Reconciliation of Liability Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3) (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Aug. 31, 2018	May 31, 2018
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value adjustments	$ 747,467	$ (3,855,468)
Ending Balance	$ 2,071,199	1,323,732
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