Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jul. 03, 2016	Jul. 05, 2015
Cash flows from operating activities:
Net income	$ 57,644	$ 64,216
Adjustments to reconcile net income to net cash provided by operating activities:
(Gain) loss on sale of discontinued business	255	0
Stock-based compensation expense	11,261	11,577
Depreciation of property, plant, and equipment	5,577	4,816
Amortization of intangible assets	1,862	2,183
Amortization of discounts or premiums on investments	204	377
Realized (gain) loss on sale of investments	(128)	(221)
Revaluation of contingent consideration	(463)	0
Change in deferred income taxes	(2,943)	(2,010)
Accounts receivable	(17,737)	(5,387)
Unbilled revenue	(25,507)	(52,697)
Inventories	11,964	(11,200)
Accounts payable	6,224	(1,645)
Accrued expenses	1,762	(3,887)
Accrued income taxes	2,245	8,719
Deferred revenue and customer deposits	3,998	8,485
Other	(6,907)	(5,323)
Net cash provided by operating activities	49,311	18,003
Cash flows from investing activities:
Purchases of investments	(455,915)	(222,834)
Maturities and sales of investments	427,196	252,768
Purchases of property, plant, and equipment	(5,347)	(9,525)
Cash paid for purchased technology	0	(10,475)
Net cash received (paid) from sale of discontinued business	(113)	0
Net cash provided by (used in) investing activities	(34,179)	9,934
Cash flows from financing activities:
Issuance of common stock under stock plans	8,700	21,457
Repurchase of common stock	(8,718)	(35,848)
Payment of dividends	(12,335)	(6,110)
Payment of contingent consideration	(337)	0
Net cash provided by (used in) financing activities	(12,690)	(20,501)
Effect of foreign exchange rate changes on cash and cash equivalents	512	(1,439)
Net change in cash and cash equivalents	2,954	5,997
Cash and cash equivalents at beginning of period	51,975	55,694
Cash and cash equivalents at end of period	54,929	61,691
Non-cash items related to discontinued operations:
Depreciation and amortization expense	0	566
Capital expenditures	0	482
Stock-based compensation expense	$ 0	$ 427