Quarterly report pursuant to Section 13 or 15(d)

Private Equity Securities Offerings (Detail)

v3.21.2
Private Equity Securities Offerings (Detail) - USD ($)
$ / shares in Units, $ in Thousands, shares in Millions
 3 Months Ended
Aug. 31, 2021
Aug. 31, 2021
Aug. 31, 2020
Class of Stock [Line Items]      
Proceeds from warrant transactions, net of offering costs   $ 775 $ 7,441
Private Placement [Member]      
Class of Stock [Line Items]      
Stock price, in dollars per share $ 1.00 $ 1.00  
Stock issued via offering, tender or placement, value   $ 2,872  
Private Warrant Exchange [Member]      
Class of Stock [Line Items]      
Shares issued during the period new issues shares   1.3  
Proceeds from warrant transactions, net of offering costs   $ 800  
Stock issued via offering, tender or placement, value   $ 775 $ 7,804
Private Warrant Exchange [Member] | Maximum      
Class of Stock [Line Items]      
Exercise price of warrants, per share 0.75 $ 0.75  
Private Warrant Exchange [Member] | Minimum      
Class of Stock [Line Items]      
Exercise price of warrants, per share 0.45 $ 0.45  
Private Warrant Exchange, Non-Inducement Shares [Member]      
Class of Stock [Line Items]      
Shares issued during the period new issues shares   0.7  
Private Warrant Exchange, Inducement Shares [Member]      
Class of Stock [Line Items]      
Shares issued during the period new issues shares   0.7  
Stock Subscription Agreements [Member]      
Class of Stock [Line Items]      
Exercise price of warrants, per share $ 1.00 $ 1.00  
Shares issued during the period new issues shares 2.9    
Stock price, in dollars per share $ 1.00 $ 1.00  
Common stock warrants to purchase shares 0.7 0.7  
Term of warrants 5 years 5 years  
Proceeds from issuance of common stock $ 2,900