Intangible Assets (Details) (USD $)	12 Months Ended
	Dec. 31, 2013 item	Dec. 31, 2012
Purchased patents
Weighted-Average Life	10 years	10 years
Gross Carrying Amount	$ 2,292,000	$ 2,292,000
Accumulated Amortization	1,838,000	1,609,000
Patent defense costs
Gross Carrying Amount	704,000
Number of U.S. patents issued	3
Additional disclosures
Amortization expense	229,000
Estimated annual aggregate amortization expense through December 31, 2015	229,000
Net book value of intangible assets	$ 1,158,000	$ 683,000