Acquisition-related Intangible Assets, Net - Schedule of Acquired Assets (Detail) - USD ($) $ in Thousands |
3 Months Ended | |||||
|---|---|---|---|---|---|---|
Apr. 30, 2017 |
Apr. 30, 2016 |
Jan. 31, 2017 |
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| Finite-Lived Intangible Assets [Line Items] | ||||||
| Intangible assets, gross | $ 65,900 | $ 65,900 | ||||
| Less accumulated amortization | (21,985) | (17,113) | ||||
| Acquisition-related intangible assets, net | 43,915 | 48,787 | [1] | |||
| Acquired developed technology | ||||||
| Finite-Lived Intangible Assets [Line Items] | ||||||
| Intangible assets, gross | 64,900 | 64,900 | ||||
| Customer relationship assets | ||||||
| Finite-Lived Intangible Assets [Line Items] | ||||||
| Intangible assets, gross | 1,000 | $ 1,000 | ||||
| Developed Technology and Customer Relationships | ||||||
| Finite-Lived Intangible Assets [Line Items] | ||||||
| Amortization of intangible assets | $ 5,000 | $ 1,000 | ||||
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