Revenue from Contracts with Customers (Details) - USD ($)	3 Months Ended	9 Months Ended
	Apr. 30, 2020	Apr. 30, 2020	Jul. 31, 2019
Revenue from Contract with Customer [Abstract]
Contract with Customer, Liability	$ 2,771,000	$ 2,771,000	$ 2,782,000
Deferred Revenue, Revenue Recognized	$ 317,000	$ 948,000