Stock-Based Compensation - Income Tax Benefit From Stock-based Awards (Details) - USD ($)	6 Months Ended
	Jan. 31, 2018	Jan. 31, 2017
Income Tax Expense | Impact of Accounting Standards Update 2016-09
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net income tax shortfalls and reversal of deferred tax assets	$ 71,000
Reduction to Additional Paid-In Capital
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net income tax shortfalls and reversal of deferred tax assets		$ 601,000