Goodwill and intangible assets Schedule of Finite-Lived Intangible Assets (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 4,370,000	$ 4,370,000
Accumulated amortization	2,826,000	2,103,000
Finite-Lived Intangible Assets, Net	1,544,000	2,267,000
Goodwill [Abstract]
Goodwill	5,575,000	5,575,000
Impairment and Amortization [Abstract]
Goodwill, Impairment Loss	0	0	0
Impairment of Intangibles (Excl. Goodwill)	0	0	0
Amortization expense	700,000	900,000	1,000,000
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted average useful life (years)	9 years
Gross carrying amount	2,350,000	2,350,000
Accumulated amortization	1,449,000	1,117,000
Finite-Lived Intangible Assets, Net	901,000	1,233,000
Developed technology
Finite-Lived Intangible Assets [Line Items]
Weighted average useful life (years)	6 years
Gross carrying amount	1,880,000	1,880,000
Accumulated amortization	1,264,000	896,000
Finite-Lived Intangible Assets, Net	616,000	984,000
Trademarks
Finite-Lived Intangible Assets [Line Items]
Weighted average useful life (years)	7 years
Gross carrying amount	70,000	70,000
Accumulated amortization	43,000	30,000
Finite-Lived Intangible Assets, Net	27,000	40,000
Non-compete Agreements
Finite-Lived Intangible Assets [Line Items]
Weighted average useful life (years)	2 years
Gross carrying amount	70,000	70,000
Accumulated amortization	70,000	60,000
Finite-Lived Intangible Assets, Net	$ 0	$ 10,000