Fair Value Measurements - Summary of Outstanding Balance Sheet Hedges (Detail) - Foreign currency derivative contracts [Member] - Derivatives not designated as hedging instruments [Member] - USD ($) $ in Thousands	Jan. 31, 2019	Jan. 31, 2018
Prepaid expenses and other current assets [Member]
Derivatives Fair Value [Line Items]
Derivative Assets		$ 127
Accrued expenses [Member]
Derivatives Fair Value [Line Items]
Derivative Liabilities	$ 88	$ 391