Note 13 - Basic and Diluted Net Loss Per Share - Antidilutive Securities Excluded from Computation of Earnings Per Share (Details) - shares	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share (in shares)	16,218,148	7,064,579
Share-Based Payment Arrangement, Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share (in shares)	7,112,573	4,279,335
Warrant [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share (in shares)	1,120,300	1,016,383
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share (in shares)	7,985,275	1,768,861