Note 10 - Stockholders' Equity - Summary of Stock Option Activity (Details)	3 Months Ended
	Jun. 30, 2024 $ / shares shares
Outstanding, option (in shares) | shares	140,000
Outstanding, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 1.87
Granted, units (in shares) | shares	0
Granted, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 0
Exercised, option (in shares) | shares	0
Exercised, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 0
Forfeited or expired, units (in shares) | shares	0
Forfeited or expired, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 0
Outstanding, option (in shares) | shares	140,000
Outstanding, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 1.87
Exercisable, option (in shares) | shares	130,000
Exercisable, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 1.64