Income taxes (Tables)

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Summary of Components of Income (Loss) Before Provision for Income Taxes

The components of income (loss) before provision for income taxes are as follows (in thousands):

	Year Ended December 31,
	2023		2022		2021
United States	$	20,713	$	29,108	$	331,447
Foreign	(37,153)		(115,052)		(10,476)
Income (loss) before provision for income taxes	$	(16,440)	$	(85,944)	$	320,971

Summary of Composition of the Provision for Income Taxes

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

	Year Ended December 31,
	2023		2022		2021
Current:
Federal	$	7,833	$	1,681	$	—
State	6,698		7,385		2,303
Foreign	6,477		4,381		2,957
Total current tax expense	21,008		13,447		5,260
Deferred:
Federal	6		(1,861)		6
State	3		(356)		6
Foreign	(1,847)		(1,127)		(739)
Total deferred tax expense (benefit)	(1,838)		(3,344)		(727)
Provision for income taxes	$	19,170	$	10,103	$	4,533

Summary of Reconciliation of the Difference Between Income Taxes Computed at the Statutory Federal Income Tax Rate and the Provision for Income Taxes

The difference between income taxes computed at the statutory federal income tax rate and the provision for income taxes is attributable to the following (in thousands):

	Year Ended December 31,
	2023		2022		2021
Tax at U.S. statutory rate	$	(3,453)	$	(18,048)	$	67,404
State income taxes, net of benefit	5,111		5,502		2,307
Foreign operations	12,018		26,985		4,448
Permanent book/tax differences	6,809		6,598		409
Share-based compensation	(18,925)		(20,663)		(269,009)
Change in valuation allowance	111,497		62,048		278,761
Tax credits	(93,887)		(52,319)		(79,787)
Provision for income taxes	$	19,170	$	10,103	$	4,533

Summary of Significant Components of Deferred Tax Assets and Liabilities

Significant components of our deferred tax assets and liabilities are as follows (in thousands):

	December 31,
	2023		2022
Deferred tax assets:
Net operating loss carryforwards	$	751,273	$	900,200
Research tax credits	570,061		473,248
Reserves, accruals, and other	26,855		31,502
Lease obligation	44,676		56,185
Share-based compensation	30,146		40,976
Research capitalization and amortization	411,113		208,373
Total deferred tax assets	1,834,124		1,710,484
Less: valuation allowance	(1,821,027)		(1,660,609)
Deferred tax assets, net of valuation allowance	13,097		49,875
Deferred tax liabilities:
Depreciation and amortization	(7,467)		(44,790)
Prepaid expenses	(2,682)		(4,190)
Total deferred tax liabilities	(10,149)		(48,980)
Deferred tax assets (liabilities)	$	2,948	$	895

Summary of Changes in Gross Unrecognized Tax Benefits

Changes in gross unrecognized tax benefits were as follows (in thousands):

	Gross Unrecognized Tax Benefits
Balance as of December 31, 2021	$	205,059
Increases for tax positions of prior years	—
Decreases for tax positions of prior years	(3,347)
Increases for tax positions of current year	38,226
Balance as of December 31, 2022	$	239,938
Increases for tax positions of prior years	3,736
Decreases for tax positions of prior years	(119)
Increases for tax positions of current year	44,377
Audit Settlement	(37,027)
Balance as of December 31, 2023	$	250,905