Composition of certain financial statement captions - Schedule Of Finite Lived Intangible Assets (Detail) - USD ($) $ in Thousands	9 Months Ended
	Oct. 31, 2020	Jan. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangibles	$ 1,470	$ 1,470
Less accumulated amortization	(450)	(271)
Net carrying value	$ 1,020	1,199
Acquired technology
Finite-Lived Intangible Assets [Line Items]
Useful life (years)	5 years
Finite-lived intangibles	$ 490	490
Customer relationship
Finite-Lived Intangible Assets [Line Items]
Useful life (years)	7 years
Finite-lived intangibles	$ 980	$ 980