Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Schedule of components of (loss) income before provision for income taxes

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

	Year Ended December 31,
	2023		2022		2021
	(in thousands)
United States	$	(481,405)	$	(659,757)	$	(384,976)
Foreign	2,641		6,308		506
Total	$	(478,764)	$	(653,449)	$	(384,470)

Schedule of components of the provision for income taxes

The components of the provision for income taxes are as follows:

	Year Ended December 31,
	2023		2022		2021
	(in thousands)
Current:
State	$	35	$	127	$	4
Foreign	1,191		1,248		118
Total current tax expense	$	1,226	$	1,375	$	122
Deferred:
Federal	$	—	$	18	$	108
State	—		3		20
Foreign	(541)		(257)		50
Total deferred tax expense	$	(541)	$	(236)	$	178
Total provision for income taxes	$	685	$	1,139	$	300

Schedule of the components of deferred tax assets and liabilities

Significant components of the Company’s deferred tax assets and deferred tax liabilities are as follows:

	As of December 31,
	2023		2022
	(in thousands)
Deferred tax assets:
Net operating losses carryforwards	$	344,314	$	294,757
Capitalized research and development costs	122,162		89,084
Property, equipment and intangible assets	12,161		7,422
Accruals and reserves	40,172		12,917
Research and development credits	62,533		49,865
Stock-based compensation	18,278		16,507
Lease liabilities	54,564		59,757
Other	73		4,378
Total deferred tax assets	$	654,257	$	534,687
Deferred tax liabilities:
Right-of-use asset	$	(40,213)	$	(44,825)
Equity security investments	(9,044)		—
Other	(206)		(316)
Total deferred tax liabilities	$	(49,463)	$	(45,141)
Less: valuation allowance	(603,747)		(489,040)
Net deferred tax assets	$	1,047	$	506

Schedule of effective tax rate reconciliation

The following table presents a reconciliation of the income tax expense computed at the statutory federal rate and the Company’s income tax expense for the periods presented:

	Year Ended December 31,
	2023		2022		2021
	(in thousands)
Taxes at the statutory federal rate	$	(100,553)	$	(137,276)	$	(80,739)
Capitalized research and expenditures true-up	8,212		—		—
Stock-based compensation	8,077		7,905		1,354
Research and development credits	(14,549)		(15,738)		(14,956)
Change in valuation allowance	114,707		175,916		106,227
State taxes, net of federal benefits	(19,117)		(28,522)		(14,998)
Other	3,908		(1,146)		3,412
Total provision for income taxes	$	685	$	1,139	$	300

Schedule of reconciliation of the balance of total gross unrecognized tax benefits

A reconciliation of the beginning and ending balance of total unrecognized tax benefits is as follows:

	Year Ended December 31,
	2023		2022		2021
	(in thousands)
Unrecognized tax benefits - Beginning of period	$	29,634	$	20,100	$	11,269
Increases related to current year’s tax positions	8,465		9,233		8,223
(Decreases) increases related to prior years’ tax positions	(1,153)		301		608
Unrecognized tax benefits - End of period	$	36,946	$	29,634	$	20,100