Quarterly report pursuant to sections 13 or 15(d)

Summary of Significant Accounting Policies - Additional Information (Detail)

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Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)
 3 Months Ended 118 Months Ended
Aug. 31, 2013
Aug. 31, 2012
Aug. 31, 2013
May 31, 2013
Class of Stock [Line Items]        
Net loss $ 2,573,551 $ 2,815,166 $ 34,974,458  
Accumulated deficit 36,576,370   36,576,370  
Working capital deficit 2,508,799   2,508,799  
Estimated future unvested option forfeitures 0.00%      
Deferred offering costs 196,929   196,929 96,930
Direct costs associated with the convertible notes 120,000      
Amortization of deferred offering costs 20,000   20,000  
Deferred finance costs, current 100,000   100,000  
Deferred finance costs associated with sale of the equity securities 200,000      
Common stock options and warrants to purchase 95,100   95,100 95,100
Common stock options and warrants to purchase 18,866,510 9,697,664    
Face amount of Notes 7,221,250   7,221,250 6,588,250
Additional common shares if convertible debt is converted to common stock 8,725,769      
Unrecognized benefits 0 0 0  
Convertible Debt
        
Class of Stock [Line Items]        
Face amount of Notes 6,301,250   6,301,250  
Stock Rescission Liability
        
Class of Stock [Line Items]        
Deferred offering costs $ 97,000   $ 97,000 $ 97,000
Series B convertible preferred stock
        
Class of Stock [Line Items]        
Common stock options and warrants to purchase 95,100   95,100  
Common shares issued upon conversion of preferred stock 951,000