Geographic Information - Additional Information (Details) - Property, Plant and Equipment - Geographic Concentration Risk |
3 Months Ended | 12 Months Ended |
|---|---|---|
Apr. 30, 2019 |
Jan. 31, 2019 |
|
| United States | ||
| Concentration Risk [Line Items] | ||
| Concentration risk, percentage | 61.00% | 48.00% |
| Canada | ||
| Concentration Risk [Line Items] | ||
| Concentration risk, percentage | 39.00% | 52.00% |