Inventory - Inventories (Detail) (USD $)	Jun. 30, 2013	Dec. 31, 2012
Inventory Disclosure [Abstract]
Raw materials	$ 8,988,668	$ 9,689,172
Work-in-process	168,103	131,492
Finished goods	4,725,827	3,492,167
Reserve for excess and obsolete inventory	(682,162)	(2,319,622)
Total inventory	$ 13,200,436	$ 10,993,209