Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Schedule of Components of Loss Before Income Taxes

The components of the Company’s loss before income taxes are as follows (in thousands):

	Year Ended December 31,
	2018		2017
Domestic	(16,835	)	(22,717	)
Foreign	(618	)	(322	)
Loss before income taxes	(17,453	)	(23,039	)

Schedule of Components of Income Tax Expense

The components of income tax expense are as follows (in thousands):

	Year Ended December 31,
	2018			2017
Current tax expense:
Federal	$	—		$	—
State	—			—
Foreign	—			—
Total current tax expense	—			—
Deferred tax expense:
Federal	3,555			(9,574		)
State	822			2,061
Foreign	200			—
Total deferred tax expense	4,577			(7,513		)
Change in deferred tax valuation allowance	(4,577		)	7,513
Net deferred tax expense	—			—
Provision for income taxes	$	—		$	—

Schedule of Effective Income Tax Rate Reconciliation

Income tax expense differs from the amount computed by applying the statutory federal income tax rate due to the following:

	Year Ended December 31,
	2018		2017
Tax at statutory federal rate	(21.0	)%	(34.0	)%
State tax, net of federal benefit	(5.3	)%	(4.3	)%
Measurement of deferred taxes as a result of tax reform	—	%	68.7	%
Tax credits	(0.7	)%	(0.3	)%
Change in deferred tax valuation allowance	26.2	%	(32.6	)%
Other	0.8	%	2.5	%
Total income tax expense	—	%	—	%

Schedule of Deferred Tax Assets

The tax effects of temporary differences and carryforwards that give rise to significant portions of the deferred tax assets are presented below (in thousands):

	December 31,
	2018			2017
Net operating loss carryforwards	$	35,067		$	32,210
Research and development credits	2,255			2,070
Depreciation and amortization	132			179
Accruals and reserves	2,958			1,376
	40,412			35,835
Less: Valuation allowance	(40,412		)	(35,835		)
Total deferred tax asset	$	—		$	—

Summary of Changes in Valuation Allowance

The following table summarizes changes in the valuation allowance for the year ended December 31, 2018 and 2017 (in thousands):

	December 31,
	2018		2017
Beginning balance	$	35,835	$	43,348
Additions during the period	4,577		—
Deductions during the period	—		(7,513		)
Ending balance	$	40,412	$	35,835

Schedule of Uncertain Income Tax Positions

The changes in the Company’s uncertain income tax positions for the years ended December 31, 2018 and 2017 consisted of the following (in thousands):

Beginning balance as of January 1, 2017	$	950
Increases in balances related to tax positions taken during 2017	43
Ending balance as of December 31, 2017	993
Increases in balances related to tax positions taken during 2018	91
Ending balance as of December 31, 2018	$	1,084