Note 11 - Stock-based Compensation - Stock Option Activity (Details) - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Options, Outstanding, Number of Shares (in shares)	4,640,660
Options, Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 6.64
Options, Outstanding, Weighted Average Remaining Contractual Term (Year)	5 years 6 months 10 days	5 years 7 months 28 days
Options, Granted, Number of Shares (in shares)	2,972,722
Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)	$ 0.72
Options, Forfeited, Number of Shares (in shares)	(128,089)
Options, Forfeitures in Period, Weighted Average Exercise Price (in dollars per share)	$ 1.55
Options, Cancelled, Number of Shares (in shares)	(36,982)
Options, Expirations in Period, Weighted Average Exercise Price (in dollars per share)	$ 21.11
Options, Exercised, Number of Shares (in shares)	(43,453)
Options, Exercises in Period, Weighted Average Exercise Price (in dollars per share)	$ 0.41
Options, Outstanding, Number of Shares (in shares)	7,404,858	4,640,660
Options, Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 4.31	$ 6.64