Quarterly report pursuant to Section 13 or 15(d)

Activity Related to Notes (Detail)

v3.8.0.1
Activity Related to Notes (Detail) - USD ($)
9 Months Ended
Jan. 31, 2018
Feb. 28, 2018
May 31, 2017
Debt Instrument [Line Items]      
Note repayment   $ (259,157)  
Short-Term Convertible Notes      
Debt Instrument [Line Items]      
Face amount of Notes $ 6,300,000 6,038,500 $ 1,150,000
Unamortized discount     (92,000)
Unamortized issuance costs   0 0
Registered direct offering   (5,788,500)  
Note repayment $ (259,000) $ (250,000)  
Carrying value of Notes, net     $ 1,058,000