Note 5 - Intangible Assets

9 Months Ended

Sep. 30, 2015

Notes to Financial Statements

Intangible Assets Disclosure [Text Block]

5 . Intangible assets

Intangible assets consist of the following:

	September 30,			December 31,
	2015			2014
Patents, at cost	$	3,502,135		$	3,502,135
Less accumulated amortization		(3,118,690	)		(2,888,622	)
Net intangible assets	$	383,445		$	613,513

The aggregate amortization charged to operations was $76,689 for the three months ended September 30, 2015 and 2014, and $230,068 and $230,067 for the nine months ended September 30, 2015 and 2014, respectively.