Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2020	Mar. 30, 2019
Income Statement [Abstract]
Net sales	$ 472,566	$ 426,445
Cost of sales	170,435	164,212
Gross profit	302,131	262,233
Operating expenses:
Sales and marketing	207,744	186,827
General and administrative	31,072	34,323
Research and development	10,501	8,376
Total operating expenses	249,317	229,526
Operating income	52,814	32,707
Interest expense, net	2,344	2,609
Income before income taxes	50,470	30,098
Income tax expense	11,330	4,680
Net income	$ 39,140	$ 25,418
Basic net income per share:
Net income per share – basic (in dollars per share)	$ 1.40	$ 0.83
Weighted-average shares – basic	27,858,000	30,620,000
Diluted net income per share:
Net income per share – diluted (in dollars per share)	$ 1.36	$ 0.80
Weighted-average shares – diluted	28,772,000	31,738,000