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Summary of Significant Accounting Policies - Changes in Product Warranty Accrual (Detail) - USD ($)
$ in Thousands
9 Months Ended
Sep. 26, 2020
Sep. 28, 2019
Movement in Standard and Extended Product Warranty Accrual, Increase (Decrease) [Roll Forward]    
Warranty accrual, beginning of period $ 3,395 $ 1,910
Accrual for warranties issued 428 1,920
Changes in pre-existing warranties (including changes in estimates) (97) 1,404
Settlements made (883) (1,276)
Warranty accrual, end of period $ 2,843 $ 3,958