Annual report pursuant to Section 13 and 15(d)

Stock Options and Warrants (Detail)

v2.4.0.8
Stock Options and Warrants (Detail) (USD $)
 12 Months Ended
May 31, 2014
May 31, 2013
May 31, 2012
Stock option and warrant activity      
Options and warrants outstanding, Number of Shares 18,146,938 10,327,664  
Granted, Number of Shares 18,414,144 11,166,274  
Exercised, Number of Shares (50,000) (780,000)  
Forfeited /expired/ cancelled, Number of Shares (5,704,721) (2,567,000)  
Options and warrants outstanding, Number of Shares 30,806,361 18,146,938 10,327,664
Outstanding exercisable - Number of Shares 29,986,581    
Options and warrants outstanding, Weighted Average Exercise Price $ 1.65 $ 1.60  
Granted, Weighted Average Exercise Price $ 0.74 $ 1.61  
Exercised, Weighted Average Exercise Price   $ 0.26  
Forfeited/expired/cancelled, Weighted Average Exercise Price $ 1.49 $ 1.73  
Options and warrants outstanding, Weighted Average Exercise Price $ 1.13 $ 1.65 $ 1.60
Outstanding exercisable, Weighted Average Exercise Price $ 1.15    
Options and warrants outstanding, Weighted Average Remaining Contractual Life 3 years 3 months 15 days 1 year 10 months 10 days 3 years 2 months 12 days
Outstanding exercisable, Weighted Average Remaining Contractual Life 3 years 2 months 16 days    
Options and warrants outstanding , Aggregate Intrinsic Value $ 177,042 $ 140,321 $ 2,308,279
Exercisable , Aggregate Intrinsic Value $ 170,042