Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities:
Net income	$ 36,146	$ 25,063
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of intangible assets	10,542	10,478
Losses on sales of property and equipment	58
(Gains) losses on investments, net	(478)	910
Deferred taxes, net	12
Excess tax benefits from equity awards	(1,078)	(4,221)
Stock-based compensation expense	34,241	29,191
Changes in operating assets and liabilities:
Accounts receivable	(2,503)	(4,845)
Inventories	(7,522)	(26,378)
Other assets	(10,869)	141
Accounts payable	5,713	3,545
Accrued liabilities	4,308	4,154
Income tax liabilities	1,668	1,912
Accrued compensation and related benefits	6,549	5,449
Net cash provided by operating activities	76,787	45,399
Cash flows from investing activities:
Property and equipment purchases	(29,036)	(8,410)
Purchases of short-term investments	(147,055)	(172,651)
Proceeds from sales of short-term investments	140,733	131,025
Contributions to employee deferred compensation plan, net	(2,314)	(3,455)
Net cash used in investing activities	(37,672)	(53,491)
Cash flows from financing activities:
Property and equipment purchased on extended payment terms	(150)	(150)
Proceeds from Stock Options Exercised	1,191	6,876
Proceeds from Stock Plans	2,463	2,227
Repurchases of common shares		(31,735)
Dividends and dividend equivalents paid	(24,634)	(21,853)
Excess tax benefits from equity awards	1,078	4,221
Net cash used in financing activities	(20,052)	(40,414)
Effect of change in exchange rates	(444)	(1,144)
Net increase (decrease) in cash and cash equivalents	18,619	(49,650)
Cash and cash equivalents, beginning of period	90,860	126,266
Cash and cash equivalents, end of period	109,479	76,616
Supplemental disclosures for cash flow information:
Cash paid for taxes and interest	843	3,070
Supplemental disclosures of non-cash investing and financing activities:
Liability accrued for property and equipment purchases	197	1,003
Liability accrued for dividends and dividend equivalents	$ 9,882	$ 9,648