Goodwill and intangible assets (Details Textual) (USD $) In Thousands, except Share data, unless otherwise specified	1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
	May 20, 2013	Sep. 30, 2013	Sep. 30, 2013	Dec. 31, 2012	Sep. 03, 2013	Apr. 26, 2013
Goodwill [Line Items]
Finite-lived Intangible Assets, Fair Value Disclosure				$ 1,913
Finite Lived Intangible Asset Acquired Cash Paid				200
Stock Issued During Period Shares Purchase Of Warrants				350,000
Warrant Term				4 years
Class of Warrant or Right, Exercise Price of Warrants or Rights		3.85	3.85	4.00	3.85	3.85
Intangible assets consideration paid	25
Adjustments To Additional Paid In Capital Reclassification Of Warrants Into Equity	1,164		1,164
Warrants and Rights Outstanding	1,164
Class of Warrant or Right, Outstanding	403,029
Gain (loss) on mark to market of intangible assets		$ 0	$ 605