Quarterly report pursuant to Section 13 or 15(d)

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

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Reconciliation of Liability Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3) (Detail) - USD ($)
6 Months Ended 12 Months Ended
Nov. 30, 2019
May 31, 2019
May 31, 2018
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Beginning Balance $ 2,407,269 $ 1,323,732  
Fair value adjustments     $ (3,855,468)
Ending Balance 1,578,770 2,407,269 1,323,732
Convertible notes [Member]      
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Fair value adjustments (548,739) (921,600)  
Warrant [Member]      
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Fair value adjustments $ (279,760) (744,869)  
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
Inception date value of redemption provision - warrants      
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Warrants issued   $ 2,750,006