8. Stock Based Compensation

The Company has a 2000 Long-Term Incentive Plan under which 10.0 million shares of common stock were originally reserved for issuance. As of June 30, 2011, there were approximately 7.2 million shares subject to outstanding stock options. This plan expired on August 6, 2010, and thus no further shares are available for future grant under this plan.

The Company also has a 2008 Stock Incentive Plan under which 10.0 million shares of common stock were originally reserved for issuance. As of June 30, 2011, there were 2.8 million shares subject to outstanding stock options and 7.2 million shares available for future grant under this plan.

The Company has adopted the provisions of ASC 718, which requires the measurement and recognition of compensation expense for all stock-based awards made to employees and non-employees.

For stock options and stock warrants paid in consideration of services rendered by non-employees, the Company recognizes compensation expense in accordance with the requirements of ASC 718, Accounting for Equity Instruments that are Issued to other thanEmployees for Acquiring, or in Conjunction with Selling Goods or Services and ASC 505, Accounting Recognition for Certain Transactions involving EquityInstruments Granted to Other Than Employees, as amended.

Non-employee option grants that do not vest immediately upon grant are recorded as an expense over the vesting period. At the end of each financial reporting period, the value of these options, as calculated using the Black-Scholes option-pricing model, is determined, and compensation expense recognized or recovered during the period is adjusted accordingly. Since the fair market value of options granted to non-employees is subject to change in the future, the amount of the future compensation expense is subject to adjustment until the common stock options are fully vested.

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,
	2011		2010		2011		2010
Research and development - employee	$	87,890	$	45,261	$	171,321	$	87,895
General and administrative - employee		343,682		338,456		541,274		483,404
Total employee stock-based compensation	$	431,572	$	383,717	$	712,595	$	571,299

Research and development - non-employee	$	19,576	$	24,990	$	41,484	$	53,312
General and administrative - non-employee		42,908		-		88,305		478,621
Total non-employee stock-based compensation	$	62,484	$	24,990	$	129,789	$	531,933

During the six-month period ended June 30, 2011, the Company issued stock options to purchase 250,000 shares of its common stock. The fair value of the stock options granted in the six-month period listed in the table below was estimated using the Black-Scholes option-pricing model, based on the following assumptions:


	Six Months Ended June 30, 2011			Six Months Ended June 30, 2010
Risk-free interest rate		2.13	%		2.37% - 2.97	%
Expected volatility		87.69	%		92.5% - 99.4	%
Expected lives (years)		10			5 – 10
Expected dividend yield		0.00	%		0.00	%

The Company's computation of expected volatility is based on the historical daily volatility of its publicly traded stock. For option grants issued during the six-month periods ended June 30, 2011 and 2010, the Company used a calculated volatility for each grant. The Company uses historical information to compute expected lives. In the six-month period ended June 30, 2011, the contractual term of the options granted was ten years and in the comparative 2010 period the contractual terms was 5 to 10 years; the Company used 6 years as the expected life in the 2010 period. The dividend yield assumption of zero is based upon the fact the Company has never paid cash dividends and presently has no intention of paying cash dividends. The risk-free interest rate used for each grant is equal to the U.S. Treasury rates in effect at the time of the grant for instruments with a similar expected life. Based on historical experience, for the six-month periods ended June 30, 2011 and 2010, the Company has estimated an annualized forfeiture rate of 13% and 14%, respectively, for options granted to its employees, 2% for options granted to senior management and 0% for options granted to directors and non-employees. Compensation costs will be adjusted for future changes in estimated forfeitures. The Company will record additional expense if the actual forfeitures are lower than estimated and will record a recovery of prior expense if the actual forfeiture rates are higher than estimated. No amounts relating to employee stock-based compensation have been capitalized.

At June 30, 2011, there remained approximately $2.5 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 1.02 years. Presented below is the Company's stock option activity:

	Six Months Ended June 30, 2011
	Number of Options (Employees)			Number of Options (Non-Employees)		Total Number of Options			Weighted-Average Exercise Price
Outstanding at January 1, 2011		8,877,460			995,000		9,872,460		$	1.05
Granted		250,000			-		250,000			0.72
Exercised		-			-		-			-
Forfeited or expired		(88,870	)		-		(88,870	)	$	1.03
Outstanding at June 30, 2011		9,038,590			995,000		10,033,590		$	1.04
Options exercisable at June 30, 2011		6,697,633			757,521		7,455,154		$	1.06

A summary of the unvested stock options as of June 30, 2011, and changes during the six-months 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, 2011		3,175,514			287,459			3,462,973		$	0.81
Granted		-			-			-		$	-
Forfeited or expired		(71,000	)		-			(71,000	)	$	0.75
Vested		(763,556	)		(49,980	)		(813,536	)	$	0.77
Non-vested at June 30, 2011		2,340,958			237,479			2,578,437		$	0.90

The following table summarizes significant ranges of outstanding stock options under the Company's plans at June 30, 2011:

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
$	0.30 - 1.00		2,392,607		7.06	$	0.61		2,103,357		7.06	$	0.61
$	1.01 –1.50		7,112,983		6.50	$	1.10		4,823,797		6.50	$	1.13
$	1.51 - 3.33		528,000		3.05	$	2.27		528,000		3.05	$	2.27
			9,808,590		6.45	$	1.04		7,455,154		6.45	$	1.06

The aggregate intrinsic value of outstanding options as of June 30, 2011 was $0.5 million, which represents the difference between the fair market value of the underlying shares based on the closing price of the Company's common stock on June 30, 2011 of $0.72 and the aggregate exercise price of the options.