Inventory - Inventories (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Inventory Disclosure [Abstract]
Raw materials	$ 9,257,735	$ 9,689,172
Work-in-process	46,348	131,492
Finished goods	3,681,059	3,492,167
Reserve for excess and obsolete inventory	(695,782)	(2,319,622)
Total inventory	$ 12,289,360	$ 10,993,209