Quarterly report pursuant to Section 13 or 15(d)

Public Warrant Tender Offerings - Additional Information (Detail)

v3.19.3.a.u2
Public Warrant Tender Offerings - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Millions
6 Months Ended
Nov. 30, 2019
May 31, 2019
Public Warrant Tender Offerings [Line Items]    
Common stock, par value $ 0.001 $ 0.001
Public Warrant Tender Offerings [Member]    
Public Warrant Tender Offerings [Line Items]    
Common stock sold at private equity offering 45,375,923  
Common stock, par value $ 0.001  
Proceeds from issuance of common shares $ 11.9  
Placement agent fees and expenses 1.1  
Noncash inducement interest expense $ 2.4  
Public Warrant Tender Offerings [Member] | Minimum [Member]    
Public Warrant Tender Offerings [Line Items]    
Purchase price, per share $ 0.30  
Public Warrant Tender Offerings [Member] | Maximum [Member]    
Public Warrant Tender Offerings [Line Items]    
Purchase price, per share $ 0.40