Note 11 - Net Loss Per Share - Summary of Antidilutive Securities (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation (in shares)	14,490,693	8,123,363	12,818,877	7,973,194
Share-Based Payment Arrangement, Option [Member]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation (in shares)	13,873,456	7,733,353	12,388,584	7,286,414
Restricted Stock Units (RSUs) [Member]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation (in shares)	389,638	0	200,277	0
Warrant [Member] | Common Stock [Member]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation (in shares)	227,599	390,010	230,016	686,780