General form of registration statement for all companies including face-amount certificate companies

Stockholders' deficit - Common stock reserved for future issuance (Q3) (Details)

v3.20.4
Stockholders' deficit - Common stock reserved for future issuance (Q3) (Details) - shares
Sep. 30, 2020
Dec. 31, 2019
Dec. 31, 2018
Stockholders' deficit [Abstract]      
Conversion of Series E (in shares) 1,760,903 1,760,903  
Exercise of options to purchase common stock (in shares) 7,241,942 7,791,833  
Warrants to purchase common stock (in shares) 19,898,859 16,981,854  
Notes payable (in shares) 7,346,568 4,437,500  
Total (in shares) 36,248,272 30,972,090 0