Inventories - Schedule of Inventories (Detail) - USD ($) $ in Thousands	Jan. 31, 2018	Jan. 31, 2017
Inventory Disclosure [Abstract]
Raw materials	$ 5,099	$ 5,781
Finished goods	6,185	5,985
Work in progress	1,247	1,146
Cost of inventories	12,531	12,912
Less allowance for obsolescence	(1,675)	(952)
Net inventories	$ 10,856	$ 11,960