Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Details)			3 Months Ended		12 Months Ended
	Apr. 15, 2020 USD ($)	Jul. 30, 2014	Mar. 25, 2020 USD ($) restaurant supplier segment	Mar. 27, 2019 USD ($) restaurant	Dec. 27, 2017	Apr. 17, 2020 USD ($) restaurant	Dec. 25, 2019 USD ($)	Dec. 26, 2018 USD ($)
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Repayments of Lines of Credit			$ 8,000,000	$ 3,000,000
Property and equipment owned, net			$ 87,902,000				$ 91,778,000
Depreciation				4,800,000
Number of operating segments | segment			1
Total amount of outstanding debt			$ 141,500,000
Cash available			43,404,000	6,699,000			8,070,000	$ 6,969,000
Assets Held-for-sale, Not Part of Disposal Group, Current				4,500,000
Proceeds from Long-term Lines of Credit			52,500,000	0
Asset Impairment Charges			1,900,000	4,124,000
Unrecognized tax benefits, accrual of interest or penalties			0				0
Unrecognized tax benefits, interest or penalties expenses			0	0
Percentage of cash savings in taxes realized as a result of utilizing net operating losses payable to pre-IPO stockholders		85.00%
Income tax receivable agreement (income) expense			(120,000)	171,000
Impairment of Long-Lived Assets to be Disposed of			1,920,000	$ 0
Impairment of Right-of-Use Assets			543,000
Indefinite-lived Intangible Assets
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Asset Impairment Charges			$ 0
Supplier Concentration Risk
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of suppliers | supplier			1
Supplier Concentration Risk | Supplier One | Accounts Payable
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration			12.20%		11.70%
Supplier Concentration Risk | Largest Supplier One | Purchased
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration			27.40%	26.60%
Geographic Concentration Risk | Revenue
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration			100.00%	100.00%
Subsequent Event
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Letters of Credit Outstanding, Amount						$ 2,700,000
Repayments of Lines of Credit	$ 2,700,000
Fair Value, Measurements, Nonrecurring
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Property and equipment owned, net			$ 39,000	$ 4,494,000
Right-of-Use Assets, Net			926,000
Fair Value, Recurring [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Derivative Liability, Fair Value, Gross Liability			1,142,000
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Nonrecurring
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Property and equipment owned, net			0	0
Right-of-Use Assets, Net			0
Fair Value, Inputs, Level 1 | Fair Value, Recurring [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Derivative Liability, Fair Value, Gross Liability			0
Derivative Asset, Fair Value, Gross Asset							0
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Nonrecurring
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Property and equipment owned, net			0	0
Right-of-Use Assets, Net			0
Fair Value, Inputs, Level 2 | Fair Value, Recurring [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Derivative Asset, Fair Value, Gross Asset							360,000
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Property and equipment owned, net			39,000	$ 4,494,000
Right-of-Use Assets, Net			926,000
Fair Value, Inputs, Level 3 | Fair Value, Recurring [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Derivative Liability, Fair Value, Gross Liability			$ 0
Derivative Asset, Fair Value, Gross Asset							$ 0
Los Angeles | Geographic Concentration Risk | Revenue
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration			72.40%	69.20%
TEXAS
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of Restaurants | restaurant			1
Number of restaurants closed			1	1
ARIZONA
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of Restaurants | restaurant				7
CALIFORNIA
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of Restaurants | restaurant			3	4
Number of restaurants closed				1
closed store [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Operating Lease, Expense			$ 500,000	$ 300,000
Common Stock [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Treasury Stock, Value, Acquired, Cost Method				(2,000)
Additional Paid-in Capital [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Treasury Stock, Value, Acquired, Cost Method				$ (3,381,000)
Entity Operated Units
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of Restaurants | restaurant			195
Entity Operated Units | Subsequent Event
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of Restaurants Remain Closed | restaurant						3
Number of Restaurants Temporary Closed | restaurant						18
Number of Restaurants Reopened | restaurant						15
Franchised Units
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of Restaurants | restaurant			284
Franchised Units | Subsequent Event
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of Restaurants Remain Closed | restaurant						4
Number of Restaurants Temporary Closed | restaurant						12
Number of Restaurants Reopened | restaurant						8