Note 8 - Stock-based Compensation - Components of Stock-based Compensation (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Total stock-based compensation expense	$ 290	$ 574
Tax benefit of stock-based compensation expense
After-tax effect of stock based compensation	290	574
Share-based Payment Arrangement, Option [Member]
Total stock-based compensation expense
Restricted Stock Units (RSUs) [Member]
Total stock-based compensation expense	$ 290	$ 574

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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