Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Schedule of Components of Pretax Loss from Operations

The components of the pretax loss from operations for the years ended December 31 are as follows (in thousands):

	2018			2017			2016
U.S. Domestic	$	(67,508	)	$	(46,849	)	$	(48,539	)
Foreign	(20,607		)	(16,686		)	(17,568		)
Net loss before income taxes	$	(88,115	)	$	(63,535	)	$	(66,107	)

Schedule of Provision for Income Taxes

The components of the provision for income taxes for the years ended December 31 is presented in the following table:

	2018		2017		2016
Current:
Federal	$	—	$	—	$	—
State	14		—		—
Foreign	197		493		267
Total current provision	211		493		267
Deferred:
Federal	—		—		—
State	—		—		—
Foreign	—		—		—
Total deferred provision	—		—		—
Total provision	$	211	$	493	$	267

Deferred Income Tax Components

Significant components of the Company’s net deferred income taxes for the years ended December 31 are as follows (in thousands):

	2018			2017
Deferred tax assets:
Net operating loss carryforward	$	53,189		$	41,086
Property & equipment	648			524
Inventory	395			58
Stock options	11,473			8,195
Intangible assets, definite-lived	40			42
General business credit	9,300			6,651
Deferred revenue	23			253
Other	24			45
Total deferred income tax assets	75,092			56,854
Valuation allowance	(63,060		)	(56,854		)
Deferred tax assets	$	12,032		$	—
Deferred income tax liabilities:
Debt amortization	$	(12,032	)	$	—
Total deferred income tax liabilities	$	(12,032	)	$	—
Net deferred income taxes	$	—		$	—

Effective Tax Rate

The difference between the U.S. federal statutory income tax rate and the Company’s effective tax rate for years ending December 31 is as follows:

	2018		2017		2016
U.S. federal statutory income tax rate	(21.00	)%	(34.00	)%	(34.00	)%
State taxes, net of federal tax benefit	(3.07	)	(2.62	)	(1.69	)
Permanent and other differences	(0.26	)	(2.31	)	(0.17	)
Change in tax rates	(0.41	)	(1.02	)	0.67
Tax rate differential	4.92		8.99		8.62
Tax cuts and jobs act	—		38.46		—
Unrecognized tax benefits	0.81		1.20		1.09
Nondeductible equity and other compensation	(0.17	)	(4.31	)	1.17
Credit for increased research activities	(3.12	)	(4.42	)	(3.31	)
Change in Valuation allowance	22.54		0.81		28.02
	0.24	%	0.78	%	0.40	%

Uncertain Tax Positions

The Company's uncertain tax positions at December 31 as follows (in thousands):

	2018			2017		2016
Balance at beginning of year	$	2,141		$	1,101	$	343
Increases for prior positions	70			97		37
Increases for current year positions	775			943		721
Other increases	—			—		—
Decreases due to settlements	—			—		—
Expiration of the statute of limitations for the assessment of taxes	—			—		—
Other decreases	(3		)	—		—
Balance at end of year	$	2,983		$	2,141	$	1,101