Investments (Tables)

12 Months Ended

Dec. 31, 2017

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Fair Value of Investments

	Note			Note
	receivable-			receivable-
Description	long-term			current			Investments
Balance at December 31, 2015	$	375		$	—		$	680
Purchases, (sales), issuances and (settlements), net		(375	)		750			—
Balance at December 31, 2016		—			750			680
Reserve for notes receivable		—			(750	)		—
Net balance at December 31, 2016		—			—			680
Write-offs		—			—			(580	)
Net balance at December 31, 2017	$	—		$	—		$	100