Summary of Fair Value Warrant Derivative Liability and Related Common Shares (Detail) - Registered Direct Equity Offering - Investor Warrants Issued with Registered Direct Equity Offering - USD ($)		12 Months Ended
	Sep. 15, 2016	May 31, 2020	May 31, 2019	May 22, 2019
Derivative [Line Items]
Shares Indexed	7,333,334	0	7,733,334
Fair value of warrants exercised		7,733,334
Change in fair value of derivative liability	$ (4,777,068)	$ 11,546,840
Fair value of warrants exercised		(11,948,972)
Derivative liability	$ 5,179,200	$ 0		$ 402,132