XML 99 R79.htm IDEA: XBRL DOCUMENT v3.21.2
Share-Based Compensation - Assumptions Used to Estimate the Fair Values (Details)
9 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]    
Expected term (in years) 1 year 10 months 17 days  
Expected volatility, minimum 112.02% 100.98%
Expected volatility, maximum 129.63% 101.55%
Expected volatility 1.0692%  
Expected dividend yield 0.00% 0.00%
Risk free interest rate, minimum 0.51%  
Risk free interest rate, maximum 1.10%  
Risk free interest rate 1.31% 0.40%
Minimum    
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]    
Expected term (in years) 4 years 9 months 14 days 5 years 4 months 13 days
Maximum    
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]    
Expected term (in years) 7 years 2 months 1 day 5 years 5 months 15 days