Annual report pursuant to Section 13 and 15(d)

Convertible Instruments - Long-term Convertible Note - July 2020 Note (Detail)

v3.21.2
Convertible Instruments - Long-term Convertible Note - July 2020 Note (Detail) - USD ($)
$ / shares in Units, shares in Millions
1 Months Ended 3 Months Ended 4 Months Ended 12 Months Ended
Nov. 10, 2020
Sep. 15, 2020
Jul. 29, 2020
Apr. 30, 2021
Mar. 31, 2021
Feb. 28, 2021
Jan. 31, 2021
Nov. 30, 2020
Apr. 30, 2021
May 31, 2021
May 31, 2020
May 31, 2019
Debt Instrument [Line Items]                        
Net Proceeds                   $ 100,000,000 $ 15,000,000 $ 14,877,000
Interest on convertible notes                   $ 4,387,000 $ 7,330,000 $ 950,000
Shares issued on debt conversion                   19.9    
Long-term Convertible Note-July 2020 Note                        
Debt Instrument [Line Items]                        
Debt instrument term     2 years                  
Convertible note, aggregate principal     $ 28,500,000                  
Net Proceeds     25,000,000.0             $ 25,000,000    
Unamortized discount     3,400,000                  
Conversion of principal and interest of convertible notes to common stock     $ 100,000                  
Convertible notes, interest rate     10.00%                  
Conversion price per share     $ 10.00                  
Debt instrument lock in period     6 months                  
Number of days of notice to be given for conversion of notes into common stock     5 days                  
Number of days of notice to be given for redemption     3 days                  
Shares under Registration Statement to cover repayment   2.9                    
Amortization inclusive of debt repayments                   3,500,000    
Interest on convertible notes                   1,901,000    
Amount of debt redemption       $ 7,900,000 $ 7,500,000 $ 7,500,000 $ 7,500,000   $ 30,400,000      
Shares issued on debt conversion     11.3                  
Beneficial conversion feature     $ 0                  
Carrying value of Note                   0    
Loss on extinguishment of convertible notes                   9,300,000    
Long-term Convertible Note-July 2020 Note | Maximum                        
Debt Instrument [Line Items]                        
Specified monthly redemption amount     $ 1,600,000                  
Long-term Convertible Note - November 2020 Note                        
Debt Instrument [Line Items]                        
Debt instrument term 2 years                      
Convertible note, aggregate principal $ 28,500,000                      
Net Proceeds 25,000,000.0                 25,000,000    
Unamortized discount 3,400,000                      
Conversion of principal and interest of convertible notes to common stock $ 100,000                      
Convertible notes, interest rate 10.00%                      
Conversion price per share $ 10.00                      
Debt instrument lock in period 6 months                      
Number of days of notice to be given for conversion of notes into common stock 5 days                      
Number of days of notice to be given for redemption 3 days                      
Specified monthly redemption amount $ 7,500,000             $ 7,500,000        
Amortization inclusive of debt repayments                   2,300,000    
Interest on convertible notes                   1,258,000    
Beneficial conversion feature 0                      
Carrying value of Note                   13,600,000    
Loss on extinguishment of convertible notes                   $ 6,400,000    
Long-term Convertible Note - November 2020 Note | Maximum                        
Debt Instrument [Line Items]                        
Specified monthly redemption amount $ 3,500,000