Quarterly report pursuant to Section 13 or 15(d)

Convertible preferred stock (Details)

v3.21.2
Convertible preferred stock (Details) - USD ($)
$ / shares in Units, $ in Thousands
 1 Months Ended 3 Months Ended
Oct. 23, 2020
Oct. 12, 2020
Oct. 01, 2020
Oct. 31, 2020
Sep. 30, 2021
Mar. 31, 2021
Mar. 31, 2020
Dec. 31, 2020
Sep. 30, 2020
Jun. 30, 2020
Mar. 17, 2020
Dec. 19, 2019
Nov. 04, 2019
Subsidiary, Sale of Stock [Line Items]                          
Stated value (in dollars per share)         $ 0.001     $ 0.001          
Common stock, par value (in dollars per share)         $ 0.001     $ 0.001          
Term of warrants                       24 months 24 months
Warrants, exercise price (in dollars per share)                 $ 3.90 $ 4.50 $ 9.72 $ 30.00 $ 30.00
Preferred stock, authorized (in shares)         30,000     30,000          
Stock issued during period         $ 36,160 $ 4,072 $ 500            
Series F Unit                          
Subsidiary, Sale of Stock [Line Items]                          
Stock issued during period (in shares)     14,264                    
Series F Unit | Cavalry                          
Subsidiary, Sale of Stock [Line Items]                          
Stock issued during period (in shares)     3,500                    
Series F Convertible Preferred Stock                          
Subsidiary, Sale of Stock [Line Items]                          
Preferred stock, authorized (in shares)     30,000                    
Stock issued during period (in shares) 100                        
Series F Convertible Preferred Stock | Accumulated Deficit                          
Subsidiary, Sale of Stock [Line Items]                          
Stock issued during period     $ 5,400                    
Series F private placement                          
Subsidiary, Sale of Stock [Line Items]                          
Common stock, par value (in dollars per share)       $ 0.001                  
Value per share (in dollars per share)       $ 3.00                  
Number of warrants included in each unit (in shares)       1                  
Term of warrants       6 years                  
Warrants, exercise price (in dollars per share)       $ 4.50                  
Gross cash proceeds       $ 18,200                  
Series F private placement | Officers and directors                          
Subsidiary, Sale of Stock [Line Items]                          
Gross cash proceeds       $ 6,500                  
Series F private placement | Series F Unit                          
Subsidiary, Sale of Stock [Line Items]                          
Purchase price (in dollars per share)       $ 1,000                  
Stock issued during period (in shares) 2,832 1,106                      
Series F private placement | Series F Convertible Preferred Stock                          
Subsidiary, Sale of Stock [Line Items]                          
Number of shares of stock included in each unit (in shares)       1                  
Stated value (in dollars per share)       $ 0.001