Annual report pursuant to Section 13 and 15(d)

Equity Awards and Warrants - Warrants (Details)

v3.21.2
Equity Awards and Warrants - Warrants (Details) - USD ($)
$ / shares in Units, $ in Thousands
1 Months Ended 6 Months Ended 12 Months Ended
Apr. 02, 2021
Mar. 18, 2021
Jan. 28, 2021
Dec. 08, 2020
Dec. 06, 2020
Dec. 04, 2020
Nov. 30, 2020
Nov. 17, 2020
Oct. 26, 2020
Oct. 14, 2020
Jun. 17, 2020
Mar. 13, 2020
Mar. 04, 2020
Feb. 28, 2020
Jan. 31, 2020
Dec. 30, 2019
Dec. 23, 2019
Dec. 20, 2019
Dec. 13, 2019
Dec. 09, 2019
Aug. 29, 2019
Jul. 31, 2019
Jan. 31, 2020
Nov. 08, 2019
Nov. 30, 2019
May 31, 2021
May 31, 2020
May 31, 2019
Aug. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                                          
Warrants to purchase common shares, shares                       300,000                                 2,600,000
Term of warrants                       5 years                                 5 years
Exercise price of warrants, per share                       $ 1.00                                 $ 0.50
Warrant exercises, value                                                   $ 19,428 $ 20,500    
Exercise of warrants for cash                                                   $ 19,400      
Warrant exercises, shares                                                   27,300,000      
Cashless exercise of warrants, shares                                                   10,600,000      
Cashless exercise of warrants, warrants                                                   11,700,000      
Stock issued via offering, tender or placement, value                                                     $ 13,409 $ 3,084  
Common Stock, Par or Stated Value Per Share           $ 0.001       $ 0.001                       $ 0.001       $ 0.001 $ 0.001    
Series C Convertible Preferred Stock                                                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                                          
Stock issued via offering, tender or placement, shares         415                               1,754     2,788          
Stock issued via offering, tender or placement, value                                         $ 1,500                
Series D Convertible Preferred Stock                                                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                                          
Stock issued via offering, tender or placement, shares                       882     7,570                            
Stock issued via offering, tender or placement, value                       $ 900     $ 7,600                            
Consultant                                                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                                          
Warrants to purchase common shares, shares                                                   100,000      
Term of warrants                                                   5 years      
Exercise price of warrants, per share                                                   $ 3.07      
Warrants grant date fair value                                                   $ 2.11      
Registered Direct Offering [Member]                                                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                                          
Warrants to purchase common shares, shares                                 7,400,000   1,800,000 1,900,000         12,000,000.0        
Term of warrants                                     5 years 5 years         5 years        
Exercise price of warrants, per share                                     $ 0.45 $ 0.45         $ 0.45        
Stock issued via offering, tender or placement, shares                                 14,800,000   2,400,000 2,600,000         19,100,000        
Stock issued via offering, tender or placement, value                                                     $ 12,666 $ 11,815  
Allotment to placement agent                                                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                                          
Warrants to purchase common shares, shares                                                 700,000     4,400,000  
Term of warrants                                                 5 years        
Private Placement [Member]                                                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                                          
Warrants to purchase common shares, shares                                                       23,500,000  
Term of warrants                                                       5 years  
Exercise price of warrants, per share                                                       $ 0.75  
Stock issued via offering, tender or placement, shares               670,000                                       47,000,000.0  
Stock issued via offering, tender or placement, value                                                   $ 1,000   $ 23,488  
Private Warrant Exchange [Member]                                                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                                          
Warrants to purchase common shares, shares                                                   37,100,000      
Exercise price of warrants, per share $ 0.45     $ 0.30   $ 0.45 $ 0.75           $ 0.75   $ 0.50 $ 0.50             $ 0.50            
Stock issued via offering, tender or placement, shares 1,100,000 200,000 3,600,000 2,000,000.0   300,000 500,000   5,000,000.0 7,000,000.0 16,500,000   88,000 8,600,000   2,700,000   4,700,000       11,300,000 4,400,000            
Stock issued via offering, tender or placement, value                                                   $ 17,556 $ 6,021 $ 2,966  
Warrants exchanged (in shares)     2,500,000 1,900,000   300,000 500,000   4,500,000 6,400,000 16,500,000                             34,100,000      
Maximum                                                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                                          
Exercise price of warrants, per share                                                   $ 1.35      
Cashless exercise of warrants, exercise price                                                   1.35      
Maximum | Allotment to placement agent                                                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                                          
Exercise price of warrants, per share                                                 $ 0.44        
Maximum | Private Warrant Exchange [Member]                                                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                                          
Exercise price of warrants, per share   $ 0.45 $ 1.50           $ 0.75 $ 1.00 $ 1.35     $ 0.75       $ 0.75                      
Minimum                                                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                                          
Exercise price of warrants, per share                                                   0.30      
Cashless exercise of warrants, exercise price                                                   $ 0.40      
Minimum | Allotment to placement agent                                                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                                          
Exercise price of warrants, per share                                                 $ 0.40        
Minimum | Private Warrant Exchange [Member]                                                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                                          
Exercise price of warrants, per share   $ 0.30 $ 0.90           $ 0.30 $ 0.30 $ 0.35     $ 0.30       $ 0.45