Schedule of Available-for-sale Securities, Unrealized Loss Position (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, Unrealized Loss Position, Accumulated Loss	$ 342	$ 50
Debt Securities, Available-for-sale, Unrealized Loss Position	14,420	4,945
Certificates of Deposit [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	3
Debt Securities, Available-for-sale, Unrealized Loss Position	1,997
US Treasury Bill Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	57	17
Debt Securities, Available-for-sale, Unrealized Loss Position	1,603	1,652
Corporate Bond Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	277	33
Debt Securities, Available-for-sale, Unrealized Loss Position	5,698	$ 3,293
Municipal Bonds [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	5
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 5,122