Debt Securities (Details) - Schedule of available-for-sale securities - USD ($) $ in Thousands		Oct. 31, 2020	Jul. 31, 2020
Marketable Securities [Line Items]
Amortized Cost		$ 23,877	$ 18,321
Gross Unrealized Gains		44	58
Gross Unrealized Losses		(31)	(16)
Fair Value		23,890	18,363
Certificates of deposit [Member]
Marketable Securities [Line Items]
Amortized Cost	[1]	7,537	13,844
Gross Unrealized Gains	[1]	30	58
Gross Unrealized Losses	[1]
Fair Value	[1]	7,567	13,902
U.S. Treasury bills [Member]
Marketable Securities [Line Items]
Amortized Cost		4,179	2,498
Gross Unrealized Gains
Gross Unrealized Losses		(8)
Fair Value		4,171	2,498
Corporate bonds [Member]
Marketable Securities [Line Items]
Amortized Cost		6,238
Gross Unrealized Gains		14
Gross Unrealized Losses		(21)
Fair Value		6,231
Municipal bonds [Member]
Marketable Securities [Line Items]
Amortized Cost		5,923	1,979
Gross Unrealized Gains
Gross Unrealized Losses		(2)	(16)
Fair Value		$ 5,921	$ 1,963

[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.