Revenue from Contracts with Customers (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jan. 31, 2021	Jan. 31, 2021	Jul. 31, 2020
Revenue from Contract with Customer [Abstract]
Contract with Customer, Liability	$ 2,531,000	$ 2,531,000	$ 2,559,000
Deferred Revenue, Revenue Recognized	$ 294,000	$ 316,000