Revenue - Schedule Of Rollforward of contract assets and contract liabilities (Detail) $ in Thousands	6 Months Ended
	Jul. 31, 2020 USD ($)
Contract With Customer Asset [Roll Forward]
Beginning balance - Contract assets (unbilled accounts receivable)	$ 676
Amount transferred to receivables from contract assets	(222)
Contract asset additions	2,693
Ending balance - Contract assets (unbilled accounts receivable)	3,147
Contract With Customer Liability [Roll Forward]
Beginning balance - Contract liabilities (deferred revenue)	5,401
Revenue recognized that was included in deferred revenue at the beginning of the period	(4,002)
Revenue recognized that was not included in deferred revenue at the beginning of the period	(679)
Increases due to invoicing prior to satisfaction or performance obligations	5,537
Ending balance - Contract liabilities (deferred revenue)	$ 6,257