Cash, Cash Equivalents and Investments - Recurring Basis (Details) - USD ($) $ in Thousands	24 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Assets, Fair Value Disclosure [Abstract]
Investments, amortized cost	$ 9,427	$ 22,846
Fair Value, Transfers Between Level 1 and Level 2, Description and Policy [Abstract]
Transfer from Level 1 to Level 2 , assets	0
Transfer from Level 2 to Level 1 , assets	0
Transfers into Level 3, assets	0
Transfer out of Level 3, assets	0
Recurring
Assets, Fair Value Disclosure [Abstract]
Total	9,427	22,846
Recurring | Certificates of Deposit [Member]
Assets, Fair Value Disclosure [Abstract]
Cash and cash equivalents, fair value disclosure	2,402	4,481
Recurring | Corporate Bonds [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, amortized cost	7,025	18,365
Recurring | Significant Other Observable Inputs (Level 2)
Assets, Fair Value Disclosure [Abstract]
Total	9,427	22,846
Recurring | Significant Other Observable Inputs (Level 2) | Certificates of Deposit [Member]
Assets, Fair Value Disclosure [Abstract]
Cash and cash equivalents, fair value disclosure	2,402	4,481
Recurring | Significant Other Observable Inputs (Level 2) | Corporate Bonds [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, amortized cost	$ 7,025	$ 18,365