Share-based compensation - Share based compensation expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share based compensation expense
Total share-based compensation expense	$ 32,477	$ 26,779	$ 12,083
Research and development expenses
Share based compensation expense
Total share-based compensation expense	15,581	10,394	4,974
General and administrative expenses
Share based compensation expense
Total share-based compensation expense	$ 16,896	$ 16,385	$ 7,109