Deferred Revenue and Deferred Cost - Schedule of Deferred Revenue and Related Cost (Detail) - USD ($) $ in Thousands	Jul. 31, 2017	Jan. 31, 2017
Deferred Revenue Disclosure [Abstract]
Deferred revenue from product shipments	$ 7,573	$ 7,725
Deferred revenue from services	1,023	1,748
Deferred cost of revenue from product shipments	(2,393)	(2,048)
Total deferred revenue, net	$ 6,203	$ 7,425