Note 6 - Commitments and Contingencies (Tables)

9 Months Ended

Sep. 30, 2020

Notes Tables

Schedule of Product Warranty Liability [Table Text Block]

Balance at December 31, 2019	$	277,000
Warranties issued during the period		62,000
Settlements made during the period		(171,000	)
Changes in liability for pre-existing warranties during the period		(20,000	)
Balance at September 30, 2020	$	148,000