Stock-based compensation - Compensation expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 3,573	$ 2,558
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	2,408	1,663
Restricted stock awards and units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	1,090	841
Employee stock purchase plan awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	75	54
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	1,280	863
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 2,293	$ 1,695