Property and Equipment, Net - Schedule of Property and Equipment (Detail) - USD ($) $ in Thousands	Jan. 31, 2017	Jan. 31, 2016
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 13,427	$ 11,301
Less: accumulated depreciation and amortization	(8,439)	(7,853)
Total property and equipment, net	4,988	3,448
Computer equipment and software [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	6,798	6,421
Machinery and equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	3,405	2,706
Furniture and fixtures [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	797	492
Leasehold improvements [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,672	1,429
Construction in progress [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 755	$ 253