Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Jan. 31, 2018 |
Jan. 31, 2017 |
Jan. 31, 2016 |
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| Commitments And Contingencies Disclosure [Abstract] | |||
| Operating leases, rent expense | $ 1.6 | $ 2.4 | $ 2.7 |
| Operating lease expiration year | 2024 | ||
| X | ||||||||||
- Definition Operating lease expiration year. No definition available.
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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