Note 4 - Net Inventories - Schedule of Inventory (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Finished goods	$ 25,753	$ 41,521
Work in process	26,626	47,386
Raw materials	44,850	42,491
Supplies	7,315	7,144
Total	$ 104,544	$ 138,542