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Marketable Securities - Maturity Schedule (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract] |  |
Interest income from cash equivalents and marketable securities | $ 135 | $ 480

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- Definition Amount of realized gain (loss) on investment in marketable security, including other-than-temporary impairment (OTTI). + References No definition available. + Details
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