Amount of receivables arising from transactions with related parties due within one year or the normal operating cycle, if longer.

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Name:	us-gaap_AccountsReceivableRelatedPartiesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Related party transactions (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2020	Jul. 31, 2019	Jan. 31, 2020
Related Party Transaction [Line Items]
Accounts receivable					$ 2,072
Affiliated Entity
Related Party Transaction [Line Items]
Recognized revenue	$ 988	$ 1,372	$ 2,425	$ 2,876
Accounts receivable	$ 699		$ 699