Quarterly report pursuant to sections 13 or 15(d)

Stock Options and Warrants - Additional Information (Detail)

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Stock Options and Warrants - Additional Information (Detail) (USD $)
3 Months Ended
Aug. 31, 2013
Aug. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock options granted, shares 1,123,072  
Stock options granted, exercise price $ 0.55  
Exercisable warrants, exercise price 0.75  
Warrants attached with convertible promissory notes $ 1,200,000  
Value of unit at conversion right $ 1.30  
Exercisable warrants, expire period 5 years  
Common Stock Warrants
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Warrants exercisable period 3 years  
Number of warrants issued 923,072  
Exercisable warrants, exercise price 0.50  
Holders of Notes
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Number of shares issued 2  
Warrants to purchase common shares, shares 1  
2012 Equity Incentive Plan
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Authorized shares that can be purchased for options and warrants issued 7,600,000  
Compensation expense related to stock options and warrants 226,000 1,612,000
Grant date fair value of options 1,115,000 2,092,000
Grant date fair value of warrants vested 1,115,000 2,092,000
Unrecognized compensation costs $ 1,615,000  
Weighted average period over which unrecognized compensation costs is expected to be recognized 2 years 3 months 26 days  
2012 Equity Incentive Plan | Stock Options
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Shares available for future issuance 3,000,000  
Shares available for future stock-based grants 1,776,710  
2012 Equity Incentive Plan | Stock Options | Director
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock options granted, shares 200,000  
Stock options granted, exercise price $ 0.80  
Percentage of option awards vest at per quarter 25.00%  
Grant date fair value of options $ 0.47  
2012 Equity Incentive Plan | Stock Options 2 | Director
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock options, vesting period 1 year