Note 4 - Supplemental Cash Flow Information (Details Textual) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Jan. 01, 2019	Dec. 31, 2018	Jan. 01, 2018
Income Taxes Paid		$ 200	$ 400
Interest Paid, Excluding Capitalized Interest, Operating Activities		$ 1,000	$ 200
Company Stock Received in Lieu of Cash Stock Options Exercised		11,183	5,863
Stock Issued During Period, Shares, New Issues		27,172	20,234
Inventory, Net, Total	[1]	$ 65,753			$ 67,301
Other Liabilities, Current, Total		15,703			14,767
Operating Lease, Right-of-Use Asset		4,581
Prepaid Expense and Other Assets, Current		11,488			9,552
Other Assets, Noncurrent, Total		9,796			8,832
Operating Lease, Liability, Noncurrent		$ 2,866
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
Operating Lease, Right-of-Use Asset				$ 4,900
Accounting Standards Update 2016-02 [Member]
Other Liabilities, Current, Total				1,000
Operating Lease, Right-of-Use Asset				4,900
Prepaid Expense and Other Assets, Current				(100)
Other Assets, Noncurrent, Total				(700)
Operating Lease, Liability, Noncurrent				$ 3,100

[1] Inventories consist of the following: March 31, 2019 December 31, (Unaudited) 2018 Finished goods $ 56,552 $ 58,196 Work in process 527 650 Raw materials 8,674 8,455 $ 65,753 $ 67,301