Warranty (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Warranty
Period of warranties, low end of the range			90 days
Period of warranties, high end of the range			1 year
Warranty provisions and claims for the years
Beginning balance	$ 245,269	$ 180,325	$ 240,621	$ 205,506
Acquired provision - Dansensor acquisition		85,413		85,413
Warranty provisions	43,611	121,052	166,500	156,878
Warranty claims	(48,330)	(135,880)	(166,571)	(196,887)
Ending balance	$ 240,550	$ 250,910	$ 240,550	$ 250,910