Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Schedule of Loss Before Provision for Income Taxes

The income (loss) before provision for income taxes for the Company’s domestic and international operations was as follows (in thousands):

	Year Ended December 31,
	2021		2020		2019
U.S.	$	15,211	$	(36,667)	$	(24,888)
Foreign	690		385		284
Income (loss) before provision for income taxes	$	15,901	$	(36,282)	$	(24,604)

Schedule of Components of Income Tax Expense (Benefit)

The components of income tax expense (benefit) were as follows (in thousands):

	Year Ended December 31,
	2021		2020		2019
Current:
Federal	$	—	$	—	$	—
State	174		75		86
Foreign	161		151		88
Total current tax expense	335		226		174
Deferred:
Federal	—		(1,760)		(21)
State	—		(366)		(4)
Foreign	—		—		—
Total deferred income tax benefit	—		(2,126)		(25)
Income tax expense (benefit)	$	335	$	(1,900)	$	149

Schedule of Effective Income Tax Rate Reconciliation

The expense (benefit) for income taxes reconciles to the amount computed by applying the federal statutory rate to loss before taxes as follows (in thousands):

	Year Ended December 31,
	2021		2020		2019
Income tax expense (benefit) at federal statutory rate (1)	$	3,339	$	(7,619)	$	(5,167)
State income tax, net of federal benefit	(254)		(2,792)		(1,174)
Warrants revaluation	356		3,588		2,326
Research and development credits	(5,703)		(5,330)		(2,091)
Section 382 limitation	(97)		1,021		25,043
Stock-based compensation	(7,609)		(18,309)		(8,974)
Officers' compensation	4,024		2,612		3,133
Other	124		479		972
Change in valuation allowance	6,155		24,450		(13,919)
Income tax expense (benefit)	$	335	$	(1,900)	$	149

(1)For the years ended December 31, 2021, 2020 and 2019, the federal statutory tax rate was 21%.

Schedule of Deferred Tax Assets and Liabilities

	December 31,
	2021		2020
Deferred tax assets:
Net operating loss (NOL) carryforwards	$	78,961	$	86,898
Research and development tax credits carryforwards	16,761		11,261
Capitalized research and development expenses	5,135		6,840
Accrued compensation	28,970		24,038
Lease liabilities	8,012		6,112
Other	20,608		12,096
Total deferred tax assets	158,447		147,245
Deferred tax liabilities:
Convertible senior notes	—		(11,224)
Fixed assets	(3,847)		(7,675)
Other	(8,177)		(6,719)
Total deferred tax liabilities	(12,024)		(25,618)
Less valuation allowance	(146,423)		(121,627)
Net deferred tax assets	$	—	$	—

Schedule of Unrecognized Tax Benefits

The following table summarizes the activity related to the Company’s gross unrecognized tax benefits at the beginning and end of the years ended December 31, 2021, 2020 and 2019 (in thousands):

	Year Ended December 31,
	2021		2020		2019
Gross unrecognized tax benefits at the beginning of the year	10,107		$	6,580	$	8,824
Increases related to current year positions	3,482		2,234		1,076
Increases (decreases) related to prior year positions	—		1,293		(3,320)
Gross unrecognized tax benefits at the end of the year	$	13,589	$	10,107	$	6,580