Note 13 - Stock-based Compensation - Summary of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Stock options	$ 613	$ 521	$ 1,258	$ 1,110
Share-based Payment Arrangement, Option [Member]
Stock options	77	81	168	145
Restricted Stock Units and Performance Share Units [Member]
Stock options	$ 536	$ 440	$ 1,090	$ 965

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

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