Summary of ASC 480 Allocation of Proceeds of Offering (Detail)	12 Months Ended
	May 31, 2018 USD ($)
Stockholders Equity Note [Line Items]
Proceeds from issuance of common shares	$ 8,990,000
Common Stock Including Additional Paid in Capital
Stockholders Equity Note [Line Items]
Proceeds from issuance of common shares	6,334,417
Warrants (equity allocation)
Stockholders Equity Note [Line Items]
Proceeds from issuance of common shares	$ 2,655,583