Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Oct. 02, 2016	Oct. 04, 2015
Cash flows from operating activities:
Net income	$ 111,319	$ 168,328
Adjustments to reconcile net income to net cash provided by operating activities:
(Gain) loss on sale of discontinued business	255	(78,290)
Stock-based compensation expense	15,883	15,964
Depreciation of property, plant, and equipment	8,551	7,223
Amortization of intangible assets	2,581	3,203
Amortization of discounts or premiums on investments	288	536
Realized (gain) loss on sale of investments	(733)	(240)
Revaluation of contingent consideration	(463)	0
Change in deferred income taxes	(1,415)	(2,134)
Accounts receivable	(37,802)	(31,380)
Unbilled revenue	(9,986)	(2,233)
Inventories	10,780	(11,363)
Accounts payable	2,089	(6,823)
Accrued expenses	7,560	(4,010)
Accrued income taxes	(531)	18,032
Deferred revenue and customer deposits	4,071	6,035
Other	(5,789)	1,147
Net cash provided by operating activities	106,658	83,995
Cash flows from investing activities:
Purchases of investments	(598,955)	(547,553)
Maturities and sales of investments	529,207	521,464
Purchases of property, plant, and equipment	(10,491)	(13,017)
Cash paid for acquisition of business	(2,483)	(1,023)
Cash paid for purchased technology	0	(10,475)
Net cash paid from sale of discontinued operations	(113)
Net cash received from sale of discontinued business		104,496
Net cash provided by (used in) investing activities	(82,835)	53,892
Cash flows from financing activities:
Issuance of common stock under stock plans	23,091	27,440
Repurchase of common stock	(18,941)	(126,351)
Payment of dividends	(18,761)	(12,137)
Payment of contingent consideration	(337)	0
Net cash provided by (used in) financing activities	(14,948)	(111,048)
Effect of foreign exchange rate changes on cash and cash equivalents	295	(2,970)
Net change in cash and cash equivalents	9,170	23,869
Cash and cash equivalents at beginning of period	51,975	55,694
Cash and cash equivalents at end of period	61,145	79,563
Non-cash items related to discontinued operations:
Stock-based compensation expense	0	1,533
Depreciation and Amortization	0	566
Capital expenditures	$ 0	$ 482