Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 28, 2014	Jun. 29, 2013	Jun. 28, 2014	Jun. 29, 2013
Income Statement [Abstract]
Net sales	$ 234,763	$ 207,391	$ 511,175	$ 465,628
Cost of sales	92,366	75,993	197,395	170,814
Gross profit	142,397	131,398	313,780	294,814
Operating expenses:
Sales and marketing	106,712	98,357	231,734	208,170
General and administrative	21,265	15,374	40,161	31,194
Research and development	1,709	2,560	3,372	5,116
Total operating expenses	129,686	116,291	275,267	244,480
Operating income	12,711	15,107	38,513	50,334
Other income, net	78	78	180	169
Income before income taxes	12,789	15,185	38,693	50,503
Income tax expense	4,308	5,259	13,220	17,106
Net income	$ 8,481	$ 9,926	$ 25,473	$ 33,397
Basic net income per share:
Net income per share – basic (in USD per share)	$ 0.16	$ 0.18	$ 0.47	$ 0.61
Weighted-average shares – basic (in shares)	53,648	55,029	53,880	55,062
Diluted net income per share:
Net income per share – diluted (in USD per share)	$ 0.16	$ 0.18	$ 0.47	$ 0.60
Weighted-average shares – diluted (in shares)	54,324	55,987	54,570	56,101