Note 15 - Supplemental Cash Flow Information (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	94,241	336,726
Inventory, Net, Total	$ 67,301	$ 64,979
Other Liabilities, Current, Total	14,767	$ 12,409
Deferred Tax Liabilities, Net, Total	$ 8,475
Accounting Standards Update 2014-09 [Member]
Contract with Customer, Asset, Net, Total				$ 43,300
Inventory, Net, Total				(24,900)
Accounts Payable, Total				2,600
Other Liabilities, Current, Total				1,100
Deferred Tax Liabilities, Net, Total				$ 3,500
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	26,234	144,443	81,608
Common Stock [Member]
Shares Received from Stock Options Exercised	6,894	50,981	27,770
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	87,347	285,745	251,996