Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2014

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

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

The fair value of each option grant is estimated on the date of grant using the Black-Scholes option-pricing model. The following assumptions were applied to stock option grants during the periods ended:



	Three Months Ended September 30,						Nine Months Ended September 30,
	2014			2013			2014			2013
Estimated weighted-average fair value	$	10.18		$	6.77		$	8.39		$	6.73
Weighted-average assumptions
Expected volatility	70		%	88		%	82		%	87		%
Expected term, in years	6.1			5.8			5.9			5.8
Risk-free interest rate	1.95		%	1.66		%	1.90		%	1.65		%
Expected dividend yield	—		%	—		%	—		%	—		%

Stock-Based Compensation Expense

Stock-based compensation expense has been reported in our Consolidated Statements of Operations and Comprehensive Loss as follows:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2014		2013		2014		2013
	(In thousands)				(In thousands)
Research and development	$	879	$	1,371	$	2,791	$	2,518
Selling, general and administrative	786		840		2,292		1,846
Total	$	1,665	$	2,211	$	5,083	$	4,364

Stock Option Activity and Related Information

Stock option activity for all stock plans and related information is as follows:



	Options Outstanding		Weighted- Average Exercise Price per Share		Remaining Contractual Life (In years)	Aggregate Intrinsic Value (In thousands)
Balance at December 31, 2013	6,969,303		$	6.38
Granted	184,250		12.00
Exercised	(159,332	)	6.39
Forfeited	(214,223	)	9.82
Balance at September 30, 2014	6,779,998		$	6.42	6.46	$	42,797
Vested and expected to vest at September 30, 2014	6,577,603		$	6.32	6.39	$	42,141
Exercisable at September 30, 2014	4,755,993		$	5.12	5.54	$	36,147