Restructuring Charges - Additional Information (Detail) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Apr. 30, 2017 USD ($)	Apr. 30, 2016 USD ($)	Apr. 30, 2017 USD ($)	Apr. 30, 2016 USD ($)	Jul. 31, 2017 USD ($) Employee
Restructuring Cost and Reserve [Line Items]
Restructuring charge	$ 2,080	$ 1,839	$ 2,379	$ 8,269
Restructuring adjustments			100
Fiscal Year 2017 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charge	2,100		2,500
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
Fiscal Year 2016 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charge		$ 1,800		$ 8,300
Restructuring adjustments	$ 0		$ (100)