Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Income Taxes

Schedule of effective income tax

	Years ended December 31,
	2021			2020
Computed “expected” income tax benefit		21.0	%		21.0	%
State income tax benefit, net of federal income tax benefit		6.3	%		6.3	%
Permanent items, primarily change in fair value of warrants and non-deductible share-based compensation		1.0	%		2.6	%
Tax credits		(2.1)	%		(0.7)	%
Stock-option cancellations		(0.2)	%		(8.2)	%
Change in valuation allowance		(26.0)	%		(21.0)	%
Total income taxes		—	%		—	%

Schedule of deferred tax assets and liabilities

	Years ended December 31,
	2021		2020
	(in thousands)
Deferred tax assets:
Operating loss and credit carryforwards	$	16,611	$	15,217
Capitalized research and development		1,470		1,873
Stock-based compensation		1,284		1,078
Accrual for contingency matter		888		—
Lease liabilities		46		50
Excess book over tax depreciation		21		34
Total deferred tax assets		20,320		18,252
Less: valuation allowance		(20,274)		(18,200)
Deferred tax assets		46		52
Deferred tax liability:
Operating lease assets		(46)		(52)
Total deferred tax liability		(46)		(52)
	$	—	$	—