Note 8 - Equity Incentive Plans - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Disclosure Text Block [Abstract]
Options Outstanding (in shares)	1,956,855
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)	792,600
Options Exercised (in shares)	0
Options Forfeited, expired or cancelled (in shares)	162,479
Options Outstanding (in shares)	2,586,976	1,956,855
Options Vested and expected to vest (in shares)	2,586,976
Options Exercisable (in shares)	1,392,169
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 7.32
Options Granted, Weighted Average Exercise Price (in dollars per share)	0.81
Options Forfeited, expired or cancelled, Weighted Average Exercise Price (in dollars per share)	0
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	5.65	$ 7.32
Options Vested and expected to vest, Weighted Average Exercise Price (in dollars per share)	5.65
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 9.20
Options Outstanding, Weighted Average Remaining Contractual Life (Year)	7 years 9 months 29 days	8 years 1 month 13 days
Granted, Weighted Average Remaining Contractual Life (Year)	9 years 6 months
Options Vested and expected to vest, Weighted Average Remaining Contractual Life (Year)	7 years 9 months 29 days
Options Exercisable, Weighted Average Remaining Contractual Life (Year)	5 years 7 months 20 days
Options Outstanding, Aggregate Intrinsic Value	$ 0	$ 0
Options Vested and expected to vest, Aggregate Intrinsic Value	0
Options Exercisable, Aggregate Intrinsic Value	$ 0