Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 27, 2014	Sep. 28, 2013
Cash flows from operating activities:
Net income	$ 84,108	$ 92,708
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	27,223	23,312
Share-based compensation	10,304	9,372
Impairment of long term investment	2,333	0
Excess tax benefit from share-based compensation	(5,779)	(4,170)
Loss on sale of property and equipment	135	172
Deferred income taxes	4,509	4,888
Loss on forward interest rate swaps	2,248	0
Changes in assets and liabilities:
Accounts receivable, net	(10,810)	(6,641)
Inventories, net	(18,606)	16,702
Other assets	(10,859)	2,257
Accounts payable	7,975	(445)
Accrued liabilities	21,160	(6,256)
Deferred revenue	2,667	1,752
Income taxes	6,664	3,040
Other operating activities	6,406	298
Net cash provided by operating activities	129,678	136,989
Cash flows from investing activities:
Purchases of property and equipment	(20,023)	(13,522)
Acquisition of intangible assets	0	(1,500)
Purchase of long-term investments	(1,870)	(1,708)
Purchase of investments and marketable securities	(384,134)	(338,227)
Maturities of investments and marketable securities	44,158	41,021
Proceeds from sales of investments and marketable securities	211,975	223,905
Net cash used in investing activities	(149,894)	(90,031)
Cash flows from financing activities:
Purchase of treasury stock	0	(58,459)
Proceeds from exercise of stock options and stock purchase plan purchases	11,964	6,470
Excess tax benefit from share-based compensation	5,779	4,170
Net cash provided by (used in) financing activities	17,743	(47,819)
Effect of exchange rate changes on cash	(140)	317
Net decrease in cash and cash equivalents	(2,613)	(544)
Cash and cash equivalents at beginning of period	62,827	64,740
Cash and cash equivalents at end of period	60,214	64,196
Supplemental disclosures of cash flow information:
Income taxes paid	$ 12,656	$ 10,951