Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2021	Jun. 27, 2020	Jul. 03, 2021	Jun. 27, 2020
Income Statement [Abstract]
Net sales	$ 484,316	$ 284,938	$ 1,052,572	$ 757,504
Cost of sales	191,465	121,928	403,803	292,363
Gross profit	292,851	163,010	648,769	465,141
Operating expenses:
Sales and marketing	205,994	130,165	429,611	337,909
General and administrative	41,220	36,716	83,812	67,788
Research and development	15,916	8,254	29,202	18,755
Total operating expenses	263,130	175,135	542,625	424,452
Operating income (loss)	29,721	(12,125)	106,144	40,689
Interest expense, net	1,607	3,940	2,584	6,284
Income (loss) before income taxes	28,114	(16,065)	103,560	34,405
Income tax expense (benefit)	5,864	(3,435)	14,676	7,895
Net income (loss)	$ 22,250	$ (12,630)	$ 88,884	$ 26,510
Basic net income (loss) per share:
Net income (loss) per share – basic (in dollars per share)	$ 0.91	$ (0.45)	$ 3.57	$ 0.95
Weighted-average shares – basic (in shares)	24,371,000	27,923,000	24,874,000	27,890,000
Diluted net income (loss) per share:
Net income (loss) per share – diluted (in dollars per share)	$ 0.88	$ (0.45)	$ 3.44	$ 0.93
Weighted-average shares – diluted (in shares)	25,194,000	27,923,000	25,869,000	28,523,000