Annual report pursuant to Section 13 and 15(d)

Registered Direct Equity Offerings (Detail)

v3.21.2
Registered Direct Equity Offerings (Detail) - USD ($)
$ / shares in Units, $ in Thousands
 6 Months Ended
Feb. 26, 2020
Dec. 23, 2019
Dec. 13, 2019
Dec. 09, 2019
Nov. 30, 2019
May 31, 2021
Mar. 13, 2020
Jan. 31, 2020
Aug. 31, 2019
Jul. 31, 2019
May 31, 2019
Stockholders Equity Note [Line Items]                      
Stock price, in dollars per share           $ 1.50         $ 0.50
Warrants to purchase common shares, shares             300,000   2,600,000    
Class of warrants, exercise price             $ 1.00   $ 0.50    
Term of warrants             5 years   5 years    
Minimum                      
Stockholders Equity Note [Line Items]                      
Class of warrants, exercise price           0.30          
Maximum                      
Stockholders Equity Note [Line Items]                      
Class of warrants, exercise price           $ 1.35          
David F Welch                      
Stockholders Equity Note [Line Items]                      
Number of shares to be sold 1,800,000 1,600,000                  
Stock price, in dollars per share $ 0.18                    
Warrants to purchase common shares, shares 2,000,000.0 800,000           500,000   1,000,000.0  
Class of warrants, exercise price $ 0.30                    
Proceeds from issuance of common shares $ 330 $ 500                  
Minority interest amount   500                  
Investor                      
Stockholders Equity Note [Line Items]                      
Proceeds from issuance of common shares   $ 4,000                  
Registered Direct Offering [Member]                      
Stockholders Equity Note [Line Items]                      
Number of shares to be sold   14,800,000 2,400,000 2,600,000 19,100,000            
Stock price, in dollars per share   $ 0.305 $ 0.30 $ 0.30              
Warrants to purchase common shares, shares   7,400,000 1,800,000 1,900,000 12,000,000.0            
Number of shares per warrant   1                  
Class of warrants, exercise price     $ 0.45 $ 0.45 $ 0.45            
Term of warrants     5 years 5 years 5 years            
Proceeds from issuance of common shares   $ 4,500 $ 730 $ 750 $ 6,300            
Percentage of shares, issued as warrants   50.00%                  
Registered Direct Offering [Member] | Minimum                      
Stockholders Equity Note [Line Items]                      
Stock price, in dollars per share         $ 0.30            
Registered Direct Offering [Member] | Maximum                      
Stockholders Equity Note [Line Items]                      
Stock price, in dollars per share         $ 0.40            
Allotment to placement agent                      
Stockholders Equity Note [Line Items]                      
Warrants to purchase common shares, shares         700,000           4,400,000
Term of warrants         5 years            
Percentage of shares, issued as warrants         1.30%            
Allotment to placement agent | Minimum                      
Stockholders Equity Note [Line Items]                      
Class of warrants, exercise price         $ 0.40            
Allotment to placement agent | Maximum                      
Stockholders Equity Note [Line Items]                      
Class of warrants, exercise price         $ 0.44