Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2015

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Assumptions Used to Compute Share-Based Compensation Costs for Stock Options Granted

The assumptions used to compute the share-based compensation costs for the stock options granted during the years ended December 31, 2015, 2014, and 2013, respectively, using the Black-Scholes option pricing model, were as follows:

	Year Ended December 31,
	2015			2014			2013
Weighted average grant-date fair value of stock options	$	0.77		$	0.57		$	0.63
Assumptions
Risk-free interest rate (weighted average)		1.1	%		1.2	%		0.6	%
Expected dividend yield		—			—			—
Weighted average expected life (years)		4			4			4
Volatility (weighted average)		83.5	%		82.9	%		68.1	%
Forfeiture rate		23.3	%		25.5	%		11.4	%

Assumptions Used Estimate Fair Value of Employee Stock Purchase Plans

Following is a schedule of the shares purchased, the fair value per share, and the Black-Scholes model assumptions for each offering period:

	(Ending)
Offering Period Ended	September 30,			March 31,			September 30,			March 31,			September 30,
	2015			2015			2014			2014			2013
Shares purchased for offering period		12,451			11,216			13,619			13,734			19,490
Fair value per share	$	0.60		$	0.43		$	0.83		$	0.30		$	0.44
Assumptions
Risk-free interest rate (average)		0.11	%		0.40	%		0.80	%		0.40	%		0.11	%
Expected dividend yield		—			—			—			—			—
Weighted average expected life (years)		0.5			0.5			0.5			0.5			0.5
Volatility (average)		103.8	%		109.1	%		74.0	%		44.0	%		45.0	%

Non-Cash Stock-Based Compensation Expenses

Non-cash stock-based compensation expenses related to stock options, restricted stock grants and the ESPP were recorded in the financial statements as follows (in thousands):

	Year Ended December 31,
	2015		2014		2013
Cost of revenues	$	12	$	13	$	20
Selling and marketing		335		270		766
Research and development		644		659		809
General and administrative		1,167		1,437		1,938
Restructuring expense		—		1,273		—
Total non-cash stock compensation expense	$	2,158	$	3,652	$	3,533

Summary of Outstanding Stock Options and Related Activity

A summary of the Company’s stock options outstanding under the 2015 Plan as of December 31, 2015 and the activity during the years ended herein are as follows (in thousands except per share amounts):

	Shares			Weighted Ave. Exercise Price		Aggregate Intrinsic Value
Outstanding as of December 31, 2012		2,275		$	7.02	$	—
(1,474 options exercisable at a weighted average exercise price of $10.09)
Granted (weighted average fair value of $0.63)		120		$	1.31
Exercised		—		$	—
Cancelled		(225	)	$	6.52
Outstanding as of December 31, 2013		2,170		$	6.76	$	—
(1,573 options exercisable at a weighted average exercise price of $8.81)
Granted (weighted average fair value of $0.57)		633		$	0.95
Exercised		(4	)	$	1.38
Cancelled		(665	)	$	5.98
Outstanding as of December 31, 2014		2,134		$	5.29	$	—
(1,291 options exercisable at a weighted average exercise price of $8.04)
Granted (weighted average fair value of $0.77)		75		$	1.27
Exercised		(8	)	$	1.19
Cancelled		(556	)	$	4.05
Outstanding as of December 31, 2015		1,645		$	5.39	$	—
Exercisable as of December 31, 2015		1,132		$	7.34	$	—
Vested and expected to vest at December 31, 2015		1,593		$	5.53	$	—

Summary of Outstanding Restricted Stock Awards and Related Activity

A summary of the Company’s restricted stock awards outstanding under the 2005 Plan as of December 31, 2015, and the activity during years ended therein, are as follows (in thousands):

	Number of shares			Weighted average grant date fair value
Unvested at December 31, 2012		1,319		$	4.60
Granted		1,495		$	1.70
Vested		(752	)	$	4.43
Cancelled and forfeited		(316	)	$	3.00
Unvested at December 31, 2013		1,746		$	2.48
Granted		1,625		$	1.79
Vested		(1,442	)	$	2.48
Cancelled and forfeited		(204	)	$	1.79
Unvested at December 31, 2014		1,725		$	1.91
Granted		1,375		$	1.50
Vested		(1,011	)	$	1.95
Cancelled and forfeited		(284	)	$	1.67
Unvested at December 31, 2015		1,805		$	1.61