Note 5 - Balance Sheet Components - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Dividends and dividend equivalents	$ 21,747	$ 15,044
Stock rotation and sales returns	5,530	5,363
Customer prepayments	3,412	2,520
Income tax payable	2,435	7,018
Commissions	1,425	1,369
Warranty	1,139	4,564
Other	7,848	3,084
Total	44,790	38,962
Accrued Liabilities, Current [Member]
Operating lease liabilities	$ 1,254	$ 0