Share-based compensation - Share based compensation expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Share based compensation expense
Total share-based compensation expense	$ 5,673	$ 2,575	$ 15,871	$ 6,396
Research and development expenses
Share based compensation expense
Total share-based compensation expense	2,642	1,089	5,006	2,299
General and administrative expenses
Share based compensation expense
Total share-based compensation expense	$ 3,031	$ 1,486	$ 10,865	$ 4,097