Income Taxes - Deferred tax assets (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Deferred tax assets:
Federal net operating loss carryforwards	$ 51,548	$ 43,953
State net operating loss carryforwards	13,745	11,433
Capitalized research and development expenditures	28,934	24,485
Research and development credit carryforwards	13,149	10,359
Lease liability	2,224	2,510
Deferred revenue	2,089
Accruals and reserves	151	210
Intangible assets	1,777	1,793
Stock-based compensation	1,362	1,213
Total deferred tax assets:	114,979	95,956
Valuation allowance	(112,522)	(92,978)
Subtotal	2,457	2,978
Deferred tax liabilities:
Property and equipment	(1,204)	(1,578)
Right of use asset	(1,253)	(1,400)
Total deferred tax liabilities	(2,457)	(2,978)
Total net deferred tax assets