Stock Incentive Plans and Stock Based Compensation (Tables)

12 Months Ended

Dec. 31, 2013

Stock Option Activity

The following table summarizes all stock option activity for the year ended December 31, 2013:

	Number of Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term		Aggregate Intrinsic Value
	(in thousands, except for per share amounts)
Outstanding January 1, 2013		10,892		$	7.29
Granted		1,217			7.49
Cancelled/Expired		(2,393	)		10.83
Exercised		(386	)		1.61
Outstanding, December 31, 2013		9,330			6.64		7.4 years	$	1,063
Exercisable, December 31, 2013		7,077			5.87		7.1 years	$	1,062
Vested and Expected to Vest, December 31, 2013		9,062			6.57		7.4 years	$	1,063
Available for future grant at December 31, 2013		9,212

Assumptions Used to Estimate Fair Value of Share-Based Payment Awards

For 2013, 2012 and 2011, the Company used the following assumptions to estimate the fair value of share-based payment awards:

	2013	2012	2011
Risk free interest rate	0.91% - 2.07%	0.81% - 1.39%	2.03% - 2.56%
Expected dividend yield	0.00%	0.00%	0.00%
Expected option life (years)	6.25	6.25	6.25
Expected volatility	91% - 110%	109% - 111%	105% - 112%

Restricted Stock Unit Activity

The following table presents the restricted stock unit activity for the years ended December 31, 2013 and 2012.

	Shares			Weighted Average Grant Date Fair Value
	(in thousands)
Outstanding—as of January 1, 2013		465			8.86
Granted		553			7.75
Vested		(93	)		8.86
Forfeited		(729	)		8.21
Outstanding—as of December 31, 2013		196			6.96

Stock-Based Compensation Expense Related to Option Awards

The following table presents the stock-based compensation expense related to stock based awards for the period ended December 31:

	2013		2012		2011
	(in thousands)
Research and development	$	2,837	$	3,700	$	1,464
Selling, general and administrative		11,848		14,375		7,830
Stock-based compensation expense	$	14,685	$	18,075	$	9,294