INCOME TAXES - Schedule of Deferred Tax Assets and Liabilities and Based on Tax Jurisdictions (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Deferred tax assets:
Net operating loss carryforwards	$ 255,860	$ 211,585
Research and development tax credit carryforwards	62,819	58,409
Stock-based compensation	4,325	3,998
Deferred revenue	1,476	0
Capitalized research	66,760	74,354
Property and equipment	17,272	15,648
Intangible assets	130	31
Lease liabilities	6,732	6,666
Accruals and reserves	4,754	331
Other	421	235
Total deferred tax asset	420,549	371,257
Valuation allowance	419,779	367,578
Deferred tax assets	770	3,679
Liabilities:
Operating lease right-of-use assets	(770)	(3,679)
Deferred tax liabilities	(770)	(3,679)
Total net deferred tax liabilities	$ 0	$ 0