Note 6 - Income Taxes - Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	3 Months Ended			12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
U.S.
Current				$ 410	$ 2,022	$ 3,032
Deferred				208	1,549	2,882
Foreign
Current				329	341	476
Withholding				2,898	3,089	3,103
Deferred				8	14	4
Tax provision	$ 1,051	$ 1,579	$ 1,026	$ 3,853	$ 7,015	$ 9,497