Schedule of Available-for-sale Securities (Details) - USD ($) $ in Thousands		Jan. 31, 2022	Jul. 31, 2021
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		$ 15,822	$ 14,021
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax		10	41
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax		(342)	(50)
Debt Securities, Available-for-sale		15,490	14,012
Certificates of Deposit [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	[1]	2,000	1,200
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	[1]		3
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	[1]	(3)
Debt Securities, Available-for-sale	[1]	1,997	1,203
US Treasury Bill Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		1,660	1,669
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax		(57)	(17)
Debt Securities, Available-for-sale		1,603	1,652
Corporate Bond Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		6,362	6,327
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax		10	38
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax		(277)	(33)
Debt Securities, Available-for-sale		6,095	6,332
Municipal Bonds [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		5,800	4,825
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax		(5)
Debt Securities, Available-for-sale		$ 5,795	$ 4,825

[1] Each of the Company’s certificates of deposit has a CUSIP, was purchased in the secondary market through a broker and may be sold in the secondary market.