Stock-based compensation - Compensation expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Stock-based compensation
Stock-based compensation	$ 3,673	$ 3,573
Employee Stock Option
Stock-based compensation
Stock-based compensation	2,391	2,408
Restricted stock awards and units
Stock-based compensation
Stock-based compensation	1,205	1,090
Employee stock purchase plan awards
Stock-based compensation
Stock-based compensation	77	75
Research and development
Stock-based compensation
Stock-based compensation	1,485	1,280
General and administrative
Stock-based compensation
Stock-based compensation	$ 2,188	$ 2,293