Quarterly report pursuant to Section 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
Aug. 31, 2014
Aug. 31, 2013
May 31, 2014
Summary Of Significant Accounting Policies [Line Items]      
Net loss $ (3,379,520) $ (2,573,551)  
Accumulated (deficit) (49,813,754)   (46,434,232)
Insurance coverage, per depositor at each financial 250,000   250,000
Balance in excess of federally insured limits 2,046,000   4,589,000
Impairment charges 0 0  
Estimated future unvested option forfeitures 0.00%    
Deferred offering costs 68,292   68,292
Common stock options and warrants to purchase 30,936,361 18,866,510  
Face amount of notes 4,271,250   7,221,250
Additional common shares if convertible debt is converted to common stock 5,695,000    
Unrecognized benefits 0 0  
Convertible Debt
      
Summary Of Significant Accounting Policies [Line Items]      
Face amount of notes 4,271,250    
Patents
      
Summary Of Significant Accounting Policies [Line Items]      
Amortization period of intangible assets 10 years    
Stock Rescission Liability
      
Summary Of Significant Accounting Policies [Line Items]      
Deferred offering costs $ 68,300   $ 68,300
Series B Convertible Preferred Stock
      
Summary Of Significant Accounting Policies [Line Items]      
Preferred Stock Shares authorized to be issued 400,000   400,000
Common stock options and warrants to purchase 95,100   95,100
Common shares issued upon conversion of preferred stock 951,000    
Maximum
      
Summary Of Significant Accounting Policies [Line Items]      
Preferred Stock Shares authorized to be issued 5,000,000    
Income tax examination, year under examination 2013    
Minimum
      
Summary Of Significant Accounting Policies [Line Items]      
Income tax examination, year under examination 2011