Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

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,
	2018		2017
Federal statutory income tax rate	21.0	%	35.0	%
Federal and state tax credits	10.3		(4.8	)
State income taxes, net of federal benefit	3.0		3.1
Change in valuation allowance	(32.5	)	14.5
Other permanent items	(1.0	)	1.9
Change in tax rate	(0.7	)	(40.7	)
Transaction costs	—		(2.9	)
Net operating loss reduction	—		(6.7	)
Other, net	(0.1	)	0.6
Effective income tax rate	—	%	—	%

Schedule of Deferred Tax Assets and Liabilities

emporary differences that give rise to significant portions of the deferred income tax assets and liabilities are presented below:

	Year Ended December 31,
	2018			2017
	(in thousands)
Net operating loss carryforwards	$	24,137		$	18,257
Tax credits	6,571			2,287
Accruals and reserves	854			697
Stock-based expense	876			439
Start-up costs	698			829
Gross deferred tax assets	33,136			22,509
Valuation allowance	(33,136		)	(22,509		)
Net deferred tax assets	$	—		$	—