Annual report pursuant to Section 13 and 15(d)

Stock Incentive Plan - Fair Value Assumptions (Details)

v3.19.3.a.u2
Stock Incentive Plan - Fair Value Assumptions (Details) - Stock Options - USD ($)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Fair value significant assumptions:      
Expected dividend yield $ 0 $ 0 $ 0
Risk-free interest rate, minimum 1.60% 2.71% 1.96%
Risk-free interest rate, maximum 2.39% 3.00% 2.36%
Expected volatility   43.00% 46.00%
Expected volatility, minimum 43.00%    
Expected volatility, maximum 44.00% 45.00%  
Expected life 6 years 6 months 6 years 6 months 6 years 6 months