Balance Sheet Components (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2020	Apr. 30, 2019	Jul. 31, 2019
Balance Sheet Related Disclosures [Abstract]
Property and equipment pledged as collateral	$ 0		$ 0		$ 0
Depreciation	3,800,000	$ 2,100,000	11,000,000.0	$ 6,500,000
Amortization	300,000	300,000	800,000	900,000
Amortization expense	6,600,000	$ 7,300,000	20,500,000	$ 21,900,000
Impairment loss	$ 10,700,000		$ 10,700,000