Note 7 - Stock-based Compensation - Summary of Stock Option Activity (Details) - USD ($)	6 Months Ended	9 Months Ended		12 Months Ended
	Jun. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Outstanding (in shares)	67,000	95,000	67,000	67,000
Outstanding, grant date weighted-average exercise price (in dollars per share)	$ 2.72	$ 2.76	$ 2.72	$ 2.72
Outstanding, weighted average remaining contractual life (Year)	4 years 10 months 6 days			4 years 9 months 29 days	3 years 3 months 29 days
Outstanding, intrinsic value			$ 9,000	$ 25,000	$ 0
Granted (in shares)		70,000	50,000
Granted, grant date weighted-average exercise price (in dollars per share)		$ 2.82	$ 2.72
weighted average remaining contractual life (Year)		7 years	5 years
Forfeited (in shares)		(19,000)	(7,000)
Forfeited, grant date weighted-average exercise price (in dollars per share)		$ 2.69	$ 2.58
Outstanding (in shares)		146,000	108,000	95,000	67,000
Outstanding, grant date weighted-average exercise price (in dollars per share)		$ 2.8	$ 2.73	$ 2.76	$ 2.72
Exercisable (in shares)		38,000	50,000
Exercisable, grant date weighted-average exercise price (in dollars per share)		$ 2.86	$ 2.74
Exercisable, weighted average remaining contractual life (Year)	2 years 8 months 26 days
Exercised (in shares)			(2,000)
Exercised, grant date weighted-average exercise price (in dollars per share)			$ 2.7
Minimum [Member]
Outstanding, weighted average remaining contractual life (Year)		5 years 6 months 3 days
Exercisable, weighted average remaining contractual life (Year)		3 years 4 months 6 days
Maximum [Member]
Outstanding, intrinsic value		$ 0