Note 9 - Stockholders' Equity - Shares of Common Stock Reserved for Issuance (Details) - shares	Mar. 31, 2026	Dec. 31, 2025
Common stock reserved for issuance (in shares)	42,413,698	43,850,083
Common Warrants [Member]
Common stock reserved for issuance (in shares)	10,914	10,914
The 2019 Plan [Member]
Common stock reserved for issuance (in shares)	6,043,856	10,831,860
The 2024 Inducement Award Plan [Member]
Common stock reserved for issuance (in shares)	76,250	43,250
Share-Based Payment Arrangement, Option [Member]
Common stock reserved for issuance (in shares)	27,767,619	25,407,299
Restricted Stock Units (RSUs) [Member]
Common stock reserved for issuance (in shares)	6,691,605	5,733,306
ESPP [Member]
Common stock reserved for issuance (in shares)	1,823,454	1,823,454