Note 6 - Stock Based Compensation (Details) - Stock Option Activity - 2005 Stock Option Plan [Member] $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($) $ / shares shares
Note 6 - Stock Based Compensation (Details) - Stock Option Activity [Line Items]
Balance at December 31, 2015 | shares	546,460
Balance at December 31, 2015 | $ / shares	$ 8.62
Balance at March 31, 2016 | shares	546,460
Balance at March 31, 2016 | $ / shares	$ 8.62
Balance at March 31, 2016	2 years 295 days
Balance at March 31, 2016 | $	$ 461,028	[1]
Exercisable at March 31, 2016 | shares	437,793
Exercisable at March 31, 2016 | $ / shares	$ 9.04
Exercisable at March 31, 2016	1 year 124 days
Exercisable at March 31, 2016 | $	$ 200,228	[1]

[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 March 31, 2016.