Deferred Revenue and Performance Obligations - Performance Obligations (Details) - USD ($) $ in Millions |
Apr. 30, 2019 |
Jan. 31, 2019 |
|---|---|---|
| Revenue from Contract with Customer [Abstract] | ||
| Future estimated revenue related to performance obligations | $ 48.6 | $ 43.6 |
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-05-01 | ||
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] | ||
| Revenue, remaining performance obligation, period | 24 months | |
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-05-01 | ||
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] | ||
| Revenue, remaining performance obligation, period |