Note 8 - Commitments and Contingencies - Changes in Product Liability Included in Accrued Liabilities (Details) - USD ($)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Beginning balance	$ 186,000	$ 291,000
Warranties originated during the year	254,000	199,000
Claims settled made during the year	(154,000)	(252,000)
Changes in reserve estimate	(9,000)	(52,000)
Ending balance	$ 277,000	$ 186,000

Carrying value as of the balance sheet date of obligations incurred through that date and payable for estimated claims under standard and extended warranty protection rights granted to customers.

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Amount of decrease in the standard and extended product warranty accrual from payments made in cash or in kind to satisfy claims under the terms of the standard and extended product warranty.

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Amount of increase (decrease) in the standard and extended product warranty accrual from changes in estimates attributable to preexisting product warranties.

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Amount of increase in the standard and extended product warranty accrual from warranties issued.

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