Intangible Assets (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2013 Item	Mar. 31, 2012	Dec. 31, 2012
Intangible Assets
Weighted-Average Amortization Period	10 years		10 years
Gross Carrying Amount	$ 10,427,000		$ 10,427,000
Accumulated Amortization	(3,981,000)		(3,716,000)
Amortization expense	265,000	265,000
Number of other patterns	0
Expected amortization expense for year one	1,100,000
Expected amortization expense for year two	1,100,000
Expected amortization expense for year three	1,100,000
Expected amortization expense for year four	1,100,000
Expected amortization expense for year five	1,100,000
Core and developed technology
Intangible Assets
Weighted-Average Amortization Period	10 years
Gross Carrying Amount	10,257,000		10,257,000
Accumulated Amortization	(3,811,000)		(3,546,000)
Non-compete agreement
Intangible Assets
Weighted-Average Amortization Period	2 years
Gross Carrying Amount	170,000		170,000
Accumulated Amortization	$ (170,000)		$ (170,000)