Transactions with Customers with Common Board Members and Officers - Additional Information (Detail) - USD ($)	12 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014
Related Party Transaction [Line Items]
Deferred revenue from sales to customer	$ 53,889,000	$ 40,802,000
Member of Board of Directors [Member]
Related Party Transaction [Line Items]
Revenue recorded from sales to customer	400,000	2,200,000	$ 0
Deferred revenue from sales to customer	300,000	700,000
Accounts receivable due from customer	0	0
Officer [Member]
Related Party Transaction [Line Items]
Revenue recorded from sales to customer	200,000
Deferred revenue from sales to customer	700,000	$ 700,000
Accounts receivable due from customer	$ 500,000