Note 2 - Significant Accounting Policies - Potentially Dilutive Securities Not Included in Calculation of Diluted Net Loss per Share (Details) - shares |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2026 |
Sep. 30, 2025 |
Sep. 30, 2026 |
Sep. 30, 2025 |
|
| Anti-dilutive securities not included in calculation of diluted net loss per share (in shares) | 3,841,951 | 5,293,021 | 3,950,049 | 6,189,484 |
| Share-Based Payment Arrangement, Option [Member] | ||||
| Anti-dilutive securities not included in calculation of diluted net loss per share (in shares) | 1,714,761 | 2,947,276 | 1,819,455 | 3,718,413 |
| Warrant [Member] | ||||
| Anti-dilutive securities not included in calculation of diluted net loss per share (in shares) | 2,116,250 | 2,116,250 | 2,116,250 | 2,116,250 |
| Unvested Restricted Stock Units [Member] | ||||
| Anti-dilutive securities not included in calculation of diluted net loss per share (in shares) | 10,940 | 229,495 | 14,344 | 354,821 |