Inventories (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Components of inventories
Raw materials	$ 1,560,581	$ 1,685,493
Work in process	2,580,155	2,602,990
Finished goods	2,215,100	1,745,052
Inventory gross	6,355,836	6,033,535
Less: reserve for obsolete inventory	(139,621)	(135,980)
Inventory net	$ 6,216,215	$ 5,897,555