Note 2 - Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Restricted Cash
Restricted Cash	$ 1.0	$ 1.4
Restricted Cash, Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssetsCurrent	us-gaap:OtherAssetsCurrent