Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Stock activity and total number of shares available for grant

The following table presents the stock activity and the total number of shares available for grant as of December 31, 2017:

	(in thousands)
Balance at December 31, 2016	2,261
Options granted	(1,751	)
Restricted Stock granted	(167	)
Forfeited/Expired shares added back	1,206
Balance at December 31, 2017	1,549

Stock-based compensation cost

Total estimated stock-based compensation expense for employees and non-employees, related to all of the Company's stock-based awards, was comprised as follows:

	Year Ended
	December 31,
	2017			2016		2015
	(in thousands)
Cost of revenue	$	(66	)	$	557	$	889
Selling and marketing	100			90		320
Research and development	232			561		784
General and administrative	1,164			2,752		3,904
Total stock-based compensation	$	1,430		$	3,960	$	5,897

Stock option activity

	Options Outstanding
	Number of Shares Underlying Outstanding Options		Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term	Aggregate Intrinsic Value
					(In years)
Outstanding at December 31, 2016	6,381,447		$	1.9	7.37	$	20,033
Granted	1,750,674		0.68
Exercised	—		—
Forfeited	(1,171,794	)	2.17
Outstanding at December 31, 2017	6,960,327		$	1.55	6.64	$	6
Vested and expected to vest at December 31, 2017	6,734,078		$	1.59	6.58	$	4
Exercisable at December 31, 2017	4,081,307		$	1.95	5.30	$	—

Schedule of weighted-average assumptions

The fair value of options granted under the Company’s Plans was estimated on the date of grant using the Black-Scholes option pricing model with the following assumptions:

	Year Ended
	December 31,
	2017	2016	2015
	(in thousands)
Expected term (in years)	6.1	6.1	6.1
Risk-free interest rate	1.9% - 2.3%	1.1% - 2.3%	1.5% - 1.9%
Expected volatility	38.7%- 41.1%	40.7% - 42.2%	40.8% - 47.1%
Dividend rate	0%	0%	0%

Unvested restricted stock awards

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Stock option activity

	Shares		Weighted Average Grant Date Fair Value Per Share
Nonvested restricted stock at December 31, 2016	135,705		$	1.84
Granted	166,665		0.90
Vested	(91,002	)	2.06
Forfeited	(43,903	)	1.16
Nonvested restricted stock at December 31, 2017	167,465		0.96