Income Taxes - Income Before Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 26, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Expense Benefit Continuing Operations Income Tax Reconciliation [Abstract]
Federal income tax provision (benefit) at statutory rate	$ 5,642	$ (125)	$ 11,203
State taxes, net of federal effect	126	113	747
Foreign taxes, net of federal effect	596	(1,277)	17
Foreign Derived Intangible Income ("FDII") Deduction	(4,262)	(2,278)	(2,217)
Global Intangible Low-Taxes Income ("GILTI") inclusion	2,013	1,786	113
Non-deductible officer's compensation	213	826	526
Research & development tax credit	(4,858)	(2,126)	(2,298)
Tax impact of IRS audit closure	(2,905)
Impact of the Tax Act			105
Impact of the CARES Act	(1,141)
Other	419	574	54
Total income tax expense (benefit)	$ (4,157)	$ (2,507)	$ 8,250
Effective tax rate	(16.00%)	(420.00%)	15.00%

Foreign derived intangible income (FDII) deduction.

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Global intangible low-taxes income inclusion.

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Tax Cuts and Jobs Act of 2017,change in tax rate, deferred tax assets, provisional income tax benefit.

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Tax impact of CARES Act.

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Tax impact of IRS audit closure.

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to foreign income tax expense (benefit).

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The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.

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Amount of reported income tax expense (benefit) in excess of (less than) expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operation, attributable to nondeductible expense for award under share-based payment arrangement. Includes, but is not limited to, expense determined to be nondeductible upon grant or after for award under share-based payment arrangement.

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