Income Taxes (Tables)

12 Months Ended

Dec. 31, 2016

Income Tax Disclosure [Abstract]

Schedule of components of the income tax provision

The components of the Company’s income tax provision are as follows (in thousands):

	Year Ended December 31,
	2016		2015		2014
Current:
Federal	$	—	$	—	$	—
State	74		25		63
Total current provision	74		25		63
Deferred:
Federal	547		547		540
State	34		34		37
Total deferred provision	581		581		577
Total income tax provision	$	655	$	606	$	640

Schedule of overall effective income tax rate

The overall effective income tax rate differs from the statutory federal rate of 34% as follows:

	Year Ended December 31,
	2016		2015		2014
Income tax benefit based on the federal statutory rate	34.0	%	34.0	%	34.0	%
State income taxes, net of federal benefit	3.2		2.4		2.0
Nondeductible expenses	(1.7	)	(0.3	)	(0.7	)
Change in valuation allowance	(33.0	)	(30.7	)	(34.7	)
Stock-based compensation	(4.1	)	(6.4	)	(2.0	)
Other	—		0.1		0.1
Overall effective income tax rate	(1.6	)%	(0.9	)%	(1.3	)%

Schedule of components of deferred tax assets (liabilities)

The components of deferred tax assets (liabilities) are as follows (in thousands):

	December 31,
	2016			2015
Deferred income tax assets:
Net operating loss carryforwards	$	95,342		$	66,340
Stock-based compensation	25,278			24,192
Accrued expenses	3,338			4,016
Research and development tax credits	543			543
Other	371			306
Gross deferred tax assets	124,872			95,397
Valuation allowance	(115,689		)	(84,167		)
Net deferred tax assets	9,183			11,230
Deferred tax liabilities:
Property, equipment and software	(5,424		)	(6,734		)
Intangible assets and goodwill	(6,753		)	(6,909		)
Gross deferred tax liabilities	(12,177		)	(13,643		)
Total net deferred tax liabilities	$	(2,994	)	$	(2,413	)

Schedule of change in the valuation allowance

The change in the valuation allowance for the years ended December 31, 2016, 2015, and 2014 is as follows (in thousands):

	Year Ended December 31,
	2016		2015		2014
Valuation allowance, at beginning of year	$	84,167	$	64,449	$	47,858
Increase in valuation allowance- share-based compensation guidance impact	17,959		—		—
Valuation allowance, at beginning of year, as adjusted	$	102,126	$	64,449	$	47,858
Increase in valuation allowance	13,563		19,718		16,591
Valuation allowance, at end of year	$	115,689	$	84,167	$	64,449

Schedule of reconciliation of the total amounts of unrecognized tax benefits

The following is a reconciliation of the total amounts of unrecognized tax benefits (in thousands):

	Year Ended December 31,
	2016		2015			2014
Unrecognized tax benefit, beginning of year	$	3	$	46		$	(4	)
Additions based on current year tax positions	—		—			21
Additions for prior years' tax positions	—		—			29
Settlements with tax authorities	—		(13		)	—
Reductions for prior years' tax positions	—		(30		)	—
Unrecognized tax benefit, end of year	$	3	$	3		$	46