Estimated Weighted Average Assumptions (Detail) |
12 Months Ended | ||
---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Expected term (years) | 6 years 6 months | ||
Volatility, minimum | 50.85% | 50.09% | 51.00% |
Volatility, maximum | 51.01% | 51.89% | 51.71% |
Risk-free interest rate, minimum | 1.51% | 1.67% | 1.88% |
Risk-free interest rate, maximum | 2.37% | 2.03% | 2.11% |
Expected dividend yield | 0.00% | 0.00% | 0.00% |
Minimum | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Expected term (years) | 6 years 8 months 12 days | 6 years 7 months 6 days | |
Maximum | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Expected term (years) | 7 years 1 month 6 days | 7 years 2 months 12 days |