Note 3 - Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Dividends and dividend equivalents	$ 9,053	$ 8,675
Deferred revenue and customer prepayments	4,806	5,236
Stock rotation reserve	3,011	2,372
Commissions	865	763
Warranty	336	289
Income tax payable	280	465
Sales rebate	188	268
Other	1,501	1,916
Total	$ 20,040	$ 19,984