Investment Securities Table (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Current	$ 20,845		$ 37,329
Debt Securities, Available-for-sale, Noncurrent	0		2,025
Debt Securities, Available-for-sale, Amortized Cost	20,845		39,354
Debt Securities, Available-for-sale, Unrealized Loss	0	$ 0
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	20,845		37,329
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value	0		2,025
Debt Securities, Available-for-sale	20,845		39,354
Available-for-sale Debt Security Current [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0		0
Available-for-sale Debt Security Noncurrent [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 0		$ 0

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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