Note 3 - Cash, Cash Equivalents, Investments and Restricted Cash (Details Textual) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2022 |
Dec. 31, 2021 |
Dec. 31, 2020 |
|
| Gain (Loss) on Sale of Investments, Total | $ 1,100 | ||
| Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale, Total | $ 0 | $ 0 | |
| Redemption, Auction Rate Securities to Date | $ 41,500 | ||
| Percentage of Auction Rate Securities Redeemed at Par Value | 96.00% | ||
| Equity Securities without Readily Determinable Fair Value, Amount | $ 5,400 | $ 3,300 | |