Summary of Charges Related to Accrued Restructuring Activities (Detail) - USD ($) $ in Thousands		3 Months Ended
		Oct. 31, 2017		Oct. 31, 2016
Restructuring Cost and Reserve [Line Items]
Balance at beginning period		$ 2,800		$ 5,200
Restructuring charge		700
Adjustments		(200)		30
Cash payments		(1,800)		(2,700)
Non-cash adjustments		(100)
Balance at end period		1,400		2,500
Employee Severance and Benefits
Restructuring Cost and Reserve [Line Items]
Balance at beginning period		2,700	[1]	5,200	[2]
Restructuring charge	[1]	400
Adjustments		(200)	[1]	30	[2]
Cash payments		(1,800)	[1]	(2,700)	[2]
Balance at end period		1,100	[1]	$ 2,500	[2]
Facility Exit Costs
Restructuring Cost and Reserve [Line Items]
Balance at beginning period	[1]	100
Restructuring charge	[1]	300
Non-cash adjustments	[1]	(100)
Balance at end period	[1]	$ 300

[1] Restructuring charges in fiscal year 2018 relate to the Fiscal Year 2017 Restructuring Plan.

[2] Activity during the period relates to our fiscal year 2016 restructuring plan, which was completed in the fourth quarter of fiscal year 2017.