Inventories - Schedule of Inventories (Detail) - USD ($) $ in Thousands	Jan. 31, 2020	Jan. 31, 2019
Inventory Disclosure [Abstract]
Raw materials	$ 7,388	$ 5,446
Finished goods	4,557	5,229
Work in progress	2,720	1,322
Cost of inventories	14,665	11,997
Less allowance for obsolescence	(1,404)	(1,223)
Net inventories	$ 13,261	$ 10,774