Note 2 - Supplemental Balance-sheet Information - Inventory (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Raw materials	$ 96	$ 136
less: Reserve	(2)	(2)
Inventories, net	$ 94	$ 134

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