Quarterly report pursuant to Section 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, 2015
Aug. 31, 2014
Feb. 28, 2015
Private Equity Offering      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Warrants granted to purchase common stock shares 5,342,790    
Warrant covering common stock shares purchased, percentage 50.00%    
Common stock, par value    
Exercise price of warrants, per share $ 0.75    
Term of warrants 5 years    
Private Equity Offering | Placement Agent      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Warrants granted to purchase common stock shares 1,272,131    
Exercise price of warrants, per share $ 0.75    
Term of warrants 5 years    
Black Scholes Valuation Model | Private Equity Offering | Placement Agent      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vested restricted stock awards 593,000    
2012 Equity Incentive Plan      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Compensation expense related to stock options and warrants $ 352,000 $ 137,500  
Grant date fair value of options 337,000 $ 82,500  
Unrecognized compensation costs $ 775,000    
Weighted average period over which unrecognized compensation costs is expected to be recognized 1 year 5 months 1 day    
2012 Equity Incentive Plan | Third Party Consulting Firm and Scientific Advisor      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Warrants granted to purchase common stock shares 200,000    
Exercise price of warrants, per share $ 1.02    
Warrants, termination date Jul. 13, 2025    
2012 Equity Incentive Plan | Yearly Vesting | Third Party Consulting Firm and Scientific Advisor      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Exercisable warrants, vesting percentage 50.00%    
2012 Equity Incentive Plan | Tranche 1 | Third Party Consulting Firm and Scientific Advisor      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Warrants, exercisable date Jan. 01, 2016    
2012 Equity Incentive Plan | Tranche 2 | Third Party Consulting Firm and Scientific Advisor      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Warrants, exercisable date Jan. 01, 2017    
2012 Equity Incentive Plan | Consultant One      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Warrants granted to purchase common stock shares 170,000    
Exercise price of warrants, per share $ 1.02    
Exercisable warrants, expire period 5 years    
2012 Equity Incentive Plan | Third party consultant Two      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Warrants granted to purchase common stock shares 10,000    
Exercise price of warrants, per share $ 1.02    
Exercisable warrants, expire period 5 years    
2012 Equity Incentive Plan | Stock Options      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Shares available for future stock-based grants 1,754,930    
2012 Equity Incentive Plan | Stock Options | Executive Management and Employee      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock options granted, shares 400,000    
Stock options granted, exercise price $ 0.90    
Stock options, vesting period 3 years    
Exercisable warrants, expire period 5 years    
2012 Equity Incentive Plan | Stock Options | Directors      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock options granted, shares 350,000    
Stock options granted, exercise price $ 0.975    
Stock options, vesting period 1 year    
Stock options grant date fair value $ 0.49    
2012 Equity Incentive Plan | Stock Options | Directors | Quarterly Vesting      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Exercisable warrants, vesting percentage 25.00%    
2012 Equity Incentive Plan | Stock Options | Director 1      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock options granted, exercise price $ 0.97    
Stock options grant date fair value $ 0.43    
Stock options, number of shares vested 250,000    
2012 Equity Incentive Plan | Stock Options | Before Amendment      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Shares available for future issuance     3,000,000
2012 Equity Incentive Plan | Stock Options | After amendment      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Shares available for future issuance     5,000,000