Note 12 - Income Taxes - Uncertain Tax Positions (Details) - USD ($) $ in Thousands  | 
12 Months Ended | |
|---|---|---|
Dec. 31, 2020  | 
Dec. 31, 2019  | 
|
| Balance, beginning of period | $ 0 | $ 9,482 | 
| Decrease during the period | 0 | (9,482) | 
| Balance, end of period | $ 0 | $ 0 | 
| X | ||||||||||
- Definition Amount of unrecognized tax benefits. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
  | 
| X | ||||||||||
- Definition Amount of increase (decrease) in unrecognized tax benefits attributable to uncertain tax positions taken in tax returns. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
  |