Condensed Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 29, 2012	Oct. 01, 2011	Sep. 29, 2012	Oct. 01, 2011
Income Statement [Abstract]
Net sales	$ 246,817	$ 199,600	$ 714,419	$ 554,130
Cost of sales	86,088	73,838	257,820	202,763
Gross profit	160,729	125,762	456,599	351,367
Operating Expenses:
Sales and marketing	101,718	83,936	296,143	234,724
General and administrative	16,936	14,331	50,085	43,074
Research and development	1,742	1,029	4,288	2,983
Asset impairment charges	108	7	115	103
CEO transition costs	0	0	5,595	0
Total operating expenses	120,504	99,303	356,226	280,884
Operating income	40,225	26,459	100,373	70,483
Other income (expense), net	73	23	128	(37)
Income before income taxes	40,298	26,482	100,501	70,446
Income tax expense	14,089	9,246	34,902	25,338
Net income	$ 26,209	$ 17,236	$ 65,599	$ 45,108
Basic net income per share:
Net income per share - basic	$ 0.47	$ 0.31	$ 1.18	$ 0.82
Weighted-average shares - basic	55,444	55,214	55,601	54,966
Diluted net income per share:
Net income per share - diluted	$ 0.46	$ 0.31	$ 1.15	$ 0.80
Weighted-average shares - diluted	56,986	56,495	57,202	56,306