Segments and Geographic Revenue - Additional Information (Details) - segment |
3 Months Ended | |
|---|---|---|
Apr. 30, 2018 |
Apr. 30, 2017 |
|
| Segment Reporting [Abstract] | ||
| Number of operating segments | 1 | |
| Geographic Concentration Risk | Revenue, Net | United States | ||
| Concentration Risk [Line Items] | ||
| Concentration risk, percentage | 61.00% | 66.00% |
| Geographic Concentration Risk | Revenue, Net | United Kingdom | ||
| Concentration Risk [Line Items] | ||
| Concentration risk, percentage | 11.00% | 10.00% |