118,517,235	¥ 54,652,991
Allowance for doubtful accounts		(3,288,535)	(228,146)	¥ (1,956,245)	¥ (47,846)
Accounts receivable, net	$ 16,551,567	¥ 115,228,700	¥ 54,424,845

ACCOUNTS RECEIVABLES, NET - Movement of the allowance for doubtful accounts (Details) - CNY (¥)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Summary of movement of the allowance for doubtful accounts
Balance at the beginning of the year	¥ 228,146	¥ 1,956,245	¥ 47,846
Additions / (reversals) charged to bad debt expense	3,060,389	(1,215,464)	1,908,399
Write-off of bad debt allowance		(512,635)
Balance at the end of the year	¥ 3,288,535	¥ 228,146	¥ 1,956,245

INVENTORIES (Details)	12 Months Ended
INVENTORIES (Details)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2017 CNY (¥)
INVENTORIES
Raw materials	¥ 120,290,456		¥ 151,975,367
Works in progress	1,948,838		1,481,938
Finished goods	20,142,911		25,175,994
Inventories	142,382,205	$ 25,659,068	178,633,299
Loss on inventories damaged from a warehouse fire accident	18,254,406
Write-downs made	¥ 0		¥ 10,491,137	¥ 0

PREPAYMENTS AND OTHER CURRENT ASSETS (Details)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)
PREPAYMENTS AND OTHER CURRENT ASSETS
Advances to suppliers		¥ 11,124,716	¥ 15,507,866
Deductible input VAT and VAT rebates receivable		8,678,443	7,855,998
Staff advances		514,328	447,791
Interest receivable		5,369,826	659,194
Others		5,294,818	2,449,105
Prepayments and other current assets	$ 4,450,305	¥ 30,982,131	¥ 26,919,954

PROPERTY, PLANT AND EQUIPMENT, NET (Details)	12 Months Ended
PROPERTY, PLANT AND EQUIPMENT, NET (Details)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)
Property, Plant and Equipment [Line Items]
Property, plant and equipment		¥ 71,236,365			¥ 210,618,873
Less: Accumulated depreciation		(30,251,191)			(59,727,529)
Property, Plant and equipment, net		40,985,174		$ 21,674,185	150,891,344
Depreciation expenses	¥ 29,501,123	16,808,987	¥ 9,049,769
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment		22,615,657			47,307,840
Furniture
Property, Plant and Equipment [Line Items]
Property, plant and equipment		36,630,720			76,258,884
Office and electronic equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment		9,071,471			16,909,504
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment		2,116,266			4,081,766
Motor vehicles
Property, Plant and Equipment [Line Items]
Property, plant and equipment		¥ 802,251			1,173,634
Building and building improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment					¥ 64,887,245

PROPERTY, PLANT AND EQUIPMENT, NET - Depreciation expenses (Details) - CNY (¥)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Depreciation expense on property and equipment
Total depreciation expense	¥ 29,501,123	¥ 16,808,987	¥ 9,049,769
Cost of revenues
Depreciation expense on property and equipment
Total depreciation expense	6,109,583	4,638,662	4,217,126
General and administrative expenses
Depreciation expense on property and equipment
Total depreciation expense	3,403,502	2,261,620	1,873,711
Selling and marketing expenses
Depreciation expense on property and equipment
Total depreciation expense	19,025,624	9,438,501	2,646,204
Research and development expenses
Depreciation expense on property and equipment
Total depreciation expense	¥ 962,414	¥ 470,204	¥ 312,728

INTANGIBLE ASSETS, NET (Details)	12 Months Ended
INTANGIBLE ASSETS, NET (Details)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2019 CNY (¥)
INTANGIBLE ASSETS, NET
Gross carrying amount		¥ 12,048,505	¥ 14,676,141
Accumulated amortization		(4,330,751)	(6,896,392)
Net carrying amount	$ 1,117,491	¥ 7,717,754	7,779,749
Estimated amortization expense for the year ending 2020			1,969,336
Estimated amortization expense for the year ending 2021			1,969,336
Estimated amortization expense for the year ending 2022			1,969,336
Estimated amortization expense for the year ending 2023			535,118
Estimated amortization expense for the year ending 2024			248,274
Trademarks
INTANGIBLE ASSETS, NET
Intangible assets, amortization period		5 years
Gross carrying amount		¥ 8,564,505	8,911,271
Accumulated amortization		(1,427,418)	(3,193,738)
Net carrying amount		¥ 7,137,087	5,717,533
Trademarks \| Maximum
INTANGIBLE ASSETS, NET
Intangible assets, amortization period	10 years
Trademarks \| Minimum
INTANGIBLE ASSETS, NET
Intangible assets, amortization period	5 years
Domain name
INTANGIBLE ASSETS, NET
Intangible assets, amortization period		5 years
Gross carrying amount		¥ 3,484,000	3,821,474
Accumulated amortization		(2,903,333)	(3,517,748)
Net carrying amount		¥ 580,667	303,726
Domain name \| Maximum
INTANGIBLE ASSETS, NET
Intangible assets, amortization period	10 years
Domain name \| Minimum
INTANGIBLE ASSETS, NET
Intangible assets, amortization period	5 years
License
INTANGIBLE ASSETS, NET
Intangible assets, amortization period	10 years
Gross carrying amount			1,943,396
Accumulated amortization			(184,906)
Net carrying amount			¥ 1,758,490

INTANGIBLE ASSETS, NET - Amortization Expense on Intangible Assets (Details) - CNY (¥)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Depreciation expense on property and equipment
Total amortization expense	¥ 2,521,709	¥ 2,072,389	¥ 696,800
Cost of revenues
Depreciation expense on property and equipment
Total amortization expense	184,906
General and administrative expenses
Depreciation expense on property and equipment
Total amortization expense	¥ 2,336,803	¥ 2,072,389	¥ 696,800

LAND USE RIGHT, NET (Details)	12 Months Ended
LAND USE RIGHT, NET (Details)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)
Property, Plant and Equipment [Line Items]
Gross carrying amount		¥ 71,236,365			¥ 210,618,873
Less: Accumulated depreciation		(30,251,191)			(59,727,529)
Property, Plant and equipment, net		40,985,174		$ 21,674,185	150,891,344
Amortization expenses	¥ 2,521,709	2,072,389	¥ 696,800
General and administrative expenses
Property, Plant and Equipment [Line Items]
Amortization expenses	2,336,803	¥ 2,072,389	¥ 696,800
Land use right, net
Property, Plant and Equipment [Line Items]
Gross carrying amount					34,761,487
Less: Accumulated depreciation					(405,551)
Property, Plant and equipment, net					¥ 34,355,936
Land use right, net \| General and administrative expenses
Property, Plant and Equipment [Line Items]
Amortization expenses	¥ 405,551

OTHER NON-CURRENT ASSETS (Details)

Dec. 31, 2019

USD ($)

Dec. 31, 2019

CNY (¥)

Dec. 31, 2018

CNY (¥)

OTHER NON-CURRENT ASSETS

Prepayments for land use right

¥ 10,000,000

Others

^[1]

¥ 6,522,561

6,805,474

Other non-current assets

$ 936,907

¥ 6,522,561

¥ 16,805,474

[1]	Others mainly include deposits and prepayments for equipment and intangible assets.

SHORT-TERM BANK BORROWINGS AND RESTRICTED CASH (Details)					1 Months Ended							12 Months Ended
	Dec. 12, 2019 CNY (¥)	Jun. 12, 2019 USD ($)	Jan. 23, 2019	Feb. 08, 2018 CNY (¥)	Nov. 30, 2019 CNY (¥)	Oct. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)	Nov. 30, 2017 USD ($)	Aug. 31, 2017 CNY (¥)	Mar. 31, 2016 USD ($) agreement	Dec. 31, 2015 USD ($) agreement	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2017 CNY (¥)	Apr. 15, 2020	Dec. 31, 2019 CNY (¥)	Jun. 23, 2019 CNY (¥)	Jun. 12, 2019 CNY (¥)	Nov. 30, 2017 CNY (¥)	Mar. 31, 2016 CNY (¥)	Dec. 31, 2015 CNY (¥)
SHORT-TERM BANK BORROWINGS AND RESTRICTED CASH
Short-term bank borrowings							¥ 179,978,003							¥ 179,978,003			¥ 217,394,132
Restricted cash							179,262,714					$ 31,838,902		179,262,714			221,656,071
Drawdowns repaid												$ 32,874,273	¥ 228,864,111	188,234,207	¥ 49,997,837
East West Bank loan
SHORT-TERM BANK BORROWINGS AND RESTRICTED CASH
Short-term bank borrowings							99,978,003							99,978,003			48,910,799
Number of line of credit agreements \| agreement										2	2
Debt term										1 year	1 year
Face amount					¥ 37,796,907
Maximum credit facility amount																					¥ 100,000,000	¥ 100,000,000
Interest rate (in percent)					4.20%					2.80%	2.80%										2.80%	2.80%
Collateral deposits										$ 16,000,000	$ 16,000,000										¥ 103,674,877	¥ 103,674,877
Restricted cash							109,811,200							109,811,200			56,525,358
Drawdowns repaid					¥ 52,933,631	¥ 35,930,480
East West Bank loan \| Subsequent Event
SHORT-TERM BANK BORROWINGS AND RESTRICTED CASH
Interest rate (in percent)																4.75%
Bank of China loan
SHORT-TERM BANK BORROWINGS AND RESTRICTED CASH
Short-term bank borrowings							¥ 20,000,000							20,000,000			20,000,000
Debt term	1 year			1 year			1 year		6 months
Face amount	¥ 20,000,000			¥ 20,000,000			¥ 20,000,000		¥ 10,000,000					¥ 20,000,000			20,000,000
Interest rate (in percent)	4.5675%			4.5675%			4.5675%		4.5675%					4.5675%
SPD Silicon Valley Bank loan
SHORT-TERM BANK BORROWINGS AND RESTRICTED CASH
Short-term bank borrowings							¥ 60,000,000							¥ 60,000,000			120,000,000
Debt term		1 year						1 year
Maximum credit facility amount																			¥ 120,000,000	¥ 60,000,000
Interest rate (in percent)		4.35%																	4.35%
Collateral deposits		$ 19,149,307						$ 10,000,000											¥ 132,000,000	¥ 66,288,600
SPD Silicon Valley Bank loan \| Jiangsu Xiaoniu
SHORT-TERM BANK BORROWINGS AND RESTRICTED CASH
Debt term		1 year
Face amount																			60,000,000
SPD Silicon Valley Bank loan \| Changzhou Niudian
SHORT-TERM BANK BORROWINGS AND RESTRICTED CASH
Debt term		1 year
Face amount																			¥ 60,000,000
Bank of Ningbo loan
SHORT-TERM BANK BORROWINGS AND RESTRICTED CASH
Short-term bank borrowings																	28,483,333
Bank of Ningbo loan \| Beijing Niudian [Member]
SHORT-TERM BANK BORROWINGS AND RESTRICTED CASH
Short-term bank borrowings																		¥ 28,483,333
Debt term			1 year
Face amount																	28,483,333
Interest rate (in percent)																		5.32%
Restricted cash																	¥ 30,000,000
Restricted Cash Borrowings Guaranteed																		¥ 30,000,000

CONVERTIBLE LOAN (Details)	Mar. 26, 2018 $ / shares shares	Dec. 16, 2016 USD ($)	Mar. 26, 2018 CNY (¥)	Dec. 16, 2016 CNY (¥)
Series A-3 Redeemable Convertible Preferred Shares
CONVERTIBLE LOAN
Number of shares issued on debt conversion \| shares	10,119,329
Conversion price per share \| $ / shares	$ 1.66
Convertible Loan
CONVERTIBLE LOAN
Convertible loan		$ 16,827,000	¥ 181,112,874	¥ 115,808,672
Debt term		1 year
Interest rate (in percent)		5.00%		5.00%
Percentage of entity valuation		80.00%		80.00%
Entity valuation \| $		$ 260,400,000

ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES (Details)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)
ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES
Accrued payroll and social insurance		¥ 30,780,693	¥ 32,008,825
Warranty-current		41,809,564	31,262,442
Sales rebate		40,344,717	34,029,433
Construction payable		18,765,855
Deposits		16,293,035	16,360,762
Deferred ADR income			4,250,126
Other taxes payable		10,273,637	3,656,732
IPO cost payable			3,130,639
Interest payable		2,010,366	318,774
Others		15,255,530	9,166,293
Accrued expenses and other current liabilities	$ 25,213,795	¥ 175,533,397	¥ 134,184,026

ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES - Warranty terms (Details)	12 Months Ended
	Dec. 31, 2019 km
Electric motor
Warranty terms
Warranty term	24 months
Kilometer covered under warranty	30,000
Lithium-ion battery packs, model 1
Warranty terms
Warranty term	24 months
Kilometer covered under warranty	20,000
Lithium-ion battery packs, model 2
Warranty terms
Warranty term	36 months
Kilometer covered under warranty	30,000
Minimum
Warranty terms
Warranty term	6 months
Minimum \| Smart electric-scooters
Warranty terms
Warranty term	6 months
Maximum
Warranty terms
Warranty term	3 years
Maximum \| Smart electric-scooters
Warranty terms
Warranty term	24 months

ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES - Movement of provision (Details) - CNY (¥)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Movement of provision
Accrued warranty-beginning of year	¥ 48,872,284	¥ 30,648,678	¥ 17,649,411
Accrual for warranties issued during the year	40,271,444	29,346,974	27,395,169
Warranty claims paid	(22,132,194)	(7,923,760)	(14,395,902)
Pre-existing warranty expired	(7,059,668)	(3,199,608)
Accrued warranty-end of year	¥ 59,951,866	¥ 48,872,284	¥ 30,648,678

OTHER NON-CURRENT LIABILITIES (Details)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)
OTHER NON-CURRENT LIABILITIES
Warranty-non-current		¥ 18,142,302	¥ 17,609,842
Deposits for construction of building-non-current		4,216,666
Other non-current liabilities	$ 3,211,665	¥ 22,358,968	¥ 17,609,842

REDEEMABLE CONVERTIBLE PREFERRED SHARES (Details)								12 Months Ended
REDEEMABLE CONVERTIBLE PREFERRED SHARES (Details)	Mar. 26, 2018 USD ($) $ / shares shares	Mar. 26, 2018 CNY (¥) shares	Jan. 29, 2016 USD ($) $ / shares shares	Jan. 29, 2016 CNY (¥)	May 27, 2015 USD ($) $ / shares shares	May 27, 2015 CNY (¥)	Mar. 05, 2015 USD ($) shares	Dec. 31, 2018 CNY (¥)	Mar. 26, 2018 CNY (¥) shares	Dec. 16, 2016 USD ($)	Dec. 16, 2016 CNY (¥)
REDEEMABLE CONVERTIBLE PREFERRED SHARES
Issuance of convertible loan \| $							$ 3,900,000
Interest on convertible loan \| $							$ 0
Proceeds from issuance of Redeemable Convertible Preferred Shares \| ¥								¥ 161,392,196
Convertible Loan
REDEEMABLE CONVERTIBLE PREFERRED SHARES
Outstanding principal converted \| $	$ 16,827,000
Convertible loan carrying amount									¥ 181,112,874	$ 16,827,000	¥ 115,808,672
Series A1 Redeemable Convertible Preferred Shares
REDEEMABLE CONVERTIBLE PREFERRED SHARES
Preferred shares, issued \| shares					16,666,667		3,250,000
Issued price per share \| $ / shares					$ 1.20
Proceeds from issuance of Redeemable Convertible Preferred Shares					$ 16,100,000	¥ 101,208,371
Series A-2 Redeemable Convertible Preferred Shares
REDEEMABLE CONVERTIBLE PREFERRED SHARES
Preferred shares, issued \| shares					3,608,247
Issued price per share \| $ / shares					$ 1.66
Proceeds from issuance of Redeemable Convertible Preferred Shares					$ 6,000,000	¥ 36,720,422
Series A-3 Redeemable Convertible Preferred Shares
REDEEMABLE CONVERTIBLE PREFERRED SHARES
Preferred shares, issued \| shares			5,003,436
Issued price per share \| $ / shares			$ 2.08
Conversion price per share \| $ / shares	$ 1.66
Number of shares issued on debt conversion \| shares	10,119,329	10,119,329
Proceeds from issuance of Redeemable Convertible Preferred Shares			$ 10,400,000	¥ 67,883,227
Series B Preferred Shares
REDEEMABLE CONVERTIBLE PREFERRED SHARES
Preferred shares, issued \| shares									5,137,859
Issued price per share \| $ / shares	$ 4.96
Proceeds from issuance of Redeemable Convertible Preferred Shares	$ 25,500,000	¥ 161,392,196

REDEEMABLE CONVERTIBLE PREFERRED SHARES - Series A Preferred Shares activities (Details)		1 Months Ended	12 Months Ended		24 Months Ended
	Feb. 28, 2018	Mar. 31, 2018	Dec. 31, 2019 USD ($) shares	Dec. 31, 2017 CNY (¥) shares	Dec. 31, 2019 CNY (¥)
Conversion Rights
Minimum percentage of shareholders approval needed to waive the foregoing pre-offering valuation and gross proceeds requirements \| $			$ 1,000,000,000
Minimum market capitalization criteria for Qualified IPO \| $			$ 100,000,000
Liquidation Preferences
Balance at beginning				¥ 252,506,413	¥ 237,844,515
Issuance of preferred shares					342,505,070
Foreign currency translation adjustment				(14,661,898)	47,712,689
Conversion to Ordinary Shares					(628,062,274)
Balance at end				¥ 237,844,515
Series A Preferred Shares
Conversion Rights
Conversion of Preferred Shares in to ordinary share \| shares			1	1
Minimum percentage of shareholders approval needed to convert Preferred Shares into Ordinary Shares			0.67%
Minimum percentage of holders consent for qualified IPO			0.67%
Liquidation Preferences
Percentage of liquidation preference on preferred share issue price	150.00%	150.00%
Series A1 Redeemable Convertible Preferred Shares
Liquidation Preferences
Balance at beginning				¥ 138,740,003	130,684,003
Foreign currency translation adjustment				(8,056,000)	8,090,000
Conversion to Ordinary Shares					(138,774,003)
Balance at end				130,684,003
Series A-2 Redeemable Convertible Preferred Shares
Liquidation Preferences
Balance at beginning				41,621,992	39,205,192
Foreign currency translation adjustment				(2,416,800)	2,427,000
Conversion to Ordinary Shares					(41,632,192)
Balance at end				39,205,192
Series A-3 Redeemable Convertible Preferred Shares
Liquidation Preferences
Balance at beginning				72,144,418	67,955,320
Issuance of preferred shares					181,112,874
Foreign currency translation adjustment				(4,189,098)	21,651,035
Conversion to Ordinary Shares					(270,719,229)
Balance at end				¥ 67,955,320
Series B Preferred Shares
Liquidation Preferences
Percentage of liquidation preference on preferred share issue price		150.00%
Issuance of preferred shares					161,392,196
Foreign currency translation adjustment					15,544,654
Conversion to Ordinary Shares					¥ (176,936,850)

ORDINARY SHARES AND SERIES SEED PREFERRED SHARES (Details)				1 Months Ended			12 Months Ended
	Sep. 05, 2019 shares	Mar. 26, 2018 USD ($) shares	Mar. 26, 2018 CNY (¥) shares	Oct. 31, 2018 USD ($) $ / shares shares	Oct. 31, 2018 CNY (¥) shares	Sep. 30, 2018 USD ($) $ / shares shares	Dec. 31, 2018 CNY (¥)	Dec. 31, 2019 $ / shares shares	Dec. 31, 2018 $ / shares shares	Dec. 31, 2017 $ / shares shares
ORDINARY SHARES AND SERIES SEED PREFERRED SHARES
Ordinary shares, authorized						5,000,000,000				444,721,650
Ordinary shares, par value (in dollars per share) \| $ / shares										$ 0.0001
Consideration for repurchase of ordinary shares \| ¥							¥ 4,202,335
Authorized share capital \| $						$ 500,000
Niu Holding Inc.
ORDINARY SHARES AND SERIES SEED PREFERRED SHARES
Number of ordinary shares repurchased		432,000	432,000
Consideration for repurchase of ordinary shares		$ 665,000	¥ 4,202,335
Share re-classified and re-designated as Class B ordinary shares (in shares)						14,027,020
ELLY Holdings
ORDINARY SHARES AND SERIES SEED PREFERRED SHARES
Share re-classified and re-designated as Class B ordinary shares (in shares)						6,615,000
Ordinary shares
ORDINARY SHARES AND SERIES SEED PREFERRED SHARES
Ordinary shares, authorized						50,000,000
Ordinary shares, par value (in dollars per share) \| $ / shares						$ 0.0001
Class A Ordinary Shares
ORDINARY SHARES AND SERIES SEED PREFERRED SHARES
Ordinary shares, authorized						4,900,000,000		4,900,000,000	4,900,000,000
Ordinary shares, par value (in dollars per share) \| $ / shares						$ 0.0001		$ 0.0001	$ 0.0001
Basis of converted preferred shares to each ordinary share						1
Share converted to Class A ordinary shares (in shares)						1
Ordinary shares, outstanding								130,174,878	128,032,038
Class A Ordinary Shares \| IPO
ORDINARY SHARES AND SERIES SEED PREFERRED SHARES
Number of newly issued ordinary shares under IPO				14,000,000	14,000,000
Public offering price (in dollars per share) \| $ / shares				$ 4.5
Net proceeds after deducting underwriting commissions and discounts				$ 58,590,000	¥ 406,538,433
Class B Ordinary Shares
ORDINARY SHARES AND SERIES SEED PREFERRED SHARES
Ordinary shares, authorized						50,000,000		50,000,000	50,000,000
Ordinary shares, par value (in dollars per share) \| $ / shares						$ 0.0001		$ 0.0001	$ 0.0001
Share converted to Class A ordinary shares (in shares)	1,400,000
Basis of re-classified and re-designated to each Class B ordinary share						1
Ordinary shares, outstanding								19,242,020	20,642,020
Series Seed Preferred Shares
ORDINARY SHARES AND SERIES SEED PREFERRED SHARES
Preferred Shares, par value (in dollars per share) \| $ / shares						$ 0.0001				$ 0.0001
Basis of converted preferred shares to each ordinary share						1
Share converted to Class A ordinary shares (in shares)						30,000,000
Preferred shares, authorized										30,000,000
Series A1 Redeemable Convertible Preferred Shares
ORDINARY SHARES AND SERIES SEED PREFERRED SHARES
Temporary equity value per share \| $ / shares						$ 0.0001
Share converted to Class A ordinary shares (in shares)						16,666,667
Series A-2 Redeemable Convertible Preferred Shares
ORDINARY SHARES AND SERIES SEED PREFERRED SHARES
Temporary equity value per share \| $ / shares						$ 0.0001
Share converted to Class A ordinary shares (in shares)						3,608,247
Series A-3 Redeemable Convertible Preferred Shares
ORDINARY SHARES AND SERIES SEED PREFERRED SHARES
Temporary equity value per share \| $ / shares						$ 0.0001
Share converted to Class A ordinary shares (in shares)						15,122,765
Series B Preferred Shares
ORDINARY SHARES AND SERIES SEED PREFERRED SHARES
Preferred shares, outstanding						5,137,859
Preferred Shares, par value (in dollars per share) \| $ / shares						$ 0.0001
Share converted to Class A ordinary shares (in shares)						5,137,859

SHARE-BASED COMPENSATION - Restricted ordinary shares (Details)					1 Months Ended		12 Months Ended
	Oct. 19, 2018 CNY (¥)	Jun. 08, 2018 CNY (¥) shares	May 27, 2016	Jan. 07, 2016 CNY (¥) shares	Feb. 29, 2016 CNY (¥)	May 31, 2015 $ / shares shares	Dec. 31, 2019 $ / shares	Dec. 31, 2019 CNY (¥) shares	Dec. 31, 2018 CNY (¥) shares	Dec. 31, 2017 CNY (¥)
Research and development expenses
SHARE-BASED COMPENSATION
Share-based compensation expenses \| ¥	¥ 8,935,076
General and administrative expenses
SHARE-BASED COMPENSATION
Share-based compensation expenses \| ¥	¥ 10,535,229	¥ 33,537,572
Restricted ordinary shares
SHARE-BASED COMPENSATION
Vesting period						4 years
Period to repurchase restricted ordinary shares						60 days
Estimated fair value of ordinary shares \| $ / shares						$ 0.53
Share-based compensation expenses, upon waiver of service condition \| ¥					¥ 7,574,133
Modification of restricted ordinary shares \| shares				3,307,500
Unrecognized compensation cost \| ¥				¥ 9,803,035
Share-based compensation expenses \| ¥									¥ 226,242,279	¥ 59,230,943
Total fair value of shares vested \| ¥									264,075,922	58,848,966
Number of Shares
Granted (in shares) \| shares						59,459,020
Restricted ordinary shares \| Research and development expenses
SHARE-BASED COMPENSATION
Share-based compensation expenses \| ¥									18,371,203	13,045,853
Restricted ordinary shares \| General and administrative expenses
SHARE-BASED COMPENSATION
Share-based compensation expenses \| ¥		¥ 173,156,580							207,871,076	¥ 46,185,090
Restricted ordinary shares \| Mr. Yi'nan Li
SHARE-BASED COMPENSATION
Restricted ordinary shares not to repurchased (in shares) \| shares		9,798,125
Restricted ordinary shares \| Mr. Mingming Huang
SHARE-BASED COMPENSATION
Restricted ordinary shares not to repurchased (in shares) \| shares		451,000
Restricted ordinary shares \| ELLY Holdings
SHARE-BASED COMPENSATION
Vesting period				4 years
Shares Issued / Transferred \| shares				3,307,500
Ordinary shares, outstanding \| shares				6,615,000
Restricted ordinary shares \| Smart Power Group Limited
SHARE-BASED COMPENSATION
Vesting period				3 years
Shares Issued / Transferred \| shares				1,804,000
Restricted ordinary shares \| Smart Power Group Limited \| Tranche One
SHARE-BASED COMPENSATION
Vesting percentage			25.00%
Restricted ordinary shares \| Smart Power Group Limited \| Tranche Two
SHARE-BASED COMPENSATION
Vesting percentage								75.00%
Unvested restricted share units
SHARE-BASED COMPENSATION
Share-based compensation expenses \| ¥								¥ 7,602,522	¥ 375,123
Number of Shares
Unvested balance as of the beginning \| shares								100,000
Granted (in shares) \| shares								1,694,600
Vested (in shares) \| shares								(50,000)
Unvested balance as of the end \| shares								1,744,600	100,000
Weighted average grant date fair value of restricted shares units
Unvested balance as of the beginning (in dollars per share) \| $ / shares							$ 4.33
Granted (in dollars per share) \| $ / shares							3.62
Vested (in dollars per share) \| $ / shares							4.33
Unvested balance as of the end (in dollars per share) \| $ / shares							$ 3.64
Unvested restricted share units \| Research and development expenses
SHARE-BASED COMPENSATION
Share-based compensation expenses \| ¥								¥ 1,146,846
Unvested restricted share units \| General and administrative expenses
SHARE-BASED COMPENSATION
Share-based compensation expenses \| ¥								¥ 4,233,758	¥ 375,123

SHARE-BASED COMPENSATION - Compensation expense recognized for restricted ordinary shares (Details) - CNY (¥)			12 Months Ended
	Oct. 19, 2018	Jun. 08, 2018	Dec. 31, 2018	Dec. 31, 2017
Research and development expenses
SHARE-BASED COMPENSATION
Total share-based compensation expenses	¥ 8,935,076
General and administrative expenses
SHARE-BASED COMPENSATION
Total share-based compensation expenses	¥ 10,535,229	¥ 33,537,572
Restricted ordinary shares
SHARE-BASED COMPENSATION
Total share-based compensation expenses			¥ 226,242,279	¥ 59,230,943
Unrecognized compensation expense			0
Restricted ordinary shares \| Research and development expenses
SHARE-BASED COMPENSATION
Total share-based compensation expenses			18,371,203	13,045,853
Restricted ordinary shares \| General and administrative expenses
SHARE-BASED COMPENSATION
Total share-based compensation expenses		¥ 173,156,580	¥ 207,871,076	¥ 46,185,090

SHARE-BASED COMPENSATION - Transfer of ordinary shares (Details) - CNY (¥)	Oct. 19, 2018	Jun. 08, 2018
SHARE-BASED COMPENSATION
Number of ordinary shares consideration transferred		2,000,000
Consideration paid for transfer of ordinary shares		¥ 0
General and administrative expenses
SHARE-BASED COMPENSATION
Share-based compensation expenses	¥ 10,535,229	¥ 33,537,572

SHARE-BASED COMPENSATION - Share options and restricted share units (Details)			1 Months Ended		12 Months Ended
	Oct. 19, 2018 CNY (¥)	Jun. 08, 2018 CNY (¥)	Sep. 30, 2018 installment shares	Mar. 31, 2018 shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2019 CNY (¥) installment shares	Dec. 31, 2018 $ / shares	Dec. 31, 2018 CNY (¥) shares	Dec. 31, 2017 $ / shares	Dec. 31, 2017 CNY (¥)	Dec. 31, 2019 CNY (¥) shares
Valuation of options granted
Weighted average grant date fair value \| $ / shares					$ 1.62		$ 2.11		$ 0.86
Research and development expenses
Valuation of options granted
Total share-based compensation expenses \| ¥	¥ 8,935,076
General and administrative expenses
Valuation of options granted
Total share-based compensation expenses \| ¥	¥ 10,535,229	¥ 33,537,572
Unvested restricted share units
Number of Shares
Unvested balance as of the beginning \| shares						100,000
Granted (in shares) \| shares						1,694,600
Unvested balance as of the end \| shares						1,744,600		100,000
Weighted average grant date fair value of restricted shares units
Unvested balance as of the beginning (in dollars per share) \| $ / shares					4.33
Granted (in dollars per share) \| $ / shares					3.62
Unvested balance as of the end (in dollars per share) \| $ / shares					3.64		4.33
Valuation of options granted
Total share-based compensation expenses \| ¥						¥ 7,602,522		¥ 375,123
Unrecognized compensation expense \| ¥											¥ 37,794,188
Expenses expected to be recognized over a weighted average period						3 years 4 months 10 days
Unvested restricted share units \| Cost of revenues
Valuation of options granted
Total share-based compensation expenses \| ¥						¥ 36,332
Unvested restricted share units \| Selling and marketing expenses
Valuation of options granted
Total share-based compensation expenses \| ¥						2,185,586
Unvested restricted share units \| Research and development expenses
Valuation of options granted
Total share-based compensation expenses \| ¥						1,146,846
Unvested restricted share units \| General and administrative expenses
Valuation of options granted
Total share-based compensation expenses \| ¥						¥ 4,233,758		¥ 375,123
2016 Global Incentive Plan
SHARE-BASED COMPENSATION
Maximum aggregate shares that may be issued \| shares				5,861,480
Expiration period				10 years
2016 Global Incentive Plan \| Restricted share units granted to five independent directors
SHARE-BASED COMPENSATION
Number of share options granted (in shares) \| shares						100,000
2016 Global Incentive Plan \| Restricted share units, two
SHARE-BASED COMPENSATION
Number of share options granted (in shares) \| shares						428,000
2016 Global Incentive Plan \| Stock options with exercise price of US$0.20 per share
SHARE-BASED COMPENSATION
Share options granted (in dollars per share) \| $ / shares					0.20
Number of share options granted (in shares) \| shares						4,540,000
2016 Global Incentive Plan \| Stock options with exercise price of nil per share
SHARE-BASED COMPENSATION
Share options granted (in dollars per share) \| $ / shares					$ 0
Number of share options granted (in shares) \| shares						705,196
Amended 2016 Plan
Number of Shares
Unvested balance as of the beginning \| shares						5,314,246
Granted (in shares) \| shares						4,180,000
Exercised (in shares) \| shares						(742,840)
Forfeited (in shares) \| shares						(69,050)
Unvested balance as of the end \| shares						8,682,356		5,314,246
Exercisable at end of period (in shares) \| shares					2,387,959						2,387,959
Weighted average grant date fair value of restricted shares units
Unvested balance as of the beginning (in dollars per share) \| $ / shares					$ 0.17
Granted (in dollars per share) \| $ / shares					3.43
Exercised (in dollars per share) \| $ / shares					0.19
Forfeited (in dollars per share) \| $ / shares					0.20
Unvested balance as of the end (in dollars per share) \| $ / shares					1.74		0.17
Options exercisable at end of period (in dollars per share) \| $ / shares					$ 0.19
Weighted Average Contractual Term
Outstanding at end of period						8 years 2 months 5 days
Options exercisable at end of period						6 years 5 months 9 days
Aggregate Intrinsic Value
Outstanding at end of period \| $					$ 21,950,316
Options exercisable at end of period \| $					$ 9,738,313
Valuation of options granted
Risk-free rate of return, Minimum						1.90%		2.78%		2.25%
Risk-free rate of return, Maximum								3.13%		2.48%
Volatility, Minimum						47.90%		49.90%		51.70%
Volatility, Maximum								50.90%		54.40%
Expected dividend yield						0.00%		0.00%		0.00%
Exercise multiple \| $ / shares							2.2		2.2
Fair value of underlying ordinary share, Minimum \| $ / shares							2.05		0.44
Fair value of underlying ordinary share, Maximum \| $ / shares							$ 4.10		$ 1.22
Fair value of underlying ordinary share \| $ / shares					3.425
Expected term						10 years		10 years		10 years
Total share-based compensation expenses \| ¥						¥ 12,020,257		¥ 5,719,953		¥ 3,296,155
Unrecognized compensation expense \| ¥											¥ 56,411,059
Expenses expected to be recognized over a weighted average period						3 years 3 months 22 days
Amended 2016 Plan \| Minimum
Valuation of options granted
Exercise multiple \| $ / shares					$ 2.2
Amended 2016 Plan \| Maximum
Valuation of options granted
Exercise multiple \| $ / shares					2.8
Amended 2016 Plan \| Cost of revenues
Valuation of options granted
Total share-based compensation expenses \| ¥						¥ 255,679		246,947		253,545
Amended 2016 Plan \| Selling and marketing expenses
Valuation of options granted
Total share-based compensation expenses \| ¥						2,471,725		2,124,728		1,611,160
Amended 2016 Plan \| Research and development expenses
Valuation of options granted
Total share-based compensation expenses \| ¥						3,060,263		955,538		832,782
Amended 2016 Plan \| General and administrative expenses
Valuation of options granted
Total share-based compensation expenses \| ¥						¥ 6,232,590		2,392,740		598,668
2018 Plan
SHARE-BASED COMPENSATION
Maximum aggregate shares that may be issued \| shares			6,733,703
Maximum percentage of total ordinary shares issued and outstanding that may be issued			1.50%
Maximum aggregate shares that may be issued, annual increase \| shares			2,230,111
Share options granted (in dollars per share) \| $ / shares					$ 3.425
Number of share options granted (in shares) \| shares						4,180,000
Number of equal installments in which the awards can be granted \| installment			4			4
Valuation of options granted
Total share-based compensation expenses \| ¥						¥ 19,622,779		265,874,927		62,527,098
2018 Plan \| Cost of revenues
Valuation of options granted
Total share-based compensation expenses \| ¥						292,011		246,947		253,545
2018 Plan \| Selling and marketing expenses
Valuation of options granted
Total share-based compensation expenses \| ¥						4,657,311		2,124,728		1,611,160
2018 Plan \| Research and development expenses
Valuation of options granted
Total share-based compensation expenses \| ¥						4,207,109		52,864,313		13,878,635
2018 Plan \| General and administrative expenses
Valuation of options granted
Total share-based compensation expenses \| ¥						¥ 10,466,348		¥ 210,638,939		¥ 46,783,758
2018 Plan \| Unvested restricted share units
SHARE-BASED COMPENSATION
Number of equal installments in which the awards can be granted \| installment						4
Number of Shares
Granted (in shares) \| shares						1,266,600
Tranche One \| 2016 Global Incentive Plan \| Stock options with exercise price of US$0.20 per share
SHARE-BASED COMPENSATION
Vesting percentage						40.00%
Tranche Two \| 2016 Global Incentive Plan \| Restricted share units granted to five independent directors
SHARE-BASED COMPENSATION
Number of equal installments in which the awards can be granted \| installment						2
Tranche Two \| 2016 Global Incentive Plan \| Restricted share units, two
SHARE-BASED COMPENSATION
Number of equal installments in which the awards can be granted \| installment						4
Tranche Two \| 2016 Global Incentive Plan \| Stock options with exercise price of US$0.20 per share
SHARE-BASED COMPENSATION
Number of equal installments in which the awards can be granted \| installment						3
Tranche Two \| 2016 Global Incentive Plan \| Stock options with exercise price of nil per share
SHARE-BASED COMPENSATION
Number of equal installments in which the awards can be granted \| installment						4

FAIR VALUE MEASUREMENT - Fair value hierarchy for assets and liabilities (Details) - CNY (¥)	Dec. 31, 2019	Dec. 31, 2018
Fair value hierarchy for assets and liabilities measured at fair value on recurring basis
Short-term investments (Note 3)	¥ 310,439,321	¥ 120,241,425
Level 2
Fair value hierarchy for assets and liabilities measured at fair value on recurring basis
Short-term investments (Note 3)	¥ 310,439,321	¥ 120,241,425

FAIR VALUE MEASUREMENT - Level 3 Reconciliation (Details) - CNY (¥)	12 Months Ended		24 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019
Level 3 Reconciliation
Conversion to Series A-3 Preferred Shares			¥ (628,062,274)
Convertible Loan
Level 3 Reconciliation
Convertible loan - beginning of year	¥ 151,557,796	¥ 116,728,899	¥ 151,557,796
Change in fair value	34,499,858	43,006,399
Conversion to Series A-3 Preferred Shares	(181,112,874)
Foreign currency translation adjustment	¥ (4,944,780)	(8,177,502)
Convertible loan - end of year		¥ 151,557,796

INCOME TAX (Details) - HKD ($) $ in Millions	12 Months Ended
INCOME TAX (Details) - HKD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Indonesia
INCOME TAX
Statutory income tax (as a percent)	25.00%
Hong Kong SAR
INCOME TAX
Statutory income tax (as a percent)	16.50%
Withholding taxes on remittance of dividends	$ 0
Threshold profit taxed at half of the current tax rate under two-tiered profits tax rates regime		$ 2
Tax rate at half of the current tax rate under two-tiered profits tax rates regime		8.25%
PRC
INCOME TAX
Statutory income tax (as a percent)	25.00%

INCOME TAX - Components of (loss)/income before income taxes and withholding tax on undistributed dividends (Details)	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2017 CNY (¥)
INCOME TAX
(Loss)/income before income taxes	$ 28,483,886	¥ 198,299,112	¥ (349,027,476)	¥ (184,662,871)
Current income tax expense		¥ 7,460,535
Withholding income tax rate	5.00%	5.00%
Percentage of ownership interests held by foreign investors (as a percent)	25.00%	25.00%
Deferred income tax expense		¥ 753,806
Income tax expense	$ 1,179,916	8,214,341	0	0
Cayman
INCOME TAX
(Loss)/income before income taxes		6,633,761	(34,397,077)	(39,610,348)
Indonesia
INCOME TAX
(Loss)/income before income taxes		(11,705)
Hong Kong SAR
INCOME TAX
(Loss)/income before income taxes		(3,820,485)	(4,507,360)	219,935
PRC, excluding Hong Kong SAR
INCOME TAX
(Loss)/income before income taxes		¥ 195,497,541	¥ (310,123,039)	¥ (145,272,458)

INCOME TAX - Reconciliation of differences between PRC statutory income tax rate and effective income tax rate (Details)	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2017 CNY (¥)
Reconciliation of differences between PRC statutory income tax rate and effective income tax rate
Computed expected income tax expense		¥ 49,574,778	¥ (87,256,869)	¥ (46,165,718)
Non-PRC entities not subject to income tax		(700,393)	9,726,109	9,847,603
Research and development expenses bonus deduction		(10,181,598)	(7,528,081)	(1,032,177)
Non-deductible share-based compensation expenses		4,532,885	66,374,951	15,631,775
Other non-deductible expenses		32,602	176,111	358,759
Expiration of loss carry forwards		304,194
Change in valuation allowance		(35,348,127)	18,507,779	21,359,758
Actual income tax expense	$ 1,179,916	¥ 8,214,341	¥ 0	¥ 0

INCOME TAX - Deferred income tax assets and deferred income tax liabilities (Details) - CNY (¥)	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Deferred income tax assets
Net operating loss carry forwards	¥ 39,342,952	¥ 74,657,570
Accrued warranty	14,987,967	12,218,071
Accrued payroll and social insurance	3,873,748	5,099,295
Advertising expense	937,639	2,955,152
Deferred revenue	6,363,254	3,225,283
Allowance for doubtful accounts	822,134	57,037
Write-downs for inventories	2,622,784
Less: Valuation allowance	(62,864,281)	¥ (98,212,408)	¥ (79,704,629)	¥ (58,344,871)
Total deferred income tax assets	6,086,197
Deferred income tax liabilities
Short-term investments	511,975
Property, plant and equipment	6,840,002
Total deferred income tax liabilities	7,351,977
Net deferred income tax assets	6,086,197
Net deferred income tax liabilities	¥ 1,265,780

INCOME TAX - Operating loss carry forwards (Details)	Dec. 31, 2019 CNY (¥)
INCOME TAX
Operating loss carry forwards, Total	¥ 157,371,809
Operating loss carry forwards, 2020	22,993,915
Operating loss carry forwards, 2021	39,644,651
Operating loss carry forwards, 2022	35,015,516
Operating loss carry forwards, 2023	50,628,062
Operating loss carry forwards, 2024	¥ 9,089,665

INCOME TAX - Changes in valuation allowance (Details) - CNY (¥)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
INCOME TAX
Balance at the beginning of the year	¥ 98,212,408	¥ 79,704,629	¥ 58,344,871
Additions/(reversals)	(35,348,127)	18,507,779	21,359,758
Balance at the end of the year	¥ 62,864,281	¥ 98,212,408	¥ 79,704,629

INCOME TAX - PRC Tax Administration and Collection Law (Details)	12 Months Ended
	Dec. 31, 2019 CNY (¥)
INCOME TAX
Period of statute of limitations, if the underpayment of taxes is due to computational errors made by the taxpayer or the withholding agent	3 years
Period of statute of limitations, if the underpayment is more than RMB 100,000	5 years
Minimum amount of underpayment of taxes for statute of limitations to be extended to five years	¥ 100,000
Period of statute of limitations for transfer pricing issues	10 years

NET (LOSS)/INCOME PER ORDINARY SHARE - Basic and diluted net loss per share computation (Details)	12 Months Ended
	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2019 CNY (¥) ¥ / shares shares	Dec. 31, 2018 CNY (¥) ¥ / shares shares	Dec. 31, 2017 CNY (¥) ¥ / shares shares
Numerator:
Net (loss)/income attributable to ordinary shareholders	$ 27,303,970	¥ 190,084,771	¥ (349,027,476)	¥ (184,662,871)
Denominator:
Weighted average number of ordinary shares outstanding	148,896,691	148,896,691	65,834,876	26,295,181
Weighted average number of ordinary shares equivalents outstanding	128,475	128,475
Denominator for basic net (loss) / income per ordinary share	149,025,166	149,025,166	65,834,876	26,295,181
Dilutive effect of outstanding share options	3,978,477	3,978,477
Dilutive effect of unvested restricted share units	244,545	244,545
Denominator for diluted net (loss) / income per ordinary share	153,248,188	153,248,188	65,834,876	26,295,181
Net (loss)/income per ordinary share
Basic (In dollars per share) \| (per share)	$ 0.18	¥ 1.28	¥ (5.30)	¥ (7.02)
Diluted (In dollars per share) \| (per share)	$ 0.18	¥ 1.24	¥ (5.30)	¥ (7.02)

NET (LOSS)/INCOME PER ORDINARY SHARE - Antidilutive securities (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share options
Antidilutive securities
Antidilutive securities	4,180,000	5,314,246	4,265,750
Unvested restricted share units
Antidilutive securities
Antidilutive securities		100,000
Restricted ordinary shares
Antidilutive securities
Antidilutive securities			32,689,010
Series Seed Preferred Shares
Antidilutive securities
Antidilutive securities			30,000,000
Series A Preferred Shares
Antidilutive securities
Antidilutive securities			25,278,350
Convertible Loan
Antidilutive securities
Antidilutive securities			10,119,329

REVENUE INFORMATION - Disaggregation of revenue (Details)	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2017 CNY (¥)
REVENUE INFORMATION
Revenues	$ 298,240,268	¥ 2,076,289,101	¥ 1,477,781,304	¥ 769,368,001
Electronic scooter sales
REVENUE INFORMATION
Revenues		1,787,274,271	1,370,522,269	709,595,841
Accessory and spare parts sales
REVENUE INFORMATION
Revenues		253,799,782	91,373,179	49,159,080
Service revenues
REVENUE INFORMATION
Revenues		¥ 35,215,048	¥ 15,885,856	¥ 10,613,080

REVENUE INFORMATION - Revenues based on geographic areas (Details)	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2017 CNY (¥)
Disaggregation of Revenue [Line Items]
Revenues	$ 298,240,268	¥ 2,076,289,101	¥ 1,477,781,304	¥ 769,368,001
PRC
Disaggregation of Revenue [Line Items]
Revenues		1,643,221,531	1,318,657,227	731,423,647
Europe
Disaggregation of Revenue [Line Items]
Revenues		274,445,360	148,963,330	36,257,165
Others
Disaggregation of Revenue [Line Items]
Revenues		¥ 158,622,210	¥ 10,160,747	¥ 1,687,189

COMMITMENTS AND CONTINGENCIES (Details) - CNY (¥)	12 Months Ended
COMMITMENTS AND CONTINGENCIES (Details) - CNY (¥)	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
COMMITMENTS AND CONTINGENCIES
Rental expenses	¥ 10,931,713	¥ 7,306,686	¥ 4,896,922
Future minimum lease commitments
2020	11,817,396
2021	11,278,557
2022	10,131,766
2023	10,131,766
2024	¥ 10,131,766

PARENT COMPANY ONLY CONDENSED FINANCIAL INFORMATION - Condensed Balance Sheets (Details)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2016 CNY (¥)
Current assets
Cash	$ 40,211,719	¥ 279,945,942	¥ 569,059,591
Term deposits	25,051,647	174,404,554	27,452,663
Restricted cash	31,838,902	221,656,071	179,262,714
Prepayments and other current assets	4,450,305	30,982,131	26,919,954
Total current assets	188,355,026	1,311,290,018	1,119,743,397
Non-current assets
Total assets	217,018,530	1,510,839,608	1,185,251,799
Current liabilities
Accrued expenses and other current liabilities	25,213,795	175,533,397	134,184,026
Total liabilities	103,322,328	719,309,388	614,844,753
Shareholders' equity:
Additional paid-in capital	249,662,837	1,738,102,741	1,717,483,548
Accumulated other comprehensive loss	(1,776,584)	(12,368,224)	(22,786,922)
Accumulated deficit	(134,203,908)	(934,300,768)	(1,124,385,539)
Total shareholders' equity	113,696,202	791,530,220	570,407,046	¥ (325,235,476)	¥ (213,194,529)
Total liabilities and shareholders' equity	217,018,530	1,510,839,608	1,185,251,799
Class A Ordinary Shares
Shareholders' equity:
Ordinary shares	12,137	84,494	83,120
Class B Ordinary Shares
Shareholders' equity:
Ordinary shares	$ 1,720	11,977	12,839
Parent Company \| Reportable Legal Entities
Current assets
Cash		120,548,511	149,901,311
Term deposits		174,404,554	27,452,663
Restricted cash		135,130,713	124,357,114
Prepayments and other current assets		7,705,862	3,707,403
Total current assets		437,789,640	305,418,491
Non-current assets
Investment in and amount due from subsidiaries, consolidated VIE and VIE's subsidiaries		479,225,101	405,843,735
Total assets		917,014,741	711,262,226
Current liabilities
Amount due to subsidiaries, consolidated VIE and VIE's subsidiaries		4,262,270	4,262,270
Accrued expenses and other current liabilities		451,354	7,593,082
Total liabilities		4,713,624	11,855,352
Shareholders' equity:
Additional paid-in capital		1,738,102,741	1,717,483,548
Accumulated other comprehensive loss		(13,895,942)	(25,394,429)
Accumulated deficit		(812,002,153)	(992,778,204)
Total shareholders' equity		912,301,117	699,406,874
Total liabilities and shareholders' equity		917,014,741	711,262,226
Parent Company \| Reportable Legal Entities \| Class A Ordinary Shares
Shareholders' equity:
Ordinary shares		84,494	83,120
Parent Company \| Reportable Legal Entities \| Class B Ordinary Shares
Shareholders' equity:
Ordinary shares		¥ 11,977	¥ 12,839

PARENT COMPANY ONLY CONDENSED FINANCIAL INFORMATION - Condensed Statements of Results of Operations (Details)	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2017 CNY (¥)
Condensed Statement of Income Captions [Line Items]
Total operating expenses	$ (47,354,912)	¥ (329,675,423)	¥ (514,427,245)	¥ (197,356,742)
Changes in fair value of a convertible loan			(34,499,858)	(43,006,399)
Interest income	2,427,359	16,898,785	2,998,796	1,006,972
(Loss) / income before income taxes	28,483,886	198,299,112	(349,027,476)	(184,662,871)
Income tax expense	1,179,916	8,214,341	0	0
Net (loss) / income	$ 27,303,970	190,084,771	(349,027,476)	(184,662,871)
Parent Company \| Reportable Legal Entities
Condensed Statement of Income Captions [Line Items]
Total operating expenses		(3,810,862)	(1,908,610)	3,029,256
Changes in fair value of a convertible loan			(34,499,858)	(43,006,399)
Share of (losses) / income from subsidiaries, consolidated VIE and VIE's subsidiaries		174,142,290	(331,955,300)	(62,527,098)
Interest income		10,444,623	2,011,390	366,795
(Loss) / income before income taxes		180,776,051	(366,352,378)	(102,137,446)
Net (loss) / income		¥ 180,776,051	¥ (366,352,378)	¥ (102,137,446)

PARENT COMPANY ONLY CONDENSED FINANCIAL INFORMATION - Condensed statements of cash flows (Details)	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2017 CNY (¥)
Condensed statements of cash flows
Net cash provided by /(used in) operating activities	$ 25,665,838	¥ 178,680,435	¥ 8,569,117	¥ 80,063,278
Net cash provided by /(used in) investing activities	(67,208,085)	(467,889,241)	(103,589,651)	(55,928,949)
Net cash provided by /(used in) financing activities	5,068,001	35,282,416	555,382,588	68,703,310
Effect of foreign currency exchange rate changes on cash and restricted cash	1,035,094	7,206,098	6,074,726	(13,064,824)
Net increase / (decrease) in cash and restricted cash	(35,439,152)	(246,720,292)	466,436,780	79,772,815
Cash and restricted cash at the beginning of the year	107,489,773	748,322,305	281,885,525	202,112,710
Cash and restricted cash at the end of the year	$ 72,050,621	501,602,013	748,322,305	281,885,525
Reportable Legal Entities \| Parent Company
Condensed statements of cash flows
Net cash provided by /(used in) operating activities		124,118,382	(351,432,253)	79,113,690
Net cash provided by /(used in) investing activities		(144,813,597)	(19,902,073)
Net cash provided by /(used in) financing activities		(2,133,713)	481,123,035
Effect of foreign currency exchange rate changes on cash and restricted cash		4,249,727	7,176,014	(6,058,261)
Net increase / (decrease) in cash and restricted cash		(18,579,201)	116,964,723	73,055,429
Cash and restricted cash at the beginning of the year		274,258,425	157,293,702	84,238,273
Cash and restricted cash at the end of the year		¥ 255,679,224	¥ 274,258,425	¥ 157,293,702