Income Taxes (Tables)

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Components of Income Taxes (Benefit)

The Company’s benefit from income taxes is as follows:

	December 31,
	2020		2019		2018
Current:
Federal	$	—	$	—	$	—
State		(691)		(816)		(389)
		(691)		(816)		(389)
Deferred:
Federal		—		—		—
State		—		—		—
		—		—		—
Benefit from income taxes	$	(691)	$	(816)	$	(389)

Schedule of Reconciliation of Income Taxes Computed Using U.S. Federal Statutory Rate to that Reflected in Operations

A reconciliation of income taxes computed using the U.S. federal statutory rate to that reflected in operations is as follows:

	December 31,
	2020		2019		2018
Income taxes using U.S. federal statutory rate	21.00	%	21.00	%	21.00	%
State income taxes, net of federal benefit	(58.68)	%	(1.99)	%	6.82	%
Tax Cuts and Jobs Act	0.00	%	0.00	%	0.00	%
Impact of R&D tax credit on effective tax rate	(52.06)	%	4.34	%	3.48	%
Stock option shortfalls and cancellations	0.35	%	(0.17)	%	(0.43)	%
Permanent items and other	(5.08)	%	0.36	%	(0.15)	%
Change in valuation allowance	84.61	%	(22.76)	%	(31.76)	%
Provision to return	0.92	%	(0.02)	%	0.03	%
Non-taxable revenue	0.00	%	0.00	%	1.54	%
	(8.94)	%	0.76	%	0.53	%

Schedule of Significant Components of Company's Deferred Tax Assets and Liabilities

Significant components of the Company’s deferred tax assets and liabilities are as follows:

	December 31,
	2020		2019
Valuation allowance	$	(120,666)	$	(114,136)
Net operating loss carryforwards		93,507		84,608
Federal and state tax credits		19,982		16,624
Deferred revenue		—		5,994
Stock-based compensation expense		6,732		4,481
Other		2,414		3,409
Deferred tax assets		122,635		115,116
Other		(1,969)		(980)
Deferred tax liabilities:		(1,969)		(980)
Net deferred tax asset:	$	—	$	—