Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Schedule of Loss Before Income Taxes

Loss before income taxes is attributable to the following tax jurisdictions (in thousands):

	Year ended December 31,
	2018			2017
United States	$	(29,162	)	$	(40,180	)
Foreign	(190		)	(651		)
Net loss before income taxes	$	(29,352	)	$	(40,831	)

Reconciliation Between Effective Tax Rate and Income Tax Rate

The reconciliation between the income tax rate and our effective tax rate as of December 31 is as follows:

	2018		2017
Federal income tax rate	21	%	34	%
Research and development tax credits	6		3
Non-deductible executive compensation	(1	)	—
Valuation allowance	(12	)	304
Impact of tax reform	—		(101	)
Expired tax attribute carryforwards	(17	)	(240	)
Gain on branch liquidation	3		—
Foreign currency gains and losses	2		—
Other	(2	)	—
Net effective tax rate	—	%	—	%

Significant Components of Deferred Tax Assets and Liabilities

The principal components of our deferred tax assets and liabilities as of December 31 were as follows (in thousands):

	2018			2017
Deferred tax assets:
Net operating loss carryforwards	$	18,792		$	21,005
Capitalized research and development	32,029			27,540
Research and development tax credit carryforwards	3,061			1,347
Stock-based compensation	2,940			2,004
Intangible assets	7,802			8,117
Depreciation and amortization	549			472
Other deferred tax assets	1,806			2,279
Total deferred tax assets	66,979			62,764
Less: valuation allowance	(66,698		)	(62,472		)
	281			292
Deferred tax liabilities:
Deductions for tax in excess of financial statements	(281		)	(292		)
Total deferred tax liabilities	(281		)	(292		)
Net deferred tax assets	$	—		$	—