Note 7 - Summary of Expired Director Plans (Details)	3 Months Ended
	Mar. 31, 2016 $ / shares shares
Exercise Price Range 1 [Member]
Range of exercise price, lower limit (in dollars per share)	$ 2.925
Range of exercise price, upper limit (in dollars per share)	$ 5.25
Outstanding stock options (in shares) | shares	4,000
Outstanding, weighted average share price (in dollars per share) (in dollars per share)	$ 2.925
Weighted average remaining life	5 years 292 days
Number of stock options exercisable (in shares) | shares	4,000
Exercisable, weighted average share price (in dollars per share)	$ 2.925
Exercise Price Range 2 [Member]
Range of exercise price, lower limit (in dollars per share)	6
Range of exercise price, upper limit (in dollars per share)	$ 7.25
Outstanding stock options (in shares) | shares	1,000
Outstanding, weighted average share price (in dollars per share) (in dollars per share)	$ 6
Weighted average remaining life	4 years
Number of stock options exercisable (in shares) | shares	1,000
Exercisable, weighted average share price (in dollars per share)	$ 6
Exercise Price Range 3 [Member]
Range of exercise price, lower limit (in dollars per share)	10.50
Range of exercise price, upper limit (in dollars per share)	$ 11
Outstanding stock options (in shares) | shares
Outstanding, weighted average share price (in dollars per share) (in dollars per share)
Weighted average remaining life
Number of stock options exercisable (in shares) | shares
Exercisable, weighted average share price (in dollars per share)
Outstanding stock options (in shares) | shares	5,000
Outstanding, weighted average share price (in dollars per share) (in dollars per share)	$ 3.54
Weighted average remaining life
Number of stock options exercisable (in shares) | shares	5,000
Exercisable, weighted average share price (in dollars per share)	$ 3.54