Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2016

Patents [Member]

Schedule of Patent Cost and Other Asset

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

	2016			2015
Patent costs	$	2,427		$	2,525
Accumulated amortization		(1,598	)		(1,583	)
	$	829		$	942