CONVERTIBLE DEBT - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jul. 01, 2022	Jul. 02, 2021	Jul. 01, 2022	Jul. 02, 2021
2022 Notes
Debt Instrument [Line Items]
Contractual interest expense	$ 412	$ 412	$ 824	$ 824
Amortization of debt discount	0	171	0	337
Amortization of debt issuance costs	70	53	138	105
Total interest expense recognized	482	636	962	1,266
2024 Notes
Debt Instrument [Line Items]
Contractual interest expense	578	578	1,156	1,156
Amortization of debt discount	0	1,166	0	2,312
Amortization of debt issuance costs	217	158	434	314
Total interest expense recognized	$ 795	$ 1,902	$ 1,590	$ 3,782

Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

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