Note 4 - Stock Options and Restricted Stock Awards (Details Textual) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
|
| Share-Based Payment Arrangement, Option [Member] | ||
| Share-Based Payment Arrangement, Expense | $ 14.5 | $ 13.7 |
| Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount | $ 20.9 | |
| Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition | 2 years 6 months | |
| Restricted Stock [Member] | ||
| Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount | $ 25.2 | |
| Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition | 1 year 7 months 6 days | |