CONVERTIBLE DEBT - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2022	Oct. 01, 2021	Sep. 30, 2022	Oct. 01, 2021
2022 Notes
Debt Instrument [Line Items]
Contractual interest expense	$ 412	$ 412	$ 1,236	$ 1,236
Amortization of debt discount	0	171	0	508
Amortization of debt issuance costs	69	54	207	159
Total interest expense recognized	481	637	1,443	1,903
2024 Notes
Debt Instrument [Line Items]
Contractual interest expense	578	578	1,734	1,734
Amortization of debt discount	0	1,193	0	3,505
Amortization of debt issuance costs	220	162	654	476
Total interest expense recognized	$ 798	$ 1,933	$ 2,388	$ 5,715

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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