Note 5 - Shareholders' Equity - Summary of Warrant Activity (Details)	3 Months Ended
	Mar. 31, 2022 $ / shares shares
Balance, shares (in shares) | shares	128,000
Balance, weighted average exercise price (in dollars per share)	$ 1.75
Granted, shares (in shares) | shares	0
Granted, weighted average exercise price (in dollars per share)	$ 0
Cancelled/Expired, weighted average exercise price (in dollars per share)	$ 0
Exercised/Issued, shares (in shares) | shares	0
Exercised/Issued, weighted average exercise price (in dollars per share)	$ 0
Balance, shares (in shares) | shares	128,000
Balance, weighted average exercise price (in dollars per share)	$ 1.75
Exercisable, shares (in shares) | shares	128,000
Exercisable, weighted average exercise price (in dollars per share)	$ 1.75