Quarterly report pursuant to Section 13 or 15(d)

Stockholders' equity (deficit) - Equity transactions (Details)

v3.21.2
Stockholders' equity (deficit) - Equity transactions (Details) - USD ($)
$ / shares in Units, $ in Millions
Jan. 22, 2021
Sep. 30, 2021
Dec. 31, 2020
Class of Stock [Line Items]      
Common stock, par value (in dollars per share)   $ 0.001 $ 0.001
PIPE transaction      
Class of Stock [Line Items]      
Gross consideration $ 4.1    
Purchase price (in dollars per share) $ 7.50    
Number of shares of stock included in each unit (in shares) 1    
Common stock, par value (in dollars per share) $ 0.001    
Number of warrants included in each unit (in shares) 1    
Number of shares issuable per warrant (in shares) 1    
PIPE transaction | Officers and directors      
Class of Stock [Line Items]      
Proceeds from shares and warrants issued pursuant to private placement, net $ 1.6