Note 3 - Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2017

Notes Tables

Schedule of Product Warranty Liability [Table Text Block]

	June 30, 2017			December 31, 2016
Balance, beginning of the year	$	240,980		$	359,654
Provision for product warranty		-			1,800
Product warranty expirations		(238,967	)		(86,301	)
Product warranty costs paid		(2,013	)		(34,173	)
Balance, end of the period	$	-		$	240,980

Research and Development Expense [Table Text Block]

	Three Months Ended June 30,				Six Months Ended June 30,
	2017		2016		2017		2016
Salaries	$	51,473	$	17,452	$	91,079	$	37,004
Other costs		25,263		6,907		27,452		8,252
	$	76,736	$	24,359	$	118,531	$	45,256