Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Schedule of loss before income taxes, domestic and foreign

Our loss before provision for income taxes was as follows (in thousands):

	Year Ended December 31,
	2018			2017			2016
United States	$	(10,653	)	$	(22,994	)	$	(8,174	)
Foreign	(262		)	79			(424		)
Loss before provision for income taxes	$	(10,915	)	$	(22,915	)	$	(8,598	)

Components of provision for income taxes

The components of the provision for income taxes are as follows (in thousands):

	Year Ended December 31,
	2018			2017		2016
Current provision (benefit):
Federal	$	—		$	—	$	—
State	5			5		5
Foreign	(13		)	64		(14		)
Total current provision (benefit)	(8		)	69		(9		)
Deferred provision (benefit):
Federal	—			—		—
State	—			—		—
Foreign	(29		)	12		(31		)
Total deferred provision (benefit)	(29		)	12		(31		)
Provision for (benefit from) income taxes	$	(37	)	$	81	$	(40	)

Reconciliation of provision for income taxes calculated at the statutory rate to provision for income taxes

Reconciliation of the provision for income taxes calculated at the statutory rate to our provision for (benefit from) income taxes is as follows (in thousands):

	Year Ended December 31,
	2018			2017			2016
Tax benefit at federal statutory rate	$	(2,292	)	$	(7,791	)	$	(2,924	)
State taxes	222			48			127
Research and development credits	(499		)	(399		)	(161		)
Foreign operations taxed at different rates	(17		)	(2		)	30
Stock-based compensation	(2,587		)	(216		)	327
Other nondeductible items	(3		)	326			405
Executive compensation	838			73			255
Change in valuation allowance	4,301			(26,058		)	1,901
Change in statutory tax rate	—			34,100			—
Provision for (benefit from) income taxes	$	(37	)	$	81		$	(40	)

Significant components of our deferred tax assets and liabilities

Significant components of our deferred tax assets and liabilities are as follows (in thousands):

	December 31,
	2018			2017
Deferred tax assets:
Net operating losses	$	60,455		$	53,901
Credits	7,174			6,221
Deferred revenues	1,879			3,334
Stock-based compensation	2,967			2,872
Reserves and accruals	1,876			2,028
Depreciation	1,376			1,573
Intangible assets	2,557			3,172
Capital losses	576			576
Unrealized gain/loss	297			295
Other assets	83			78
Total deferred tax assets:	79,240			74,050
Deferred tax liabilities:
Other	(64		)	(115		)
Total deferred tax liabilities:	(64		)	(115		)
Valuation allowance	(79,222		)	(74,010		)
Net deferred tax liabilities	$	(46	)	$	(75	)

Summary of federal, state and foreign NOL carryforwards and federal research and development tax credits

The following table sets forth our federal, state and foreign NOL carryforwards and federal research and development tax credits as of December 31, 2018 (in thousands):

	December 31, 2018
	Amount		Expiration Years
Net operating losses, federal	$	254,208	2022-2038
Net operating losses, state	115,420		2018-2038
Tax credits, federal	7,430		2022-2038
Tax credits, state	9,121		Do not expire
Net operating losses, foreign	383		Various

Reconciliation of the beginning and ending amount of unrecognized tax benefits

A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands):

	Rollforward Table (at Gross): As of
	December 31,
	2018			2017			2016
Balance at beginning of year	$	9,422		$	8,566		$	8,152
Additions based on tax positions related to current year	1,087			880			459
Reductions to tax provision of prior years	(529		)	(24		)	(45		)
Balance at end of year	$	9,980		$	9,422		$	8,566