Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Accounts receivable, allowance for doubtful accounts	$ 86	$ 47
Patents and licenses, accumulated amortization	$ 11,032	$ 10,853
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	1,428	1,399