Annual report pursuant to Section 13 and 15(d)

Reconciliation of Liability Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3) (Detail)

v3.10.0.1
Reconciliation of Liability Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3) (Detail) - USD ($)
 12 Months Ended
May 31, 2018
May 31, 2017
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Beginning Balance $ 1,323,732 $ 3,014,667
Fair value adjustments (1,690,935) (2,164,533)
Ending Balance $ 1,323,732 3,014,667
Investor Warrants Issued with Registered Direct Equity Offering    
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Warrants issued   4,360,000
Placement Agent Warrants Issued with Registered Direct Equity Offering    
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Warrants issued   $ 819,200