Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 28, 2014	Jun. 29, 2013
Cash flows from operating activities:
Net income	$ 25,473	$ 33,397
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	19,213	14,153
Stock-based compensation	2,035	1,992
Net loss (gain) on disposals and impairments of assets	87	(58)
Excess tax benefits from stock-based compensation	(720)	(2,837)
Deferred income taxes	(2,003)	4,072
Changes in operating assets and liabilities, net of effect of acquisition:
Accounts receivable	651	2,541
Inventories	(3,004)	1,769
Income taxes	(394)	(3,084)
Prepaid expenses and other assets	(4,355)	(3,933)
Accounts payable	(1,042)	(1,708)
Customer prepayments	2,695	(2,857)
Accrued compensation and benefits	9,724	(4,802)
Other taxes and withholding	(529)	(1,156)
Warranty liabilities	281	(571)
Other accruals and liabilities	1,466	(775)
Net cash provided by operating activities	49,578	36,143
Cash flows from investing activities:
Purchases of property and equipment	(39,766)	(37,096)
Proceeds from maturities of marketable debt securities	23,548	23,463
Investments in marketable debt securities	(28,405)	(16,504)
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	(45,118)	(48,520)
Cash flows from financing activities:
Repurchases of common stock	(21,470)	(22,031)
Net decrease in short-term borrowings	(6,192)	(4,750)
Proceeds from issuance of common stock	1,366	6,595
Excess tax benefits from stock-based compensation	720	2,837
Net cash used in financing activities	(25,576)	(17,349)
Net decrease in cash and cash equivalents	(21,116)	(29,726)
Cash and cash equivalents, at beginning of period	58,223	87,915
Cash and cash equivalents, at end of period	$ 37,107	$ 58,189