Income taxes (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Computed tax benefit at the federal statutory rate of 35%	$ 2,894	$ 591	$ 19,069
State income taxes, net of federal benefit	(52)	(19)	(57)
Non-deductible compensation	(647)	(91)	(537)
Non-deductible expense	(189)	(113)	(131)
Non-deductible goodwill impairment	(323)	1,257	(15,490)
Tax on foreign income	(94)	(104)	(252)
Valuation allowance	1,579	(1,686)	(4,186)
Other	41	81	(18)
Income tax provision	$ 3,209us-gaap_IncomeTaxExpenseBenefit	$ (84)us-gaap_IncomeTaxExpenseBenefit	$ (1,602)us-gaap_IncomeTaxExpenseBenefit
Effective tax rate	(38.80%)	5.00%	2.90%

Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of current and deferred income tax expense (benefit) attributable to income (loss) from continuing foreign operations not within the country of domicile of the entity.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to increase (decrease) in the valuation allowance for deferred tax assets.

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The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.

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