Share-based compensation - Share based compensation expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Share based compensation expense
Total share-based compensation expense	$ 7,430	$ 5,368	$ 24,665	$ 21,239
Research and development expenses
Share based compensation expense
Total share-based compensation expense	3,357	2,637	11,941	7,643
General and administrative expenses
Share based compensation expense
Total share-based compensation expense	$ 4,073	$ 2,731	$ 12,724	$ 13,596