Stock Compensation (Tables)

9 Months Ended

Sep. 30, 2012

Stock Compensation [Abstract]

Summary of the Company's stock option activity

Stock Options	Underlying Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term		Aggregate Intrinsic Value
Outstanding at December 31, 2011		2,417,659		$	11.18
Granted		921,790			9.19
Exercised		(167,341	)		7.28
Canceled or expired		(731,638	)		11.32
Outstanding at September 30, 2012		2,440,470		$	10.65		8.01	$	14,315,000
Vested at September 30, 2012 and expected to vest		2,325,299		$	10.75		7.93	$	13,547,000
Exercisable at September 30, 2012		770,611		$	14.54		5.20	$	3,174,000

Fair values of stock options granted

	Three and Nine Months Ended September 30,
	2012			2011
Risk-free interest rate		0.6%-1.1	%		1.1%-2.4	%
Expected dividend yield		0	%		0	%
Expected lives		5.1-5.3 years			5.4-5.5 years
Expected volatility		79.7%-94.8	%		78.2%-81.6	%

Restricted Stock

	Nine Months Ended September 30, 2012
Restricted Stock Units	Shares			Weighted Average Grant Date Fair Value per Share
Outstanding at December 31, 2011		—		$	—
Granted		39,877			6.28
Vested		—			—
Forfeited or canceled		(966	)		5.40
Outstanding at September 30, 2012		38,911		$	6.30

Summary of the stock-based compensation expense recognized in the statements of operations

	Three Months Ended				Nine Months Ended
	September 30, 2012		September 30, 2011		September 30, 2012		September 30, 2011
	(in thousands)				(in thousands)
Research and development	$	271	$	266	$	783	$	998
General and administrative		421		326		1,057		1,456
Total	$	692	$	592	$	1,840	$	2,454