Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 27, 2014	Sep. 28, 2013
Cash flows from operating activities:
Net income	$ 49,027	$ 53,656
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	29,579	22,199
Stock-based compensation	4,294	3,058
Net loss (gain) on disposals and impairments of assets	115	(10)
Excess tax benefits from stock-based compensation	(754)	(3,088)
Deferred income taxes	(4,306)	4,288
Changes in operating assets and liabilities, net of effect of acquisition:
Accounts receivable	(14,195)	1,717
Inventories	(8,552)	(5,069)
Income taxes	9,883	7,114
Prepaid expenses and other assets	(4,146)	(5,144)
Accounts payable	27,359	11,029
Customer prepayments	13,847	97
Accrued compensation and benefits	17,318	(5,607)
Other taxes and withholding	4,484	1,504
Warranty liabilities	953	(1,218)
Other accruals and liabilities	10,929	5,556
Net cash provided by operating activities	135,835	90,082
Cash flows from investing activities:
Purchases of property and equipment	(58,377)	(57,820)
Investments in marketable debt securities	(58,403)	(26,041)
Proceeds from maturities of marketable debt securities	38,237	31,973
Increase in restricted cash	(500)	0
Proceeds from sales of property and equipment	5	117
Acquisition of business	0	(15,500)
Investment in non-marketable equity securities	0	(3,000)
Net cash used in investing activities	(79,038)	(70,271)
Cash flows from financing activities:
Repurchases of common stock	(31,480)	(32,054)
Net decrease in short-term borrowings	(7,499)	(4,567)
Proceeds from issuance of common stock	1,631	7,108
Excess tax benefits from stock-based compensation	754	3,088
Net cash used in financing activities	(36,594)	(26,425)
Net increase (decrease) in cash and cash equivalents	20,203	(6,614)
Cash and cash equivalents, at beginning of period	58,223	87,915
Cash and cash equivalents, at end of period	$ 78,426	$ 81,301