Stock-Based Compensation - Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2017
Income statement components of stock-based compensation expense recognized in Consolidated Statements of Income
Stock-based compensation before income taxes	$ 15,562	$ 9,615	$ 8,844
Maximum share attainment as a percentage of initially granted shares	200.00%
Total unrecognized stock-based compensation cost	$ 13,874
Remaining weighted average period for unrecognized compensation cost	12 months
Cost of sales
Income statement components of stock-based compensation expense recognized in Consolidated Statements of Income
Stock-based compensation before income taxes	$ 1,010	663	371
Selling
Income statement components of stock-based compensation expense recognized in Consolidated Statements of Income
Stock-based compensation before income taxes	2,428	1,458	1,582
General and administrative
Income statement components of stock-based compensation expense recognized in Consolidated Statements of Income
Stock-based compensation before income taxes	11,828	7,292	6,774
Research and development
Income statement components of stock-based compensation expense recognized in Consolidated Statements of Income
Stock-based compensation before income taxes	296	202	117
Total operating expenses
Income statement components of stock-based compensation expense recognized in Consolidated Statements of Income
Stock-based compensation before income taxes	$ 14,552	$ 8,952	$ 8,473