Commitments and Contingencies (Details) - USD ($) |
3 Months Ended | ||
|---|---|---|---|
Apr. 30, 2018 |
Apr. 30, 2017 |
Jan. 31, 2018 |
|
| Commitments and Contingencies Disclosure [Abstract] | |||
| Operating leases, rent expense | $ 3,100,000 | $ 2,100,000 | |
| Accrual for contingencies | $ 0 | $ 0 | |