Stockholders' Equity - Additional Information (Detail)
$ / shares in Units, $ in Millions |
3 Months Ended |
|
Apr. 30, 2018
USD ($)
$ / shares
shares
|
|---|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |
|
| Stock options, granted |
175,000
|
| Unrecognized compensation cost related to unvested stock options granted | $ |
$ 113.4
|
| Intrinsic value of options exercised | $ |
$ 48.4
|
| Stock Options [Member] |
|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |
|
| Weighted average period of unvested stock |
3 years 10 months 24 days
|
| Restricted Stock Units (RSUs) [Member] |
|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |
|
| Weighted average period of unvested stock |
2 years 7 months 6 days
|
| Weighted average grant date fair value, RSUs granted | $ / shares |
$ 69.94
|
| Number of shares, RSUs granted |
637,710
|
| Unrecognized compensation cost related to unvested RSUs | $ |
$ 134.0
|
| 2013 Equity Incentive Plan [Member] |
|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |
|
| Weighted-average grant date fair value of options granted | $ / shares |
$ 35.04
|
| Stock options, granted |
175,000
|
| 2013 Equity Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member] |
|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |
|
| Weighted average grant date fair value, RSUs granted | $ / shares |
$ 69.94
|
| Number of shares, RSUs granted |
637,710
|
| 2012 and 2013 Equity Incentive Plan [Member] | Minimum [Member] |
|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |
|
| Share-based compensation cost recognition vesting service period |
4 years
|
| 2012 and 2013 Equity Incentive Plan [Member] | Maximum [Member] |
|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |
|
| Share-based compensation cost recognition vesting service period |
9 years
|