Fair Value Measurement, Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value by Investment Category (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Financial Assets [Abstract]
Adjusted Cost	$ 3,135	$ 7,611
Adjusted Cost	3,450	4,366
Unrealized Gains	3	0
Unrealized Losses	0	0
Fair Value	3,453	4,366
Adjusted Cost	5,526	9,414
Fair Value	$ 5,529	9,414
Minimum [Member]
Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Financial Assets [Abstract]
Maturities of available for sale securities	1 year
Maximum [Member]
Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Financial Assets [Abstract]
Maturities of available for sale securities	2 years
Cash [Member]
Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Financial Assets [Abstract]
Adjusted Cost	$ 2,076	5,048
Fair Value	2,076	5,048
Cash and Cash Equivalents	2,076	5,048
Mutual Funds [Member]
Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Financial Assets [Abstract]
Adjusted Cost	613	1,107
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	613	1,107
US Agency Securities [Member]
Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Financial Assets [Abstract]
Adjusted Cost	2,837	3,259
Unrealized Gains	3	0
Unrealized Losses	0	0
Fair Value	2,840	3,259
Recurring [Member]
Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Financial Assets [Abstract]
Fair Value	3,135	7,611
Cash and Cash Equivalents	3,135	7,611
Investments Available for Sale	2,394	1,803
Recurring [Member] \| Cash [Member]
Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Financial Assets [Abstract]
Fair Value	2,076	5,048
Cash and Cash Equivalents	2,076	5,048
Recurring [Member] \| Level 1 [Member]
Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Financial Assets [Abstract]
Fair Value	1,059	2,563
Cash and Cash Equivalents	1,059	2,563
Investments Available for Sale	2,394	1,803
Recurring [Member] \| Level 1 [Member] \| Mutual Funds [Member]
Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Financial Assets [Abstract]
Fair Value	613	1,107
Cash and Cash Equivalents	613	1,107
Investments Available for Sale	0	0
Recurring [Member] \| Level 1 [Member] \| US Agency Securities [Member]
Adjusted Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Financial Assets [Abstract]
Fair Value	446	1,456
Cash and Cash Equivalents	446	1,456
Investments Available for Sale	$ 2,394	$ 1,803

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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-Publisher FASB
-Name Accounting Standards Codification
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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Period of maturity of a debt security categorized as neither trading nor held-to-maturity, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading, excluding cash and cash equivalents.

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This item represents the cost of cash and debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Fair value portion of cash and investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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