Share-based compensation - Share based compensation expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Share based compensation expense
Total share-based compensation expense	$ 8,193	$ 5,673	$ 17,235	$ 15,871
Research and development expenses
Share based compensation expense
Total share-based compensation expense	3,988	2,642	8,584	5,006
General and administrative expenses
Share based compensation expense
Total share-based compensation expense	$ 4,205	$ 3,031	$ 8,651	$ 10,865