INCOME TAXES (Tables)

12 Months Ended

Dec. 31, 2019

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:



	Year Ended December 31,
	2019		2018
Federal statutory income tax rate	21.0	%	21.0	%
Federal and state tax credits	10.1		10.3
State income taxes, net of federal benefit	3.7		3.0
Change in valuation allowance	(31.3	)	(32.5	)
Other permanent items	(3.9	)	(1.0	)
Change in tax rate	—		(0.7	)
Other, net	0.4		(0.1	)
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 presented below:



	Year Ended December 31,
	2019			2018
	(in thousands)
Net operating loss carryforwards	$	32,792		$	24,137
Tax credits	10,812			6,571
Accruals and reserves	829			854
Stock-based expense	1,202			876
Start-up costs	605			698
Gross deferred tax assets	46,240			33,136
Valuation allowance	(46,240		)	(33,136		)
Net deferred tax assets	$	—		$	—