Stock-Based Compensation (Tables)

106 Months Ended

Jun. 30, 2012

Stock-Based Compensation Expense on All Employee and Non-Employee Awards

The Company recognized stock-based compensation expense on all employee and non-employee awards as follows:

	For the three months				For the six months
	ended June 30,				ended June 30,
(in thousands)	2012		2011		2012		2011
Research and development	$	426	$	166	$	942	$	276
General and administrative		652		446		1,348		1,038
Stock-based employee compensation expense	$	1,078	$	612	$	2,290	$	1,314

Fair Value of Stock Options Assumptions Using Black-Scholes Option Valuation Model

For the three months ended June 30, 2012 and 2011, the fair value of stock options was estimated on the date of grant using a Black-Scholes option valuation model with the following assumptions:

	For the three months ended June 30,
	2012			2011
Risk-free interest rate		0.93 - 1.10	%		1.83 - 2.61	%
Expected life in years		6			5.77 - 6
Expected volatility		83.36 - 83.52	%		84.4 - 87.4	%
Expected dividend yield		0			0

Stock Option Activity Under Stock Option Plan

Stock option activity under the Company’s stock option plan for the six months ended June 30, 2012 is as follows:

(in thousands, except share and per share data)	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Contractual Term (Years)		Aggregate Intrinsic Value
Outstanding, December 31, 2011		5,138,486		$	4.08
Granted		425,400			4.96
Exercised		(8,300	)		3.61
Cancelled		(158,432	)		5.90
Outstanding, June 30, 2012		5,397,154		$	4.10		7.19	$	10,320
Vested and unvested expected to vest at June 30, 2012		5,340,550		$	4.10		7.19	$	10,212
Options exercisable, June 30, 2012		3,124,387		$	3.40		5.28	$	8,137
Options exercisable, December 31, 2011		2,911,186		$	3.21		5.52	$	4,232
Options available for future grant		3,678,000

Summary of Unvested Restricted Stock

A summary of the status of unvested restricted stock for the six months ended June 30, 2012 is as follows:

	Number of Shares			Weighted-Average Grant Date Fair Value
Non-vested, December 31, 2011		950,906		$	4.34
Granted		170,302			4.51
Vested		(25,000	)		5.21
Cancelled		(66,360	)		4.41
Non-vested, June 30, 2012		1,029,848		$	4.34