Income Taxes - Schedule of Significant Components of Deferred Tax Assets for Federal and State Income Taxes (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Deferred tax assets:
Federal and state net operating loss carryforwards	$ 5	$ 1
Research and development credits carryforwards	42	26
Stock-based compensation	27	21
Depreciation and amortization	3	3
Deferred revenue	45	66
Lease liability	24	26
Capitalized research and development costs	178	109
Other	6	1
Total deferred tax assets	330	253
Deferred tax liabilities:
Right-of-use assets	(14)	(20)
Total deferred tax liabilities	(14)	(20)
Less valuation allowance	(316)	(233)
Net deferred tax assets (liabilities)	$ 0	$ 0