Stock Plans (Tables)

3 Months Ended

Mar. 31, 2014

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

Schedule of stock-based compensation expense

Compensation cost for restricted stock, 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
	March 31,
	2014		2013
Cost of revenue	$	251	$	273
Selling, general and administrative	255		497
Research and development	249		187
Total stock-based compensation expense	$	755	$	957

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 months endedMarch 31, 2014 and 2013 (in thousands):

	Three Months Ended
	March 31,
	2014		2013
Service-based restricted stock	$	433	$	648
Performance-based restricted stock	6		18
Total compensation expense recognized for restricted stock awards	$	439	$	666

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 was estimated using the Black-Scholes valuation model for a call and a put option with the following weighted-average assumptions:

	Three Months Ended
	March 31,
	2014
Expected dividends	$	—
Exercise price	$	7.77
Expected volatility	82		%
Average risk-free interest rate	0.04		%
Expected life/term (in years)	0.3
Fair value per share	$	5.75