Revenue - Additional Information (Details) - USD ($) |
3 Months Ended | |
|---|---|---|
Apr. 30, 2019 |
Apr. 30, 2018 |
|
| Revenues [Abstract] | ||
| Deferred revenue | $ 143,700,000 | $ 137,700,000 |
| Revenue recognized | 45,100,000 | 30,300,000 |
| Remaining performance obligation | $ 178,800,000 | |
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] | ||
| Expected timing of satisfaction of remaining performance obligation | 12 months | |
| Unbilled receivables | $ 7,900,000 | |
| Deferred commissions | 51,600,000 | |
| Amortization of deferred commissions | 4,400,000 | 3,100,000 |
| Impairment loss | $ 0 | $ 0 |
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-05-01 | ||
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] | ||
| Remaining performance obligation, percentage | 53.00% | |