Note 10 - Shareholders' Equity - Stock Option Activity (Details) - USD ($)		12 Months Ended
	Oct. 14, 2022	Dec. 31, 2022
Options balance, number of shares (in shares)		403,000
Options balance, weighted average exercise price per share (in dollars per share)		$ 2.90
Granted, number of shares (in shares)		0
Granted, weighted average exercise price per share (in dollars per share)		$ 0
Cancelled/Expired, number of shares (in shares)		(12,000)
Cancelled/Expired, weighted average exercise price per share (in dollars per share)		$ 0.98
Exercised, number of shares (in shares)	20,000	20,000
Exercised, weighted average exercise price per share (in dollars per share)	$ 0.975	$ 0.98
Options balance, , number of shares (in shares)		371,000
Option balance, weighted average exercise price per share (in dollars per share)		$ 3.07
Exercised, number of shares (in shares)	(20,000)	(20,000)
Options outstanding and expected to vest, weighted average remaining contractual life (Year)		6 years 3 months 10 days
Options outstanding and expected to vest, aggregate instrinsic value		$ 6,838
Options exercisable (in shares)		335,133
Options exercisable, weighted average price (in dollars per share)		$ 3.10
Options exercisable, weighted average remaining contractual life (Year)		6 years 1 month 6 days
Options exercisable, aggregate intrinsic value		$ 6,338
The 2018 Non-qualified Stock Option Plan [Member]
Options balance, number of shares (in shares)		314,000
Options balance, weighted average exercise price per share (in dollars per share)		$ 3.17
Granted, number of shares (in shares)		0
Granted, weighted average exercise price per share (in dollars per share)		$ 0
Cancelled/Expired, number of shares (in shares)		0
Cancelled/Expired, weighted average exercise price per share (in dollars per share)		$ 0
Exercised, number of shares (in shares)		0
Exercised, weighted average exercise price per share (in dollars per share)		$ 0
Options balance, , number of shares (in shares)		314,000
Option balance, weighted average exercise price per share (in dollars per share)		$ 3.17
Exercised, number of shares (in shares)		0
The 2012 Non-qualified Stock Option Plan [Member]
Options balance, number of shares (in shares)		36,000
Options balance, weighted average exercise price per share (in dollars per share)		$ 0.98
Granted, number of shares (in shares)		0
Granted, weighted average exercise price per share (in dollars per share)		$ 0
Exercised, number of shares (in shares)		20,000
Exercised, weighted average exercise price per share (in dollars per share)		$ 0.98
Options balance, , number of shares (in shares)		14,000
Option balance, weighted average exercise price per share (in dollars per share)		$ 0.98
Cancelled, number of shares (in shares)		(2,000)
Cancelled, weighted average exercise price per share (in dollars per share)		$ 0.98
Exercised, number of shares (in shares)		(20,000)
The 2011 Non-qualified Stock Option [Member]
Options balance, number of shares (in shares)		43,000
Options balance, weighted average exercise price per share (in dollars per share)		$ 3.00
Granted, number of shares (in shares)		0
Granted, weighted average exercise price per share (in dollars per share)		$ 0
Exercised, number of shares (in shares)		0
Exercised, weighted average exercise price per share (in dollars per share)		$ 0
Options balance, , number of shares (in shares)		43,000
Option balance, weighted average exercise price per share (in dollars per share)		$ 3.00
Cancelled, number of shares (in shares)		0
Cancelled, weighted average exercise price per share (in dollars per share)		$ 0
Exercised, number of shares (in shares)		0
The 2002 Stock Option Plan [Member]
Options balance, number of shares (in shares)		10,000
Options balance, weighted average exercise price per share (in dollars per share)		$ 0.98
Granted, number of shares (in shares)		0
Granted, weighted average exercise price per share (in dollars per share)		$ 0
Cancelled/Expired, number of shares (in shares)		(10,000)
Cancelled/Expired, weighted average exercise price per share (in dollars per share)		$ 0.98
Exercised, number of shares (in shares)		0
Exercised, weighted average exercise price per share (in dollars per share)		$ 0
Options balance, , number of shares (in shares)		0
Option balance, weighted average exercise price per share (in dollars per share)		$ 0
Exercised, number of shares (in shares)		0