Note 3 - Significant Accounting Policies - Reserve for Product Warranty Activity (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Beginning balance	$ 359,654	$ 33,500
Provision for product warranty		400,500
Product warranty expirations	(20,801)
Product warranty costs paid	(14,278)	(74,346)
Ending balance	$ 324,575	$ 359,654