Note 9 - Incentive Plans - Number of Shares Available for Grant Pursuant to Long-term Incentive Plan (Details) - shares	Jun. 30, 2025	Dec. 31, 2024	Dec. 31, 2022
Shares subject to awards issued under plan (in shares)	(13,434,394)	(13,444,062)	(13,449,061)
The 2020 Long-term Incentive Plan [Member]
Approved and authorized shares (in shares)	16,414,015	16,414,015
Shares subject to awards issued under plan (in shares)	(15,863,795)	(15,808,671)
Shares available for future grant (in shares)	550,220	605,344