Stock Plans (Tables)

6 Months Ended

Jun. 30, 2014

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

Schedule of stock-based compensation expense

Compensation cost for restricted stock awards, restricted stock units, stock options and the ESPP included in cost of revenue; selling, general and administrative expense; and research and development expense is as follows (in thousands):

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2014		2013		2014		2013
Cost of revenue	$	190	$	261	$	442	$	535
Selling, general and administrative	733		507		988		1,004
Research and development	243		178		491		365
Total stock-based compensation expense	$	1,166	$	946	$	1,921	$	1,904

Restricted Stock Awards

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

Schedule of employee stock purchase plan weighted-average assumptions

The following table summarizes the amount of compensation expense recognized for restricted stock awards for the three and six months endedJune 30, 2014 and 2013 (in thousands):

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2014		2013		2014		2013
Service-based restricted stock awards	$	716	$	621	$	1,149	$	1,270
Performance-based restricted stock awards	7		25		13		43
Total compensation expense recognized for restricted stock awards	$	723	$	646	$	1,162	$	1,313

Restricted Stock Unit

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

Schedule of employee stock purchase plan weighted-average assumptions

Since the vesting of the market-condition restricted stock units is dependent on stock price performance, the fair values of these awards were estimated using a Monte-Carlo valuation model with the following weighted-average assumptions:

Market price at grant per share	$	15.03
Expected dividends	$	—
Expected volatility	65		%
Risk-free interest rate	0.86		%
Fair value per unit	$	7.71

Schedule of stock-based compensation expense

The following table summarizes the amount of compensation expense recognized for employee restricted stock units for the three and six months endedJune 30, 2014 and 2013 (in thousands):

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2014		2013		2014		2013
Service-based restricted stock units	$	32	$	—	$	32	$	—
Market-condition restricted stock units	22		—		22		—
Total compensation expense recognized for employee restricted stock units	$	54	$	—	$	54	$	—

Employee Stock [Member]

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

Schedule of stock-based compensation expense

The fair value of the ESPP shares for the three and six months ended June 30, 2014 was estimated using the Black-Scholes valuation model for a call and a put option with the following weighted-average assumptions:

Expected dividends	$	—
Exercise price	$	7.77
Expected volatility	71		%
Risk-free interest rate	0.07		%
Expected life/term (in years)	0.5
Fair value per share	$	7.65