CONVERTIBLE DEBT - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended
Apr. 01, 2022	Apr. 02, 2021
2022 Notes
Debt Instrument [Line Items]
Contractual interest expense	$ 412	$ 412
Amortization of debt discount		166
Amortization of debt issuance costs	68	52
Total interest expense recognized	480	630
2024 Notes
Debt Instrument [Line Items]
Contractual interest expense	578	578
Amortization of debt discount		1,146
Amortization of debt issuance costs	217	156
Total interest expense recognized	$ 795	$ 1,880

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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Amount of amortization expense attributable to debt issuance costs.

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Amount of the cost of borrowed funds accounted for as interest expense for debt.

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