Note 5 - Balance Sheet Components - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Dividends and dividend equivalents	$ 8,946	$ 8,675
Deferred revenue and customer prepayments	6,799	5,236
Stock rotation reserve	1,937	2,372
Income tax payable	1,239	465
Warranty	1,030	289
Commissions	1,008	763
Sales rebate	441	268
Other	1,516	1,916
Total	$ 22,916	$ 19,984