Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Apr. 01, 2012	Apr. 03, 2011
Cash flows from operating activities:
Net income	$ 33,564	$ 96,844
Less: Income from discontinued operations		1,703
Less: Gain on disposal of discontinued operations		25,203
Income from continuing operations	33,564	69,938
Adjustments to reconcile income from continuing operations to net cash provided by operating activities:
Depreciation	12,288	13,057
Amortization	21,815	10,355
Stock-based compensation	10,766	7,464
Provision for excess and obsolete inventory	1,574	4,627
Non cash charge for the sale of inventories revalued at the date of acquisition	4,871
Contingent consideration adjustment	(1,858)
Deferred taxes	7,699
Other	(454)	618
Changes in operating assets and liabilities, net of businesses sold:
Accounts receivable	(92,217)	(17,498)
Inventories	23,636	(10,709)
Other assets	1,885	(2,266)
Deferred revenue and customer advances	(1,704)	(24,553)
Accounts payable and other accrued expenses	(9,635)	(26,014)
Retirement plan contributions	(1,061)	(1,176)
Net cash provided by continuing operations	11,169	23,843
Net cash used for discontinued operations		(4,225)
Net cash provided by operating activities	11,169	19,618
Cash flows from investing activities:
Investments in property, plant and equipment	(27,074)	(22,131)
Purchases of available-for-sale marketable securities	(80,095)	(211,289)
Proceeds from sales and maturities of available-for-sale marketable securities	52,805	188,448
Net cash used for continuing operations	(54,364)	(44,972)
Net cash provided by discontinued operations		39,030
Net cash used for investing activities	(54,364)	(5,942)
Cash flows from financing activities:
Issuance of common stock under employee stock option and stock purchase plans	9,925	10,076
Payment of contingent consideration	(5,824)
Payments of long-term debt	(1,246)	(1,222)
Net cash provided by financing activities	2,855	8,854
(Decrease) Increase in cash and cash equivalents	(40,340)	22,530
Cash and cash equivalents at beginning of period	573,736	397,737
Cash and cash equivalents at end of period	$ 533,396	$ 420,267