Marketable Securities (Details 2) - USD ($) $ in Thousands	Apr. 30, 2017	Jul. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Unrealized Losses	$ 38	$ 181
Fair Value	27,929	10,716
Certificates of deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized Losses	5
Fair Value	10,455
Federal Government Sponsored Enterprise notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized Losses	19
Fair Value	7,469
Corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized Losses	1
Fair Value	749
U.S. Treasury notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized Losses	6	1
Fair Value	1,773	199
Municipal bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized Losses	4	1
Fair Value	7,412	3,112
Mutual funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized Losses		39
Fair Value		5,082
Equity [Member]
Schedule of Available-for-sale Securities [Line Items]
Unrealized Losses	3	140
Fair Value	$ 71	$ 2,323

Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27337-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27290-111563

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- Definition

This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27290-111563

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No definition available.

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