Note 17 - 401(k) Plan (Details Textual) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Defined Contribution Plan, Employer Discretionary Contribution Percentage     4.00%
Contributions by Employer to Postemployment Benefit Obligations $ 0.4 $ 0.5