Income Taxes (Tables)

12 Months Ended

Dec. 31, 2022

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,
	2022		2021		2020
Domestic	$	(371,900)	$	(524,440)	$	(445,370)
Foreign	6,917		1,160		1,423
Loss before provision for income taxes	$	(364,983)	$	(523,280)	$	(443,947)

Schedule of Provision for Income Taxes

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

	Year Ended December 31,
	2022		2021		2020
Current:
Federal	$	—	$	—	$	—
State	(608)		50		165
Foreign	1,115		609		364
Total current income tax expense	507		659		529
Deferred:
Federal	—		—		—
State	—		—		—
Foreign	2,708		(102)		(36)
Total deferred income tax expense	2,708		(102)		(36)
Provision for income taxes	$	3,215	$	557	$	493

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,
	2022		2021		2020
Income tax benefit at federal statutory rate	$	(76,647)	$	(109,889)	$	(93,229)
Research credits	(987)		(4,727)		(3,081)
Change in valuation allowance	51,108		97,914		87,060
Expiration of net operating loss carryforwards	12,348		286		286
Stock-based compensation	15,778		6,627		7,929
Non-cash interest expense on liability related to sales of future royalties	6,071		9,936		6,356
Non-cash royalty revenue related to sales of future royalties	(7,112)		(7,891)		(7,967)
Loss on revaluation of liability related to the sale of future royalties	—		4,940		—
Other	2,656		3,361		3,139
Provision for income taxes	$	3,215	$	557	$	493

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,
	2022		2021
Deferred tax assets:
Net operating loss carryforwards	$	545,508	$	564,712
Research and other credits	142,198		139,996
Net capital loss carryforwards	38,445		—
Operating lease liabilities	28,254		34,680
Stock-based compensation	22,110		33,408
Capitalized research and development costs	24,134		—
Liability related to the sale of future royalties	13,424		23,757
Other	13,935		17,290
Deferred tax assets before valuation allowance	828,008		813,843
Valuation allowance for deferred tax assets	(816,235)		(785,748)
Total deferred tax assets	11,773		28,095
Deferred tax liabilities:
Operating lease right-of-use assets	(11,335)		(27,204)
Investment in foreign subsidiary	(2,451)		—
Other	(392)		(564)
Total deferred tax liabilities	(14,178)		(27,768)
Net deferred tax assets (liabilities)	$	(2,405)	$	327

Schedule of Unrecognized Tax Benefits

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

	Year Ended December 31,
	2022		2021		2020
Beginning balance	$	80,604	$	78,665	$	77,410
Tax positions related to current year:
Additions	378		2,371		2,512
Reductions	—		—		—
Tax positions related to prior years:
Additions	5,272		58		193
Reductions	—		(490)		(1,450)
Settlements	—		—		—
Lapses in statute of limitations	(409)		—		—
Ending balance	$	85,845	$	80,604	$	78,665