Quarterly report pursuant to Section 13 or 15(d)

Stockholders' equity (deficit) - Common stock reserved for future issuance (Details)

v3.21.2
Stockholders' equity (deficit) - Common stock reserved for future issuance (Details) - shares
Sep. 30, 2021
Dec. 31, 2020
Equity [Abstract]    
Conversion of Series F Preferred Stock (in shares) 0 7,251,189
Exercise of options to purchase common stock (in shares) 2,672,937 1,302,574
Exercise of warrants to purchase common stock (in shares) 9,433,584 9,916,997
Conversion of notes payable (in shares) 0 1,255,039
Total (in shares) 12,106,521 19,725,799