Revenue - Schedule Of Deferred contract acquisition costs (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2020	Jan. 31, 2020
Capitalized Contract Cost [Roll Forward]
Beginning balance, January 31, 2020			$ 3,314
Additions to deferred contract acquisition costs			1,401
Amortization of deferred contract acquisition costs	$ (1,250)	$ (489)	(1,775)	$ (974)
Ending balance, July 31, 2020	2,940		2,940
Deferred contract acquisition costs, current (to be amortized in next 12 months)					$ 1,684	$ 1,720
Deferred contract acquisition costs, non-current					1,256	1,594
Total deferred contract acquisition costs	$ 2,940		$ 2,940		$ 2,940	$ 3,314