Net Loss Per Ordinary Share - Weighted-Average Potentially Dilutive Securities Excluded from Computation of Diluted Loss Per Ordinary Share (Detail) - shares
|
3 Months Ended |
Apr. 30, 2019 |
Apr. 30, 2018 |
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
|
|
| Antidilutive shares excluded from computation of earnings per share |
1,946,685
|
2,228,273
|
| Options to purchase ordinary shares [Member] |
|
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
|
|
| Antidilutive shares excluded from computation of earnings per share |
1,003,060
|
1,192,294
|
| Restricted stock and restricted stock units [Member] |
|
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
|
|
| Antidilutive shares excluded from computation of earnings per share |
926,156
|
996,098
|
| Employee stock purchase plan awards [Member] |
|
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
|
|
| Antidilutive shares excluded from computation of earnings per share |
17,469
|
39,881
|