Annual report pursuant to Section 13 and 15(d)

Share-Based Compensation - Schedule of Assumptions Used to Determine Grant Date Fair Value of Employee and Director Options Granted (Details)

v3.20.1
Share-Based Compensation - Schedule of Assumptions Used to Determine Grant Date Fair Value of Employee and Director Options Granted (Details) - $ / shares
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Volatility   60.00% 60.00%
Volatility, minimum 68.90%    
Volatility, maximum 74.50%    
Expected term in years   6 years 3 months 6 years 3 months
Dividend rate 0.00% 0.00% 0.00%
Risk-free interest rate     1.63%
Risk-free interest rate, minimum 1.73% 2.16%  
Risk-free interest rate, maximum 2.57% 2.91%  
Minimum      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Expected term in years 5 years 6 months    
Share price $ 3.55 $ 7.06 $ 3.30
Fair value of option on grant date $ 2.37 4.41 1.88
Maximum      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Expected term in years 6 years 3 months    
Share price $ 6.80 13.00 4.40
Fair value of option on grant date $ 4.41 $ 7.49 $ 2.50