Income Taxes (Tables)

12 Months Ended

Dec. 31, 2025

Income Tax Disclosure [Abstract]

Schedule of Loss Before Provision for Income Taxes

Loss before income taxes included the following (in millions):

	Year Ended December 31,
	2025		2024		2023
Domestic	$	(353)	$	(283)	$	(301)
Foreign	—		1		-
Loss before income taxes	$	(353)	$	(282)	$	(301)

Schedule of Components of Provision for Income Taxes

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

	Year Ended December 31,
	2025		2024		2023
Current provision:
Federal	$	—	$	—	$	4
State	—		1		2
Total income tax expense	$	—	$	1	$	6

Schedule of Cash Paid for Income Taxes, Net of Refunds

Cash paid for income taxes, net of refunds consisted of the following (in millions):

	Year Ended December 31,
	2025		2024		2023
Federal	$	—	$	—	$	4
State
Pennsylvania	$	—	$	—	$	1
Total state	$	—	$	—	$	1
Total cash paid for income taxes, net of refunds	$	—	$	—	$	5

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

The reconciliation between the federal statutory income tax and our effective tax was as follows (in millions and as a rate):

	Year Ended December 31,
	2025				2024				2023
Federal statutory income taxes	$	(74)	21.0	%	$	(59)	21.0	%	$	(63)	21.0	%
State taxes, net of federal benefit (1)	—		0.1	%	—		(0.1)	%	2		(0.8)	%
Tax credits
Domestic research and development credits	(15)		4.2	%	(12)		4.4	%	(14)		4.6	%
Nontaxable or nondeductible items
Equity investment	(12)		3.4	%	(12)		4.1	%	(1)		0.4	%
Stock based compensation	4		(1.1)	%	5		(1.9)	%	6		(2.1)	%
Other items	5		(1.4)	%	2		(0.5)	%	—		—	%
Change in valuation allowance	92		(26.1)	%	77		(27.2)	%	76		(25.1)	%
Provision for income taxes	$	—	0.1	%	$	1	(0.2)	%	$	6	(2.0)	%

(1) State taxes in Pennsylvania and New York made up the majority (greater than 50%) of the tax effect in this category for the year ended December 31, 2023.

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,
	2025		2024
Deferred tax assets:
Federal and state net operating loss carryforwards	$	39	$	5
Research and development credits carryforwards	59		42
Stock-based compensation	26		27
Depreciation and amortization	3		3
Deferred revenue	19		45
Lease liability	22		24
Capitalized research and development costs	250		178
Other	7		6
Total deferred tax assets	425		330
Deferred tax liabilities:
Right-of-use assets	(13)		(14)
Total deferred tax liabilities	(13)		(14)
Less valuation allowance	(412)		(316)
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,
	2025		2024
Beginning balance	$	19	$	13
Additions for tax positions taken in prior year	1		1
Additions for tax positions taken in current year	5		5
Statute of limitations expiration	(1)		—
Ending balance	$	24	$	19