Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016
Statement of Cash Flows [Abstract]
Cash and cash equivalents at beginning of period	$ 465,232	$ 616,686
Cash flows from operating activities:
Net income	137,386	99,897
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	58,304	62,759
Amortization of debt discount and fees	633	527
Stock-based compensation	57,918	49,988
Gain on investments, net	(2,083)	(3,265)
Deferred income taxes	4,813	10,252
Other non-cash items	2,157	750
Changes in operating assets and liabilities, net of effect of acquired businesses:
Receivables	6,342	(3,532)
Inventories	2,535	(10,296)
Prepaid expenses and other	(1,557)	(8,690)
Other assets	(8,790)	(8,709)
Accounts payable and accrued liabilities	(21,995)	(14,012)
Deferred revenue	18,733	(7,412)
Other long-term liabilities	174	(4,700)
Net cash provided by operating activities	254,570	163,557
Cash flows from investing activities:
Purchases of available-for-sale securities	0	(20,525)
Proceeds from the sale of available-for-sale securities	189	55,168
Proceeds from the maturity of available-for-sale securities	0	26,115
Proceeds from the sale of long-term investments	0	2,583
Purchases of property, plant and equipment	(27,488)	(28,287)
Cash paid in business combinations and asset acquisitions, net of cash acquired	0	(41,627)
Net cash used for investing activities	(27,299)	(6,573)
Cash flows from financing activities:
Proceeds from term loan	0	300,000
Proceeds from revolving credit facility	50,000	50,000
Payment on revolving credit facility	(100,000)	0
Payment of debt issuance costs	(793)	(622)
Proceeds from issuance of common stock	29,967	36,296
Stock received for payment of employee taxes on vesting of restricted stock	(25,819)	(17,490)
Payments for repurchases of common stock	0	(480,100)
Net cash used for financing activities	(46,645)	(111,916)
Effect of exchange rate changes on cash and cash equivalents	10,140	7,819
Increase in cash and cash equivalents	190,766	52,887
Cash and cash equivalents at end of period	655,998	669,573
Supplemental cash flow information:
Cash paid for interest	12,112	9,423
Cash paid for taxes, net	$ 27,236	$ 13,730