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Fair Value Measurements (Details 1) - Level 3 [Member] - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
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Jan. 31, 2019 | Jan. 31, 2018 | Jan. 31, 2019 | Jan. 31, 2018
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Balance, beginning of period | $ 2,816 | $ 6,300 |  | $ 6,300
Transfer into Level 3 from adoption of change in accounting for equity investments |  |  | 2,794 |
Total losses recognized in "Other income (expense), net" | (71) |  | (49) |
Balance, end of period | 2,745 | 6,300 | 2,745 | 6,300
Change in unrealized gains or losses for the period included in earnings for assets held at the end of the period | $ (71) |  | $ (49) |

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- Definition Amount of fair value measurement with unobservable inputs reconciliation recurring basis asset transfers into level three from adoption of accounting change. + References No definition available. + Details
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- Definition Amount of gain (loss) recognized in the income statement for financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258 + Details
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- Definition Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258 + Details
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