Note 10 - Stockholders' Equity - Shares of Common Stock Reserved for Issuance (Details) - shares	Dec. 31, 2023	Dec. 31, 2022
Common stock reserved for issuance (in shares)	27,043,664	29,635,697
Common Warrants [Member]
Common stock reserved for issuance (in shares)	227,434	227,434
Share-Based Payment Arrangement, Option [Member]
Common stock reserved for issuance (in shares)	17,938,726	14,725,261
Restricted Stock Units (RSUs) [Member]
Common stock reserved for issuance (in shares)	2,126,373	808,310
Future Grants of Equity Awards [Member]
Common stock reserved for issuance (in shares)	5,685,806	12,074,692
ESPP [Member]
Common stock reserved for issuance (in shares)	1,065,325	1,800,000