Note 10 - Stockholders' Equity - Summary of Stock Option Activity for Stock Option Plan (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Outstanding, shares (in shares)	2,897,663
Outstanding, weighted average exercise price (in dollars per share)	$ 5.57
Outstanding, aggregate intrinsic value	$ 206		$ 252
Granted, shares (in shares)	429,328
Granted, weighted average exercise price (in dollars per share)	$ 1.52	$ 2.16
Granted, aggregate intrinsic value
Exercised, shares (in shares)	0
Exercised, weighted average exercise price (in dollars per share)	$ 0
Exercised, aggregate intrinsic value	$ 0
Cancelled, shares (in shares)	(311,067)
Cancelled, weighted average exercise price (in dollars per share)	$ 9.73
Outstanding, shares (in shares)	3,015,924
Outstanding, weighted average exercise price (in dollars per share)	$ 4.56
Options Exercisable (in shares)	1,516,875		1,593,935
Options Exercisable, weighted average exercise price (in dollars per share)	$ 7.18		$ 8.08
Options Exercisable, aggregate intrinsic value	$ 26		$ 30