Nature of the business and basis of presentation (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Net loss	$ 84,508	$ 70,743
Accumulated deficit	718,207		$ 633,699
Cash, cash equivalents and marketable securities	$ 199,800