Stock-Based Compensation (Detail) - shares |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Number of shares granted (in shares) | 161,000 | 0 | |
| ESPP obligations | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Expected volatility, minimum | 30.00% | 26.00% | 28.00% |
| Expected volatility, maximum | 49.00% | 31.00% | 49.00% |
| Expected term (in years) | 15 days | 15 days | 15 days |
| Risk-free interest rate. minimum | 2.04% | 1.15% | 0.40% |
| Risk-free interest rate, maximum | 2.46% | 2.22% | 1.15% |
| Dividend yield (in percent) | 0.00% | 0.00% | 0.00% |
| Common stock options | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Expected volatility, minimum | 39.00% | ||
| Expected volatility, maximum | 42.00% | ||
| Expected term (in years) | 4 years 10 months 20 days | ||
| Risk-free interest rate. minimum | 1.78% | ||
| Risk-free interest rate, maximum | 2.47% | ||
| Dividend yield (in percent) | 0.00% | ||
| Number of shares granted (in shares) | 0 | ||