Note 5 - Commitments and Contingencies (Tables)

3 Months Ended

Mar. 31, 2018

Notes Tables

Schedule of Product Warranty Liability [Table Text Block]

Balance at December 31, 2017	$	291,000
Warranties issued during the period		18,000
Settlements made during the period		(211,000	)
Changes in liability for pre-existing warranties during the period		(1,000	)
Balance at March 31, 2018	$	97,000