Note 12 - Basic and Diluted Net Loss Per Share - Antidilutive Securities Excluded from Computation of Earnings Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share (in shares)	23,997,339	15,185,931
Share-Based Payment Arrangement, Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share (in shares)	10,319,169	6,766,520
Warrant [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share (in shares)	1,021,076	1,120,300
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share (in shares)	12,657,094	7,299,111