Income taxes - Schedule of deferred tax assets and liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Deferred tax assets:
Net operating loss carryforwards	$ 100,151	$ 62,429
Capitalized Research and Experimental Expenditures	50,877	68,370
R&D and investment tax credits	27,984	23,646
Deferred revenue	6,160	6,671
Stock-based compensation	13,684	11,003
Operating lease liability	17,395	19,083
Capitalized start-up costs	230	392
Other	22	25
Total gross deferred tax assets	216,503	191,619
Deferred tax liabilities:
Right-of-use asset	(11,754)	(16,697)
Fixed assets	(1,112)	(1,382)
Deferred Tax Liabilities, Gross	(12,866)	(18,079)
Less: valuation allowance	(203,637)	(173,540)
Net deferred taxes	$ 0	$ 0