Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

Income Taxes

Schedule of effective tax rates differing from U.S. federal statutory rate

	December 31,
	2023				2022				2021
	(in thousands, except percentages)
U.S. federal taxes (benefit) at statutory rate	$	(91,251)	21.00	%	$	(114,832)	21.00	%	$	(98,931)	21.00	%
State tax expense		(13,492)	3.10	%		(21,676)	3.96	%		(29,206)	6.20	%
Research and development credits		(10,837)	2.49	%		(7,024)	1.28	%		(9,193)	1.95	%
Stock-based compensation		(6,422)	1.48	%		3,949	(0.72)	%		(46,128)	9.79	%
Foreign tax		(106)	0.02	%		332	(0.06)	%		167	(0.04)	%
Nondeductible officers' compensation		8,651	(1.99)	%		4,883	(0.89)	%		24,387	(5.18)	%
Acquisition costs		563	(0.13)	%		3,226	(0.59)	%		8,901	(1.89)	%
Other		(3,397)	0.79	%		1,964	(0.36)	%		344	(0.05)	%
Change in valuation allowance		116,562	(26.82)	%		130,156	(23.80)	%		150,277	(31.90)	%
Provision for income taxes	$	271	(0.06)	%	$	978	(0.18)	%	$	618	(0.13)	%

Schedule of tax effects of temporary differences that give rise to significant portions of the deferred tax assets

	December 31,
	2023		2022
	(in thousands)
Deferred tax assets:
Net operating loss carryforwards	$	399,287	$	358,109
Research and development tax credit carryforwards		67,035		52,319
Capitalized research costs		95,923		59,128
Reserves and accruals		34,898		22,781
Lease Liabilities		19,339		21,000
Stock-based compensation		29,005		23,814
Other		9,449		9,162
Total deferred tax assets before valuation allowance		654,936		546,313
Less: valuation allowance		(639,510)		(526,235)
Total deferred tax assets after valuation allowance		15,426		20,078
Deferred tax liabilities:
Fixed Assets		(1,524)		(1,219)
Right-of-use lease assets		(13,902)		(18,859)
Total deferred tax liabilities		(15,426)		(20,078)
Net deferred tax assets	$	—	$	—

Schedule of reconciliation of the beginning and ending amount of gross unrecognized tax benefits

	December 31,
	2023		2022		2021
	(in thousands)
Balance at beginning of year	$	23,844	$	17,514	$	11,500
Additions based on tax positions related to the current year		7,034		6,301		6,017
Additions (reductions) for tax positions of prior years		34		29		(3)
Balance at end of year	$	30,912	$	23,844	$	17,514