Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2013

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

Assumptions used in the Black-Scholes Option-Pricing Model

The assumptions used in the Black-Scholes option-pricing model for the three and six months ended June 30, 2013 and 2012 are as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
	2013		2012		2013		2012
Risk free interest rate	1.2%		0.7% to 1.0%		0.8% to 1.2%		0.2% to 1.2%
Expected term	5.1 to 6.0 years		5.0 to 6.1 years		5.0 to 6.1 years		5.0 to 6.1 years
Expected volatility	84.5% to 85.6%		81.5% to 82.8%		84.5% to 87.9%		80.6% to 82.8%
Expected dividend yield	—	%	—	%	—	%	—	%

Stock-Based Compensation Expense

The Company recognized stock-based compensation expense as follows (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
	2013		2012		2013		2012
Cost of sales	$	63	$	47	$	108	$	76
Research and development	250		236		466		431
Selling, general and administrative	1,465		1,255		2,790		2,287
Restructuring	201		—		201		—
Total	$	1,979	$	1,538	$	3,565	$	2,794