Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Income Before Taxes

The domestic and foreign components of loss before income taxes were as follows (in thousands):

	Year Ended December 31,
	2021			2020
United States	$	(44,321	)	$	(28,803	)
Foreign		142			87
	$	(44,179	)	$	(28,716	)

Reconciliation of U.S. Federal Statutory Income Tax Rate to Company's Effective Income Tax Rate

A reconciliation of the U.S. federal statutory income tax rate to the Company’s effective income tax rate is as follows:

	Year Ended December 31,
	2021			2020
Federal statutory income tax rate		(21.0	)%		(21.0	)%
State taxes, net of federal benefit		(6.9	)%		(5.7	)%
Federal and state research and development tax credits		(2.4	)%		(3.6	)%
Nondeductible items		(3.2	)%		(0.2	)%
Deferred tax effect of change in state blended rate		(1.7	)%		7.8	%
Return to provision		1.1	%		1.7	%
Other		(0.2	)%		0.0	%
Change in deferred tax asset valuation allowance		34.3	%		20.9	%
Effective income tax rate		0.0	%		(0.1	)%

Schedule of Net deferred Tax Assets

Net deferred tax assets consisted of the following (in thousands):

	December 31,
	2021			2020
Deferred tax assets:
Net operating loss carryforwards	$	94,672		$	81,390
Capitalized research and development expense		4,291			6,136
Research and development tax credit carryforwards		12,186			11,541
Accrued expenses		2,528			1,390
Stock-based compensation expense		2,254			791
Deferred rent		—			79
Lease liability		2,299			—
Other		170			132
Total deferred tax assets		118,400			101,459
Deferred tax liabilities:
Other		(674	)		(218	)
Right-of-use assets		(1,562	)		—
Unrealized gain (loss)		—			(212	)
Total deferred tax liabilities		(2,236	)		(430	)
Valuation allowance		(116,164	)		(101,029	)
Net deferred tax assets	$	—		$	—

Summary Changes in the Valuation Allowance for Deferred Tax Assets

Changes in the valuation allowance for deferred tax assets during the years ended December 31, 2021 and 2020 related primarily to the increase in net operating loss carryforwards and research and development tax credit carryforwards in 2021 and 2020, and were as follows (in thousands):

	Year Ended December 31,
	2021			2020
Valuation allowance as of beginning of year	$	(101,029	)	$	(95,024	)
Decreases recorded as benefit to income tax provision		—			—
Increases recorded to income tax provision		(15,135	)		(6,005	)
Valuation allowance as of end of year	$	(116,164	)	$	(101,029	)