Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities
Debt securities, Cost	$ 896	$ 4,306
Debt securities, Carrying Value	897	4,382
Total, Cost	2,065	14,706
Total, Gross Unrealized Gains	1,306	10,409
Total, Gross Unrealized Losses	(17)	(44)
Total, Carrying Value	3,354	25,071
Available-for-sale Securities, Debt Maturities [Abstract]
Due in one year or less, Amortized Cost	275	182
Due after one year through five years, Amortized Cost	621	4,124
Due in one year or less, Carrying Value	275	183
Due after one year through five years, Carrying Value	622	4,199
Corporate Bond Securities
Schedule of Available-for-sale Securities
Debt securities, Cost	896	4,306
Debt securities, Gross Unrealized Gains	13	82
Debt securities, Gross Unrealized Losses	(12)	(6)
Debt securities, Carrying Value	897	4,382
Equity Securities
Schedule of Available-for-sale Securities
Marketable equity securities, Cost	1,169	10,400
Marketable equity securities, Gross Unrealized Gains	1,293	10,327
Marketable equity securities, Gross Unrealized Losses	(5)	(38)
Marketable equity securities, carrying value	$ 2,457	$ 20,689

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

Name:	us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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