Income Taxes - Summary of deferred tax assets and liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Gross deferred tax assets
Net operating loss carryforwards	$ 245,763	$ 176,816
Tax credit carryforwards	37,516	24,718
Deferred research and development expenses	86,252	101,047
Stock-based compensation	8,856	20,940
Fixed assets	392	1,033
Accrued expenses and other	1,623	429
Deferred tax assets, gross	380,402	324,983
Gross deferred tax liabilities
IPR&D intangibles	(6,840)	(6,840)
Other	(670)
Total deferred tax assets and liabilities	372,892	318,143
Valuation allowance	(374,505)	(319,756)
Net deferred tax liability	$ (1,613)	$ (1,613)