Stock-Based Compensation (Tables)

9 Months Ended

Sep. 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 months and nine months ended September 30, 2014 and 2013 (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2014		2013		2014		2013
Research and development (1)	$	227	$	97	$	734	$	989
Selling, general and administrative	828		529		2,896		2,372
Total	$	1,055	$	626	$	3,630	$	3,361

(1) Stock-based compensation expense associated with cost of biocatalyst product sales is included in research and development. Amounts were immaterial for all periods presented.

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 months and nine months ended September 30, 2014 and 2013 (in thousands):

	Three Months Ended September 30,					Nine Months Ended September 30,
	2014		2013			2014		2013
Stock options	$	247	$	397		$	843	$	1,538
RSUs and RSAs	722		527			2,383		1,823
PSUs	86		(298		)	404		—
Total	$	1,055	$	626		$	3,630	$	3,361

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

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

	Three months ended September 30,						Nine months ended September 30,
	2014			2013			2014			2013
Expected term (in years)	6.0			6.0			6.0			6.0
Volatility	0.676 - 0.679			0.640			0.639 - 0.679			0.640 - 0.652
Risk-free interest rate	1.90% - 2.13%			1.81		%	1.90% - 2.13%			1.07% - 1.81%
Dividend yield	—		%	—		%	—		%	—		%
Weighted-average estimated fair value of stock options granted	$	1.21		$	1.17		$	1.16		$	1.34