Stock-based Compensation (Tables)

9 Months Ended

Sep. 30, 2012

Stock-based Compensation [Abstract]

Weighted average assumptions

The fair value of stock-based awards was estimated based on the following weighted average assumptions for the three and nine months ended September 30, 2012 and 2011:

	Three Months Ended September 30,						Nine Months Ended September 30,
	2012			2011			2012			2011
Dividend yield		0	%		0	%		0	%		0	%
Expected volatility		92	%		89	%		92	%		87	%
Risk-free interest rate		0.65	%		0.96	%		0.83	%		1.86	%
Expected term	5.6 years			5.6 years			5.6 years			5.3 years

Stock option activity

Stock option activity for the nine months ended September 30, 2012 was as follows:

	Options			Weighted Average Exercise Price Per Share		Weighted Average Remaining Contractual Life (in years)		Aggregate Intrinsic Value (in thousands)
Options outstanding at December 31, 2011		5,053,435		$	12.55		6.89	$	-
Granted		2,161,920			2.57
Exercised		(77,797	)		1.69
Forfeited, expired or cancelled		(484,144	)		15.96
Options outstanding at September 30, 2012		6,653,414		$	9.19		7.51	$	4,520,629
Options exercisable at September 30, 2012		4,003,868		$	13.10		6.53	$	2,106,931

Unvested RSU activity

Unvested RSU activity for the nine months ended September 30, 2012 is summarized below:

				Weighted-
	Number of			Average Grant-
	Shares			Date Fair Value
Unvested balance at December 31, 2011		903,874		$	1.69
Granted		1,190,323			2.84
Vested		(194,629	)		3.44
Forfeited		(200,261	)		1.69
Unvested balance at September 30, 2012		1,699,307		$	2.29

Stock-based compensation expense

The following table shows total stock-based compensation expense included in the condensed consolidated statements of comprehensive loss for the three and nine months ended September 30, 2012 and 2011 (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2012		2011		2012		2011
Research and development	$	1,304	$	458	$	1,984	$	2,404
Selling, general and administrative		818		1,084		1,384		3,194
Total stock-based compensation expense	$	2,122	$	1,542	$	3,368	$	5,598