Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019	Dec. 28, 2019
Income Taxes [Line Items]
Provision for income taxes	$ 8,000	$ 7,000	$ 20,000	$ 22,000
Unrecognized tax benefits					$ 1,200,000
Unrecognized tax benefits recognition impact on income tax rate					$ 0
Federal
Income Taxes [Line Items]
Income tax returns examination period			3 years
Minimum | State Jurisdictions
Income Taxes [Line Items]
Income tax returns examination period			3 years
Maximum | State Jurisdictions
Income Taxes [Line Items]
Income tax returns examination period			5 years