Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Stock Option Valuation Assumptions (Details)

v3.21.1
Stockholders' Equity - Stock Option Valuation Assumptions (Details)
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Stockholders’ Equity    
Dividend yield 0.00% 0.00%
Minimum    
Stockholders’ Equity    
Expected volatility 83.13% 89.59%
Risk-free interest rate 0.26% 1.63%
Expected lives (years) 5 years 5 years 4 months 24 days
Maximum    
Stockholders’ Equity    
Expected volatility 101.68% 91.03%
Risk-free interest rate 1.69% 2.52%
Expected lives (years) 6 years 3 months 18 days 6 years 3 months 18 days