Stock-based Compensation (Tables)

6 Months Ended

Jun. 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 six months ended June 30, 2012 and 2011:

	Three Months Ended June 30,						Six Months Ended June 30,
	2012			2011			2012			2011
Dividend yield		0	%		0	%		0	%		0	%
Expected volatility		92	%		87	%		92	%		87	%
Risk-free interest rate		0.72	%		1.76	%		1.02	%		1.87	%
Expected term	5.6 years			5.6 years			5.6 years			5.3 years

Stock option activity

Stock option activity for the six months ended June 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		1,043,550			1.54
Exercised		(49,864	)		1.69
Forfeited, expired or cancelled		(337,522	)		20.18
Options outstanding at June 30, 2012		5,709,599		$	10.18		7.26	$	2,790
Options exercisable at June 30, 2012		3,745,862		$	13.79		6.54	$	1,152

Unvested RSU activity

Unvested RSU activity for the six months ended June 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		391,765			1.42
Vested		(9,231	)		1.69
Forfeited		(181,030	)		1.69
Unvested balance at June 30, 2012		1,105,378		$	1.59

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 six months ended June 30, 2012 and 2011 (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
	2012		2011		2012		2011
Research and development	$	295	$	885	$	680	$	1,946
Selling, general and administrative		277		1,399		566		2,110
Total stock-based compensation expense	$	572	$	2,284	$	1,246	$	4,056