STOCK-BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2012

STOCK-BASED COMPENSATION

Summary of stock option activity

	Shares			Weighted Average Exercise Price Per Share		Weighted Average Remaining Contractual Term (In Years)
Options Outstanding at December 31, 2011		4,459,034		$	6.08		6.9
Granted		1,144,484		$	5.83
Exercised		(52,652	)	$	2.83
Canceled		(201,056	)	$	8.22
Options Outstanding at December 31, 2012		5,349,810		$	5.98		7.0
Options Vested and Expected to Vest at December 31, 2012		5,279,983		$	5.99		6.9
Options Exercisable at December 31, 2012		3,306,468		$	6.71		5.7
Shares Available for Grant under the 2008 Plan		3,352,081

Summary of restricted stock activity

	Shares			Weighted Average Grant Date Fair Value (per share)
Outstanding and unvested at December 31, 2011		6,000		$	3.24
Granted		12,000		$	4.50
Vested		(12,000	)	$	3.87
Canceled		—			—
Outstanding and unvested at December 31, 2012		6,000		$	4.50

Schedule of stock-based compensation expense

	2012		2011		2010
	(In thousands)
Research and development	$	1,415	$	1,412	$	1,625
General and administrative		883		930		1,177
Total stock-based compensation expense	$	2,298	$	2,342	$	2,802

Schedule of assumptions used for the fair values of employee stock options granted

	Year Ended December 31, 2012	Year Ended December 31, 2011	Year Ended December 31, 2010
Expected stock price volatility	70 - 72%	68 - 70%	65 - 67%
Expected option term	6.0 Years	6.0 Years	6.2 Years
Risk-free interest rate	0.9 - 1.4%	1.4 - 2.9%	1.8 - 3.2%
Expected dividend yield	None	None	None