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Fair Value Measurements - Financial Assets and Liabilities Carried at Fair Value on Recurring Basis (Details) - Recurring [Member] - USD ($) $ in Thousands | Mar. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Assets: |  |
Long-term equity securities | $ 1,107 | $ 392
Liabilities: |  |
Contingent consideration | 75 |
Significant Unobservable Inputs (Level 3) [Member] |  |
Assets: |  |
Long-term equity securities | 1,107 | $ 392
Liabilities: |  |
Contingent consideration | $ 75 |

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- Definition Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258 + Details
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