Net Income per Share Attributable to Common Stockholders - Potential Common Share Equivalents Excluded where the Inclusion would be Anti-dilutive (Detail) - shares |
3 Months Ended | |
|---|---|---|
Apr. 30, 2018 |
Apr. 30, 2017 |
|
| Earnings Per Share [Abstract] | ||
| Options and awards to purchase shares not included in the computation of diluted net income per share because their inclusion would be anti-dilutive | 3,062,246 | 559,045 |