Condensed Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Apr. 02, 2011
Condensed Consolidated Statements of Operations and Comprehensive Income [Abstract]
Net sales	$ 262,383	$ 193,068
Cost of sales	98,084	69,967
Gross profit	164,299	123,101
Operating expenses:
Sales and marketing	106,185	80,271
General and administrative	16,929	15,623
Research and development	1,290	731
CEO transition costs	5,595	0
Asset impairment charges	4	78
Total operating expenses	130,003	96,703
Operating income	34,296	26,398
Other income (expense), net	7	(30)
Income before income taxes	34,303	26,368
Income tax expense	11,886	9,785
Net income	$ 22,417	$ 16,583
Net income per share - basic (in dollars per share)	$ 0.40	$ 0.30
Weighted-average shares - basic (in shares)	55,640	54,726
Net income per share - diluted (in dollars per share)	$ 0.39	$ 0.30
Weighted-average shares - diluted (in shares)	57,440	55,977