Stock Options and Warrants (Tables)

12 Months Ended

May 31, 2013

Estimated Fair Value of Options and Warrants is determined using Black-Scholes Option Valuation Model

The estimated fair value of options and warrants is determined using the Black-Scholes option valuation model with the following weighted-average assumptions for the periods ended May 31, 2013 and 2012:

	2013	2012
Risk free rate	0.12% - 0.70%	0.12% -.87%
Dividend yield	—	—
Volatility	87% - 102%	93% - 102%
Expected term	1 - 4 years	1 - 4 years

Stock Option and Warrant Activity

The following table represents stock option and warrants activity for the periods ended May 31, 2013 and 2012:

	Number of Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life		Aggregate Intrinsic Value
Options and warrants outstanding - May 31, 2011		7,473,576		$	1.34		3.84	$	10,495,913
Granted		3,456,088		$	2.04		—		—
Exercised		(527,500	)	$	.62		—		—
Forfeited/expired/cancelled		(74,500	)	$	2.49		—		—
Options and warrants outstanding - May 31, 2012		10,327,664		$	1.60		3.20	$	2,308,279
Granted		11,166,274		$	1.61		—		—
Exercised		(780,000	)	$	0.26		—		—
Forfeited/expired/cancelled		(2,567,000	)	$	1.73		—		—
Options and warrants outstanding - May 31, 2013		18,146,938		$	1.65		1.86	$	140,321
Exercisable - May 31, 2013		16,253,188		$	1.68		1.65	$	140,321