Quarterly report pursuant to Section 13 or 15(d)

Stock-based Compensation Plans and Awards - Schedule of Assumptions Used for Determining the Per-Share Fair Value (Details)

v3.8.0.1
Stock-based Compensation Plans and Awards - Schedule of Assumptions Used for Determining the Per-Share Fair Value (Details) - Black Scholes Options Pricing Model
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Employee stock    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected life (in years) 6 months 6 months
Risk-free interest rate, minimum 1.13% 0.44%
Risk-free interest rate, maximum 1.83% 0.65%
Expected volatility, minimum 45.00% 39.00%
Expected volatility, maximum 57.00% 52.00%
Expected dividend yield 0.00% 0.00%
Stock options    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected life (in years) 6 years 3 months  
Risk-free interest rate 2.64%  
Risk-free interest rate, minimum   2.03%
Risk-free interest rate, maximum   2.18%
Expected volatility 60.00% 61.00%
Expected dividend yield 0.00% 0.00%
Stock options | Minimum    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected life (in years)   5 years 11 months 6 days
Stock options | Maximum    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected life (in years)   6 years 18 days