Note 6 - Commitments and Contingencies (Tables)

3 Months Ended

Mar. 31, 2020

Notes Tables

Schedule of Product Warranty Liability [Table Text Block]

Balance at December 31, 2019	$	277,000
Warranties issued during the period		30,000
Settlements made during the period		(133,000	)
Changes in liability for pre-existing warranties during the period		(31,000	)
Balance at March 31, 2020	$	143,000