Share-based payment (Tables)

6 Months Ended

12 Months Ended

Jun. 30, 2021

Dec. 31, 2020

Share-based Payment Arrangement [Abstract]

Schedule of stock option activity plan

Share options	Number of shares		Weighted average exercise price		Weighted average grant date fair value		Weighted average remaining contractual life
			(US$)		(US$)
Outstanding as of January 1, 2020	47,277		$	881.97	$	343.83	7.1
Forfeited	(4,462	)		366.00		285.11
Outstanding as of March 31, 2020	42,815		$	935.74	$	349.95	7.0
Outstanding as of June 30, 2020	42,815		$	935.74	$	349.95	6.8
Expected to vest and exercisable as of June 30, 2020	42,815		$	935.74	$	349.95	6.8
Outstanding as of January 1, 2021	216,706			991.99		468.60	9.0
Forfeited	(5,700	)		1005.85		475.71
Outstanding as of March 31, 2021	211,006		$	991.62	$	468.41	8.7
Forfeited	(800	)		1005.85		475.71
Outstanding as of June 30, 2021	210,206		$	991.57	$	468.38	8.5
Expected to vest and exercisable as of June 30, 2021	210,206		$	991.57	$	468.38	8.5

Share options	Number of shares		Weighted average exercise price		Weighted average grant date fair value		Weighted average remaining contractual life
			(US$)		(US$)
Outstanding as of January 1, 2018	56,362		$	892.24	$	350.52	9.1
Granted	1,000			1,005.85	$	225.30
Forfeited	(2,400	)		1,005.85	$	387.63
Outstanding as of December 31, 2018	54,962		$	889.35	$	346.63	8.1
Forfeited	(7,685	)		934.82	$	363.82
Outstanding as of December 31, 2019	47,277		$	881.97	$	343.83	7.1
Granted	176,890			1,005.85	$	495.95
Forfeited	(7,461	)		623.31	$	326.36
Outstanding as of December 31, 2020	216,706			991.99		468.60	9.0
Expected to vest and exercisable as of December 31, 2020	216,706		$	991.99	$	468.60	9.0

Schedule of weighted average assumptions applied to options

Grant date	For the years ended December 31, 2018
Risk-free interest rate(1)	3.55	%
Expected dividend yield(2)	0.0	%
Volatility(3)	51.7	%
Exercise multiple(4)	2.2
Life of options(5)	10 years
Fair value of underlying ordinary shares(6)	$515.40
Grant date	For the years ended December 31, 2020
Risk-free interest rate(1)	1.54% ~ 1.61%
Expected dividend yield(2)	0.0%
Volatility(3)	50.2% ~ 51.8%
Exercise multiple(4)	2.2 ~ 2.8
Life of options(5)	10 years
Fair value of underlying ordinary shares(6)	$976.98 ~ $1,316.40

Schedule non-vested shares activity

	Number of non-vested shares		Weighted average grant date fair value per share
			(US$)
Outstanding as of January 1, 2020	20,523		$	182.13
Transfer to non-vested share units	(20,523	)	$	182.13
Outstanding as of March 31, 2020	—		$	—
Outstanding as of June 30, 2020	—		$	—

	Number of non-vested shares		Weighted average grant date fair value per share
			(US$)
Outstanding as of January 1, 2020	123,575		$	143.89
Forfeited	(446	)	$	227.24
Transfer from non-vested shares	20,523		$	182.13
Outstanding as of March 31, 2020	143,652		$	149.10
Outstanding as of June 30, 2020	143,652		$	149.10
Outstanding as of January 1, 2021	143,652		$	149.10
Forfeited	—		$	—
Outstanding as of June 30, 2021	143,652		$	149.10

	Number of non-vested shares		Weighted Average Grant date fair value per share
			(US$)
Outstanding as of January 1, 2018	43,723		$	139.80
Forfeited	(8,923	)	$	102.35
Outstanding as of December 31, 2018	34,800		$	149.40
Transfer to non-vested share units	(14,277	)	$	102.35
Outstanding as of December 31, 2019	20,523		$	182.13
Transfer to non-vested share units	(20,523	)	$	182.13
Outstanding as of December 31, 2020	—		$	—

	Number of non-vested share units		Weighted Average Grant date fair value per share
			(US$)
Outstanding as of January 1, 2018	120,007		$	155.55
Forfeited	(5,890	)	$	188.84
Outstanding as of December 31, 2018	114,117		$	153.83
Forfeited	(4,819	)	$	255.99
Transfer from non-vested shares	14,277		$	102.35
Outstanding as of December 31, 2019	123,575		$	143.89
Forfeited	(446	)	$	227.24
Transfer from non-vested shares	20,523		$	182.13
Outstanding as of December 31, 2020	143,652		$	149.10