Income Taxes (Tables)

12 Months Ended

Dec. 31, 2020

Schedule of Effective Income Tax Rate Reconciliation

The effective income tax rate of the provision for income taxes differs from the federal statutory rate as follows:

	Years Ended December 31,
	2020			2019
Federal statutory income tax rate		21	%		21	%
State income taxes, net of federal benefit		2			4
Research and developments credits		(1	)		2
Permanent items		(6	)		(4	)
Change in valuation allowance		(16	)		(23	)
Effective income tax rate		—	%		—	%

Schedule of Deferred Tax Assets and Liabilities

The tax effects of temporary differences that give rise to significant portions of the deferred income tax assets and liabilities are as follows (in thousands):

	Years Ended December 31,
	2020			2019
Deferred Tax Assets:
Net operating loss carryforwards	$	53,128		$	50,360
Research and development tax credits		2,860			3,040
Property and equipment		279			370
Stock-based compensation		865			—
Accruals and reserves		1,406			286
Total		58,538			54,056
Valuation allowance		(56,083	)		(51,135	)
Total deferred tax assets after valuation allowance		2,455			2,921
Deferred Tax Liabilities:
Intangible assets		(2,455	)		(2,921	)
Total deferred tax liabilities		(2,455	)		(2,921	)
Net deferred tax assets and liabilities	$	—		$	—

Reconciliation of Unrecognized Tax Benefits

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

	Year Ended December 31,
	2020
Balance at January 1	$	—
Additions for tax positions related to the current year		106
Additions for tax positions related to prior years		609
Reductions for tax positions related to prior years		—
Reductions related to settlements		—
Reductions related to a lapse of statute		—
Balance at December 31	$	715