Condensed Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Per Share data	3 Months Ended		6 Months Ended
	Jul. 02, 2011	Jul. 03, 2010	Jul. 02, 2011	Jul. 03, 2010
Condensed Consolidated Statements of Operations [Abstract]
Net sales	$ 161,462	$ 138,952	$ 354,530	$ 296,905
Cost of sales	58,958	52,487	128,925	112,356
Gross profit	102,504	86,465	225,605	184,549
Operating expenses:
Sales and marketing	70,517	62,981	150,788	133,073
General and administrative	13,120	12,934	28,743	26,083
Research and development	1,223	613	1,954	1,267
Asset impairment charges	18	0	96	0
Total operating expenses	84,878	76,528	181,581	160,423
Operating income	17,626	9,937	44,024	24,126
Other expense, net	30	56	60	1,776
Income before income taxes	17,596	9,881	43,964	22,350
Income tax expense	6,307	3,679	16,092	8,388
Net income	$ 11,289	$ 6,202	$ 27,872	$ 13,962
Net income per share - basic	$ 0.21	$ 0.12	$ 0.51	$ 0.26
Weighted-average shares - basic	54,958	53,911	54,842	53,763
Net income per share - diluted	$ 0.20	$ 0.11	$ 0.50	$ 0.25
Weighted-average shares - diluted	56,407	55,253	56,157	55,186