Note 15 - Stockholders' Equity (Deficit) - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Outstanding, number of shares (in shares)	981,834
Outstanding, weighted average exercise price (in dollars per share)	$ 19.85
Outstanding, weighted average remaining contractual term (Year)	7 years 6 months 7 days	7 years 6 months 29 days
Options granted, number of shares (in shares)	82,000
Options granted, weighted average exercise price (in dollars per share)	$ 0.71
Options exercised, number of shares (in shares)	0
Options exercised, weighted average exercise price (in dollars per share)	$ 0
Options forfeited/cancelled, number of shares (in shares)	(15,760)
Options forfeited/cancelled, weighted average exercise price (in dollars per share)	$ 25.54
Outstanding, number of shares (in shares)	1,048,074	981,834
Outstanding, weighted average exercise price (in dollars per share)	$ 18.26	$ 19.85
Outstanding, aggregate intrinsic value	$ 0
Exercisable, number of shares (in shares)	448,819
Exercisable, weighted average exercise price (in dollars per share)	$ 33.24
Exercisable, weighted average remaining contractual term (Year)	6 years 2 months 12 days
Exercisable, aggregate intrinsic value	$ 0
Expected to vest, number of shares (in shares)	599,255
Expected to vest, weighted average exercise price (in dollars per share)	$ 7.05
Expected to vest, weighted average remaining contractual term (Year)	8 years 6 months 3 days
Expected to vest, aggregate intrinsic value	$ 0