Components of Other Accrued Expenses (Detail) - USD ($) $ in Thousands	Jan. 31, 2018	Jul. 31, 2017	Jan. 31, 2017	Jul. 31, 2016
Accrued Liabilities [Line Items]
Accrued compensation	$ 15,771	$ 18,864
Accrued income and other taxes	7,984	13,163
Warranty reserve	3,872	3,610	$ 2,531	$ 2,725
Accrued vendor liability	2,503	2,229
Accrued commissions	2,364	2,931
Accrued professional fees	1,538	3,218
Other accrued expenses	5,811	6,247
Total accrued expenses	$ 39,843	$ 50,262