Marketable Securities Marketable Securities - Schedule of Maturities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Total	$ 39,977	$ 54,384
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Less than 1 Year	592
1-5 Years	3,030
5-10 Years	391
Greater than 10 Years	0
Total	4,013	4,098
Government securities - U.S.
Debt Securities, Available-for-sale [Line Items]
Less than 1 Year	0
1-5 Years	5,269
5-10 Years	329
Greater than 10 Years	487
Total	6,085	5,446
Other fixed-income securities
Debt Securities, Available-for-sale [Line Items]
Less than 1 Year	50
1-5 Years	1,357
5-10 Years	0
Greater than 10 Years	0
Total	1,407	$ 1,637
Total
Debt Securities, Available-for-sale [Line Items]
Less than 1 Year	642
1-5 Years	9,656
5-10 Years	720
Greater than 10 Years	487
Total	$ 11,505