Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Assumptions Used (Details)

v3.20.4
Stockholders' Equity - Assumptions Used (Details) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Stockholders' Equity    
Dividend yield 0.00%  
Employee Stock Option    
Stockholders' Equity    
Weighted average grant date fair value (in dollars per share) $ 1.48 $ 0.86
Expected term of options (in years) 6 years 1 month 6 days 6 years 1 month 6 days
Risk-free interest rate (as a percent) 0.60% 1.90%
Expected volatility (as a percent) 97.30% 98.90%
Dividend yield 0.00% 0.00%
Unrecognized compensation expense $ 4.4  
Weighted average remaining period for recognition of unrecognized compensation expense 3 years 3 months 3 days