Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 03, 2015	Dec. 28, 2013	Dec. 29, 2012
Cash flows from operating activities:
Net income	$ 67,974	$ 60,081	$ 78,094
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	39,809	30,811	20,401
Stock-based compensation	6,798	4,232	10,306
Net loss on disposals and impairments of assets	492	24	115
Excess tax benefits from stock-based compensation	(1,163)	(3,831)	(6,446)
Deferred income taxes	(311)	2,037	3,499
Changes in operating assets and liabilities, net of effect of acquisition:
Accounts receivable	(4,717)	1,993	(2,705)
Inventories	(13,383)	(3,910)	(10,713)
Income taxes	(4,314)	4,395	4,299
Prepaid expenses and other assets	(9,973)	(3,169)	(2,382)
Accounts payable	14,340	(3,477)	7,114
Customer prepayments	13,334	198	1,665
Accrued compensation and benefits	17,735	(5,202)	(8,108)
Other taxes and withholding	2,584	(153)	765
Warranty liabilities	1,671	(1,236)	(1,454)
Other accruals and liabilities	13,592	5,312	6,176
Net cash provided by operating activities	144,468	88,105	100,626
Cash flows from investing activities:
Investments in marketable debt securities	(90,349)	(44,170)	(86,803)
Purchases of property and equipment	(76,594)	(76,811)	(51,593)
Proceeds from maturities of marketable debt securities	54,506	53,565	26,249
Investment in non-marketable equity securities	(1,500)	(4,500)	0
Proceeds from sales of property and equipment	5	117	45
Increase in restricted cash	(500)	0	0
Acquisition of business	0	(15,500)	0
Net cash used in investing activities	(114,432)	(87,299)	(112,102)
Cash flows from financing activities:
Repurchases of common stock	(46,492)	(42,072)	(34,892)
Net increase (decrease) in short-term borrowings	6,192	(223)	6,494
Proceeds from issuance of common stock	2,873	7,966	5,138
Excess tax benefits from stock-based compensation	1,163	3,831	6,446
Debt issuance costs	0	0	(50)
Net cash used in financing activities	(36,264)	(30,498)	(16,864)
Net decrease in cash and cash equivalents	(6,228)	(29,692)	(28,340)
Cash and cash equivalents, at beginning of period	58,223	87,915	116,255
Cash and cash equivalents, at end of period	51,995	58,223	87,915
Income taxes paid	38,474	24,253	34,181
Interest paid	49	34	81
Purchases of property and equipment included in accounts payable	$ 5,802	$ 3,465	$ 3,817