Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Summary of 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		2019
Income tax computed at federal statutory rate	21.0	%	21.0	%	21.0	%
State taxes, net of federal tax benefit	7.7	%	7.4	%	2.7	%
General business credit—federal	5.3	%	5.3	%	295.9	%
Stock-based compensation	(0.7)	%	(1.0)	%	(50.0)	%
Other permanent differences	(0.1)	%	(0.1)	%	(2.4)	%
Change in valuation allowance	(33.2)	%	(32.6)	%	(267.7)	%
Effective income tax rate	0.0	%	—	%	(0.5)	%

Summary of Deferred Tax Assets and Liabilities

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

	December 31,
	2021		2020
Deferred tax assets:
Net operating losses	$	51,554	$	27,047
Research and development credits	13,989		7,617
Accrued expenses	292		291
Other	775		474
Deferred rent	—		266
Lease liability	2,000		—
Stock based compensation	1,816		428
Total deferred tax assets	70,426		36,123
Deferred tax liabilities:
Fixed asset basis	$	(61)	$	(124)
Prepaid expenses	(921)		(558)
Right of use asset	(1,760)		—
Total deferred tax liabilities	(2,742)		(682)
Valuation allowance	67,684		35,441
Net deferred taxes	$	—	$	—

Summary of Net Operating Losses and Tax Credit Carryforwards

Net operating losses and tax credit carryforwards were as follows (in thousands):

	December 31, 2021		Expiration Year
Net operating losses, federal (starting from January 1, 2018)	$	155,231	Does not expire
Net operating losses, federal (before January 1, 2018)	$	29,486	2035-2037
Net operating losses, state	$	182,964	2035-2041
Tax credits, federal	$	14,094	2036-2041
Tax credits, state	$	4,069	Does not expire

Summary of Changes in 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 increases in net operating loss carryforwards and research and development tax credit carryforwards and were as follows (in thousands):

	Year Ended December 31,
	2021		2020
Valuation allowance at the beginning of the year	$	35,441	$	21,929
Increases recorded to income tax provision	32,243		13,512
Valuation allowance at the end of the year	$	67,684	$	35,441

Summary of Reconciliation of Unrecognized Tax Benefits

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

	Year Ended December 31,
	2021		2020		2019
January 1	$	2,007	$	1,355	$	855
Additions based on tax positions related to current year	1,081		513		570
Additions (reductions) for tax positions of prior year	417		139		(70)
December 31	$	3,505	$	2,007	$	1,355