Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation Schedule of Assumptions (Details)

v3.19.3.a.u2
Stock-Based Compensation Schedule of Assumptions (Details)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected life of options (in years)     4 years 273 days
Minimum risk free interest rate 1.80% 2.60% 1.70%
Maximum risk free interest rate 2.50% 2.90% 2.00%
Expected minimum volatility rate 69.70% 69.60% 64.20%
Expected maximum volatility rate 73.60% 70.50% 66.20%
Expected dividend yield 0.00% 0.00%  
Minimum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected life of options (in years) 4 years 256 days 4 years 197 days  
Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected life of options (in years) 4 years 273 days 4 years 273 days