Income Taxes (Tables)

12 Months Ended

Dec. 31, 2022

Income Tax Disclosure [Abstract]

Schedule of Components of Provision for Income Taxes

The components of our provision for income taxes for the years ended December 31, 2022, 2021 and 2020, are as follows (in thousands):

	Year Ended December 31,
	2022		2021		2020
Current:
State	$	8	$	4	$	2
Foreign	—		—		—
Total current	8		4		2
Deferred:
Federal	—		—		—
Total deferred	—		—		—
Provision for income taxes	$	8	$	4	$	2

Schedule of Reconciliation of Effective Tax Rate

A reconciliation of the statutory federal income tax rate to our effective tax rate is as follows:

	Year Ended December 31,
	2022		2021		2020
Income tax at the federal statutory rate	21.0	%	21.0	%	21.0	%
State taxes, net of federal benefit	1.9		0.4		0.7
Tax credits	1.5		1.0		1.3
Executive compensation disallowed under IRC Sec 162(m)	(1.6)		(1.1)		(0.5)
Stock based compensation	(2.3)		(1.3)		(0.1)
Other	(0.8)		—		(0.1)
Change in valuation allowance	(19.7)		(20.0)		(22.3)
Income tax provision	—	%	—	%	—	%

Schedule of Components of Deferred Tax Assets

Significant components of our deferred tax assets are as follows as of December 31, 2022 and 2021 (in thousands):

	December 31,
	2022		2021
Deferred tax assets:
Amortization and depreciation	$	64,111	$	61,098
Net operating loss carryforwards	86,547		74,989
Tax credits	14,411		13,827
Stock-based compensation	5,244		4,054
Other	7,486		3,867
Gross deferred tax assets	177,799		157,835
Valuation allowance	(175,670)		(155,141)
Deferred tax assets net of valuation allowance	2,129		2,694
Deferred tax liabilities:
Right-of-use asset	(2,129)		(2,689)
Other	—		(5)
Net deferred tax assets	$	—	$	—

Schedule of Reconciliation of Unrecognized Tax Benefits

A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands):

	December 31,
	2022		2021		2020
Balance at beginning of year	$	24,426	$	23,624	$	24,538
Additions based on tax positions related to current year	460		1,613		474
Subtractions related to lapse of statute of limitation	(811)		—		—
Subtractions based on tax positions related to prior year	—		(811)		(1,388)
Balance at end of year	$	24,075	$	24,426	$	23,624