Property and Equipment, Net - Schedule of Property and Equipment (Detail) - USD ($) $ in Thousands	Jul. 31, 2017	Jan. 31, 2017
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 14,788	$ 13,427
Less: accumulated depreciation and amortization	(9,152)	(8,439)
Total property and equipment, net	5,636	4,988
Computer equipment and software [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	7,352	6,798
Machinery and equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	3,610	3,405
Furniture and fixtures [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	829	797
Leasehold improvements [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,625	1,672
Construction in progress [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 1,372	$ 755