Stock-Based Compensation - Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2020	Apr. 30, 2019
Income statement components of stock-based compensation expense recognized in Consolidated Statements of Income
Stock-based compensation expense	$ 3,027	$ 5,722	$ 8,843	$ 11,885
Cost of sales
Income statement components of stock-based compensation expense recognized in Consolidated Statements of Income
Stock-based compensation expense	328	245	978	769
Total operating expenses
Income statement components of stock-based compensation expense recognized in Consolidated Statements of Income
Stock-based compensation expense	2,699	5,477	7,865	11,116
Selling
Income statement components of stock-based compensation expense recognized in Consolidated Statements of Income
Stock-based compensation expense	657	538	1,802	1,684
General and administrative
Income statement components of stock-based compensation expense recognized in Consolidated Statements of Income
Stock-based compensation expense	1,931	4,874	5,764	9,249
Research and development
Income statement components of stock-based compensation expense recognized in Consolidated Statements of Income
Stock-based compensation expense	$ 111	$ 65	$ 299	$ 183