Note 3 - Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2019

Notes Tables

Schedule of Product Warranty Liability [Table Text Block]

	September 30, 2019			December 31, 2018
Balance, beginning of the period	$	153,723		$	40,000
Provision for product warranty		-			142,000
Product warranty expirations		(40,400	)		-
Product warranty costs paid		(12,488	)		(28,277	)
Balance, end of the period	$	100,835		$	153,723

Research and Development Expense [Table Text Block]

	Three months ended September 30,				Nine months ended September 30,
	2019		2018		2019		2018
Salaries	$	15,841	$	7,047	$	33,482	$	69,727
Other costs		4,584		14,000		17,038		38,401
	$	20,425	$	21,047	$	50,520	$	108,128