Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Option pricing model (Details)

v3.21.2
Stockholders' Equity - Option pricing model (Details)
6 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Stockholders' Equity    
Risk-free interest rate, Minimum 1.04%  
Risk-free interest rate   1.02%
Risk-free interest rate, Maximum 1.50%  
Expected term in years 10 years 10 years
Expected volatility, Minimum 100.65%  
Expected volatility   101.27%
Expected volatility, Maximum 102.71%