Investments (Summary of Available-for-sale Investments) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 511	$ 23,256
Gross Unrealized Gains	142	112
Gross Unrealized Losses	0	(698)
Fair Value	653	22,670
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	511	23,256
Gross Unrealized Gains	142	112
Gross Unrealized Losses	0	(698)
Fair Value	$ 653	$ 22,670

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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