Restructuring Accrual Activity (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014	Jul. 31, 2014
Restructuring Cost and Reserve [Line Items]
Beginning Balance			$ 2,552	$ 2,774
Balance assumed from the Acquisition				447
Additions to expense	230	2,159	938	2,159
Accretion			155	124
Cash paid			(1,764)	(801)
Ending Balance	1,881	4,703	1,881	4,703
Restructuring reserve, current	1,183		1,183		1,497
Accrued expenses
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, current	1,183	3,187	1,183	3,187
Other long-term liabilities
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, noncurrent	698	1,516	698	1,516
Employee Severance
Restructuring Cost and Reserve [Line Items]
Beginning Balance			421	2
Balance assumed from the Acquisition				447
Additions to expense			445	2,159
Cash paid			(592)	(180)
Ending Balance	274	2,428	274	2,428
Employee Severance | Accrued expenses
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, current	274	2,303	274	2,303
Employee Severance | Other long-term liabilities
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, noncurrent		125		125
Facility Lease
Restructuring Cost and Reserve [Line Items]
Beginning Balance			2,131	2,772
Additions to expense			493
Accretion			155	124
Cash paid			(1,172)	(621)
Ending Balance	1,607	2,275	1,607	2,275
Facility Lease | Accrued expenses
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, current	909	884	909	884
Facility Lease | Other long-term liabilities
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, noncurrent	$ 698	$ 1,391	$ 698	$ 1,391