Investments - Schedule of Investments' Gross Unrealized Loss and Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 Months	$ 2,021	$ 0
Unrealized Losses, Less than 12 Months	(69)	0
Fair Value, 12 Months or More	0	8,051
Unrealized Losses, 12 Months or More	0	(47)
Fair Value	2,021	8,051
Unrealized Losses	(69)	(47)
U.S. Treasury securities, obligations of U.S. Government agencies and Municipalities
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 Months	1,080	0
Unrealized Losses, Less than 12 Months	(4)	0
Fair Value, 12 Months or More	0	7,053
Unrealized Losses, 12 Months or More	0	(39)
Fair Value	1,080	7,053
Unrealized Losses	(4)	(39)
Corporate debt
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 Months	941	0
Unrealized Losses, Less than 12 Months	(65)	0
Fair Value, 12 Months or More	0	998
Unrealized Losses, 12 Months or More	0	(8)
Fair Value	941	998
Unrealized Losses	$ (65)	$ (8)