Commitments and contingencies - Contractual Obligations (Details) $ in Thousands	12 Months Ended
Jan. 30, 2021 USD ($)
Purchase commitments for products and services for a new fast fulfillment center
Contractual obligations
Contractual obligations related to commitments	$ 1,020
Advertising and other goods and service contracts
Contractual obligations
Agreement term	1 year

Term of the unrecognized unconditional purchase obligation, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 440
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121559207&loc=d3e25336-109308

Name:	us-gaap_UnrecordedUnconditionalPurchaseObligationTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration