Note 5 - Commitments and Contingencies (Tables)

6 Months Ended

Jun. 30, 2018

Notes Tables

Schedule of Product Warranty Liability [Table Text Block]

Balance at December 31, 2017	$	291,000
Warranties issued during the period		30,000
Settlements made during the period		(216,000	)
Changes in liability for pre-existing warranties during the period		(5,000	)
Balance at June 30, 2018	$	100,000