Note 5 - Inventories (Details Textual) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Inventory Write-down	$ 1,000	$ 19,000	$ 10,000	$ 37,000