Marketable Securities - Schedule of Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Fair Value	$ 54,384	$ 90,590
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Less than 1 Year	293
1-5 Years	3,464
5-10 Years	341
Greater than 10 Years	0
Fair Value	4,098	6,339
Government securities - U.S.
Debt Securities, Available-for-sale [Line Items]
Less than 1 Year	0
1-5 Years	4,744
5-10 Years	315
Greater than 10 Years	387
Fair Value	5,446	12,701
Other fixed-income securities
Debt Securities, Available-for-sale [Line Items]
Less than 1 Year	0
1-5 Years	1,637
5-10 Years	0
Greater than 10 Years	0
Fair Value	1,637	$ 9,409
Debt Securities
Debt Securities, Available-for-sale [Line Items]
Less than 1 Year	293
1-5 Years	9,845
5-10 Years	656
Greater than 10 Years	387
Fair Value	$ 11,181

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