Unaudited Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jul. 01, 2012	Jul. 03, 2011
Cash flows from operating activities:
Net income	$ 46,669	$ 41,786
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	7,493	7,453
Purchase premium amortization on investments	1,468	390
Non-cash stock-based compensation	6,787	6,880
Income tax benefit associated with stock option exercises	808	3,157
Excess tax benefit from stock-based compensation	(1,093)	(3,330)
Deferred income taxes	(176)	482
Changes in assets and liabilities, net of effect of acquisitions:
Accounts receivable	(10,462)	16,771
Inventories	10,904	(4,105)
Prepaid expenses and other assets	(3,681)	(12,579)
Accounts payable	(16,110)	(16,779)
Accrued employee compensation	(7,739)	(4,454)
Other accrued liabilities	428	(8,567)
Deferred revenue	(14,614)	(4,695)
Income taxes payable	(6,046)	(2,446)
Net cash provided by operating activities	14,636	19,964
Cash flows from investing activities:
Purchases of short-term investments	(153,862)	(135,949)
Proceeds from maturities of short-term investments	93,883	131,690
Purchase of property and equipment	(6,864)	(3,920)
Payments made in connection with business acquisitions	(7,100)	(37,509)
Net cash used in investing activities	(73,943)	(45,688)
Cash flows from financing activities:
Purchase and retirement of treasury stock	(815)	(899)
Proceeds from exercise of stock options	6,331	25,834
Proceeds from issuance of common stock under employee stock purchase plan	955	709
Excess tax benefit from stock-based compensation	1,093	3,330
Net cash provided by financing activities	7,564	28,974
Net (decrease) increase in cash and cash equivalents	(51,743)	3,250
Cash and cash equivalents, at beginning of period	208,898	126,173
Cash and cash equivalents, at end of period	$ 157,155	$ 129,423