Annual report pursuant to Section 13 and 15(d)

Stock Options and Warrants - Additional Information (Detail)

v3.5.0.2
Stock Options and Warrants - Additional Information (Detail) - USD ($)
 12 Months Ended
May 31, 2016
May 31, 2015
Mar. 31, 2016
Feb. 28, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Warrants to purchase common shares, shares 795,593      
Proceeds from exercise of warrants $ 548,619 $ 1,141,435    
Non Cash Exercise        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Warrants to purchase common shares, shares 254,708      
Exercise Price 2        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Exercise price of warrants, per share $ 0.75      
Exercise Price 1        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Exercise price of warrants, per share 0.50      
Exercise Price 3        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Exercise price of warrants, per share 0.75      
Private Equity Offering        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Exercise price of warrants, per share $ 0.675      
Term of warrants 5 years      
Private Equity Offering | Exercise Price 2        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Exercise price of warrants, per share $ 1.35      
Private Equity Offering | Exercise Price 1        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Exercise price of warrants, per share 0.75      
Private Equity Offering | Minimum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Exercise price of warrants, per share 0.75      
Private Equity Offering | Maximum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Exercise price of warrants, per share $ 1.00      
Private Equity Offering | Alpha Venture Capital Partners, L.P.        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Warrants to purchase common shares, shares 1,000,000      
Private Equity Offering | Investors and Placement Agent        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Warrants to purchase common shares, shares 28,214,535      
2012 Equity Incentive Plan        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Compensation expense $ 2,353,000 631,000    
Grant date fair value of options and warrants 1,711,500 $ 886,000    
Unrecognized compensation costs $ 712,000      
Weighted average period over which unrecognized compensation costs is expected to be recognized 1 year 1 month 6 days      
2012 Equity Incentive Plan | Consultant | Minimum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Exercise price of warrants, per share $ 0.81      
Warrants, grant date fair value $ 0.25      
Warrants expiration period 5 years      
2012 Equity Incentive Plan | Consultant | Maximum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Exercise price of warrants, per share $ 1.35      
Warrants, grant date fair value $ 0.60      
Warrants expiration period 10 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 2,000,930      
Share-based compensation arrangement by share-based payment award, period 5 years      
Share-based compensation arrangement by share-based payment award, extended period 5 years      
Share price $ 0.81      
Compensation expense $ 548,000      
Share-based compensation arrangement by share-based payment award, options outstanding 1,924,513      
Share-based compensation arrangement by share-based payment award, options, weighted average exercise price $ 1.39      
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      
Vesting period 1 year      
Stock options grant date fair value $ 0.49      
2012 Equity Incentive Plan | Stock Options | Director 1        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock options granted, shares 250,000      
Stock options granted, exercise price $ 0.97      
Stock options grant date fair value $ 0.43      
Share-based compensation arrangement by share-based payment award, period 5 years      
2012 Equity Incentive Plan | Stock Options | Director 2        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock options granted, shares 100,000      
Stock options granted, exercise price $ 0.84      
Stock options grant date fair value $ 0.58      
Share-based compensation arrangement by share-based payment award, period 5 years      
Vesting rights, description Vests equally upon issuance date and one year from issuance date      
2012 Equity Incentive Plan | Stock Options | Executive Management and Employees        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock options granted, shares 2,054,000      
Vesting period 3 years      
Share-based compensation arrangement by share-based payment award, period 10 years      
Stock options granted, exercise price, lower range limit $ 0.75      
Stock options granted, exercise price, upper range limit $ 0.90      
Stock options granted, number of shares covered by one option 100,000      
Stock options, number of shares vested 500,000      
2012 Equity Incentive Plan | Stock Options | Executive Management and Employees | Minimum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock options grant date fair value $ 0.48      
2012 Equity Incentive Plan | Stock Options | Executive Management and Employees | Maximum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock options grant date fair value $ 0.61      
2012 Equity Incentive Plan | Stock Options | Executive Management and Employees | Stock Option Grant Date        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting rights percentage 50.00%      
2012 Equity Incentive Plan | Stock Options | Executive Management and Employees | First Anniversary of Grant Date        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting rights percentage 50.00%      
2012 Equity Incentive Plan | Stock Options | Executive Management and Employees | Vesting Schedule One        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting rights percentage 50.00%      
Stock options, number of shares vested 1,554,000      
2012 Equity Incentive Plan | Stock Options | Executive Management and Employees | Vesting Schedule Two        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock options, number of shares vested 400,000      
2012 Equity Incentive Plan | Stock Options | Before Amendment        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Shares available for future issuance     5,000,000 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     7,000,000 5,000,000