Stock-based compensation - Stock Based Compensation Expense by Award Type (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Stock options
Stock-based compensation expense included in total operating expenses	$ 4,660	$ 6,407
Stock options
Stock options
Stock-based compensation expense included in total operating expenses	2,597	4,219
Restricted stock units and other stock awards
Stock options
Stock-based compensation expense included in total operating expenses	1,949	1,893
Employee stock purchase plan
Stock options
Stock-based compensation expense included in total operating expenses	$ 114	$ 295