Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2018

Patents [Member]

Schedule of Patent Cost and Other Asset

Patent costs, which are included in other assets in the accompanying Consolidated Balance Sheets, as of December 31 were as follows (in thousands):

	2018			2017
Patent costs	$	1,979		$	2,093
Accumulated amortization		(1,380	)		(1,386	)
	$	599		$	707