Note 9 - Fair Value Measurements (Details Textual) - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018
Assets, Fair Value Disclosure	[1]	$ 10,542	$ 12,668
Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure		0	0
Financial Liabilities Fair Value Disclosure, Total		0	0
Fair Value, Nonrecurring [Member]
Assets, Fair Value Disclosure		0	0
Financial and Nonfinancial Liabilities, Fair Value Disclosure		$ 0	$ 0

[1] Included in other assets