Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2012

Stock-Based Compensation [Abstract]

Stock-Based Compensation Expense

The Company recorded stock-based compensation expense in the statements of operations and comprehensive loss as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2012		2011		2012		2011
Research and development	$	219	$	176	$	638	$	449
General and administrative		274		366		1,030		1,228
Total stock-based compensation expense	$	493	$	542	$	1,668	$	1,677

Summary of Option Activity

The following is a summary of option activity under the 2005 Plan and the 1995 Plan for the nine months ended September 30, 2012:

	2005 Stock Incentive Plan					1995 Stock Option Plan
	Stock Options			Weighted- Average Exercise Price		Stock Options			Weighted- Average Exercise Price
Outstanding at January 1, 2012		7,412,746		$	2.22		474,650		$	4.38
Granted		3,483,000		$	1.29		-		$	-
Exercised		(80,784	)	$	0.61		-		$	-
Canceled		(1,546,562	)	$	2.26		(184,750	)	$	4.01
Outstanding at September 30, 2012		9,268,400		$	1.88		289,900		$	4.59
Shares exercisable at September 30, 2012		3,503,043		$	2.38		289,900		$	4.59
Shares available for grant at September 30, 2012		5,559,536

Assumptions used to Estimate Grant Date Fair Value of Stock Options granted using Black-Scholes Option-Pricing Model

The fair value of stock options granted was estimated at the date of grant using the Black-Scholes option-pricing model with the following assumptions:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2012		2011		2012		2011
Weighted-average fair value of stock options granted		$1.09		$0.78		$0.71		$1.19
Risk-free interest rate		0.55%		0.48%-0.68%		0.55%-1.54%		0.48%-1.91%
Dividend yield		0%		0%		0%		0%
Volatility		76.60%-76.71%		75.86%-80.40%		75.47%-80.48%		73.28%-80.48%
Expected term (in years)		4.24		3.49-4.21		3.34-7.09		3.26-4.47
Expected forfeiture rate		0%-23.15%		0%-23.15%		0%-23.15%		0%-23.15%

Summary of Restricted Stock Awards Activity

The following is a summary of restricted stock awards activity for the nine months ended September 30, 2012:

	Number of Shares		Per Share Weighted- Average Grant-Date Fair Value
Outstanding at January 1, 2012		53,333	$	1.63
Restricted stock granted		-	$	-
Restricted stock vested		3,333	$	5.21
Restricted stock forfeited		-	$	-
Outstanding at September 30, 2012		50,000	$	1.39