Note 10 - Stock-based Compensation - Stock Option Activity (Details) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Options, Outstanding, Number of Shares (in shares)	7,584,967
Options, Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 4.22
Options, Outstanding, Weighted Average Remaining Contractual Term (Year)	5 years 6 months 14 days	5 years 3 months 21 days
Options, Granted, Number of Shares (in shares)	2,748,415
Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)	$ 0.73
Options, Forfeited, Number of Shares (in shares)	0
Options, Forfeitures in Period, Weighted Average Exercise Price (in dollars per share)	$ 0
Options, Cancelled, Number of Shares (in shares)	(913)
Options, Expirations in Period, Weighted Average Exercise Price (in dollars per share)	$ 4.21
Options, Exercised, Number of Shares (in shares)	(13,300)
Options, Exercises in Period, Weighted Average Exercise Price (in dollars per share)	$ 0.38
Options, Outstanding, Number of Shares (in shares)	10,319,169	7,584,967
Options, Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 3.30	$ 4.22