QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 297,602	$ 229,125	$ 231,654	$ 155,353	$ 241,179	$ 196,109	$ 206,288	$ 135,257	$ 913,734	$ 778,833	$ 639,239
Gross profit	162,334	120,076	116,277	76,627	127,828	97,541	100,570	57,189	475,314	383,128	294,601
Net income	$ 4,742	$ 21,302	$ 22,223	$ 2,167	$ 25,169	$ 17,030	$ 18,825	$ (3,261)	$ 50,434	$ 57,763	$ 15,401
Net income per share - basic (in dollars per share)	$ 0.05	$ 0.25	$ 0.26	$ 0.03	$ 0.30	$ 0.21	$ 0.23	$ (0.04)	$ 0.59	$ 0.71	$ 0.19
Net income per share - diluted (in dollars per share)	$ 0.05	$ 0.25	$ 0.26	$ 0.03	$ 0.30	$ 0.21	$ 0.23	$ (0.04)	$ 0.58	$ 0.69	$ 0.19