Note 6 - Stockholders' Equity - Stock Option Activity (Details)	12 Months Ended
	Dec. 31, 2018 $ / shares shares
Outstanding, Shares (in shares) | shares	18,168
Outstanding, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 13.81
Granted, Shares (in shares) | shares	2,750
Granted, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 8.63
Exercised, Shares (in shares) | shares	0
Exercised, Weighted Average Exercise Price (in dollars per share) | $ / shares
Expired and forfeited, Shares (in shares) | shares	(2,918)
Expired and forfeited, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 12.56
Outstanding, Shares (in shares) | shares	18,000
Outstanding, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 13.22
Exercisable, Shares (in shares) | shares	12,247
Exercisable, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 15.09