Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Schedule of Loss Before Provision for Income Taxes

Income (loss) before income taxes included the following (in millions):

	Year Ended December 31,
	2023		2022		2021
Domestic	$	(301)	$	(267)	$	54
Foreign	—		1		1
Income (loss) before income tax	$	(301)	$	(266)	$	55

Schedule of Components of Provision for Income Taxes

The provision for income taxes included the following (in millions):

	Year Ended December 31,
	2023		2022		2021
Current provision:
Federal	$	4	$	—	$	1
State	2		1		1
Total income tax expense	$	6	$	1	$	2

Schedule of Effective Tax Rate of Provision for Income Taxes Differs from Federal Statutory Rate

The reconciliation between the federal statutory income tax rate and our effective tax rate was as follows:

	Year Ended December 31,
	2023		2022		2021
Federal statutory income tax rate	21.0	%	21.0	%	21.0	%
State taxes, net of federal benefit	(0.7)	%	(0.1)	%	0.8	%
Equity investment	0.4	%	0.9	%	(4.1)	%
Research and development credits	5.2	%	3.1	%	(11.9)	%
Change in valuation allowance	(26.3)	%	(24.5)	%	(2.6)	%
Stock based compensation	(2.1)	%	0.1	%	(0.8)	%
Non-deductible expenses and other	0.5	%	(0.6)	%	0.9	%
Provision for income taxes	(2.0)	%	(0.1)	%	3.3	%

Schedule of Significant Components of Deferred Tax Assets for Federal and State Income Taxes

Significant components of our deferred tax assets and liabilities were as follows (in millions):

	Year Ended December 31,
	2023		2022
Deferred tax assets:
Federal and state net operating loss carryforwards	$	1	$	24
Research and development credits carryforwards	26		22
Stock-based compensation	21		16
Depreciation and amortization	3		6
Deferred revenue	66		19
Lease liability	26		25
Capitalized research and development costs	109		53
Other	1		7
Total deferred tax assets	253		172
Deferred tax liabilities:
Right-of-use assets	(20)		(22)
Total deferred tax liabilities	(20)		(22)
Less valuation allowance	(233)		(150)
Net deferred tax assets (liabilities)	$	—	$	—

Summary of Activity Related to Unrecognized Tax Benefits

The following table summarizes the activity related to our unrecognized tax benefits (in millions):

	Year Ended December 31,
	2023		2022
Beginning balance	$	8	$	5
Additions for tax positions taken in prior year	2		—
Additions for tax positions taken in current year	3		3
Ending balance	$	13	$	8