Capital Stock - Schedule of Ordinary Shares Reserved for Future Issuance under EIP and ESPP (Detail) - shares |
Apr. 30, 2019 |
Jan. 31, 2019 |
|---|---|---|
| EIP [Member] | ||
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||
| Shares reserved | 7,034,012 | 5,915,654 |
| ESPP [Member] | ||
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||
| Shares reserved | 2,137,609 | 1,833,574 |