Quarterly report pursuant to Section 13 or 15(d)

Warrant derivative liability - Fair value measurements and valuation techniques (Details)

v3.20.2
Warrant derivative liability - Fair value measurements and valuation techniques (Details) - Warrant
Sep. 30, 2020
$ / shares
Dec. 31, 2019
$ / shares
May 06, 2019
$ / shares
Stock price      
Fair Value Measurement Inputs and Valuation Techniques [Abstract]      
Derivative liability 0.49 2.70 6.00
Exercise price      
Fair Value Measurement Inputs and Valuation Techniques [Abstract]      
Derivative liability 0.65 1.62 3.90
Expected remaining term (in years)      
Fair Value Measurement Inputs and Valuation Techniques [Abstract]      
Derivative liability 0.22    
Expected remaining term (in years) | Minimum      
Fair Value Measurement Inputs and Valuation Techniques [Abstract]      
Derivative liability   0.95 1.60
Expected remaining term (in years) | Maximum      
Fair Value Measurement Inputs and Valuation Techniques [Abstract]      
Derivative liability   1.02 1.68
Volatility      
Fair Value Measurement Inputs and Valuation Techniques [Abstract]      
Derivative liability 0.75 0.69 0.64
Risk-free interest rate      
Fair Value Measurement Inputs and Valuation Techniques [Abstract]      
Derivative liability 0.0009 0.0160 0.0239