CONSOLIDATED BALANCE SHEET (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 71	$ 50
Patents and licenses, accumulated amortization	$ 11,911	$ 11,647
Common stock, par value	$ 0.10	$ 0.10
Common stock, authorized	10,000	10,000
Common stock, issued	3,420	3,420
Treasury shares, shares	1,596	1,596