Property and Equipment - Estimated Useful Life Property and Equipment (Detail) |
12 Months Ended |
|---|---|
Jan. 31, 2018 | |
| Computer and network equipment | Minimum | |
| Property, Plant and Equipment [Line Items] | |
| Property plant and equipment useful life | 2 years |
| Computer and network equipment | Maximum | |
| Property, Plant and Equipment [Line Items] | |
| Property plant and equipment useful life | 3 years |
| Software, including capitalized software development costs | |
| Property, Plant and Equipment [Line Items] | |
| Property plant and equipment useful life | 3 years |
| Furniture and office equipment | Minimum | |
| Property, Plant and Equipment [Line Items] | |
| Property plant and equipment useful life | 3 years |
| Furniture and office equipment | Maximum | |
| Property, Plant and Equipment [Line Items] | |
| Property plant and equipment useful life | 4 years |
| Leasehold improvements | |
| Property, Plant and Equipment [Line Items] | |
| Property plant and equipment useful life | Lesser of lease term or 10 years |