Note 1 - Summary of Significant Accounting Policies - Potentially Dilutive Securities (Details) - shares |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Potentially dilutive securities (in shares) | 65,072,860 | 68,118,061 | 72,224,967 | 68,118,061 |
| Share-Based Payment Arrangement, Option [Member] | ||||
| Potentially dilutive securities (in shares) | 35,936,577 | 39,331,086 | 40,988,116 | 39,331,086 |
| Convertible Debt Securities [Member] | ||||
| Potentially dilutive securities (in shares) | 26,020,693 | 23,570,817 | 26,020,693 | 23,570,817 |
| Warrant [Member] | ||||
| Potentially dilutive securities (in shares) | 3,115,590 | 5,216,158 | 5,216,158 | 5,216,158 |