Stock Based Compensation (Tables)

6 Months Ended

Jun. 30, 2012

Stock Based Compensation [Abstract]

Schedule of total stock-based compensation expense from stock options and warrants

The following table sets forth the total stock-based compensation expense resulting from stock options and warrants included in the Company's unaudited interim statements of operations:

	Three Months Ended June 30,				Six Months Ended June 30,
	2012		2011		2012		2011
Research and development - employee	$	98,242	$	87,890	$	193,366	$	171,321
General and administrative - employee		263,007		343,682		437,079		541,274
Total employee stock-based compensation	$	361,249	$	431,572	$	630,445	$	712,595
Research and development - non-employee	$	-	$	19,576	$	-	$	41,484
General and administrative - non-employee		176,074		42,908		228,492		88,305
Total non-employee stock-based compensation	$	176,074	$	62,484	$	228,492	$	129,789

Schedule of share-based payment award, fair value of the stock options granted , assumptions

During the six-month period ended June 30, 2012, the Company issued stock options to purchase 53,500 shares of its common stock. The fair value of the stock options granted in the current six-month period was estimated using the Black-Scholes option-pricing model, based on the following assumptions:

	Six Months Ended June 30, 2012			Six Months Ended June 30, 2011
Risk-free interest rate		1.54	%		2.13	%
Expected volatility		89.7% - 97.7	%		87.69	%
Expected lives (years)		6 - 10			10
Expected dividend yield		0.00	%		0.00	%

Schedule of share-based compensation, stock options, activity

As of June 30, 2012, there remained approximately $1.2 million of unrecognized compensation expense related to unvested stock options granted to current and former employees, directors and consultants, to be recognized as expense over a weighted-average period of 1.09 years. Presented below is the Company's stock option activity:

	Six Months Ended June 30, 2012
	Number of Options (Employees)			Number of Options (Non-Employees)		Total Number of Options			Weighted-Average Exercise Price
Outstanding at January 1, 2012		1,763,923			143,572		1,907,495		$	6.06
Granted		53,502			-		53,502		$	2.77
Exercised		(2,500	)		-		(2,500	)	$	2.88
Forfeited or expired		(26,384	)		-		(26,384	)	$	4.97
Outstanding at June 30, 2012		1,788,541			143,572		1,932,113		$	5.99
Options exercisable at June 30, 2012		1,238,545			125,715		1,364,260		$	6.94

Schedule of unvested stock options activity

A summary of the unvested stock options as of June 30, 2012, and changes during the six-month period then ended, is presented below:

	Number of Options (Employees)			Number of Options (Non-Employees)		Total Number of Options			Weighted-Average Grant Date Fair Value per Share
Non-vested at January 1, 2012		693,504			17,857		711,361		$	3.28
Granted		53,502			-		53,502		$	2.32
Forfeited or expired		(26,384	)		-		(26,384	)	$	3.88
Vested		(173,181	)		-		(173,181	)	$	3.26
Non-vested at June 30, 2012		547,441			17,857		565,298		$	3.18

Schedule of share-based compensation, summarizes significant ranges of outstanding stock options

The following table summarizes significant ranges of outstanding stock options under the Company's plans at June 30, 2012:

Range of Exercise Prices	Number of Options		Weighted-Average Remaining Contractual Life (years)		Weighted-Average Exercise Price		Number of Options Exercisable		Weighted-Average Contractual Life		Weighted-Average Exercise Price
$1.96 - 3.00		648,768		8.83	$	2.29		245,220		8.83	$	2.46
$3.01 -7.00		204,942		5.88	$	5.40		195,680		5.88	$	5.39
$7.01 -8.50		946,117		5.64	$	7.66		791,074		5.64	$	7.74
$8.51 - 32.55		132,284		2.33	$	12.75		132,286		2.33	$	12.75
		1,932,113		6.49	$	5.99		1,364,260		6.49	$	6.96