Annual report pursuant to Section 13 and 15(d)

Convertible preferred stock (Details)

v3.22.1
Convertible preferred stock (Details) - USD ($)
$ / shares in Units, $ in Millions
 1 Months Ended
Oct. 23, 2020
Oct. 12, 2020
Oct. 01, 2020
Oct. 31, 2020
Dec. 31, 2021
Dec. 31, 2020
Nov. 30, 2020
Sep. 30, 2020
Jul. 20, 2020
Jun. 30, 2020
Jun. 24, 2020
Mar. 17, 2020
Dec. 19, 2019
Nov. 04, 2019
Class of Stock [Line Items]                            
Preferred stock, par value (in dollars per share)         $ 0.001 $ 0.001                
Common stock, par value (in dollars per share)         $ 0.001 $ 0.001                
Warrant term             72 months       84 months   24 months 24 months
Warrants, exercise price (in dollars per share)             $ 6.00 $ 3.90 $ 6.30 $ 4.50 $ 7.50 $ 9.72 $ 30.00 $ 30.00
Preferred stock, authorized (in shares)         30,000 30,000                
Gain on share exchange     $ 5.4                      
Series F Private Placement                            
Class of Stock [Line Items]                            
Common stock, par value (in dollars per share)       $ 0.001                    
Value of each share of common stock (in dollars per share)       $ 3.00                    
Number of warrants in each unit (in shares)       1                    
Warrant term       6 years                    
Warrants, exercise price (in dollars per share)       $ 4.50                    
Gross proceeds       $ 18.2                    
Officers and directors | Series F Private Placement                            
Class of Stock [Line Items]                            
Gross proceeds       $ 6.5                    
Series F Unit                            
Class of Stock [Line Items]                            
Shares pursuant to private placement (in shares)     14,264                      
Series F Unit | Series F Private Placement                            
Class of Stock [Line Items]                            
Sale of stock, purchase price (in dollars per share)       $ 1,000                    
Shares pursuant to private placement (in shares) 2,832 1,106                        
Series F Unit | Cavalry                            
Class of Stock [Line Items]                            
Shares pursuant to private placement (in shares)     3,500                      
Series F Preferred Stock                            
Class of Stock [Line Items]                            
Preferred stock, authorized (in shares)     30,000                      
Shares pursuant to private placement (in shares) 100                          
Series F Preferred Stock | Series F Private Placement                            
Class of Stock [Line Items]                            
Number of shares of stock in each unit (in shares)       1                    
Preferred stock, par value (in dollars per share)       $ 0.001