Annual report pursuant to section 13 and 15(d)

Convertible Instruments - Additional Information (Detail)

v2.4.0.8
Convertible Instruments - Additional Information (Detail) (USD $)
 12 Months Ended
May 31, 2013
May 31, 2012
May 31, 2010
Class of Stock [Line Items]      
Preferred Stock, Shares issued 95,100 98,900  
Preferred Stock, Share price     $ 5.00
Constructive dividend to Preferred stock holders $ 6,000,000    
Liquidation preference on common shares 5.00    
Dividends are payable to preferred stock holders $ 0.25    
Face amount of notes 6,588,250    
Earliest date for repayment of principal on notes Nov. 30, 2013    
Latest date for repayment of principal on notes Mar. 06, 2016    
US Phase III trial
      
Class of Stock [Line Items]      
Convertible note conversion price per share $ 0.75    
Convertible note, conversion amount 6,208,250    
US new drug application approval by the FDA
      
Class of Stock [Line Items]      
Convertible note conversion price per share $ 0.65    
Convertible note, conversion amount $ 380,000    
Investor
      
Class of Stock [Line Items]      
Interest on convertible notes payment start date Apr. 01, 2013    
Common stock warrant term 2 years    
Warrants to purchase common shares, shares 8,527,984    
Minimum
      
Class of Stock [Line Items]      
Convertible note conversion price per share $ 0.65    
Interest rate on convertible notes 5.00%    
Minimum | Investor
      
Class of Stock [Line Items]      
Warrants exercise price per share 0.75    
Warrants exercisable expiration date Oct. 01, 2014    
Maximum
      
Class of Stock [Line Items]      
Convertible note conversion price per share $ 0.75    
Interest rate on convertible notes 10.00%    
Maximum | Investor
      
Class of Stock [Line Items]      
Warrants exercise price per share 2.00    
Warrants exercisable expiration date May 31, 2015    
Series B convertible preferred stock
      
Class of Stock [Line Items]      
Preferred Stock, Shares issued     400,000
Preferred Stock, Conversion shares 3,800    
Common Stock
      
Class of Stock [Line Items]      
Preferred Stock, Share price     $ 10
Converted Common Stock 38,000    
Convertible note conversion price per share     $ 0.50