Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Summary of (loss) before income taxes

	Year ended December 31,
	2018			2017
	(in thousands)
U.S.	$	1,017		$	(17,104	)
Foreign		(30	)		(659	)
Total	$	987		$	(17,763	)

Summary of income tax expense (benefit)

	Year ended December 31,
	2018		2017
	(in thousands)
Current
U.S.	$	—	$	—
State		—		—
Foreign		24		88
Total current income tax expense		24		88
Deferred
U.S.		—		—
State		—		—
Foreign		—		—
Total deferred income tax expense (benefit)		—		—
Total income tax expense (benefit)	$	24	$	88

Summary of reconciliation of income tax computed at federal statutory rate to income before taxes

	Year ended December 31,
	2018			2017
U.S. federal statutory rate		(21	)%		(33.6	)%
State taxes net of federal benefit		(7.7	)		(4.9	)
Impact of new federal tax rate		0.0			157.8
Foreign rate differential and transactional tax		0.1			0.3
Tax credits		(14.0	)		—
Valuation allowance		42.7			(118.4	)
Other		(2.5	)		(0.7	)
		(2.4	)%		0.5	%

Summary of significant components of net deferred income taxes

	2018			2017
	(in thousands)
Deferred tax assets:
Allowance for doubtful accounts	$	2		$	2
Inventory reserves		3,323			3,672
Consumables excess reserve		170			-
Accrued liabilities		55			4
Warrant interest expense		196			196
Stock compensation expense		881			2,022
State net operating loss		14,633			15,954
Net operating loss carryforward		38,525			37,856
Tax credits		740			999
Depreciation		2,993			5,117
Valuation allowance		(61,512	)		(65,817	)
Total deferred tax assets		6			5
Deferred tax liability:
Prepaid expenses		(6	)		(5	)
Net deferred tax liability	$	-		$	-