Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Schedule of Income Before Income Tax, Domestic and Foreign

Loss before provision for income taxes includes the following components (in thousands):

	Year Ended December 31,
	2023			2022			2021
Domestic	$	(274,998	)	$	(371,900	)	$	(524,440	)
Foreign		(1,258	)		6,917			1,160
Loss before provision for income taxes	$	(276,256	)	$	(364,983	)	$	(523,280	)

Schedule of Provision for Income Taxes

The provision for income taxes consists of the following (in thousands):

	Year Ended December 31,
	2023			2022			2021
Current:
Federal	$	—		$	—		$	—
State		(43	)		(608	)		50
Foreign		(17	)		1,115			609
Total current income tax expense		(60	)		507			659
Deferred:
Federal		—			—			—
State		—			—			—
Foreign		(140	)		2,708			(102	)
Total deferred income tax expense		(140	)		2,708			(102	)
Provision (benefit) for income taxes	$	(200	)	$	3,215		$	557

Schedule of Income Tax Provision Related to Continuing Operations

Our income tax provision related to continuing operations differs from the amount computed by applying the statutory income tax rate of 21% to our pretax loss as follows (in thousands):

	Year Ended December 31,
	2023			2022			2021
Income tax benefit at federal statutory rate	$	(58,013	)	$	(76,647	)	$	(109,889	)
Research credits		(1,192	)		(987	)		(4,727	)
Change in valuation allowance		35,033			51,108			97,914
Expiration of net operating loss carryforwards		312			12,348			286
Stock-based compensation		8,919			15,778			6,627
Non-cash interest expense on liability related to sales of future royalties		5,320			6,071			9,936
Non-cash royalty revenue related to sales of future royalties		(7,838	)		(7,112	)		(7,891	)
Loss on revaluation of liability related to the sale of future royalties		—			—			4,940
Impairment of goodwill		16,065			—			—
Other		1,194			2,656			3,361
Provision (benefit) for income taxes	$	(200	)	$	3,215		$	557

Schedule of Significant Components of Deferred Tax Assets and Liabilities

We measure deferred tax assets and liabilities based on the rates at which they are expected to reverse in the future. Significant components of our deferred tax assets for federal and state income taxes are as follows (in thousands):

	December 31,
	2023			2022
Deferred tax assets:
Net operating loss carryforwards	$	574,737		$	545,508
Research and other credits		144,128			142,198
Net capital loss carryforwards		39,655			38,445
Operating lease liabilities		25,384			28,254
Stock-based compensation		19,447			22,110
Capitalized research and development costs		34,675			24,134
Liability related to the sale of future royalties		6,729			13,424
Other		13,863			13,935
Deferred tax assets before valuation allowance		858,618			828,008
Valuation allowance for deferred tax assets		(854,528	)		(816,235	)
Total deferred tax assets		4,090			11,773
Deferred tax liabilities:
Operating lease right-of-use assets		(3,824	)		(11,335	)
Investment in foreign subsidiary		(521	)		(2,451	)
Other		(265	)		(392	)
Total deferred tax liabilities		(4,610	)		(14,178	)
Net deferred tax assets (liabilities)	$	(520	)	$	(2,405	)

Schedule of Unrecognized Tax Benefits

We have the following activity relating to unrecognized tax benefits (in thousands):

	Year Ended December 31,
	2023			2022			2021
Beginning balance	$	85,845		$	80,604		$	78,665
Tax positions related to current year:
Additions		848			378			2,371
Reductions		—			—			—
Tax positions related to prior years:
Additions		40,079			5,272			58
Reductions		—			—			(490	)
Settlements		—			—			—
Lapses in statute of limitations		(274	)		(409	)		—
Ending balance	$	126,498		$	85,845		$	80,604