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Marketable Securities (Details 2) - USD ($) $ in Thousands | Jul. 31, 2018 | Jul. 31, 2017
--- | --- | ---
Schedule of Available-for-sale Securities [Line Items] |  |
Unrealized Losses | $ 34 | $ 48
Fair Value | 2,052 | 19,081
Certificates of deposit [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Unrealized Losses |  | 7
Fair Value |  | 12,155
Federal Government Sponsored Enterprise notes [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Unrealized Losses |  | 14
Fair Value |  | 3,529
Equity [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Unrealized Losses | 33 | 26
Fair Value | 360 | 48
U.S. Treasury notes [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Unrealized Losses | 1 |
Fair Value | $ 1,692 |
Municipal bonds [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Unrealized Losses |  | 1
Fair Value |  | $ 3,349

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- Definition Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27337-111563 + Details
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