Share-based compensation - Share-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Total share-based compensation expense included in the consolidated statements of operations
Total share-based compensation expense	$ 3,663	$ 5,019	$ 14,294	$ 15,802
Research and development
Total share-based compensation expense included in the consolidated statements of operations
Total share-based compensation expense	447	2,177	5,003	7,064
General and administrative
Total share-based compensation expense included in the consolidated statements of operations
Total share-based compensation expense	$ 3,216	$ 2,842	$ 9,291	$ 8,738