Note 6 - Net Inventories (Details Textual) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Inventory Net [Abstract]
Inventory Valuation Reserves	$ 14,231	$ 14,052

Amount of valuation reserve for inventory.

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Name:	us-gaap_InventoryValuationReserves
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant