Property, Plant and Equipment, Net - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Depreciation, property plant and equipment	$ 734,064	$ 447,842	$ 1,813,675	$ 1,343,388
Property and equipment, net book value pledged as collateral	$ 40,766,557		$ 40,766,557		$ 25,778,015