Restructuring Accrual Activity (Detail) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Apr. 30, 2017
Apr. 30, 2016
Apr. 30, 2017
Apr. 30, 2016
Jul. 31, 2016
Restructuring Cost and Reserve [Line Items]          
Beginning Balance     $ 876 $ 2,128  
Additions to expense $ 187 $ 120 592 504  
Accretion     253 289  
Cash paid     (1,453) (2,098)  
Ending Balance 268 823 268 823  
Restructuring reserve, current 268   268   $ 876
Restructuring Charges          
Restructuring Cost and Reserve [Line Items]          
Additions to expense     592 504  
Other accrued expenses          
Restructuring Cost and Reserve [Line Items]          
Restructuring reserve, current 268 823 268 823  
Severance Costs          
Restructuring Cost and Reserve [Line Items]          
Beginning Balance     142 684  
Cash paid     (348) (972)  
Ending Balance 142 68 142 68  
Severance Costs | Restructuring Charges          
Restructuring Cost and Reserve [Line Items]          
Additions to expense     348 356  
Severance Costs | Other accrued expenses          
Restructuring Cost and Reserve [Line Items]          
Restructuring reserve, current 142 68 142 68  
Facility Lease          
Restructuring Cost and Reserve [Line Items]          
Beginning Balance     734 1,444  
Accretion     253 289  
Cash paid     (1,105) (1,126)  
Ending Balance 126 755 126 755  
Facility Lease | Restructuring Charges          
Restructuring Cost and Reserve [Line Items]          
Additions to expense     244 148  
Facility Lease | Other accrued expenses          
Restructuring Cost and Reserve [Line Items]          
Restructuring reserve, current $ 126 $ 755 $ 126 $ 755