Income taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands  | 
12 Months Ended | |
|---|---|---|
Feb. 01, 2020  | 
Feb. 02, 2019  | 
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| Reconciliation of unrecognized tax benefits, excluding interest and penalties | ||
| Balance at beginning of the year | $ 3,844 | $ 3,565 | 
| Increase due to a prior year tax position | 602 | 1,008 | 
| Decrease due to a prior year tax position | (910) | (729) | 
| Balance at the end of the year | $ 3,536 | $ 3,844 | 
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available. 
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- Definition Amount of unrecognized tax benefits. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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