Note 8 - Equity Incentive Plans - Stock Options Outstanding (Details)	12 Months Ended
	Dec. 31, 2015 $ / shares shares
Range One [Member]
Range of Exercise Prices - lower (in dollars per share)	$ 9.19
Range of Exercise Prices - upper (in dollars per share)	$ 46.57
Oustanding Shares (in shares) | shares	220,619
Oustanding Weighted Average Exercise Price (in dollars per share)	$ 27.01
Oustanding Weighted Average Remaining Life
Exercisable Shares (in shares) | shares	140,293
Exercisable Weighted Average Exercise Price (in dollars per share)	$ 41.68
Oustanding Shares (in shares) | shares	220,619
Oustanding Weighted Average Exercise Price (in dollars per share)	$ 27.01
Exercisable Shares (in shares) | shares	140,293
Exercisable Weighted Average Exercise Price (in dollars per share)	$ 41.68