STOCK-BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2011

STOCK-BASED COMPENSATION

Schedule of weighted average assumptions used in estimation of the fair value of options granted

	2011	2010			2009
Expected option life (years)	5.5 - 6.25		6.00			6.00
Risk-free interest rate	1.175% - 2.57%		2.42	%		2.74	%
Expected stock price volatility	69.07% - 72.16%		76.05	%		76.75	%
Dividend yield	—		—			—

Summary of stock option compensation expense for employees and non-employees

	2011		2010		2009
Research and development	$	423,925	$	325,208	$	361,773
General and administrative		753,758		667,549		892,730
Total stock-based compensation expense	$	1,177,683	$	992,757	$	1,254,503

Summary of activity under the plans

Options	Option Shares		Weighted Average Exercise Price		Weighted Average Remaining Term		Aggregate Intrinsic Value
Outstanding December 31, 2010		619,572	$	22.14		6.74	$	162,892
Granted		346,541	$	11.40
Exercised		3,194	$	10.14
Forfeited or expired		56,059	$	17.70
Outstanding December 31, 2011		906,860	$	18.36		6.97	$	0
Exercisable at December 31, 2011		474,671	$	25.14		5.40	$	0
Vested or expected to vest at December 31, 2011		879,777	$	18.36		6.95	$	0