Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Apr. 01, 2012
Cash flows from operating activities:
Net income	$ 26,801	$ 25,667
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation	5,810	5,204
Amortization	2,557	913
Stock-based compensation	4,364	3,613
Income taxes payable, net	600	1,357
Deferred income taxes	976	(3,282)
(Increase) decrease, net of acquisitions, in:
Receivables	(9,284)	(28,249)
Inventories	(1,606)	(11,247)
Other assets	(512)	(2,834)
Increase (decrease), net of acquisitions, in:
Accounts payable	3,212	3,576
Accrued payroll liabilities	(9,645)	(22,634)
Accrued warranty reserves	421	(83)
Deferred revenue	10,587	(148)
Accrued restructuring, reorganization, relocation and severance	188	48
Other liabilities	341	(4,110)
Net cash provided by (used in) operating activities	34,810	(32,209)
Cash flows from investing activities:
(Increase) decrease in restricted cash	(3,462)	16,957
Acquisition of property, plant and equipment	(5,043)	(6,189)
Payments for acquisitions, net of cash acquired	0	(30,171)
Purchase of investments in marketable securities	(50,715)	(50,012)
Redemption of investments in marketable securities	34,030	26,638
Other	(293)	(319)
Net cash used in investing activities	(25,483)	(43,096)
Cash flows from financing activities:
Dividends paid on common stock	(3,078)	0
Withholding taxes paid on issuance of vested restricted stock units	(363)	(1,366)
Proceeds from exercise of stock options and employee stock purchases	4,146	2,804
Excess tax benefit for share based payment arrangements	586	433
Repurchases of common stock	0	(818)
Net cash provided by financing activities	1,291	1,053
Effect of exchange rate changes	(5,245)	6,168
Increase (decrease) in cash and cash equivalents	5,373	(68,084)
Cash and cash equivalents:
Beginning of period	266,302	320,361
End of period	271,675	252,277
Supplemental Cash Flow Information:
Cash paid for income taxes, net	2,656	7,807
Cash paid for interest	56	322
Increase in fixed assets related to transfers with inventories	1,664	8,839
Dividends declared but not paid	$ 3,078	$ 0