Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2014

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

Schedule of stock-based compensation expense

The following table presents total stock-based compensation expense by functional areas included in the condensed consolidated statements of operations for the three and six months ended June 30, 2014 and 2013 (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
	2014		2013		2014		2013
Research and development	$	268	$	502	$	507	$	1,706
Selling, general and administrative	1,078		760		2,068		1,029
Total	$	1,346	$	1,262	$	2,575	$	2,735

Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity

The following table presents total stock-based compensation expense by security types included in the condensed consolidated statements of operations for the three and six months ended June 30, 2014 and 2013 (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
	2014		2013		2014		2013
Stock options	$	320	$	531	$	596	$	1,141
RSUs and RSAs	792		604		1,661		1,296
PSUs	234		127		318		298
Total	$	1,346	$	1,262	$	2,575	$	2,735

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

The range of weighted-average assumptions used to estimate the fair value of employee stock options granted was as follows:

	Three months ended June 30,						Six months ended June 30,
	2014			2013			2014			2013
Expected term (in years)	—			6.0			6.0			6.0
Volatility	—			.6520			0.6394			0.6520
Risk-free interest rate	—		%	1.13		%	0.19		%	1.07%-1.13%
Dividend yield	—		%	—		%	—		%	—		%
Weighted-average estimated fair value of stock options granted	$	—		$	1.26		$	1.15		$	1.36