Interest Expense on Convertible Senior Notes (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 29, 2020	Mar. 31, 2019
Debt Instrument
Contractual interest expense on the coupon	$ 1,438	$ 1,438
Amortization of the discount component and debt issue fees recognized as interest expense	3,792	3,608
Total interest expense on the convertible debt	$ 5,230	$ 5,046

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.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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