Intangible assets (Details Textual) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	$ 300	$ 120	$ 500	$ 170
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			4 years 8 months 12 days
Fujian Qiaolong Special Purpose Vehicle Co., Ltd [Member]
Finite-Lived Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		900		900
Fujian Qiaolong Special Purpose Vehicle Co., Ltd [Member] | Patent Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		$ 900		$ 900
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		4 years 8 months 12 days
Fujian Qiaolong Special Purpose Vehicle Co., Ltd [Member] | Management Software Licenses [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		1 year 1 month 6 days