Income Taxes (Tables)

12 Months Ended

Dec. 31, 2022

Income Tax Disclosure [Abstract]

Schedule of Income before Income Tax

The components of loss before income taxes are as follows (in thousands):

	December 31,			December 31,
	2022			2021
U.S. loss before taxes	$	(66,750	)	$	(48,694	)
Foreign income before taxes		3			14
Loss before income taxes	$	(66,747	)	$	(48,680	)

Schedule of Components of Income Tax Expense (Benefit)

Income tax expense for the years ended December 31, 2022 and 2021 consists of the following (in thousands):

	Year ended December 31,
	2022			2021
Current:
Federal	$	—		$	—
State		8			7
Foreign		1			1
		9			8
Deferred:
Federal		(11,366	)		(9,950	)
State		(3,542	)		(3,241	)
Foreign		—			—
		(14,908	)		(13,191	)
Change in valuation allowance		14,908			13,191
Income tax expense	$	9		$	8

Schedule of Deferred Tax Assets and Liabilities

The significant components that comprised the Company’s net deferred taxes are as follows (in thousands):

	Year ended December 31,
Deferred tax assets:	2022			2021
Net operating loss	$	70,179		$	62,347
Amortization		99			117
R&D expenditures capitalization		4,879			—
Stock-based compensation		2,960			2,829
Research and development credit		9,202			7,902
Right-of-use liability		1,204			1,290
Depreciation		779			536
Other		2,332			1,745
Gross deferred tax assets		91,634			76,766
Less: valuation allowance		(90,471	)		(75,546	)
Total net deferred tax assets	$	1,163		$	1,220
Deferred tax liabilities:
Right-of-use asset		(1,163	)		(1,220	)
Total deferred tax liabilities		(1,163	)		(1,220	)
Net deferred tax assets	$	—		$	—

Schedule of Effective Income Tax Rate Reconciliation

A reconciliation of the provision for income taxes with the expected income tax computed by applying the federal statutory income tax rate to loss before provision for income taxes was calculated as follows (amounts in thousands):

	December 31, 2022						December 31, 2021
	Rate			Amount			Rate			Amount
Income tax provision at the federal statutory tax rate		21.0	%	$	(14,017	)		21.0	%	$	(10,223	)
State taxes, net of federal benefit		3.5	%		(2,358	)		4.1	%		(1,989	)
Research and development credits		1.9	%		(1,269	)		2.6	%		(1,241	)
Stock-based compensation		(2.4	)%		1,625			(1.4	)%		677
Other non-deductible permanent items		(0.2	)%		105			2.6	%		(1,252	)
Expired tax attributes		(1.5	)%		988			(2.0	)%		960
Other		0.0	%		27			0.2	%		(113	)
Change in valuation allowance		(22.3	)%		14,908			(27.1	)%		13,189
Income tax expense		0.0	%		9			0.0	%	$	8

Schedule of Unrecognized Tax Benefits [Roll Forward]

The following reconciliation of the beginning and ending amount of gross unrecognized tax benefits, excluding interest and penalties, is as follows (in thousands):

	Year ended December 31,
	2022		2021
Beginning balance of unrecognized tax benefits	$	3,013	$	2,554
Additions for current year tax positions		481		459
Ending balance	$	3,494	$	3,013