Note 5 - Concentrations (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allowance for Doubtful Accounts Receivable, Ending Balance	$ 1,152	$ 155
Allowance for Distributors' Price Adjustment	$ 1,634	$ 1,292
Customer Concentration Risk [Member] | Sales Revenue, Goods, Net [Member] | Customer D And Subcontractors [Member]
Concentration Risk, Percentage	18.00%	17.00%
Customer Concentration Risk [Member] | Sales Revenue, Goods, Net [Member] | Customer E and Subcontractors [Member]
Concentration Risk, Percentage	14.00%	14.00%	16.00%
Customer Concentration Risk [Member] | Sales Revenue, Goods, Net [Member] | Customer F and Subcontractors [Member]
Concentration Risk, Percentage	11.00%	11.00%	12.00%