Quarterly report pursuant to Section 13 or 15(d)

Weighted Average Assumptions to Value Investor Warrants (Detail)

v3.5.0.2
Weighted Average Assumptions to Value Investor Warrants (Detail) - Investor Warrants
12 Months Ended
May 31, 2015
$ / shares
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]  
Expected dividend yield 0.00%
Stock price volatility 88.79%
Expected term 5 years
Minimum  
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]  
Risk-free interest rate 1.46%
Grant-date fair value $ 0.52
Maximum  
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]  
Risk-free interest rate 1.58%
Grant-date fair value $ 0.76