Operating leases - Additional Information (Detail) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | |
|---|---|---|---|
Jul. 31, 2019 |
Jul. 31, 2019 |
Feb. 01, 2019 |
|
| Leases [Abstract] | |||
| Operating lease right-of-use assets | $ 1,745 | $ 1,745 | $ 1,700 |
| Operating lease liability | 1,889 | 1,889 | $ 1,700 |
| Rent payments | $ 200 | $ 400 |
| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Amount of operating lease expense. Excludes sublease income. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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| X | ||||||||||
- Definition Present value of lessee's discounted obligation for lease payments from operating lease. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Amount of lessee's right to use underlying asset under operating lease. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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