Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Schedule of Effective Income Tax Rate Reconciliation

The reconciliation of federal statutory income tax to the Company's provision for income taxes is as follows:

	As of December 31,
	2021		2020		2019
Expected provision at statutory rate	21.0	%	21.0	%	21.0	%
State tax - net of federal benefit	7.9	%	7.5	%	5.3	%
Tax credits	3.2	%	2.8	%	3.2	%
Permanent differences	(0.1)	%	(1.0)	%	(8.1)	%
Other	—	%	1.1	%	2.9	%
Change in valuation allowance	(31.9)	%	(31.4)	%	(24.3)	%
Total provision for income taxes	0.1	%	—	%	—	%

Schedule of Deferred Tax Assets

The significant components of the Company’s deferred tax assets and liabilities as of December 31, 2021 and 2020 are comprised of the following (in thousands):

	As of December 31,
	2021		2020
Deferred tax assets:
Net operating loss carryforwards	$	52,038	$	35,714
Capital loss carryforwards	7,298		7,298
Start-up costs	11,235		11,235
Accruals and reserves	448		398
Intellectual property amortization	1,960		2,285
Stock-based compensation expense	2,064		1,290
Tax credits	4,350		2,541
Lease liability	461		125
Total deferred tax assets	79,854		60,886
Valuation allowance	(79,395)		(60,761)
Deferred tax assets, net of allowance	$	459	$	125
Deferred tax liabilities:
Lease right-of-use assets	(459)		(125)
Net deferred tax assets	$	—	$	—

Summary of Income Tax Contingencies

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

	Year ended December 31,
	2021		2020		2019
Gross unrecognized tax benefits at beginning of year	$	303	$	303	$	—
Additions for tax positions taken in a prior year	—		—		303
Additions for tax positions taken in the current year	—		—		—
Reductions for tax positions taken in the prior year due to settlement	—		—		—
Reductions for tax positions taken in the prior year due to statutes lapsing	—		—		—
Gross unrecognized tax benefits at end of year	$	303	$	303	$	303