Marketable Securities (Details 2) - USD ($) $ in Thousands	Jul. 31, 2016	Jul. 31, 2015
Schedule Of Available For Sale Securities [Line Items]
Unrealized Losses	$ 181	$ 587
Fair Value	10,716	13,284
Certificates of Deposit [Member]
Schedule Of Available For Sale Securities [Line Items]
Unrealized Losses		2
Fair Value		2,194
International agency notes [Member]
Schedule Of Available For Sale Securities [Line Items]
Unrealized Losses		1
Fair Value		1,119
Mutual funds [Member]
Schedule Of Available For Sale Securities [Line Items]
Unrealized Losses	39	18
Fair Value	5,082	4,982
Straight Path Communications Inc. common stock [Member]
Schedule Of Available For Sale Securities [Line Items]
Unrealized Losses		563
Fair Value		1,523
Equity [Member]
Schedule Of Available For Sale Securities [Line Items]
Unrealized Losses	140
Fair Value	2,323
U.S. Treasury notes [Member]
Schedule Of Available For Sale Securities [Line Items]
Unrealized Losses	1
Fair Value	199
Municipal bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Unrealized Losses	1	3
Fair Value	$ 3,112	$ 3,466

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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+ References

No definition available.

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