Property and Equipment (Details Textual) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Property and equipment (Textual) [Abstract]
Depreciation expense related to plant and equipment	$ 837	$ 875	$ 879
Amount disposed of property plant and equipment	251	856
Gain or loss on disposal of property plant and equipment	$ 0	$ (11)	$ 0