Note 4 - Balance Sheet Components (Details) - Accrued Liabilities - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Accrued Liabilities [Abstract]
Dividends and dividend equivalents	$ 8,525	$ 6,080
Deferred revenue and customer prepayments	4,083	3,908
Stock rotation reserve	2,667	1,757
Commissions	819	767
Sales rebate	446	586
Warranty	268	240
Other	1,895	1,365
Total	$ 18,703	$ 14,703