Property and Equipment (Details) (USD $)	6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Components of property and equipment
Property and equipment, gross	$ 86,421,587	$ 78,079,102
Less: accumulated depreciation	(22,280,578)	(18,643,002)
Property and equipment, net	64,141,009	59,436,100
Office equipment and furniture [Member]
Components of property and equipment
Property and equipment, useful life	5 years
Property and equipment, gross	250,743	222,853
Manufacturing equipment [Member]
Components of property and equipment
Property and equipment, gross	64,775,587	56,916,700
Manufacturing equipment [Member] | Minimum [Member]
Components of property and equipment
Property and equipment, useful life	5 years
Manufacturing equipment [Member] | Maximum [Member]
Components of property and equipment
Property and equipment, useful life	10 years
Vehicles [Member]
Components of property and equipment
Property and equipment, useful life	5 years
Property and equipment, gross	127,754	125,167
Construction in progress [Member]
Components of property and equipment
Property and equipment, useful life
Property and equipment, gross	52,302	28,785
Building and building improvements [Member]
Components of property and equipment
Property and equipment, useful life	20 years
Property and equipment, gross	$ 21,215,201	$ 20,785,597