Note 6 - Stock Based Compensation - Stock Option Activity (Details) - 2005 Stock Option Plan [Member]	6 Months Ended
	Jun. 30, 2016 USD ($) $ / shares shares
Beginning balance (in shares) | shares	546,460
Beginning balance (in dollars per share) | $ / shares	$ 8.62
Expired (in shares) | shares	(333,960)
Expired (in dollars per share) | $ / shares	$ (9.09)
Forfeited (in shares) | shares	(6,000)
Forfeited (in dollars per share) | $ / shares	$ (6.90)
Ending balance (in shares) | shares	206,500
Ending balance (in dollars per share) | $ / shares	$ 7.90
Ending balance | $	$ 406,630	[1]
Balance at June 30, 2016	6 years 306 days
Exercisable at June 30, 2016 (in shares) | shares	82,100
Exercisable at June 30, 2016 (in dollars per share) | $ / shares	$ 9.41
Exercisable at June 30, 2016 | $	$ 84,434	[1]
Exercisable at June 30, 2016	4 years 131 days

[1] The aggregate intrinsic value of a stock option in the table above represents the total pre-tax intrinsic value (the amount by which the current market value of the underlying stock exceeds the exercise price of the option) that would have been received by the option holders had all option holders exercised their options on June 30, 2016.