Share-based compensation - Share Options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Additional Information
Total share-based compensation expense	$ 26,779	$ 12,083	$ 6,514
Stock option
Number of Shares
Outstanding number of shares at beginning	4,603,486
Granted	1,548,167
Exercised	(78,074)
Forfeited	(174,691)
Outstanding number of shares at end	5,898,888	4,603,486
Number of shares, vested and expected to vest	5,898,888
Number of shares, options exercisable	3,352,315
Weighted Average Exercise Price
Weighted average exercise price at beginning	$ 14.97
Granted	44.83
Exercised	12.67
Forfeited	27.92
Weighted average exercise price at ending	22.45	$ 14.97
Weighted average exercise price, vested and expected to vest	22.45
Weighted average exercise price, options exercisable	$ 13.93
Weighted Average Contractual Term
Weighted average contractual term, outstanding	7 years 7 months 20 days	8 years 1 month 17 days
Weighted average contractual term, vested and expected to vest	7 years 7 months 20 days
Weighted average contractual term ,options exercisable	6 years 10 months 13 days
Aggregate Intrinsic Value
Aggregate intrinsic value outstanding	$ 71,002	$ 207,009
Aggregate intrinsic value, vested and expected to vest	71,002
Aggregate intrinsic value, options exercisable	$ 55,749
Additional Information
Granted	$ 31.45	$ 15.66	$ 7.87
Exercised	$ 1,500	$ 22,000	$ 1,300
Total share-based compensation expense	$ 21,900	$ 12,100	$ 6,500