Summary of Property and Equipment (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Buildings	$ 2,496,865	$ 2,412,024
Plant and machinery	19,321,199	18,807,970
Motor vehicles	71,535	69,667
Office and electric equipment	625,271	584,515
Subtotal	22,514,870	21,874,176
Less: accumulated depreciation	(11,492,383)	(10,190,189)
Property and equipment, net	$ 11,022,487	$ 11,683,987