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Stockholders' Equity - Weighted Average Assumptions of Fair Value Options Using Black-Scholes Option-Pricing Model (Details)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Equity [Abstract]      
Dividend yield 0.00% 0.00% 0.00%
Risk-free interest rate, minimum 1.66% 2.50% 1.70%
Risk-free interest rate, maximum 3.05% 3.10% 2.10%
Expected life (in years) 5 years 5 years 5 years
Historical volatility, minimum 43.42% 43.50% 46.60%
Historical volatility, maximum 44.00% 48.40% 48.10%