Share-based compensation - Share Options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Additional Information
Total share-based compensation expense	$ 32,477	$ 26,779	$ 12,083
Stock option
Number of Shares
Outstanding number of shares at beginning	5,898,888
Granted	2,099,895
Exercised	(54,023)
Forfeited	(475,233)
Outstanding number of shares at end	7,469,527	5,898,888
Number of shares, vested and expected to vest	7,469,527
Number of shares, options exercisable	4,561,511
Weighted Average Exercise Price
Weighted average exercise price at beginning	$ 22.45
Granted	26.53
Exercised	12.57
Forfeited	30.94
Weighted average exercise price at ending	23.13	$ 22.45
Weighted average exercise price, vested and expected to vest	23.13
Weighted average exercise price, options exercisable	$ 18.95
Weighted Average Contractual Term
Weighted average contractual term, outstanding	6 years 9 months 29 days	7 years 7 months 20 days
Weighted average contractual term, vested and expected to vest	6 years 9 months 29 days
Weighted average contractual term ,options exercisable	5 years 7 months 9 days
Aggregate Intrinsic Value
Aggregate intrinsic value outstanding	$ 21,920	$ 71,002
Aggregate intrinsic value, vested and expected to vest	21,920
Aggregate intrinsic value, options exercisable	$ 21,358
Additional Information
Granted	$ 19.36	$ 31.45	$ 15.66
Exercised	$ 500	$ 1,500	$ 22,000
Total share-based compensation expense	$ 27,000	$ 21,900	$ 12,100