Identifiable intangible assets (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Software costs capitalized	$ 1,590,000	$ 871,000	$ 3,216,000	$ 2,493,000
Amortization of capitalized software costs	402,000	402,000	894,000	1,166,000
Amortization of identifiable intangible assets	0		0
Components of identifiable intangible assets [Abstract]
Intangible assets - gross	17,004,000		17,004,000		13,788,000
Less accumulated amortization	(2,935,000)		(2,935,000)		(2,041,000)
Intangible assets - net	14,069,000		14,069,000		11,747,000
Future amortization of intangible assets assuming straight-line amortization of capitalized software costs [Abstract]
2013	431,000		431,000
2014	1,903,000		1,903,000
2015	1,863,000		1,863,000
2016	1,832,000		1,832,000
2017	1,800,000		1,800,000
2018	1,699,000		1,699,000
Thereafter	2,741,000		2,741,000
Total	12,269,000		12,269,000
Acquired and internally developed software costs [Member]
Components of identifiable intangible assets [Abstract]
Intangible assets - gross	15,204,000		15,204,000		11,988,000
Trademarks (non-amortizable) [Member]
Components of identifiable intangible assets [Abstract]
Intangible assets - gross	$ 1,800,000		$ 1,800,000		$ 1,800,000
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Remaining estimated economic life of the product	3 years		3 years
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Remaining estimated economic life of the product		7 years		7 years