Note 4 - Balance Sheet Components - Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Dividends and dividend equivalents	$ 14,737	$ 9,248
Stock rotation and sales returns	7,464	2,647
Warranty	4,934	2,416
Income tax payable	1,911	2,861
Customer prepayments	1,818	4,742
Commissions	1,334	938
Sales rebate	380	1,036
Deferred income		1,845
Other	2,330	1,774
Total	$ 34,908	$ 27,507

Represents accrued sales rebate.

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Represents dividends and dividend equivalents.

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Carrying value as of the balance sheet date of obligations related to the stock rotation reserve and other returns.

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Carrying amount as of the balance sheet date of the unpaid sum of the known and estimated amounts payable to satisfy all currently due domestic and foreign income tax obligations.

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Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Carrying value as of the balance sheet date of obligations incurred through that date and payable for sales commissions. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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The current portion of prepayments received from customers for goods or services to be provided in the future.

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The carrying amount of consideration received or receivable as of the balance sheet date on potential earnings that were not recognized as revenue in conformity with GAAP, and which are expected to be recognized as such within one year or the normal operating cycle, if longer, including sales, license fees, and royalties, but excluding interest income.

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Amount of expenses incurred but not yet paid classified as other, due within one year or the normal operating cycle, if longer.

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Carrying value as of the balance sheet date of obligations incurred through that date and payable for estimated claims under standard and extended warranty protection rights granted to customers. For classified balance sheets, represents the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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