Unaudited 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	$ 25,147	$ 21,189
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	3,609	3,707
Purchase premium amortization on investments	718	252
Non-cash stock-based compensation	3,392	3,372
Income tax benefit associated with stock option exercises	937	835
Excess tax benefit from stock-based compensation	(910)	(893)
Deferred income taxes	(477)	36
Changes in assets and liabilities:
Accounts receivable	12,099	29,109
Inventories	29,410	(12,719)
Prepaid expenses and other assets	3,273	(3,167)
Accounts payable	(37,751)	(7,922)
Accrued employee compensation	(9,121)	(8,773)
Other accrued liabilities	(4,079)	(8,318)
Deferred revenue	(14,937)	(9,157)
Income taxes payable	1,482	(2,989)
Net cash provided by operating activities	12,792	4,562
Cash flows from investing activities:
Purchases of short-term investments	(108,517)	(96,904)
Proceeds from maturities of short-term investments	32,400	119,590
Purchase of property and equipment	(1,462)	(1,906)
Payments made in connection with business acquisitions	(500)	(500)
Net cash (used in) provided by investing activities	(78,079)	20,280
Cash flows from financing activities:
Purchase and retirement of treasury stock	(596)	(899)
Proceeds from exercise of stock options	4,378	5,818
Proceeds from issuance of common stock under employee stock purchase plan	955	709
Excess tax benefit from stock-based compensation	910	893
Net cash provided by financing activities	5,647	6,521
Net (decrease) increase in cash and cash equivalents	(59,640)	31,363
Cash and cash equivalents, at beginning of period	208,898	126,173
Cash and cash equivalents, at end of period	$ 149,258	$ 157,536