Note 11 - Fair Value of Financial Instruments and Fair Value Measurements - Fair Value Measurement Using Significant Unobservable Inputs (Details) - Available-for-sale Securities [Member] - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Balance, available for sale securities	$ 576	$ 930
Maturities	(345)	(330)
Unrealized Gains included in Other Comprehensive Income (Loss)	(1)	(24)
Balance, available for sale securities	$ 230	$ 576