Restructuring Charges - Additional Information (Detail) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jan. 31, 2017 USD ($)	Jan. 31, 2016 USD ($)	Jan. 31, 2017 USD ($)	Jan. 31, 2016 USD ($)	Jul. 31, 2017 USD ($) Employee
Restructuring Cost and Reserve [Line Items]
Restructuring charge	$ 267	$ 3,147	$ 299	$ 6,430
Restructuring adjustments	200		200
Fiscal Year 2016 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charge		$ 3,100		$ 6,400
Restructuring adjustments	$ (200)		(200)
Fiscal Year 2017 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charge			$ 500
Fiscal Year 2017 Restructuring Plan | Scenario, Forecast
Restructuring Cost and Reserve [Line Items]
Expected reduction in number of employees | Employee					130
Restructuring charge					$ 5,000