0001564590-21-012800 | 10-K | XBRL Viewer

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 27, 2020	Feb. 24, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 27, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Trading Symbol	PBPB
Entity Registrant Name	Potbelly Corporation
Entity Central Index Key	0001195734
Current Fiscal Year End Date	--12-27
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
ICFR Auditor Attestation Flag	true
Entity Common Stock, Shares Outstanding		27,951,077
Entity Public Float			$ 55.9
Title of 12(b) Security	Common Stock, $0.01 par value
Entity File Number	001-36104
Entity Tax Identification Number	36-4466837
Entity Address, Address Line One	111 N. Canal Street
Entity Address, Address Line Two	Suite 850
Entity Address, City or Town	Chicago
Entity Address, State or Province	IL
Entity Incorporation, State or Country Code	DE
Entity Address, Postal Zip Code	60606
City Area Code	312
Local Phone Number	951-0600
Document Annual Report	true
Document Transition Report	false
Entity Interactive Data Current	Yes
Security Exchange Name	NASDAQ
Documents Incorporated by Reference	Portions of the registrant’s definitive proxy statement for its 2021 Annual Meeting to be filed with the Securities and Exchange Commission not later than 120 days after the end of the year covered by this Annual Report are incorporated by reference into Part III of this Annual Report.

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 27, 2020	Dec. 29, 2019
Current assets
Cash and cash equivalents	$ 11,126	$ 18,806
Accounts receivable, net of allowances of $47 and $202 as of December 27, 2020 and December 29, 2019, respectively	4,354	4,257
Inventories	2,989	3,473
Prepaid expenses and other current assets	4,839	5,687
Total current assets	23,308	32,223
Property and equipment, net	61,193	79,032
Right-of-use assets for operating leases	189,141	211,988
Indefinite-lived intangible assets	3,404	3,404
Goodwill	2,222	2,222
Deferred expenses, net and other assets	4,089	4,010
Total assets	283,357	332,879
Current liabilities
Accounts payable	6,206	3,886
Accrued expenses	23,742	20,569
Current portion of long-term debt	333
Short-term operating lease liabilities	35,325	29,319
Total current liabilities	65,606	53,774
Long-term debt, net of current portion	15,953
Long-term operating lease liabilities	189,146	206,726
Other long-term liabilities	7,157	3,210
Total liabilities	277,862	263,710
Commitments and contingencies (Note 15)
Equity
Common stock, $0.01 par value—authorized 200,000 shares; outstanding 24,323 and 23,638 shares as of December 27, 2020 and December 29, 2019, respectively	339	331
Additional paid-in-capital	438,174	435,278
Treasury stock, held at cost, 9,612 and 9,465 shares as of December 27, 2020, and December 29, 2019, respectively	(113,266)	(112,680)
Accumulated deficit	(319,477)	(254,081)
Total stockholders’ equity	5,770	68,848
Non-controlling interest	(275)	321
Total equity	5,495	69,169
Total liabilities and equity	$ 283,357	$ 332,879

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 27, 2020	Dec. 29, 2019
Statement Of Financial Position [Abstract]
Allowances on accounts receivable	$ 47	$ 202
Common stock, par value	$ 0.01	$ 0.01
Common stock, authorized	200,000,000	200,000,000
Common stock, outstanding	24,323,000	23,638,000
Treasury stock, shares	9,612,000	9,465,000

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2020	Dec. 29, 2019	Dec. 30, 2018
Revenues
Total revenues	$ 291,281	$ 409,707	$ 422,638
Sandwich shop operating expenses
Labor and related expenses	105,241	128,403	127,962
Occupancy expenses	56,882	58,977	59,789
Other operating expenses	49,054	50,178	50,363
General and administrative expenses	35,009	44,831	44,826
Depreciation expense	19,830	22,103	23,142
Pre-opening costs	229	35	472
Impairment, loss on disposal of property and equipment and shop closures	12,346	6,050	15,603
Restructuring costs	1,668
Total expenses	362,413	418,903	433,240
Loss from operations	(71,132)	(9,196)	(10,602)
Interest expense	1,076	199	142
Loss before income taxes	(72,208)	(9,395)	(10,744)
Income tax expense (benefit)	(6,536)	14,190	(2,195)
Net loss	(65,672)	(23,585)	(8,549)
Net income attributable to non-controlling interest	(281)	407	329
Net loss attributable to Potbelly Corporation	$ (65,391)	$ (23,992)	$ (8,878)
Net loss per common share attributable to common stockholders:
Basic	$ (2.74)	$ (1.01)	$ (0.35)
Diluted	$ (2.74)	$ (1.01)	$ (0.35)
Weighted average shares outstanding:
Basic	23,899	23,850	25,173
Diluted	23,899	23,850	25,173
Product
Revenues
Total revenues	$ 289,337	$ 406,688	$ 419,426
Sandwich shop operating expenses
Cost of goods sold, excluding depreciation	82,154	108,326	111,083
Franchise Royalties And Fees
Revenues
Total revenues	$ 1,944	$ 3,019	$ 3,212

Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment [Member] Revision of Prior Period, Adjustment [Member]	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in-Capital [Member]	Accumulated Deficit [Member]	Accumulated Deficit [Member] Cumulative Effect, Period of Adoption, Adjustment [Member] Revision of Prior Period, Adjustment [Member]	Non-Controlling Interest [Member]
Beginning balance at Dec. 31, 2017	$ 117,238		$ 318	$ (85,262)	$ 421,657	$ (219,990)		$ 515
Beginning balance, common shares at Dec. 31, 2017			25,000,000
Net income (loss)	(8,549)					(8,878)		329
Cumulative impact (ASU 2014-09 (Topic 606) [Member]) at Dec. 31, 2017		$ (690)					$ (690)
Shares issued under equity compensation plan	8,244		$ 12		8,232
Shares issued under equity compensation plan, shares			1,112,000
Exercise of stock warrants	$ (194)			(194)
Exercise of stock warrants, shares	(993,000)		(16,000)
Repurchases of common stock	$ (22,916)			(22,916)
Repurchases of common stock, shares			(1,953,000)
Distributions to non-controlling interest	(580)							(580)
Contributions from non-controlling interest	98							98
Stock-based compensation expense	2,882				2,882
Ending balance at Dec. 30, 2018	95,533		$ 330	(108,372)	432,771	(229,558)		362
Ending balance, common shares at Dec. 30, 2018			24,143,000
Net income (loss)	(23,585)					(23,992)		407
Cumulative impact (ASU 2016-02 (Topic 842) [Member]) at Dec. 30, 2018		(531)					(531)
Shares issued under equity compensation plan	$ 173		$ 1		172
Shares issued under equity compensation plan, shares			159,000
Exercise of stock warrants, shares	(22,000)
Treasury shares used for stock-basedplans	$ (91)			(91)
Treasury shares used for stock-based plans, shares			(16,000)
Repurchases of common stock	(4,217)			(4,217)
Repurchases of common stock, shares			(648,000)
Distributions to non-controlling interest	(523)							(523)
Contributions from non-controlling interest	75							75
Stock-based compensation expense	2,335				2,335
Ending balance at Dec. 29, 2019	$ 69,169		$ 331	(112,680)	435,278	(254,081)		321
Ending balance, common shares at Dec. 29, 2019	23,638,000		23,638,000
Net income (loss)	$ (65,672)					(65,391)		(281)
Cumulative impact at Dec. 29, 2019	(254,081)
Cumulative impact (ASU 2016-13 (Topic 326) [Member]) at Dec. 29, 2019		$ (5)					$ (5)
Shares issued under equity compensation plan			$ 7		(7)
Shares issued under equity compensation plan, shares			702,000
Shares issued for proxy-related expenses	389		$ 1		388
Shares issued for proxy-related expenses, shares			130,000
Treasury shares used for stock-basedplans	(586)			(586)
Treasury shares used for stock-based plans, shares			(147,000)
Distributions to non-controlling interest	(458)							(458)
Contributions from non-controlling interest	143							143
Stock-based compensation expense	2,515				2,515
Ending balance at Dec. 27, 2020	$ 5,495		$ 339	$ (113,266)	$ 438,174	$ (319,477)		$ (275)
Ending balance, common shares at Dec. 27, 2020	24,323,000		24,323,000

Consolidated Statements of Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2020	Dec. 29, 2019	Dec. 30, 2018
ASU 2016-13 (Topic 326) [Member]
Cumulative impact tax	$ 2
ASU 2016-02 (Topic 842) [Member]
Cumulative impact tax		$ 196
ASU 2014-09 (Topic 606) [Member]
Cumulative impact tax			$ 250

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2020	Dec. 29, 2019	Dec. 30, 2018
Cash flows from operating activities:
Net income (loss)	$ (65,672)	$ (23,585)	$ (8,549)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation expense	19,830	22,103	23,142
Noncash lease expense	26,579	27,853
Deferred income tax	10	13,808	(3,016)
Deferred rent and landlord allowances			(82)
Stock-based compensation expense	2,515	2,335	2,882
Excess tax deficiency from stock-based compensation			1,089
Asset impairment, store closure and disposal of property and equipment	9,440	1,829	13,762
Other operating activities	723	55	37
Changes in operating assets and liabilities:
Accounts receivable, net	(35)	480	100
Inventories	484	9	43
Prepaid expenses and other assets	617	5,917	(694)
Accounts payable	2,458	(249)	177
Operating lease liabilities	(15,895)	(28,565)
Accrued expenses and other liabilities	7,337	(3,822)	2,097
Net cash (used in) provided by operating activities	(11,609)	18,168	30,988
Cash flows from investing activities:
Purchases of property and equipment	(10,920)	(14,365)	(21,395)
Net cash used in investing activities	(10,920)	(14,365)	(21,395)
Cash flows from financing activities:
Borrowings under Credit Facility	61,286
Repayments under Credit Facility	(55,000)
Proceeds from Paycheck Protection Program loan	10,000
Payment of debt issuance costs	(538)	(189)
Proceeds from exercise of stock options		173	8,244
Employee taxes on certain stock-based payment arrangements	(584)	(91)	(194)
Treasury stock repurchase		(4,217)	(22,916)
Distributions to non-controlling interest	(458)	(523)	(580)
Contributions from non-controlling interest	143	75	98
Net cash provided by (used in) financing activities	14,849	(4,772)	(15,348)
Net decrease in cash and cash equivalents	(7,680)	(969)	(5,755)
Cash and cash equivalents at beginning of period	18,806	19,775	25,530
Cash and cash equivalents at end of period	11,126	18,806	19,775
Supplemental cash flow information:
Income taxes paid	206	187	250
Interest paid	896	108	110
Supplemental non-cash investing and financing activities:
Unpaid liability for purchases of property and equipment	$ 801	$ 1,198	$ 751

Organization and Other Matters

12 Months Ended

Dec. 27, 2020

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Organization and Other Matters

(1) Organization and Other Matters

Business

Potbelly Corporation, a Delaware corporation, together with its subsidiaries (collectively referred to as “the Company,” “Potbelly,” “we,” “us”, or “our”), owns and operates 400 company-owned shops in the United States as of December 27, 2020. Additionally, Potbelly franchisees operate over 46 shops domestically.

Basis of Presentation

Beginning with the third quarter of 2020, shop closure and lease termination expenses are presented within impairment, loss on disposal of property and equipment and shop closures on the consolidated statements of operations. Prior to the third quarter of 2020, shop closure and lease termination expenses were presented within general and administrative expenses. Prior period amounts have been reclassified to conform to the current presentation. This reclassification had no impact on the loss from operations, balance sheets or statements of cash flows.

The Company does not have any components of other comprehensive income recorded within its consolidated financial statements and therefore, does not separately present a statement of comprehensive income in its consolidated financial statements.

COVID-19

On January 30, 2020, the World Health Organization (“WHO”) announced a global health emergency because of a new strain of coronavirus ("COVID-19") and the risks to the international community as the virus spreads globally. On March 11, 2020, the WHO classified the COVID-19 outbreak as a pandemic, based on the rapid increase in exposure globally. In response to the pandemic, many states and jurisdictions in which we operate have issued stay-at-home orders and other measures aimed at slowing the spread of the coronavirus. To comply with government regulations and guidance, we initially closed the vast majority of our dining rooms and shifted to off-premise operations only, and we experienced a sudden and drastic decrease in revenues. As of the issuance of these financial statements, many of our shops have reopened their dining rooms with restrictions, such as social distancing and limited capacities, to ensure the health and safety of our guests and employees. We continue to follow guidance from local authorities in determining the appropriate restrictions to put in place for each shop, including the suspension or reduction of in-shop dining if required due to changes in the pandemic response in each jurisdiction.

The disruption in operations and reduction in revenues have led the Company to consider the impact of the COVID-19 pandemic on the recoverability of its assets, including property and equipment, right-of-use assets for operating leases, goodwill and intangible assets, and others.

Due to the impact of the COVID-19 pandemic, the Company evaluated its goodwill, intangible assets, and long-lived assets, which includes property and equipment and right-of-use assets for operating leases for impairment. The Company did not record any impairment to its goodwill or indefinite-lived intangible assets during 2020. The Company recorded impairment charges for its long-lived assets of $10.3 million in 2020, primarily driven by the expected impact of the COVID-19 pandemic on future cash flows. The ultimate severity and longevity of the COVID-19 pandemic is unknown, and therefore, it is possible that impairments could be identified in future periods, and such amounts could be material. See Note 2 for further details.

The Company recognized an income tax benefit of $6.7 million during 2020 due to the impact of the Coronavirus Aid, Relief and Economic Security Act (the “CARES Act”) which enabled the Company to obtain a tax refund from the carryback of net operating losses (“NOLs”) and a refund of prior alternative minimum tax (“AMT”) credits. See Note 7 for further details.

To preserve financial flexibility, the Company borrowed the $39.8 million of available capacity under its Revolving Credit Facility on March 17, 2020. The Company subsequently repaid $33.5 million of these borrowings through the end of 2020. On August 10, 2020, the Company entered into a loan agreement with Harvest Small Business Finance, LLC in the aggregate amount of $10.0 million pursuant to the Paycheck Protection Program (“PPP”) under the CARES Act. As of December 27, 2020, the Company had total liquidity of $44.6 million, consisting of cash and cash equivalents and amounts available on its Revolving Credit Facility. See Note 9 for further details.

The full impact of the COVID-19 outbreak continues to evolve as of the date of this report. Due to the rapid development and fluidity of this situation, the Company cannot determine the ultimate impact that the COVID-19 pandemic will have on its consolidated financial condition, liquidity, and future results of operations, and therefore any prediction as to the ultimate impact on the Company’s consolidated financial condition, liquidity, and future results of operations is uncertain.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 27, 2020

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

(2) Summary of Significant Accounting Policies

(a) Principles of Consolidation

The consolidated financial statements include the accounts of Potbelly Corporation; its wholly owned subsidiary, Potbelly Illinois, Inc. (“PII”); PII’s wholly owned subsidiaries, Potbelly Franchising, LLC and Potbelly Sandwich Works LLC (“LLC”); seven of LLC’s wholly owned subsidiaries and LLC’s seven joint ventures, collectively, the “Company.” All intercompany balances and transactions have been eliminated in consolidation. For consolidated joint ventures, non-controlling interest represents a non-controlling partner’s share of the assets, liabilities and operations related to the seven joint venture investments. The Company has ownership interests ranging from 51-80% in these consolidated joint ventures.

The Company does not have any components of other comprehensive income (loss) recorded within its consolidated financial statements, and, therefore, does not separately present a statement of comprehensive income (loss) in its consolidated financial statements.

(b) Reporting Period

The Company uses a 52/53-week fiscal year that ends on the last Sunday of the calendar year. Approximately every five or six years a 53rd week is added. Fiscal years 2020, 2019 and 2018 each consisted of 52 weeks.

The Company owns and operates Potbelly Sandwich Shop concepts in the United States. The Company also has domestic franchise operations of Potbelly Sandwich Shops concepts. The Company’s chief operating decision maker (the “CODM”) is its Chief Executive Officer. As the CODM reviews financial performance and allocates resources at a consolidated level on a recurring basis, the Company has one operating segment and one reportable segment.

(d) Use of Estimates

The preparation of financial statements in conformity with generally accepted accounting principles in the United States of America (“U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, revenues and expenses and the disclosure of contingent assets and liabilities. Significant estimates include amounts for long-lived assets and income taxes. Actual results could differ from those estimates.

(e) Fair Value Measurements

The Company applies fair value accounting for all financial assets and liabilities and nonfinancial assets and liabilities that are recognized or disclosed at fair value in the financial statements on a recurring basis. Fair value is defined as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities that are required to be recorded at fair value, the Company assumes the highest and best use of the asset by market participants in which the Company would transact and the market-based risk measurements or assumptions that market participants would use in pricing the asset or liability, such as inherent risk, transfer restrictions, and credit risk.

The Company applies the following fair value hierarchy, which prioritizes the inputs used to measure fair value into three levels, and bases the categorization within the hierarchy upon the lowest level of input that is available and significant to the fair value measurement:

•

Level 1 — Quoted prices in active markets for identical assets or liabilities.

•

Level 2 — Observable inputs other than quoted prices in active markets for identical assets or liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

•

Level 3 — Inputs that are both unobservable and significant to the overall fair value measurement reflect an entity’s estimates of assumptions that market participants would use in pricing the asset or liability.

(f) Financial Instruments

The Company records all financial instruments at cost, which is the fair value at the date of transaction. The amounts reported in the consolidated balance sheets for cash and cash equivalents, accounts receivable, accounts payable and all other current liabilities approximate their fair value because of the short-term maturities of these instruments.

(g) Cash and Cash Equivalents

The Company considers all highly liquid investment instruments with an original maturity of three months or less when purchased to be cash equivalents. The Company maintains its cash in bank deposit accounts that, at times, may exceed federally insured limits; however, the Company has not experienced any losses in these accounts. The Company believes it is not exposed to any significant credit risk. These are valued within the fair value hierarchy as Level 1 measurements.

(h) Accounts Receivable, net

Accounts receivable, net consists of amounts owed from credit card processors, customers, third-party delivery platforms, vendors and other miscellaneous receivables.

(i) Inventories

Inventories, which consist of food products, paper goods and supplies, and promotional items, are valued at the lower of cost (first-in, first-out) or net realizable value. No adjustment is deemed necessary to reduce inventory to the lower of cost or net realizable value due to the rapid turnover and high utilization of inventory.

(j) Property and Equipment

Property and equipment acquired is recorded at cost less accumulated depreciation. Property and equipment is depreciated based on the straight-line method over the estimated useful lives, generally ranging from three to five years for furniture and fixtures, computer equipment, computer software, and machinery and equipment. Leasehold improvements are depreciated over the shorter of their estimated useful lives or the related lease life, generally 10 to 15 years. For leases with renewal periods at the Company’s option, the Company determines the expected lease period based on whether the renewal of any options are reasonably assured at the inception of the lease.

Direct costs and expenditures for refurbishments and improvements that significantly add to the productive capacity or extend the useful life of an asset are capitalized, whereas the costs of repairs and maintenance are expensed when incurred. Capitalized costs are recorded as part of the asset to which they relate, primarily to leasehold improvements, and such costs are amortized over the asset’s useful life. When assets are retired or sold, the asset cost and related accumulated depreciation are removed from the consolidated balance sheet and any gain or loss is recorded in the consolidated statement of operations.

(k) Indefinite-Lived Intangible Assets

The Company reviews indefinite-lived intangible assets, which includes goodwill and tradenames, annually at fiscal year-end for impairment or more frequently if events or circumstances indicate that the carrying value may not be recoverable. An impaired asset is written down to its estimated fair value based on the most recent information available. The Company assesses the fair values of its intangible assets, and its reporting unit for goodwill testing purposes, using an income-based approach. Under the income approach, fair value is based on the present value of estimated future cash flows. The income approach is dependent on a number of factors, including forecasted revenues and expenses, appropriate discount rates and other variables. The annual impairment review utilizes the estimated fair value of the intangible assets and the overall reporting unit and compares the estimated fair values to the carrying values as of the testing date. If the carrying value of these intangible assets or the reporting unit exceeds the fair values, the Company would then use the fair values to measure the amount of any required impairment charge. No impairment charge was recognized for intangible assets or goodwill for any of the fiscal periods presented.

(l) Pre-opening Costs

Pre-opening costs consist of costs incurred prior to opening a new shop and are made up primarily of travel, employee payroll and training costs incurred prior to the shop opening, as well as occupancy costs incurred from when the Company takes site possession to shop opening. Shop pre-opening costs are expensed as incurred.

(m) Advertising Expenses

Advertising costs are expensed as incurred and are included in general and administrative expenses in the consolidated statements of operations. Advertising expenses were $1.0 million, $4.1 million and $4.3 million in fiscal years 2020, 2019 and 2018, respectively.

(n) Income Taxes

Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are attributed to differences between financial statement and income tax reporting. Deferred tax assets, net of any valuation allowances, represent the future tax return consequences of those differences and for operating loss and tax credit carryforwards, which will be deductible when the assets are recovered. Deferred tax assets are reduced by a valuation allowance if it is deemed more likely than not that some or all of the deferred tax assets will not be realized. In making this assessment of the realizability of deferred tax assets, the Company considers all positive and negative evidence as to whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. The Company considers the scheduled reversal of deferred tax liabilities, projected future taxable income, and tax planning strategies in making this assessment. Deferred tax liabilities are recognized for temporary differences that will be taxable in future years’ tax returns.

The Company accounts for uncertain tax positions under current accounting guidance, which prescribes a minimum probability threshold that a tax position must meet before a financial statement benefit is recognized. The minimum threshold is defined as a tax position that is more likely than not to be sustained upon examination by tax authorities, based on the technical merits of the position. The tax benefit to be recognized is measured as the largest amount of benefit that is greater than fifty percent likely of being realized upon ultimate settlement.

(o) Stock-Based Compensation

The Company accounts for its stock-based compensation in accordance with Accounting Standards Codification (“ASC”) 718, Stock Based Compensation. For employees, the Company records stock-based compensation expense on a straight-line basis over the vesting period based on the grant-date fair value of the awards, which is determined using the Black-Scholes option pricing valuation model for stock options and the quoted share price of Potbelly’s common stock on the date of grant for restricted stock units (“RSUs”). For the Company’s non-employee directors, the Company records stock compensation expense on the grant date of the RSUs.

The Company awards performance share units (“PSUs”) to eligible employees; the PSUs are subject to service and performance vesting conditions. The PSUs will vest based on the Company’s achievement of certain targets specified in the awards which may include adjusted EBITDA, same store sales, or stock price targets. Refer to Note 11 and Note 13 for more details regarding the Company’s Equity Plans.

(p) Leases

The Company determines if an arrangement is a lease at inception of the arrangement. The Company leases retail shops, warehouse, and office space under operating leases. The Company’s leases generally have terms of ten years and most include options to extend the leases for additional five-year periods. For leases with renewal periods at the Company’s option, the Company determines the expected lease period based on whether the renewal of any options are reasonably assured at the inception of the lease.

Operating leases result in the Company recording a right-of-use asset and lease liability on the balance sheet. Right-of-use assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent its obligation to make lease payments arising from the lease. Operating lease assets and liabilities are recognized at the lease commencement date, which is the date we take possession of the property. Operating lease liabilities represent the present value of lease payments not yet paid. Operating right-of-use assets represent the operating lease liability adjusted for prepayments or accrued lease payments, initial direct costs, lease incentives, and impairment of operating lease assets. In determining the present value of lease payments not yet paid, the Company estimates its incremental secured borrowing rates corresponding to the maturities of its leases. We estimate this rate based on prevailing financial market conditions, comparable company and credit analysis, and management judgment.

Our leases typically contain rent escalations over the lease term and lease expense is recognized on a straight-line basis over the lease term. Tenant incentives used to fund leasehold improvements are recognized when earned and reduce right-of-use assets related to the lease. The tenant incentives are amortized through the right-of-use asset as reductions of rent expense over the lease term.

Operating leases are included in right-of-use assets for operating leases, short-term operating lease liabilities, and long-term operating lease liabilities on the Company’s Consolidated Balance Sheets.

(q) Revenue Recognition

The Company primarily earns revenue at a point in time for sandwich shop sales which can occur in person at the shop, over our online or app platforms, or through a third-party platform. Sales taxes collected from customers are excluded from revenues and the obligation is included in accrued liabilities until the taxes are remitted to the appropriate taxing authorities. The Company has other revenue generating activities outlined below.

Franchise Revenue

The Company earns an initial franchise fee, a franchise development agreement fee and ongoing royalty fees under the Company’s franchise agreements. Initial franchise fees are considered highly dependent upon and interrelated with the franchise right granted in the franchise agreement. As such, these franchise fees are recognized over the contractual term of the franchise agreement. The Company records a contract liability for the unearned portion of the initial franchise fees. Franchise development agreement fees represent the exclusivity rights for a geographical area paid by a third party to develop Potbelly shops for a certain period of time. Franchise development agreement fee payments received by the Company are recorded as deferred revenue in the consolidated balance sheet and amortized over the life of the franchise development agreement. Royalty fees are based on a percentage of sales and are recorded as revenue as the fees are earned and become receivable from the franchisee.

Gift Card Redemptions / Breakage Revenue

Potbelly sells gift cards to customers, records the sale as a contract liability and recognizes the associated revenue as the gift card is redeemed. A portion of these gift cards are not redeemed by the customer, which is recognized by the Company as revenue as a percentage of customers gift card redemptions. The expected breakage amount recognized is determined by a historical data analysis on gift card redemption patterns. The Company recognizes gift card breakage income within gross sales in the consolidated statements of operations.

Loyalty Program

During the second quarter of 2020, the Company implemented a new customer loyalty program for customers using the Potbelly Perks application at the point of sale. The customer will typically earn 10 points for every dollar spent, and the customer will earn a free entrée after earning 1,000 points. The Company defers revenue associated with the estimated selling price of points earned by Potbelly Perks members towards free entrées as each point is earned, and a corresponding liability is established in deferred revenue. The deferral is based on the estimated value of the product for which the reward is expected to be redeemed, net of estimated unredeemed points. Once a customer earns a free entrée, that entrée reward will expire after 30 days. Any point in a customer’s account that does not go toward earning a full entrée will expire a year after the point is earned. When points are redeemed, the Company recognizes revenue for the redeemed product and reduces deferred revenue.

(r) Impairment of Long-Lived Assets

The Company assesses potential impairments to its long-lived assets, which includes property and equipment and right-of-use assets for operating leases, whenever events or circumstances indicate that the carrying amount of an asset may not be recoverable. Assets are grouped at the individual shop-level for the purposes of the impairment assessment because a shop represents the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets and liabilities. Recoverability of an asset group is measured by a comparison of the carrying amount of an asset group to its estimated forecasted shop cash flows expected to be generated by the asset group. If the carrying amount of the asset group exceeds its estimated forecasted shop cash flows, an impairment charge is recognized as the amount by which the carrying amount of the asset exceeds the fair value of the asset group. The fair value of the shop assets is determined using the income approach. Key inputs to this approach include forecasted shop cash flows, discount rate, and estimated market rent, which are all classified as Level 3 inputs. See “Fair Value Measurements” above for a definition of Level 3 inputs.

At transition of adoption to ASC 842, the Company impaired $0.7 million of pre-tax right-of-use assets related to previously impaired shops. This amount is recorded, net of tax, as an opening reduction to retained earnings. After performing periodic reviews of the long-lived assets, including company-operated shops, during each quarter of 2020, 2019 and 2018, it was determined that indicators of impairment were present for certain long-lived assets, including company-operated shops as a result of continued underperformance. The Company performed an impairment analysis for these long-lived assets and recorded impairment charges of $10.3 million, $2.6 million, and $13.4 million for the fiscal years 2020, 2019, and 2018, respectively, which is included in impairment, loss on disposal of property and equipment and shop closures in the consolidated statements of operations.

Assets recognized or disclosed at fair value on the consolidated financial statements on a nonrecurring basis included items such as leasehold improvements, property and equipment, right-of-use assets for operating leases, goodwill, and other intangible assets. These assets are measured at fair value if determined to be impaired.

(s) Recent Accounting Pronouncements

On December 31, 2018, the Company adopted Accounting Standards Update (ASU) 2016-02, “Leases (Topic 842),” along with related clarifications and improvements. This pronouncement requires lessees to recognize a liability for lease obligations, which represents the discounted obligation to make future lease payments, and a corresponding right-of-use asset on the balance sheet. The guidance requires disclosure of key information about leasing arrangements that is intended to give financial statement users the ability to assess the amount, timing, and potential uncertainty of cash flows related to leases. We elected the optional transition method to apply the standard as of the effective date and therefore, prior period amounts have not been adjusted and continue to be reported in accordance with our historical accounting under previous lease guidance. The adoption of Topic 842 had a material impact on the consolidated balance sheets and an immaterial impact on the consolidated statements of operations, consolidated statements of equity and consolidated statements of cash flows.

On December 30, 2019, the Company adopted Accounting Standard Update No. 2016-13, Financial Instruments—Credit Losses (Topic 326). This pronouncement requires the measurement and recognition of expected credit losses on financial instruments. ASU 2016-13 replaces the existing incurred loss model with a forward-looking expected credit loss model that requires consideration of a broader range of information to estimate credit losses. The Company recorded a net reduction of $5 thousand to opening accumulated deficit as of December 30, 2019, due to the cumulative impact of adopting Topic 326.

Revenue

12 Months Ended

Dec. 27, 2020

Revenue From Contract With Customer [Abstract]

Revenue

(3) Revenue

Potbelly primarily earns revenue at a point in time through sales at our sandwich shop locations and records such revenue net of sales-related taxes collected from customers. The payment on these sales is generally due at the time of the customer’s purchase. The Company also has other revenue generating activities, including franchise revenue, gift card redemptions / breakage revenue, and loyalty programs as described in Note 2.

For the fiscal year ended December 27, 2020, revenue recognized from all revenue sources on point in time sales was $290.7 million, and revenue recognized from sales over time was $0.6 million. For the fiscal year ended December 29, 2019, revenue recognized from all revenue sources on point in time sales was $408.8 million, and revenue recognized from sales over time was $0.9 million.

The Company recognized gift card breakage income of $0.2 million, $0.2 million and $0.3 million for the fiscal years ended 2020, 2019 and 2018, respectively, which is recorded within net sandwich shop sales in the consolidated statements of operations

Contract Liabilities

As described in Note 2, the Company records current and noncurrent contract liabilities for initial franchise fees, gift cards, and loyalty programs. There are no other contract liabilities or contract assets recorded by the Company. The opening and closing balances of the Company’s current and noncurrent contract liabilities from contracts with customers were as follows:

	Current Contract Liability			Noncurrent Contract Liability
	(Thousands)			(Thousands)
Beginning balance as of December 29, 2019	$	(1,594	)	$	(2,054	)
Ending balance as of December 27, 2020		(3,138	)		(1,707	)
Increase (decrease) in contract liability	$	1,544		$	(347)	))

The aggregate value of remaining performance obligations on outstanding contracts was $4.8 million as of December 27, 2020. The overall increase in the liability during the 52 weeks ended December 27, 2020 was a result of purchases of new gift cards and addition of the loyalty programs in 2020 partially offset by gift card redemptions. The Company expects to recognize revenue related to contract liabilities as follows (in thousands), which may vary based upon franchise activity, and gift card and loyalty program redemption patterns:

Years Ending	Amount
2021	$	1,854
2022		1,194
2023		240
2024		202
2025		465
Thereafter		890
Total revenue recognized	$	4,845

For the 52 weeks ended December 27, 2020, the amount of revenue recognized related to the December 29, 2019 liability ending balance was $1.1 million. For the 52 weeks ended December 29, 2019, the amount of revenue recognized related to the January 1, 2018 liability ending balance was $2.2 million. This revenue related to the recognition of gift card redemptions and upfront franchise fees. For the year ended December 27, 2020 and December 29, 2019, the Company did not recognize any revenue from obligations satisfied (or partially satisfied) in prior periods.

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-URI http://asc.fasb.org/topic&trid=49130388

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130551-203045

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130556-203045

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130550-203045

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130558-203045

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

+ Details

Earnings (Loss) Per Share

12 Months Ended

Dec. 27, 2020

Earnings Per Share [Abstract]

Earnings (Loss) Per Share

(4) Earnings (Loss) Per Share

Basic earnings (loss) per common share attributable to common stockholders are calculated using the weighted average number of common shares outstanding for the period. Diluted earnings (loss) per common share attributable to common stockholders is computed by dividing the income allocated to common stockholders by the weighted average number of fully diluted common shares outstanding. In periods of a net loss, no potential common shares are included in diluted shares outstanding as the effect is anti-dilutive. For fiscal years 2020, 2019 and 2018, the Company had a loss per share, therefore, shares were excluded for potential stock option exercises.

The following table summarizes the earnings (loss) per share calculation (in thousands):

	Fiscal Year
	2020			2019			2018
Net loss attributable to Potbelly Corporation	$	(65,391	)	$	(23,992	)	$	(8,878	)
Weighted average common shares outstanding-basic		23,899			23,850			25,173
Plus: Effect of potential stock options exercise		—			—			—
Weighted average common shares outstanding-diluted		23,899			23,850			25,173
Loss per share available to common stockholders- basic	$	(2.74	)	$	(1.01	)	$	(0.35	)
Loss per share available to common stockholders- diluted	$	(2.74	)	$	(1.01	)	$	(0.35	)
Potentially dilutive shares that are considered anti-dilutive:
Shares		2,754			2,334			2,499

Property and Equipment

12 Months Ended

Dec. 27, 2020

Property Plant And Equipment [Abstract]

Property and Equipment

(5) Property and Equipment

Property and equipment, net consisted of the following (in thousands):

	December 27,			December 29,
	2020			2019
Leasehold improvements	$	158,797		$	171,586
Machinery and equipment		46,653			49,943
Furniture and fixtures		33,194			34,325
Computer equipment and software		36,225			38,881
Construction in progress		863			2,615
		275,732			297,350
Less: Accumulated depreciation		(214,539	)		(218,318	)
	$	61,193		$	79,032

Accrued Expenses

12 Months Ended

Dec. 27, 2020

Accrued Liabilities Current [Abstract]

Accrued Expenses

(6) Accrued Expenses

Accrued expenses consisted of the following (in thousands):

	December 27,		December 29,
	2020		2019
Accrued labor and related expenses	$	7,313	$	7,403
Accrued Restructuring		1,489		—
Deferred gift card revenue		1,868		1,415
Accrued occupancy expenses		2,275		2,010
Accrued corporate and shop expenses		3,095		1,859
Accrued utilities		1,421		1,137
Accrued sales and use tax		1,477		2,063
Accrued construction		361		293
Accrued legal and professional fees		90		716
Deferred revenue		1,491		376
Accrued income tax		69		171
Accrued other		2,793		3,126
Total	$	23,742	$	20,569

(a)	The Company incurs expenses associated with exit activity for certain signed lease agreements, which are recognized in general and administrative expenses. Accrued contract termination costs consisted of the following (in thousands):

	December 27,			December 29,
	2020			2019
Accrued contract termination costs—beginning balance	$	—		$	392
Contract termination costs incurred		3,231			3,449
Contract termination costs settled and paid		(3,231	)		(3,841	)
Accrued contract termination costs—ending balance	$	—		$	—

Income Taxes

12 Months Ended

Dec. 27, 2020

Income Tax Disclosure [Abstract]

Income Taxes

(7) Income Taxes

On March 27, 2020, the CARES Act was enacted into law. The CARES Act is a tax and spending package intended to provide economic relief to address the impact of the COVID-19 pandemic. The CARES Act includes several significant business tax provisions that, among other things, would eliminate the taxable income limit for certain NOLs and allow businesses to carry back NOLs arising in 2018, 2019, and 2020 to the five prior tax years, accelerate refunds of previously generated corporate AMT credits, loosen the business interest limitation under section 163(j), and fix the qualified improvement property regulations in the 2017 Tax Cuts and Jobs Act. As a result of the CARES Act, the Company was able to obtain a tax refund of $6.7 million from the carryback of NOLs and a refund of prior AMT credits. The Company received the entire amount of the refund during the fiscal year 2020. The

Company recognized an income tax benefit of $6.7 million during fiscal year 2020 due to the impact of the CARES Act and the finalization of the Company’s 2019 federal tax return.

Income (loss) before income taxes for the Company’s domestic and foreign operations was as follows (in thousands):

	Fiscal Year
	2020			2019			2018
Domestic operations	$	(72,708	)	$	(9,790	)	$	(11,381	)
Foreign operations		—			395			637
Total	$	(72,208	)	$	(9,395	)	$	(10,744	)

Income tax expense (benefit) consisted of the following (in thousands):

	Fiscal Year
	2020			2019		2018
Federal:
Current	$	(6,739	)	$	159	$	(339	)
Deferred		13			9,379		(1,644	)
		(6,726	)		9,538		(1,983	)
State and Local:
Current		185			227		73
Deferred		5			4,425		(305	)
		190			4,652		(232	)
Foreign:
Current		—			—		20
		—			—		20
Income tax expense (benefit)	$	(6,536	)	$	14,190	$	(2,195	)

Income tax expense (benefit) differed from the amounts computed by applying the U.S. federal income tax rates to income (loss) before income taxes as a result of the following (in thousands):

	Fiscal Year
	2020			2019			2018
U.S. federal statutory tax		21.0	%		21.0	%		21.0	%
Computed “expected” tax benefit	$	(15,164	)	$	(1,973	)	$	(2,256	)
Increase (reduction) resulting from:
Valuation allowance		14,265			16,116			-
Rate change impact of net operating loss carryback		(2,592	)		-			-
Minority interest		74			(107	)		(87	)
Permanent differences		99			425			220
State and local income taxes, net of federal income tax effect		(3,338	)		(361	)		(436	)
FICA and other tax credits		(248	)		(504	)		(522	)
Equity compensation		477			577			1,089
Other		(109	)		(106	)		(252	)
Tax rate change		—			123			49
	$	(6,536	)	$	14,190		$	(2,195	)

The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and liabilities reflected in the consolidated balance sheets are presented below (in thousands):

	December 27,			December 29,
	2020			2019
Deferred tax assets:
Net operating loss carryforwards	$	14,364		$	3,721
Accrued liabilities		2,152			848
Deferred revenue		573			423
Stock-based compensation		1,993			2,516
Property and equipment		3,505			4,568
Operating lease liabilities		59,230			62,313
Tax credits and other carryforwards		2,319			1,538
Gross deferred tax assets		84,136			75,927
Valuation allowance		(30,381	)		(16,116	)
Net deferred tax assets		53,755			59,811
Deferred tax liabilities:
Prepaids		(285	)		(492	)
Right-of-use asset for operating leases		(51,637	)		(57,717	)
Intangible assets		(1,249	)		(1,162	)
Smallwares		(482	)		(533	)
Other		(348	)		(134	)
Total deferred tax liabilities		(54,001	)		(60,038	)
Net deferred tax liabilities	$	(246	)	$	(227	)

The Company has recorded deferred tax assets related to federal and state income tax net operating loss (“NOL”) carryforwards of approximately $14.3 million and $3.7 million for the years ended December 27, 2020 and December 29, 2019, respectively. The federal NOL, and a portion of the state NOLs, can be carried forward indefinitely, although certain jurisdictions, including federal and numerous states, limit NOL carryforwards to a percentage of current year taxable income.

The Company regularly assesses the need for a valuation allowance related to its deferred tax assets, which includes consideration of both positive and negative evidence related to the likelihood of realization of such deferred tax assets to determine, based on the weight of the available evidence, whether it is more-likely-than-not that some or all of its deferred tax assets will not be realized. In its assessment, the Company considers recent financial operating results, projected future taxable income, the reversal of existing taxable differences, and tax planning strategies. The Company recorded a full valuation allowance against its net deferred tax assets during the first quarter of 2019, resulting in a non-cash charge to income tax expense of $13.6 million. The Company continued to maintain a valuation allowance against all of its deferred tax assets as of December 27, 2020. The Company did not provide for an income tax benefit on its pre-tax loss for the years ended December 27, 2020 and December 29, 2019. The Company assesses the likelihood of the realization of its deferred tax assets each quarter and the valuation allowance is adjusted accordingly.

As of December 27, 2020, the Company has a valuation allowance related to its deferred tax assets of $30.4 million. As of December 29, 2019, the Company has a valuation allowance related to its deferred tax assets of $16.1 million.

In accordance with its accounting policy, the Company recognizes accrued interest and penalties related to unrecognized tax benefits as a component of income tax expense. As of December 27, 2020 and December 29, 2019, the Company had no interest or penalties accrued. As of December 27, 2020 and December 29, 2019, the Company had no uncertain tax positions.

The tax years prior to 2015 are generally closed for examination by the United States Internal Revenue Service. However, certain of these tax years are open for examination as a result of net operating losses generated in these years and utilized in subsequent years. The Company’s last IRS examination was for the 2014 tax year; no IRS audits are currently ongoing. State statutes are generally open for audit for the 2015 to 2019 tax years.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References + Details

Leases

12 Months Ended

Dec. 27, 2020

Leases [Abstract]

Leases

(8) Leases

As a result of COVID-19, the Company suspended the payment of rent on the majority of its leases in April 2020 and entered into discussions with landlords regarding the restructuring of those leases in light of various contractual and legal defenses. The Company entered into 321 amendments with our respective landlords during the year ended December 27, 2020. Under these agreements, certain rent payments will be abated, deferred or modified without penalty for various periods, generally covering two to four months of rent payments. In April 2020, the Financial Accounting Standards Board issued guidance allowing entities to make a policy election whether to account for lease concessions related to the COVID-19 pandemic as lease modifications. The election applies to any lessor-provided lease concession related to the impact of the COVID-19 pandemic, provided the concession does not result in a substantial increase in the rights of the lessor or in the obligations of the lessee. For the lease concessions we received from certain landlords in the form of rent deferrals and abatements which were not substantial, we have elected to not account for these rent concessions as lease modifications.

The gains recognized upon lease terminations are recorded in impairment, loss on disposal of property and equipment and shop closures. The right-of use assets, liabilities and gains recognized upon termination of lease contracts were as follows:

	Fiscal Year		Fiscal Year
	2020		2019
Leases of terminated		28		11
Lease termination fees	$	2,832	$	3,130
Right-of-use assets derecognized upon lease termination		14,774		6,506
Lease liabilities derecognized upon lease termination		16,103		7,450
Gain recognized upon lease termination	$	1,329	$	944

Operating lease term and discount rate were as follows:

	December 27,			December 29,
	2020			2019
Weighted average remaining lease term (years)	7.82			8.52
Weighted average discount rate		7.88	%		7.95	%

Certain of the Company’s operating lease agreements include variable payments that are passed through by the landlord, such as common area maintenance and real estate taxes, as well as variable payments based on percentage rent for certain of our shops. Pass-through charges and payments based on percentage rent are included within variable lease cost.

The components of lease cost were as follows (in thousands):

-		Fiscal Year		Fiscal Year
	Classification	2020		2019
Operating lease cost	Occupancy and general and administrative expenses	$	45,350	$	45,604
Variable lease cost	Occupancy and general and administrative expenses		11,885		13,692
Total lease cost		$	57,235	$	59,296

Supplemental disclosures of cash flow information relating to leases is as follows (in thousands):

	Fiscal Year			Fiscal Year
	2020			2019
Operating cash flows rent paid for operating lease liabilities	$	35,168		$	47,335
Operating right-of-use assets obtained in exchange for new operating lease liabilities		20,369			15,765
Reduction in operating right-of-use assets due to lease terminations	$	(14,774	)	$	(6,506	)

Maturities of lease liabilities were as follows at December 27, 2020 (in thousands):

	Operating Leases
2021	$	51,156
2022		41,151
2023		36,628
2024		34,144
2025		31,481
Thereafter		110,376
Total lease payments		304,936
Less: imputed interest		(80,465	)
Present value of lease liabilities	$	224,471

Debt and Credit Facilities

12 Months Ended

Dec. 27, 2020

Debt Disclosure [Abstract]

Debt and Credit Facilities

(9) Debt and Credit Facilities

The components of long-term debt were as follows:

	December 27,			December 29,
	2020			2019
Revolving Credit Facility	$	6,286		$	—
Paycheck Protection Program loan		10,000			—
Less: current portion of long-term debt		(333	)		—
Total long-term debt	$	15,953		$	—

Current portion of long-term debt	$	333		$	—

Revolving Credit Facility

On August 7, 2019, the Company entered into a second amended and restated Revolving Credit Facility agreement (the "Credit Agreement") with JPMorgan Chase Bank, N.A. (“JPMorgan”) that expires in July 2022. The Credit Agreement amends and restates that certain amended and restated Revolving Credit Facility agreement, dated as of December 9, 2015, and amended on May 3, 2019 (collectively, the "Prior Credit Agreement") with JPMorgan. The Credit Agreement provides, among other things, for a Revolving Credit Facility in a maximum principal amount $40 million, with possible future increases of up to $20 million under an expansion feature. Borrowings under the credit facility generally bear interest at the Company’s option at either (i) a eurocurrency rate determined by reference to the applicable LIBOR rate plus a margin ranging from 1.25% to 1.75% or (ii) a prime rate as announced by JP Morgan plus a margin ranging from 0.00% to 0.50%. The applicable margin is determined based upon the Company’s consolidated total leverage ratio. On the last day of each calendar quarter, the Company is required to pay a commitment fee of 0.20% per annum in respect of any unused commitments under the credit facility. So long as certain total leverage ratios, EBITDA thresholds and minimum liquidity requirements are met and no default or event of default has occurred or would result, there is no limit on the “restricted payments” (primarily distributions and equity repurchases) that the Company may make, provided that proceeds of the loans under the Credit Agreement may not be used for purposes of making restricted payments.

On March 17, 2020, the Company fully borrowed the available capacity of $39.8 million under the Credit Agreement as a precautionary measure in order to increase its cash position and preserve financial flexibility in light of current uncertainty in the global markets resulting from the COVID-19 pandemic. In accordance with the terms of the Credit Agreement, the proceeds from these borrowings may in the future be used for working capital, general corporate or other permitted purposes.

The Credit Agreement was subsequently amended as of May 15, 2020 (the “Credit Agreement Amendment”) to, among other things (i) change the maturity date from July 31, 2022 to March 31, 2022; (ii) eliminate the $20.0 million expansion feature; (iii) amend the interest rate to the Company’s option at either (a) a eurocurrency rate determined by reference to the applicable LIBOR rate with a 1.00% floor plus a margin of 5.00% or (b) a prime rate as announced by JP Morgan plus 4.00%; (iv) amend the commitment fee to 1.00% per annum in respect of any unused commitments under the credit facility; (v) implement additional restrictions on restricted payments, acquisitions and other indebtedness; and (vi) implement additional financial covenants. Per the terms of the

Credit Agreement Amendment, the Company repaid $15.0 million of its outstanding borrowing at the signing of the Credit Agreement Amendment, and may re-borrow this $15.0 million when its cash balance held by JP Morgan declines below $28.0 million. Lastly, the Company was required to pay a fee of 1% of the outstanding loan balance after the signing of the Credit Agreement Amendment.

On July 17, 2020, the Company entered into Amendment No. 2 (the “Second Amendment”) to the Credit Agreement to, among other things: (i) revise its financial covenants; (ii) decrease the aggregate amount of loan commitment available under the Credit Agreement from $40.0 million to $30.0 million after March 31, 2021 and (iii) decrease the interest rate to the Company’s option at either (a) a eurocurrency rate determined by reference to the applicable LIBOR rate with a 1.00% floor plus a margin of 4.75% or (b) a prime rate as announced by JP Morgan plus 2.25%. Per the terms of the Second Amendment, the Company repaid $14.5 million of its outstanding borrowing at the signing of the Second Amendment, and may reborrow the entire amount available under the credit facility when its cash balance held by JP Morgan declines below $10.0 million in total.

The Second Amendment includes financial covenants that require the Company to (i) maintain periodic minimum liquidity levels through February 28, 2022 ranging from $15.0 million to $30.0 million and (ii) maintain monthly minimum adjusted EBITDA thresholds for specified computation periods through February 28, 2022 ranging from ($18.0) million to $8.3 million.

On August 19, 2020, the Company entered into Amendment No. 3 to the Credit Agreement to permit the Company to incur indebtedness in the form of a loan agreement with Harvest Small Business Finance, LLC in the aggregate amount of $10.0 million pursuant to the PPP under the CARES Act and (ii) revise financial covenants for the impact of the PPP proceeds.

On November 4, 2020, the Company entered into Amendment No. 4 to the Credit Agreement. The Amendment (i) reduced the periodic minimum liquidity level requirement for the Company through February 28, 2022 from a range of $25.0 million to $37.5 million to a range of $23.0 million to $37.5 million and (ii) adjusted the benchmark replacement rate.

As of December 27, 2020, the Company had $6.3 million outstanding under the Credit Agreement. There were no borrowings outstanding as of December 29, 2019. The Company is currently in compliance with all financial debt covenants.

On February 26, 2021, the Company entered into Amendment No. 5 (the “Fifth Amendment”) to the Credit Agreement. The Amendment (i) extends the maturity date from March 31, 2022 to January 31, 2023, (ii) decreases the revolving credit commitment from $40 million to $25 million, (iii) increases the interest rate by 50 basis points with respect to any CBFR Loan, (iv) increases the interest rate by 25 basis points with respect to any Eurodollar Loan, (v) amends the definition of EBITDA to exclude non-cash charges/gains in connection with certain equity interests of the Company, (vi) includes certain borrowing conditions relating to the Company’s Consolidated Cash Balance, (vii) permits the Company to repurchase/redeem its equity interests under certain conditions and (viii) revises the minimum monthly EBITDA and Liquidity thresholds the Company must maintain.

Paycheck Protection Program Loan

On August 10, 2020, PSW, an indirect subsidiary of the Company, entered into a loan agreement with Harvest Small Business Finance, LLC in the aggregate amount of $10.0 million (the “Loan”), pursuant to the PPP under the CARES Act. The Loan was necessary to support the ongoing operations of the Company due to the economic uncertainty resulting from the COVID-19 pandemic and lack of access to alternative sources of liquidity.

The Loan is scheduled to mature five years from the date on which PSW applies for loan forgiveness under the CARES Act, bears interest at a rate of 1% per annum and is subject to the terms and conditions applicable to loans administered by the U.S. Small Business Administration under the CARES Act. The PPP provides that the use of the Loan amount shall be limited to certain qualifying expenses and may be partially or wholly forgiven in accordance with the requirements set forth in the CARES Act. The Company has used all of the PPP proceeds toward qualifying expenses and intends to pursue forgiveness of the Loan amount, but it is not able to determine the likelihood or the amount of forgiveness that will be obtained.

The Company has recorded the amount of the Loan as long-term debt in its consolidated balance sheet as of December 27, 2020 and related interest has been recorded to interest expense on its consolidated statement of operations for the year ended December 27, 2020.

Restructuring

12 Months Ended

Dec. 27, 2020

Restructuring And Related Activities [Abstract]

Restructuring

(10) Restructuring

On November 3, 2020, as part of the Company’s COVID-related cost reduction efforts and to better align the Company’s general and administrative expenses with future strategy, we made the determination to reorganize and restructure the Company’s corporate team. The Company expects that this restructuring plan will result in annual general and administrative expense savings of $3.5 to $4.0 million. This was accomplished through corporate expense optimization, consolidating our shop support services, and through other expense and staff reductions. As a result, we reduced corporate employment levels by approximately 35 employees in

the fourth quarter of 2020. The restructuring charges recognized in the fourth quarter of 2020 consist primarily of one-time termination benefits to employees. The Company substantially completed its planned restructuring actions during 2020, but we will continue to evaluate our cost structure and seek opportunities for further efficiencies and cost savings as part of our ongoing strategy. As such, we may incur additional restructuring related charges or adjustments to previously recorded charges in the future, however, we are unable to estimate the amount of charges at this time.

The accrued restructuring balances as of December 27, 2020 represent expected future cash payments required to satisfy our remaining obligations, which are expected to be paid throughout 2021.

	Total
	(Thousands)
Balance as of December 29, 2019	$	—
Charges incurred		1,667
Payments made		(178	)
Balance as of December 27, 2020	$	1,489

Capital Stock

12 Months Ended

Dec. 27, 2020

Equity [Abstract]

Capital Stock

(11) Capital Stock

As of December 27, 2020 and December 29, 2019, the Company had authorized an aggregate of 210,000 thousand shares of capital stock, of which 200,000 thousand shares were designated as common stock and 10,000 thousand shares were designated as preferred stock. As of December 27, 2020, the Company had issued and outstanding 33,935 thousand and 24,323 thousand shares of common stock, respectively. As of December 29, 2019, the Company had issued and outstanding 33,103 thousand and 23,638 thousand shares of common stock, respectively.

Common Stock

As of December 27, 2020, each share of common stock has the same relative rights and was identical in all respects to each other share of common stock. Each holder of shares of common stock is entitled to one vote for each share held by such holder at all meetings of stockholders.

On May 8, 2018, the Company announced that its Board of Directors authorized a stock repurchase program for up to $65.0 million of its outstanding common stock. The program permits the Company, from time to time, to purchase shares in the open market (including in pre-arranged stock trading plans in accordance with the guidelines specified in Rule 10b5-1 under the Securities and Exchange Act of 1934, as amended) or in privately negotiated transactions. The number of common shares actually repurchased, and the timing and price of repurchases, will depend upon market conditions, SEC requirements and other factors. Purchases may be started or stopped at any time without prior notice depending on market conditions and other factors. The Company did not repurchase any shares of its commons stock during 2020. In light of the COVID-19 pandemic, the Company does not have plans to repurchase any common stock under its stock repurchase program at this time. During the fiscal year 2019, the Company repurchased 648 thousand shares of its common stock for approximately $4.2 million under the stock repurchase program. As of December 27, 2020, the remaining dollar value of authorization under the share repurchase program was $37.9 million, which includes commission. Repurchased shares are included as treasury stock in the consolidated balance sheets and the consolidated statements of equity.

Employee Benefit Plan

12 Months Ended

Dec. 27, 2020

Postemployment Benefits [Abstract]

Employee Benefit Plan

(12) Employee Benefit Plan

The Company sponsors a 401(k) profit sharing plan for all employees who are eligible based upon age and length of service. The Company made matching contributions of $0.2 million, $0.5 million, and $0.4 million for fiscal years 2020, 2019 and 2018, respectively.

Stock-Based Compensation

12 Months Ended

Dec. 27, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation

(13) Stock-Based Compensation

Stock-Based Compensation Granted Under the 2019 Long-Term Incentive Plan

Stock options and restricted stock units are awarded under the 2019 Long-Term Incentive Plan (the “2019 Plan”) to eligible employees and certain non-employee members of the Board of Directors. The 2019 Plan gives broad powers to the Company’s Board of Directors to administer and interpret the 2019 Plan, including the authority to select the individuals to be granted equity awards and rights and to prescribe the particular form and conditions of each equity award to be granted.

On May 16, 2019, the Company’s stockholders approved the 2019 Plan and, in connection therewith, all equity awards made after that date were made under the 2019 Plan. On June 10, 2019, the Company registered 1,200 thousand shares of its common stock reserved for issuance under the 2019 Plan. The Amended and Restated 2013 Long-Term Incentive Plan (the “2013 Plan”) had 626 thousand remaining shares of common stock reserved for issuance, which are available for issuance under the 2019 Plan and no future awards will be made under the 2013 Plan. On June 24, 2020 the 2019 Plan was amended and restated effective to increase the number of shares of common stock authorized for issuance by 900 thousand shares, for a total of 2,100 thousand shares. As of December 27, 2020, there have been 2,908 thousand shares of restricted stock units and performance stock units granted under the 2019 Plan. There were no options or shares of common stock granted in 2020 or 2019 under the 2019 Plan. As of December 27, 2020, there are 2,068 thousand shares reserved for future issuance.

Stock Options

Under the Plans, the number of shares and exercise price of each option are determined by the committee designated by the Company’s Board of Directors. The options granted are generally exercisable within a 10-year period from the date of grant. The company awards options to certain employees including the senior leadership team. Options outstanding expire on various dates through the year 2028. The range of exercise prices for options outstanding as of December 27, 2020 is $7.22 to $20.53 per option, and the options generally vest in one-fourth and one-fifth increments over four and five-year periods, respectively.

A summary of stock option activity is as follows:

Options	Shares (Thousands)			Weighted Average Exercise Price		Aggregate Intrinsic Value (Thousands)		Weighted Average Remaining Term (Years)
Outstanding—December 31, 2017		3,309		$	10.71	$	7,699		4.90
Granted		203			11.27
Exercised		(993	)		8.30
Canceled		(369	)		13.63
Outstanding—December 30, 2018		2,150		$	11.49	$	378		5.13
Granted		—			—
Exercised		(22	)		7.93
Canceled		(354	)		12.45
Outstanding—December 29, 2019		1,774		$	11.34	$	—		4.33
Granted		—			—
Exercised		—			—
Canceled		(541	)		12.84
Outstanding—December 27, 2020		1,233		$	10.68	$	—		2.49
Exercisable—December 27, 2020		1,217		$	10.65	$	—		2.43

There were no stock option grants in 2020 and 2019. The following table reflects the average assumptions utilized in the Black-Scholes option-pricing model to value the options granted for 2018:

	2018
Risk-free interest rate		3.0	%
Expected life (years)		6.25
Expected dividend yield		—
Volatility		35.0	%
Weighted average grant date fair value	$	4.52

The risk-free rate is based on U.S. Treasury rates in effect at the time of the grant with a similar duration of the expected life of the options. The expected life of options granted is derived from the average of the vesting period and the term of the option. The Company has not paid dividends to date (with exception to the one-time dividend paid to stockholders prior to the initial public offering) and does not plan to pay dividends in the near future.

Stock-based compensation related to stock options is measured at the grant date based on the calculated fair value of the award, and is recognized as expense over the requisite employee service period, which is generally the vesting period of the grant with a

corresponding increase to additional paid-in capital. For the years ended December 27, 2020, December 29, 2019 and December 30, 2018, the Company recognized stock-based compensation expense related to stock options of $0.1 million, $0.8 million and $1.4 million, respectively. The Company records stock-based compensation expense within general and administrative expenses in the consolidated statements of operations. As of December 27, 2020, unrecognized stock-based compensation expense related to stock options was $0.1 million, which will be recognized through fiscal year 2022.

Restricted stock units

The Company awards restricted stock units (“RSUs”) to certain employees of the Company and certain non-employee members of its Board of Directors. The Board of Director grants have a vesting schedule of 50% on the first anniversary of the grant date and 50% on the second anniversary of the grant date. The employee grants vest in one-third increments over a three-year period.

A summary of RSU activity is as follows:

RSUs	Number of RSUs (Thousands)			Weighted Average Fair Value per Share
Non-vested as of December 31, 2017		267		$	11.79
Granted		131			12.12
Vested		(121	)		11.92
Canceled		(30	)		11.05
Non-vested as of December 30, 2018		247		$	11.99
Granted		402			6.47
Vested		(135	)		11.94
Canceled		(51	)		8.48
Non-vested as of December 29, 2019		463		$	7.59
Granted		1,604			2.79
Vested		(231	)		2.87
Canceled		(842	)		3.65
Non-vested as of December 27, 2020		994		$	3.35

For the years ended December 27, 2020, December 29, 2019 and December 30, 2018, the Company recognized stock-based compensation expense related to RSUs of $1.5 million, $1.5 million and $1.5 million, respectively. As of December 27, 2020, unrecognized stock-based compensation expense for RSUs was $1.3 million, which will be recognized though fiscal year 2023.

Performance stock units

The Company awards performance share units (“PSUs”) to certain employees. The PSUs have certain vesting conditions based upon the Company’s financial performance or the Company’s stock price.

The Company previously granted PSUs that are subject to service and performance vesting conditions. The PSUs will vest based on the Company’s achievement of certain targets related to adjusted EBITDA and same store sales goals. The quantity of shares that will vest ranges from 0% to 200% of the targeted number of shares. If the defined minimum targets are not met, then no shares will vest. For the year ended December 27, 2020, no expense was recognized related to PSUs with performance vesting conditions. These shares were not presented in the PSU table below given they are not expected to vest.

In 2020, the Company granted PSUs with multiple tranches that are subject to service and market vesting conditions. The fair market value was established using a Monte Carlo simulation model. Participants are entitled to receive a specified number of shares of the Company’s common stock contingent on the Company’s achievement of a stock return on the Company’s common stock. The PSUs may vest during a performance period of five years. Compensation expense for these awards is being amortized over an average expected service period or earlier based on when each tranche’s vesting conditions are met. For the year ended December 27, 2020, the Company recognized stock-based compensation expense for PSUs with market vesting conditions of $0.9 million.

A summary of activity for PSUs with market vesting conditions is as follows:

PSUs	Number of PSUs (Thousands)			Weighted Average Fair Value per Share
Non-vested as of December 29, 2019		—		$	—
Granted		1,475			1.43
Vested		(501	)		4.45
Canceled		(472	)		1.50
Non-vested as of December 27, 2020		502		$	1.38

Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 27, 2020

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Data (Unaudited)

(14) Quarterly Financial Data (Unaudited)

The unaudited quarterly information includes all normal recurring adjustments that the Company considers necessary for the fair presentation of the information shown below. The Company’s quarterly results have been and will continue to be affected by the timing of new shop openings and their associated pre-opening costs. As a result of these and other factors, the financial results for any quarter may not be indicative of the results for any future period.

The following table presents selected unaudited quarterly financial data for periods indicated (in thousands, except per share data):

	Fiscal Year 2020
	March 29			June 28			September 27			December 27
Total revenues	$	87,590		$	56,162		$	72,663		$	74,866
Loss from operations		(16,985	)		(21,887	)		(16,138	)		(16,122	)
Net loss attributable to Potbelly Corporation		(13,336	)		(22,216	)		(13,412	)		(16,427	)
Loss per share attributable to common stockholders-basic		(0.56	)		(0.93	)		(0.56	)		(0.68	)
Loss per share attributable to common stockholders-diluted		(0.56	)		(0.93	)		(0.56	)		(0.68	)

	Fiscal Year 2019
	March 31			June 30			September 29			December 29
Total revenues	$	98,087		$	105,630		$	104,238		$	101,752
Income (loss) from operations		(4,723	)		(1,468	)		(2,143	)		(862	)
Loss attributable to Potbelly Corporation		(18,439	)		(1,866	)		(2,355	)		(1,332	)
Loss per share attributable to common stockholders-basic		(0.76	)		(0.08	)		(0.10	)		(0.06	)
Loss per share attributable to common stockholders-diluted		(0.76	)		(0.08	)		(0.10	)		(0.06	)

Commitments and Contingencies

12 Months Ended

Dec. 27, 2020

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

(15) Commitments and Contingencies

The Company is subject to legal proceedings, claims and liabilities, such as employment-related claims and slip and fall cases, which arise in the ordinary course of business and are generally covered by insurance. The Company accrues for such liabilities when it is probable that future costs will be incurred and such costs can be reasonably estimated. Such accruals are based on developments to date, the Company’s estimates of the outcomes of these matters and its experience in contesting, litigating and settling other similar matters. In the opinion of management, the amount of ultimate liability with respect to those actions should not have a material adverse impact on the Company’s financial position or results of operations and cash flows.

Many of the food products the Company purchases are subject to changes in the price and availability of food commodities, including, among other things, beef, poultry, grains, dairy and produce. The Company works with its suppliers and uses a mix of forward pricing protocols for certain items including agreements with its supplier on fixed prices for deliveries at a time in the future and agreements on a fixed price with its supplier for the duration of those protocols. The Company also utilizes formula pricing protocols under which the prices the Company pays are based on a specified formula related to the prices of the goods, such as spot prices. The Company’s use of any forward pricing arrangements varies substantially from time to time and these arrangements tend to cover relatively short periods (i.e., typically twelve months or less). Such contracts are used in the normal purchases of the Company’s food products and not for speculative purposes, and as such are not required to be evaluated as derivative instruments.

Related Party Transactions

12 Months Ended

Dec. 27, 2020

Related Party Transactions

(16) Related Party Transactions

On May 10, 2020, the Company entered into a Settlement Agreement (the “Settlement Agreement”) with Intrinsic Investment Holdings, LLC, the Vann A. Avedisian Trust U/A 8/29/85, Vann A. Avedisian, KGT Investments, LLC, The Khimji Foundation, Mahmood Khimji, Bryant L. Keil and Neil Luthra (the foregoing, collectively with each of their respective affiliates, the “Vann Group”). In connection with the Settlement Agreement with the Vann Group, the Company issued 130,000 shares of common stock (including 41,311 shares issued to the Vann A. Avedisian Trust U/A 8/29/85, 43,571 shares issued to KGT Investments, LLC and 45,118 shares issued to The Khimji Foundation) to reimburse the Vann Group for its documented out-of-pocket costs, fees and expenses incurred in connection with the Settlement Agreement. The Company recorded expense of $0.4 million within general and administrative expenses related to the issuance of these shares. Based on a report of Schedule 13D filed by the Vann Group on August 17, 2020, the Vann Group beneficially owns 2.69% of the common stock of the Company.

Subsequent Events

12 Months Ended

Dec. 27, 2020

Subsequent Events [Abstract]

Subsequent Events

(17) Subsequent Events

Securities Purchase Agreement

On February 9, 2021, the Company entered into a securities purchase agreement (the “Securities Purchase Agreement”) with accredited Purchasers (the “Purchasers”), pursuant to which the Company agreed to issue and sell to the Purchasers in a private placement an aggregate of (i) 3,249,668 shares (the “Shares”) of the Company’s common stock, par value $0.01 per share (the “Common Stock”) and (ii) warrants (the “Warrants”) to purchase an aggregate of 1,299,861 shares of common stock, for an aggregate purchase price of $15.9 million (the “Offering”). The Warrants will be exercisable at an exercise price of $5.45 per share at any time on or after August 13, 2021 and will and expire five years from the date of issuance. The Warrants will be exercisable by net exercise.

The Offering closed on February 12, 2021. The Company received aggregate gross proceeds of approximately $15.9 million, before deducting placement agent fees and offering expenses of approximately $1 million, and excluding the exercise of any warrants.

Credit Facility

A Fifth Amendment to the Credit Agreement was entered into as of February 26, 2021. See Note 9 for further details.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 27, 2020

Accounting Policies [Abstract]

Business

Basis of Presentation

COVID-19

Principles of Consolidation

(a) Principles of Consolidation

Reporting Period

(b) Reporting Period

Segment Reporting

Use of Estimates

(d) Use of Estimates

Fair Value Measurements

(e) Fair Value Measurements

•

Level 1 — Quoted prices in active markets for identical assets or liabilities.

•

Financial Instruments

(f) Financial Instruments

Cash and Cash Equivalents

(g) Cash and Cash Equivalents

Accounts Receivable, net

(h) Accounts Receivable, net

Accounts receivable, net consists of amounts owed from credit card processors, customers, third-party delivery platforms, vendors and other miscellaneous receivables.

Inventories

(i) Inventories

Property and Equipment

(j) Property and Equipment

Indefinite-Lived Intangible Assets

(k) Indefinite-Lived Intangible Assets

Pre-opening Costs

(l) Pre-opening Costs

Advertising Expenses

(m) Advertising Expenses

Income Taxes

(n) Income Taxes

Stock-Based Compensation

(o) Stock-Based Compensation

Leases

(p) Leases

Revenue Recognition

(q) Revenue Recognition

Franchise Revenue

Gift Card Redemptions / Breakage Revenue

Loyalty Program

Impairment of Long-Lived Assets

(r) Impairment of Long-Lived Assets

Recent Accounting Pronouncements

(s) Recent Accounting Pronouncements

Revenue (Tables)

12 Months Ended

Dec. 27, 2020

Revenue From Contract With Customer [Abstract]

Summary of Current and Noncurrent Contract Liabilities from Contracts with Customers

The opening and closing balances of the Company’s current and noncurrent contract liabilities from contracts with customers were as follows:

	Current Contract Liability			Noncurrent Contract Liability
	(Thousands)			(Thousands)
Beginning balance as of December 29, 2019	$	(1,594	)	$	(2,054	)
Ending balance as of December 27, 2020		(3,138	)		(1,707	)
Increase (decrease) in contract liability	$	1,544		$	(347)	))

Summary of Expected Revenue Recognition Related to Contract Liabilities

The Company expects to recognize revenue related to contract liabilities as follows (in thousands), which may vary based upon franchise activity, and gift card and loyalty program redemption patterns:

Years Ending	Amount
2021	$	1,854
2022		1,194
2023		240
2024		202
2025		465
Thereafter		890
Total revenue recognized	$	4,845

Earnings (Loss) Per Share (Tables)

12 Months Ended

Dec. 27, 2020

Earnings Per Share [Abstract]

Summary of Earnings (Loss) Per Share Calculation

The following table summarizes the earnings (loss) per share calculation (in thousands):

	Fiscal Year
	2020			2019			2018
Net loss attributable to Potbelly Corporation	$	(65,391	)	$	(23,992	)	$	(8,878	)
Weighted average common shares outstanding-basic		23,899			23,850			25,173
Plus: Effect of potential stock options exercise		—			—			—
Weighted average common shares outstanding-diluted		23,899			23,850			25,173
Loss per share available to common stockholders- basic	$	(2.74	)	$	(1.01	)	$	(0.35	)
Loss per share available to common stockholders- diluted	$	(2.74	)	$	(1.01	)	$	(0.35	)
Potentially dilutive shares that are considered anti-dilutive:
Shares		2,754			2,334			2,499

Property and Equipment (Tables)

12 Months Ended

Dec. 27, 2020

Property Plant And Equipment [Abstract]

Components of Property and Equipment, Net

Property and equipment, net consisted of the following (in thousands):

	December 27,			December 29,
	2020			2019
Leasehold improvements	$	158,797		$	171,586
Machinery and equipment		46,653			49,943
Furniture and fixtures		33,194			34,325
Computer equipment and software		36,225			38,881
Construction in progress		863			2,615
		275,732			297,350
Less: Accumulated depreciation		(214,539	)		(218,318	)
	$	61,193		$	79,032

Accrued Expenses (Tables)

12 Months Ended

Dec. 27, 2020

Accrued Liabilities Current [Abstract]

Summary of Accrued Expenses

Accrued expenses consisted of the following (in thousands):

	December 27,		December 29,
	2020		2019
Accrued labor and related expenses	$	7,313	$	7,403
Accrued Restructuring		1,489		—
Deferred gift card revenue		1,868		1,415
Accrued occupancy expenses		2,275		2,010
Accrued corporate and shop expenses		3,095		1,859
Accrued utilities		1,421		1,137
Accrued sales and use tax		1,477		2,063
Accrued construction		361		293
Accrued legal and professional fees		90		716
Deferred revenue		1,491		376
Accrued income tax		69		171
Accrued other		2,793		3,126
Total	$	23,742	$	20,569

The Company incurs expenses associated with exit activity for certain signed lease agreements, which are recognized in general and administrative expenses.

Summary of Accrued Contract Termination Costs

Accrued contract termination costs consisted of the following (in thousands):

	December 27,			December 29,
	2020			2019
Accrued contract termination costs—beginning balance	$	—		$	392
Contract termination costs incurred		3,231			3,449
Contract termination costs settled and paid		(3,231	)		(3,841	)
Accrued contract termination costs—ending balance	$	—		$	—

Income Taxes (Tables)

12 Months Ended

Dec. 27, 2020

Income Tax Disclosure [Abstract]

Schedule of Income (Loss) Before Income Taxes

Income (loss) before income taxes for the Company’s domestic and foreign operations was as follows (in thousands):

	Fiscal Year
	2020			2019			2018
Domestic operations	$	(72,708	)	$	(9,790	)	$	(11,381	)
Foreign operations		—			395			637
Total	$	(72,208	)	$	(9,395	)	$	(10,744	)

Components of Income Tax Expense (Benefit)

Income tax expense (benefit) consisted of the following (in thousands):

	Fiscal Year
	2020			2019		2018
Federal:
Current	$	(6,739	)	$	159	$	(339	)
Deferred		13			9,379		(1,644	)
		(6,726	)		9,538		(1,983	)
State and Local:
Current		185			227		73
Deferred		5			4,425		(305	)
		190			4,652		(232	)
Foreign:
Current		—			—		20
		—			—		20
Income tax expense (benefit)	$	(6,536	)	$	14,190	$	(2,195	)

Reconciliation of Differences Between Federal Statutory and Effective Income (Loss) Tax Rate

Income tax expense (benefit) differed from the amounts computed by applying the U.S. federal income tax rates to income (loss) before income taxes as a result of the following (in thousands):

	Fiscal Year
	2020			2019			2018
U.S. federal statutory tax		21.0	%		21.0	%		21.0	%
Computed “expected” tax benefit	$	(15,164	)	$	(1,973	)	$	(2,256	)
Increase (reduction) resulting from:
Valuation allowance		14,265			16,116			-
Rate change impact of net operating loss carryback		(2,592	)		-			-
Minority interest		74			(107	)		(87	)
Permanent differences		99			425			220
State and local income taxes, net of federal income tax effect		(3,338	)		(361	)		(436	)
FICA and other tax credits		(248	)		(504	)		(522	)
Equity compensation		477			577			1,089
Other		(109	)		(106	)		(252	)
Tax rate change		—			123			49
	$	(6,536	)	$	14,190		$	(2,195	)

Schedule of Deferred Tax Assets and Liabilities

	December 27,			December 29,
	2020			2019
Deferred tax assets:
Net operating loss carryforwards	$	14,364		$	3,721
Accrued liabilities		2,152			848
Deferred revenue		573			423
Stock-based compensation		1,993			2,516
Property and equipment		3,505			4,568
Operating lease liabilities		59,230			62,313
Tax credits and other carryforwards		2,319			1,538
Gross deferred tax assets		84,136			75,927
Valuation allowance		(30,381	)		(16,116	)
Net deferred tax assets		53,755			59,811
Deferred tax liabilities:
Prepaids		(285	)		(492	)
Right-of-use asset for operating leases		(51,637	)		(57,717	)
Intangible assets		(1,249	)		(1,162	)
Smallwares		(482	)		(533	)
Other		(348	)		(134	)
Total deferred tax liabilities		(54,001	)		(60,038	)
Net deferred tax liabilities	$	(246	)	$	(227	)

Leases (Tables)

12 Months Ended

Dec. 27, 2020

Leases [Abstract]

Gains Recognized Upon Termination of Lease Contracts

The right-of use assets, liabilities and gains recognized upon termination of lease contracts were as follows:

	Fiscal Year		Fiscal Year
	2020		2019
Leases of terminated		28		11
Lease termination fees	$	2,832	$	3,130
Right-of-use assets derecognized upon lease termination		14,774		6,506
Lease liabilities derecognized upon lease termination		16,103		7,450
Gain recognized upon lease termination	$	1,329	$	944

Operating Lease Term and Discount Rate

Operating lease term and discount rate were as follows:

	December 27,			December 29,
	2020			2019
Weighted average remaining lease term (years)	7.82			8.52
Weighted average discount rate		7.88	%		7.95	%

Components of Lease Cost

The components of lease cost were as follows (in thousands):

Supplemental Disclosures of Cash Flow Information Related to Leases

Supplemental disclosures of cash flow information relating to leases is as follows (in thousands):

	Fiscal Year			Fiscal Year
	2020			2019
Operating cash flows rent paid for operating lease liabilities	$	35,168		$	47,335
Operating right-of-use assets obtained in exchange for new operating lease liabilities		20,369			15,765
Reduction in operating right-of-use assets due to lease terminations	$	(14,774	)	$	(6,506	)

Maturities of Lease Liabilities

Maturities of lease liabilities were as follows at December 27, 2020 (in thousands):

	Operating Leases
2021	$	51,156
2022		41,151
2023		36,628
2024		34,144
2025		31,481
Thereafter		110,376
Total lease payments		304,936
Less: imputed interest		(80,465	)
Present value of lease liabilities	$	224,471

Debt and Credit Facilities (Tables)

12 Months Ended

Dec. 27, 2020

Debt Disclosure [Abstract]

Component of Long-term Debt

The components of long-term debt were as follows:

	December 27,			December 29,
	2020			2019
Revolving Credit Facility	$	6,286		$	—
Paycheck Protection Program loan		10,000			—
Less: current portion of long-term debt		(333	)		—
Total long-term debt	$	15,953		$	—

Current portion of long-term debt	$	333		$	—

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Paragraph 1
-Subparagraph (SX 210.5-02.22)
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+ Details

Restructuring (Tables)

12 Months Ended

Dec. 27, 2020

Restructuring And Related Activities [Abstract]

Schedule Future Cash Payments Required to Satisfy Our Remaining Obligations

The accrued restructuring balances as of December 27, 2020 represent expected future cash payments required to satisfy our remaining obligations, which are expected to be paid throughout 2021.

	Total
	(Thousands)
Balance as of December 29, 2019	$	—
Charges incurred		1,667
Payments made		(178	)
Balance as of December 27, 2020	$	1,489

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 27, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Stock Options Activity Under Plans and Agreement

A summary of stock option activity is as follows:

Options	Shares (Thousands)			Weighted Average Exercise Price		Aggregate Intrinsic Value (Thousands)		Weighted Average Remaining Term (Years)
Outstanding—December 31, 2017		3,309		$	10.71	$	7,699		4.90
Granted		203			11.27
Exercised		(993	)		8.30
Canceled		(369	)		13.63
Outstanding—December 30, 2018		2,150		$	11.49	$	378		5.13
Granted		—			—
Exercised		(22	)		7.93
Canceled		(354	)		12.45
Outstanding—December 29, 2019		1,774		$	11.34	$	—		4.33
Granted		—			—
Exercised		—			—
Canceled		(541	)		12.84
Outstanding—December 27, 2020		1,233		$	10.68	$	—		2.49
Exercisable—December 27, 2020		1,217		$	10.65	$	—		2.43

Schedule of Average Assumptions to Value Options

There were no stock option grants in 2020 and 2019. The following table reflects the average assumptions utilized in the Black-Scholes option-pricing model to value the options granted for 2018:

	2018
Risk-free interest rate		3.0	%
Expected life (years)		6.25
Expected dividend yield		—
Volatility		35.0	%
Weighted average grant date fair value	$	4.52

Summary of RSU Activity

A summary of RSU activity is as follows:

RSUs	Number of RSUs (Thousands)			Weighted Average Fair Value per Share
Non-vested as of December 31, 2017		267		$	11.79
Granted		131			12.12
Vested		(121	)		11.92
Canceled		(30	)		11.05
Non-vested as of December 30, 2018		247		$	11.99
Granted		402			6.47
Vested		(135	)		11.94
Canceled		(51	)		8.48
Non-vested as of December 29, 2019		463		$	7.59
Granted		1,604			2.79
Vested		(231	)		2.87
Canceled		(842	)		3.65
Non-vested as of December 27, 2020		994		$	3.35

Summary of PSU Activity

A summary of activity for PSUs with market vesting conditions is as follows:

PSUs	Number of PSUs (Thousands)			Weighted Average Fair Value per Share
Non-vested as of December 29, 2019		—		$	—
Granted		1,475			1.43
Vested		(501	)		4.45
Canceled		(472	)		1.50
Non-vested as of December 27, 2020		502		$	1.38

Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 27, 2020

Quarterly Financial Information Disclosure [Abstract]

Summary of Unaudited Quarterly Financial Data

The following table presents selected unaudited quarterly financial data for periods indicated (in thousands, except per share data):

	Fiscal Year 2020
	March 29			June 28			September 27			December 27
Total revenues	$	87,590		$	56,162		$	72,663		$	74,866
Loss from operations		(16,985	)		(21,887	)		(16,138	)		(16,122	)
Net loss attributable to Potbelly Corporation		(13,336	)		(22,216	)		(13,412	)		(16,427	)
Loss per share attributable to common stockholders-basic		(0.56	)		(0.93	)		(0.56	)		(0.68	)
Loss per share attributable to common stockholders-diluted		(0.56	)		(0.93	)		(0.56	)		(0.68	)

	Fiscal Year 2019
	March 31			June 30			September 29			December 29
Total revenues	$	98,087		$	105,630		$	104,238		$	101,752
Income (loss) from operations		(4,723	)		(1,468	)		(2,143	)		(862	)
Loss attributable to Potbelly Corporation		(18,439	)		(1,866	)		(2,355	)		(1,332	)
Loss per share attributable to common stockholders-basic		(0.76	)		(0.08	)		(0.10	)		(0.06	)
Loss per share attributable to common stockholders-diluted		(0.76	)		(0.08	)		(0.10	)		(0.06	)

Organization and Other Matters - Additional Information (Detail) $ in Thousands	1 Months Ended	12 Months Ended
	Jul. 17, 2020 USD ($)	Dec. 27, 2020 USD ($) Shop	Dec. 29, 2019 USD ($)	Dec. 30, 2018 USD ($)	Aug. 10, 2020 USD ($)	Mar. 17, 2020 USD ($)	Dec. 31, 2017 USD ($)
Nature Of Business And Basis Of Presentation [Line Items]
Number of shops franchisees operate \| Shop		46
Income tax expense (benefit)		$ (6,536)	$ 14,190	$ (2,195)
Line of credit facility amount borrowed	$ 10,000
Line of credit facility amount borrowed		55,000
Cash and cash equivalents		11,126	$ 18,806	$ 19,775			$ 25,530
Revolving Credit Facility [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Line of credit facility amount borrowed	$ 14,500
COVID 19 [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Impairment charge		10,300
Income tax expense (benefit)		6,700
CARES Act Of 2020 [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Line of credit facility amount borrowed		33,500
CARES Act Of 2020 [Member] \| Revolving Credit Facility [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Line of credit facility amount borrowed						$ 39,800
Cash and cash equivalents		$ 44,600
CARES Act Of 2020 [Member] \| Harvest Small Business Finance [Member] \| Paycheck Protection Program Loan [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Loan amount					$ 10,000
Minimum [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Number of shops Potbelly Corporation owns or operates \| Shop		400

Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 27, 2020 USD ($) Subsidiary JointVenture Segment	Dec. 29, 2019 USD ($)	Dec. 30, 2018 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of wholly owned subsidiaries \| Subsidiary	7
Number of joint ventures \| JointVenture	7
Number of operating segments \| Segment	1
Number of reportable segments \| Segment	1
Recognized impairment for intangible assets	$ 0	$ 0	$ 0
Advertising expenses	1,000,000.0	4,100,000	4,300,000
impairment of long lived assets	10,300,000	2,600,000	$ 13,400,000
ASU 2016-02 (Topic 842) [Member]
Summary Of Significant Accounting Policies [Line Items]
Operating Lease, Impairment Loss	$ 700,000
ASU 2016-13 (Topic 326) [Member]
Summary Of Significant Accounting Policies [Line Items]
Reduction in accumulated deficit		$ 5,000
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Ownership interest rate	51.00%
Minimum [Member] \| Computer Software [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful life	3 years
Minimum [Member] \| Furniture and Fixtures [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful life	3 years
Minimum [Member] \| Computer Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful life	3 years
Minimum [Member] \| Machinery and Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful life	3 years
Minimum [Member] \| Leasehold Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful life	10 years
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Ownership interest rate	80.00%
Maximum [Member] \| Computer Software [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful life	5 years
Maximum [Member] \| Furniture and Fixtures [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful life	5 years
Maximum [Member] \| Computer Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful life	5 years
Maximum [Member] \| Machinery and Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful life	5 years
Maximum [Member] \| Leasehold Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated useful life	15 years

Revenue - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 27, 2020	Sep. 27, 2020	Jun. 28, 2020	Mar. 29, 2020	Dec. 29, 2019	Sep. 29, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 27, 2020	Dec. 29, 2019	Dec. 30, 2018
Disaggregation Of Revenue [Line Items]
Amount of revenue recognized	$ 74,866	$ 72,663	$ 56,162	$ 87,590	$ 101,752	$ 104,238	$ 105,630	$ 98,087	$ 291,281	$ 409,707	$ 422,638
Revenue recognized related to prior periods									200	200	$ 300
Aggregate value of remaining performance obligation on outstanding contracts	$ 4,845								4,845
Revenue recognized related to prior periods									0	0
December 30, 2019 Liability Ending Balance [Member]
Disaggregation Of Revenue [Line Items]
Amount of revenue recognized									1,100	2,200
Point in Time Sales [Member]
Disaggregation Of Revenue [Line Items]
Amount of revenue recognized									290,700	408,800
Over Time Sales [Member]
Disaggregation Of Revenue [Line Items]
Amount of revenue recognized									$ 600	$ 900

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

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+ Details

Revenue - Summary of Current and Noncurrent Contract Liabilities from Contracts with Customers (Detail) $ in Thousands	12 Months Ended
	Dec. 27, 2020 USD ($)
Revenue From Contract With Customer [Abstract]
Beginning balance of current contract liability	$ (1,594)
Ending balance of current contract liability	(3,138)
Increase (decrease) in contract liability	1,544
Beginning balance of noncurrent contract liability	(2,054)
Ending balance of noncurrent contract liability	(1,707)
Increase (decrease) in contract liability	$ (347)

Revenue - Summary of Expected Revenue Recognition Related to Contract Liabilities (Detail1) $ in Thousands	Dec. 27, 2020 USD ($)
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, remaining performance obligations	$ 4,845
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, remaining performance obligations	$ 1,854
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2022-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, remaining performance obligations	$ 1,194
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2023-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, remaining performance obligations	$ 240
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2024-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, remaining performance obligations	$ 202
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2025-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, remaining performance obligations	$ 465
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2026-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, remaining performance obligations	$ 890
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year

Revenue - Summary of Expected Revenue Recognition Related to Contract Liabilities (Detail) $ in Thousands	Dec. 27, 2020 USD ($)
Revenue From Contract With Customer [Abstract]
Aggregate value of remaining performance obligation on outstanding contracts	$ 4,845

Earnings (Loss) Per Share - Additional Information (Detail) - shares	12 Months Ended
	Dec. 27, 2020	Dec. 29, 2019	Dec. 30, 2018
Earnings (Loss) Per Share [Line Items]
Potential common shares included in diluted shares outstanding	2,754	2,334	2,499
Common Share Options [Member]
Earnings (Loss) Per Share [Line Items]
Potential common shares included in diluted shares outstanding	0

Earnings (Loss) Per Share - Summary of Earnings (Loss) Per Share Calculation (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 27, 2020	Sep. 27, 2020	Jun. 28, 2020	Mar. 29, 2020	Dec. 29, 2019	Sep. 29, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 27, 2020	Dec. 29, 2019	Dec. 30, 2018
Earnings Per Share [Abstract]
Net loss attributable to Potbelly Corporation	$ (16,427)	$ (13,412)	$ (22,216)	$ (13,336)	$ (1,332)	$ (2,355)	$ (1,866)	$ (18,439)	$ (65,391)	$ (23,992)	$ (8,878)
Weighted average common shares outstanding-basic									23,899	23,850	25,173
Weighted average common shares outstanding-diluted									23,899	23,850	25,173
Loss per share available to common stockholders-basic	$ (0.68)	$ (0.56)	$ (0.93)	$ (0.56)	$ (0.06)	$ (0.10)	$ (0.08)	$ (0.76)	$ (2.74)	$ (1.01)	$ (0.35)
Loss per share available to common stockholders-diluted	$ (0.68)	$ (0.56)	$ (0.93)	$ (0.56)	$ (0.06)	$ (0.10)	$ (0.08)	$ (0.76)	$ (2.74)	$ (1.01)	$ (0.35)
Potentially dilutive shares that are considered anti-dilutive									2,754	2,334	2,499

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

Property and Equipment - Components of Property and Equipment (Detail) - USD ($) $ in Thousands	Dec. 27, 2020	Dec. 29, 2019
Property Plant And Equipment [Abstract]
Leasehold improvements	$ 158,797	$ 171,586
Machinery and equipment	46,653	49,943
Furniture and fixtures	33,194	34,325
Computer equipment and software	36,225	38,881
Construction in progress	863	2,615
Property and equipment, gross	275,732	297,350
Less: Accumulated depreciation	(214,539)	(218,318)
Property and equipment, net	$ 61,193	$ 79,032

Property and Equipment - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 27, 2020	Dec. 29, 2019	Dec. 30, 2018
Property Plant And Equipment [Abstract]
Losses on disposal of property and equipment	$ 0.5	$ 0.4	$ 0.1

Accrued Expenses - Summary of Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 27, 2020	Dec. 29, 2019
Accrued Liabilities And Other Liabilities [Abstract]
Accrued labor and related expenses	$ 7,313	$ 7,403
Accrued Restructuring	1,489
Deferred gift card revenue	1,868	1,415
Accrued occupancy expenses	2,275	2,010
Accrued corporate and shop expenses	3,095	1,859
Accrued utilities	1,421	1,137
Accrued sales and use tax	1,477	2,063
Accrued construction	361	293
Accrued legal and professional fees	90	716
Deferred revenue	1,491	376
Accrued income tax	69	171
Accrued other	2,793	3,126
Total	$ 23,742	$ 20,569

Accrued Expenses - Summary of Accrued Contract Termination Costs (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2020	Dec. 29, 2019
Accrued Liabilities And Other Liabilities [Abstract]
Accrued contract termination costs—beginning balance		$ 392
Contract termination costs incurred	$ 3,231	3,449
Contract termination costs settled and paid	$ (3,231)	$ (3,841)

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 27, 2020	Dec. 29, 2019	Dec. 30, 2018	Mar. 27, 2020	Mar. 31, 2019
Income Tax [Line Items]
Income tax expense (benefit)	$ (6,536,000)	$ 14,190,000	$ (2,195,000)
Net operating loss carryforwards	14,364,000	3,721,000
Deferred tax assets, valuation allowance	30,381,000	16,116,000			$ 13,600,000
Unrecognized tax benefits, income tax penalties and interest accrued	0	0
Uncertain tax positions	0	0
Valuation Allowance Tax Credit Carryforward [Member]
Income Tax [Line Items]
Deferred tax assets, valuation allowance	30,400,000	16,100,000
Federal and State Income Tax [Member]
Income Tax [Line Items]
Net operating loss carryforwards	14,300,000	$ 3,700,000
COVID 19 [Member]
Income Tax [Line Items]
Tax refund from net operating loss carryback				$ 6,700,000
Income tax expense (benefit)	$ 6,700,000

Income Taxes - Schedule of Income (Loss) Before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2020	Dec. 29, 2019	Dec. 30, 2018
Income Tax Disclosure [Abstract]
Domestic operations	$ (72,708)	$ (9,790)	$ (11,381)
Foreign operations		395	637
Loss before income taxes	$ (72,208)	$ (9,395)	$ (10,744)

- Definition

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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Income Taxes - Components of Income Tax Expense (Benefit) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2020	Dec. 29, 2019	Dec. 30, 2018
Income Tax Disclosure [Abstract]
Federal, Current	$ (6,739)	$ 159	$ (339)
Federal, Deferred	13	9,379	(1,644)
Federal, Total	(6,726)	9,538	(1,983)
State and Local, Current	185	227	73
State and Local, Deferred	5	4,425	(305)
State and Local, Total	190	4,652	(232)
Foreign, Current			20
Foreign, Total			20
Income tax expense (benefit)	$ (6,536)	$ 14,190	$ (2,195)

Income Taxes - Reconciliation of Differences Between Federal Statutory and Effective Income (Loss) Tax Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2020	Dec. 29, 2019	Dec. 30, 2018
Income Tax Disclosure [Abstract]
U.S. federal statutory tax	21.00%	21.00%	21.00%
Computed “expected” tax benefit	$ (15,164)	$ (1,973)	$ (2,256)
Valuation allowance	14,265	16,116
Rate change impact of net operating loss carryback	(2,592)
Minority interest	74	(107)	(87)
Permanent differences	99	425	220
State and local income taxes, net of federal income tax effect	(3,338)	(361)	(436)
FICA and other tax credits	(248)	(504)	(522)
Equity compensation	477	577	1,089
Other	(109)	(106)	(252)
Tax rate change		123	49
Income tax expense (benefit)	$ (6,536)	$ 14,190	$ (2,195)

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 27, 2020	Dec. 29, 2019	Mar. 31, 2019
Deferred tax assets:
Net operating loss carryforwards	$ 14,364	$ 3,721
Accrued liabilities	2,152	848
Deferred revenue	573	423
Stock-based compensation	1,993	2,516
Property and equipment	3,505	4,568
Operating lease liabilities	59,230	62,313
Tax credits and other carryforwards	2,319	1,538
Gross deferred tax assets	84,136	75,927
Valuation allowance	(30,381)	(16,116)	$ (13,600)
Net deferred tax assets	53,755	59,811
Deferred tax liabilities:
Prepaids	(285)	(492)
Right-of-use asset for operating leases	(51,637)	(57,717)
Intangible assets	(1,249)	(1,162)
Smallwares	(482)	(533)
Other	(348)	(134)
Total deferred tax liabilities	(54,001)	(60,038)
Net deferred tax liabilities	$ 246	$ 227

Leases - Gains Recognized Upon Termination of Lease Contracts (Detail) $ in Thousands	12 Months Ended
	Dec. 27, 2020 USD ($) Termination	Dec. 29, 2019 USD ($) Termination
Leases [Abstract]
Leases of terminated \| Termination	28	11
Lease termination fees	$ 2,832	$ 3,130
Right-of-use assets derecognized upon lease termination	14,774	6,506
Lease liabilities derecognized upon lease termination	16,103	7,450
Gain recognized upon lease termination	$ 1,329	$ 944

Leases - Operating Lease Term and Discount Rate (Detail)	Dec. 27, 2020	Dec. 29, 2019
Leases [Abstract]
Weighted average remaining lease term (years)	7 years 9 months 25 days	8 years 6 months 7 days
Weighted average discount rate	7.88%	7.95%

Leases - Components of Lease Cost (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2020	Dec. 29, 2019
Lessee Lease Description [Line Items]
Total lease cost	$ 57,235	$ 59,296
Occupancy and General and Administrative Expenses [Member]
Lessee Lease Description [Line Items]
Operating lease cost	45,350	45,604
Occupancy Expenses [Member]
Lessee Lease Description [Line Items]
Variable lease cost	$ 11,885	$ 13,692

Leases - Supplemental Disclosures of Cash Flow Information Related to Leases (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2020	Dec. 29, 2019
Leases [Abstract]
Operating cash flows rent paid for operating lease liabilities	$ 35,168	$ 47,335
Operating right-of-use assets obtained in exchange for new operating lease liabilities	20,369	15,765
Reduction in operating right-of-use assets due to lease terminations	$ (14,774)	$ (6,506)

Leases - Maturities of Lease Liabilities (Detail) $ in Thousands	Dec. 27, 2020 USD ($)
Operating Leases
2021	$ 51,156
2022	41,151
2023	36,628
2024	34,144
2025	31,481
Thereafter	110,376
Total lease payments	304,936
Less: imputed interest	(80,465)
Present value of lease liabilities	$ 224,471

Debt and Credit Facilities - Component of Long-term Debt (Detail) $ in Thousands	Dec. 27, 2020 USD ($)
Debt Instrument [Line Items]
Less: current portion of long-term debt	$ (333)
Long-term debt, net of current portion	15,953
Current portion of long-term debt	333
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long-term debt	6,286
Paycheck Protection Program Loan [Member]
Debt Instrument [Line Items]
Long-term debt	$ 10,000

Debt and Credit Facilities - Additional Information (Detail) - USD ($)					1 Months Ended		12 Months Ended
	Feb. 26, 2021	Nov. 04, 2020	Aug. 10, 2020	Aug. 07, 2019	Jul. 17, 2020	May 15, 2020	Dec. 27, 2020	Dec. 29, 2019	Mar. 17, 2020
Debt Instrument [Line Items]
Line of credit facility amount borrowed							$ 55,000,000
Line of credit facility amount borrowed					$ 10,000,000.0
February 28, 2022 [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Minimum Liquidity Level							15,000,000.0
Minimum Building Adjusted EBITDA							(18,000,000.0)
February 28, 2022 [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Minimum Liquidity Level							30,000,000.0
Minimum Building Adjusted EBITDA							8,300,000
Credit Agreement Amendment [Member]
Debt Instrument [Line Items]
Upfront fee payable						1.00%
CARES Act Of 2020 [Member]
Debt Instrument [Line Items]
Line of credit facility amount borrowed							33,500,000
CARES Act Of 2020 [Member] \| Minimum [Member] \| Fourth Credit Agreement Amendment
Debt Instrument [Line Items]
Debt instrumnet estimated periodic Minimum Liquidity		$ 23,000.0						$ 25,000.0
CARES Act Of 2020 [Member] \| Minimum [Member] \| Fifth Credit Agreement Amendment [Member]
Debt Instrument [Line Items]
Debt Instrument, maturity date	Mar. 31, 2022
CARES Act Of 2020 [Member] \| Maximum [Member] \| Fourth Credit Agreement Amendment
Debt Instrument [Line Items]
Debt instrumnet estimated periodic Minimum Liquidity		$ 37,500						37,500
CARES Act Of 2020 [Member] \| Maximum [Member] \| Fifth Credit Agreement Amendment [Member]
Debt Instrument [Line Items]
Debt Instrument, maturity date	Jan. 31, 2023
London Interbank Offered Rate (LIBOR) [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Credit facility agreement, interest rate				1.75%	4.75%
London Interbank Offered Rate (LIBOR) [Member] \| Maximum [Member] \| Credit Agreement Amendment [Member]
Debt Instrument [Line Items]
Credit facility agreement, interest rate						5.00%
London Interbank Offered Rate (LIBOR) [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Credit facility agreement, interest rate				1.25%	1.00%
London Interbank Offered Rate (LIBOR) [Member] \| Minimum [Member] \| Credit Agreement Amendment [Member]
Debt Instrument [Line Items]
Credit facility agreement, interest rate						1.00%
Prime Rate [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Credit facility agreement, interest rate					2.25%
JPMorgan Chase Bank, N.A. [Member]
Debt Instrument [Line Items]
Commitment fee, percentage				0.20%
JPMorgan Chase Bank, N.A. [Member] \| Credit Agreement Amendment [Member]
Debt Instrument [Line Items]
Commitment fee, percentage						1.00%
Debt instrument, elimination expansion						$ 20,000,000.0
Credit facility agreement, amount outstanding						15,000,000.0
Line of credit facility amount borrowed						$ 28,000,000.0
JPMorgan Chase Bank, N.A. [Member] \| Maximum [Member] \| Credit Agreement Amendment [Member]
Debt Instrument [Line Items]
Credit facility agreement, Maturity date						Mar. 31, 2022
JPMorgan Chase Bank, N.A. [Member] \| Minimum [Member] \| Credit Agreement Amendment [Member]
Debt Instrument [Line Items]
Credit facility agreement, Maturity date						Jul. 31, 2022
JPMorgan Chase Bank, N.A. [Member] \| Prime Rate [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Credit facility agreement, interest rate				0.50%
JPMorgan Chase Bank, N.A. [Member] \| Prime Rate [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Credit facility agreement, interest rate				0.00%
JPMorgan Chase Bank, N.A. [Member] \| Prime Rate [Member] \| Minimum [Member] \| Credit Agreement Amendment [Member]
Debt Instrument [Line Items]
Credit facility agreement, interest rate						4.00%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility agreement, maximum principal amount					$ 40,000,000.0
Credit facility agreement, future increases					30,000,000.0
Line of credit facility amount borrowed					$ 14,500,000
Revolving Credit Facility [Member] \| CARES Act Of 2020 [Member]
Debt Instrument [Line Items]
Line of credit facility amount borrowed									$ 39,800,000
Revolving Credit Facility [Member] \| JPMorgan Chase Bank, N.A. [Member]
Debt Instrument [Line Items]
Credit facility agreement, expiration date				Jul. 31, 2022
Credit facility agreement, maximum principal amount				$ 40,000,000
Revolving Credit Facility [Member] \| JPMorgan Chase Bank, N.A. [Member] \| Credit Agreement Amendment [Member]
Debt Instrument [Line Items]
Line of credit facility amount borrowed						$ 15,000,000.0
Revolving Credit Facility [Member] \| JPMorgan Chase Bank, N.A. [Member] \| COVID 19 [Member]
Debt Instrument [Line Items]
Line of credit facility amount borrowed									$ 39,800,000
Revolving Credit Facility [Member] \| JPMorgan Chase Bank, N.A. [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Credit facility agreement, future increases				$ 20,000,000
Paycheck Protection Program Loan [Member] \| Harvest Small Business Finance [Member] \| Commercial Loan [Member] \| Potbelly Sandwich Works, LLC [Member]
Debt Instrument [Line Items]
Loan amount			$ 10,000,000.0
Paycheck Protection Program Loan [Member] \| CARES Act Of 2020 [Member] \| Potbelly Sandwich Works, LLC [Member]
Debt Instrument [Line Items]
Credit facility agreement, interest rate			1.00%
Loan maturity period			5 years
Paycheck Protection Program Loan [Member] \| CARES Act Of 2020 [Member] \| Harvest Small Business Finance [Member] \| Third Credit Agreement Amendment [Member]
Debt Instrument [Line Items]
Line of credit facility amount borrowed							10,000,000.0
Credit facility agreement, amount outstanding							$ 6,300,000	$ 0
Revolving Credit Commitment [Member] \| CARES Act Of 2020 [Member] \| Minimum [Member] \| Fifth Credit Agreement Amendment [Member]
Debt Instrument [Line Items]
Credit facility agreement, future increases	$ 40,000,000
Revolving Credit Commitment [Member] \| CARES Act Of 2020 [Member] \| Maximum [Member] \| Fifth Credit Agreement Amendment [Member]
Debt Instrument [Line Items]
Credit facility agreement, future increases	$ 25,000,000
CBFR Loan [Member] \| CARES Act Of 2020 [Member] \| Fifth Credit Agreement Amendment [Member]
Debt Instrument [Line Items]
Debt instrument, increase in interest rate	50.00%
Eurodollar Loan [Member] \| CARES Act Of 2020 [Member] \| Fifth Credit Agreement Amendment [Member]
Debt Instrument [Line Items]
Debt instrument, increase in interest rate	25.00%

Restructuring - Additional Information (Detail)	1 Months Ended	3 Months Ended	12 Months Ended
Restructuring - Additional Information (Detail)	Nov. 03, 2020 USD ($)	Dec. 27, 2020 Employee	Dec. 27, 2020 USD ($)	Dec. 29, 2019 USD ($)	Dec. 30, 2018 USD ($)
Number of employee reduce \| Employee		35
General and administrative expenses			$ 35,009,000	$ 44,831,000	$ 44,826,000
Minimum [Member]
General and administrative expenses	$ 3,500,000
Maximum [Member]
General and administrative expenses	$ 4,000,000.0

Restructuring - Schedule Future Cash Payments Required to Satisfy Our Remaining Obligations (Detail) $ in Thousands	12 Months Ended
	Dec. 27, 2020 USD ($)
Restructuring Reserve Roll Forward
Charges incurred	$ 1,667
Payments made	(178)
Ending balance	$ 1,489

Capital Stock - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 27, 2020	Dec. 29, 2019	Dec. 30, 2018	May 08, 2018
Capital Unit [Line Items]
Capital stock, authorized	210,000,000	210,000,000
Common stock, authorized	200,000,000	200,000,000
Preferred stock, authorized	10,000,000	10,000,000
Common stock, issued	33,935,000	33,103,000
Common stock, outstanding	24,323,000	23,638,000
Stock repurchase program, authorized amount				$ 65,000,000.0
Common stock repurchased value		$ 4,217,000	$ 22,916,000
Remaining dollar value of authorization under the share repurchase program	$ 37,900,000
Stock Repurchase Program [Member]
Capital Unit [Line Items]
Common stock shares repurchased	0	648,000
Common stock repurchased value	$ 0	$ 4,200,000

Employee Benefit Plan - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 27, 2020	Dec. 29, 2019	Dec. 30, 2018
Defined Benefit Plans And Other Postretirement Benefit Plans Disclosures [Abstract]
Contributions made to profit sharing plan	$ 0.2	$ 0.5	$ 0.4

Stock-Based Compensation - Additional Information (Detail) - USD ($)		12 Months Ended
	Jun. 14, 2020	Dec. 27, 2020	Dec. 29, 2019	Dec. 30, 2018	May 16, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 2,515,000	$ 2,335,000	$ 2,882,000
Stock Options [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercisable period from the date of grant		10 years
Accounting Standards Update 2016-09
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for issuance					626,000
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock units issued		1,604,000	402,000	131,000
Stock-based compensation expense		$ 1,500,000	$ 1,500,000	$ 1,500,000
Unrecognized stock compensation expense		$ 1,300,000
Unrecognized stock compensation expense, recognition period		2023
Restricted Stock Units (RSUs) [Member] \| Non-Employee Board Of Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options vesting period		3 years
Vesting description		The employee grants vest in one-third increments over a three-year period
Restricted Stock Units (RSUs) [Member] \| First Anniversary [Member] \| Non-Employee Board Of Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		50.00%
Restricted Stock Units (RSUs) [Member] \| Second Anniversary [Member] \| Non-Employee Board Of Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		50.00%
Common Share Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 100,000	$ 800,000	$ 1,400,000
Unrecognized stock compensation expense		$ 100,000
Unrecognized stock compensation expense, recognition period		2022
Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock units issued		1,475,000
Options vesting period		5 years
Performance Stock Units [Member] \| Market Vesting Conditions [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 900,000
Performance Stock Units [Member] \| Performance Vesting Conditions [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 0
Performance Stock Units [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage of targeted number of shares		200.00%
Performance Stock Units [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage of targeted number of shares		0.00%
Non-Employee Board Of Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting description		The PSUs will vest based on the Company’s achievement of certain targets related to adjusted EBITDA and same store sales goals. The quantity of shares that will vest ranges from 0% to 200% of the targeted number of shares. If the defined minimum targets are not met, then no shares will vest.
2019 Long Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for issuance		2,068,000
Options granted		0	0
Exercise price of options outstanding, lower limit		$ 7.22
Exercise price of options outstanding, higher limit		$ 20.53
2019 Long Term Incentive Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options issued and outstanding, last expiration date		Dec. 31, 2028
Options vesting period		5 years
2019 Long Term Incentive Plan [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options vesting period		4 years
2019 Long Term Incentive Plan [Member] \| Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for issuance					1,200,000
Issuance of common stock			0
2019 Long Term Incentive Plan [Member] \| Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock units issued		2,908,000
2019 Plan Amanded and Restated [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of additional shares authorized	2,100,000
2019 Plan Amanded and Restated [Member] \| Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of additional shares authorized	900,000

Stock-Based Compensation - Summary of Stock Options Activity Under Plans and Agreement (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 27, 2020	Dec. 29, 2019	Dec. 30, 2018	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options outstanding shares, beginning balance	1,774	2,150	3,309
Options, granted			203
Exercise of stock warrants, shares		(22)	(993)
Options, canceled	(541)	(354)	(369)
Options outstanding shares, ending balance	1,233	1,774	2,150	3,309
Options outstanding shares, exercisable	1,217
Options outstanding weighted average exercise price, beginning balance	$ 11.34	$ 11.49	$ 10.71
Options, weighted average exercise price, granted			11.27
Options, weighted average exercise price, exercised		7.93	8.30
Options, weighted average exercise price, canceled	12.84	12.45	13.63
Options outstanding weighted average exercise price, ending balance	10.68	$ 11.34	$ 11.49	$ 10.71
Options outstanding weighted average exercise price, exercisable	$ 10.65
Options outstanding aggregate intrinsic value			$ 378	$ 7,699
Option outstanding weighted average remaining term	2 years 5 months 26 days	4 years 3 months 29 days	5 years 1 month 17 days	4 years 10 months 24 days
Options exercisable weighted average remaining term	2 years 5 months 4 days

Stock-Based Compensation - Schedule of Average Assumptions to Value Options (Detail)	12 Months Ended
	Dec. 30, 2018 $ / shares
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions And Methodology [Abstract]
Risk-free interest rate	3.00%
Expected life (years)	6 years 3 months
Expected dividend yield	0.00%
Volatility	35.00%
Weighted average grant date fair value	$ 4.52

Stock-Based Compensation - Summary of RSU Activity (Detail) - Restricted Stock Units (RSUs) [Member] - $ / shares shares in Thousands	12 Months Ended
	Dec. 27, 2020	Dec. 29, 2019	Dec. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of RSUs, Non-vested, beginning balance	463	247	267
Stock units issued	1,604	402	131
Number of RSUs, Vested	(231)	(135)	(121)
Number of RSUs, Canceled	(842)	(51)	(30)
Number of RSUs, Non-vested, ending balance \| shares	994	463	247
Weighted Average Fair Value per Share, Non-vested, beginning balance	$ 7.59	$ 11.99	$ 11.79
Weighted Average Fair Value per Share, Granted	2.79	6.47	12.12
Weighted Average Fair Value per Share, Vested	2.87	11.94	11.92
Weighted Average Fair Value per Share, Canceled	3.65	8.48	11.05
Weighted Average Fair Value per Share, Non-vested, ending balance	$ 3.35	$ 7.59	$ 11.99

Stock-Based Compensation - Summary of PSU Activity (Detail) - Performance Stock Units [Member] shares in Thousands	12 Months Ended
	Dec. 27, 2020 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares, Granted \| shares	1,475
Number of RSUs, Vested \| shares	(501)
Number of RSUs, Canceled \| shares	(472)
Number of RSUs, Non-vested, ending balance \| shares \| shares	502
Weighted Average Fair Value per Share, Granted \| $ / shares	$ 1.43
Weighted Average Fair Value per Share, Vested \| $ / shares	4.45
Weighted Average Fair Value per Share, Canceled \| $ / shares	1.50
Weighted Average Fair Value per Share, Non-vested, ending balance \| $ / shares	$ 1.38

Quarterly Financial Data (Unaudited) - Summary of Unaudited Quarterly Financial Data (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 27, 2020	Sep. 27, 2020	Jun. 28, 2020	Mar. 29, 2020	Dec. 29, 2019	Sep. 29, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 27, 2020	Dec. 29, 2019	Dec. 30, 2018
Quarterly Financial Information Disclosure [Abstract]
Amount of revenue recognized	$ 74,866	$ 72,663	$ 56,162	$ 87,590	$ 101,752	$ 104,238	$ 105,630	$ 98,087	$ 291,281	$ 409,707	$ 422,638
Income (Loss) from operations	(16,122)	(16,138)	(21,887)	(16,985)	(862)	(2,143)	(1,468)	(4,723)	(71,132)	(9,196)	(10,602)
Net loss attributable to Potbelly Corporation	$ (16,427)	$ (13,412)	$ (22,216)	$ (13,336)	$ (1,332)	$ (2,355)	$ (1,866)	$ (18,439)	$ (65,391)	$ (23,992)	$ (8,878)
Loss per share available to common stockholders-basic	$ (0.68)	$ (0.56)	$ (0.93)	$ (0.56)	$ (0.06)	$ (0.10)	$ (0.08)	$ (0.76)	$ (2.74)	$ (1.01)	$ (0.35)
Loss per share available to common stockholders-diluted	$ (0.68)	$ (0.56)	$ (0.93)	$ (0.56)	$ (0.06)	$ (0.10)	$ (0.08)	$ (0.76)	$ (2.74)	$ (1.01)	$ (0.35)

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Millions		12 Months Ended
	Aug. 17, 2020	Dec. 27, 2020	May 10, 2020
Related Party Transaction [Line Items]
Shares issued to related parties			130,000
Expense related to issuance of shares		$ 0.4
Vann A. Avedisian Trust [Member]
Related Party Transaction [Line Items]
Shares issued to related parties			41,311
KGT Investments [Member]
Related Party Transaction [Line Items]
Shares issued to related parties			43,571
The Khimji Foundation [Member]
Related Party Transaction [Line Items]
Shares issued to related parties			45,118
The Vann Group [Member]
Related Party Transaction [Line Items]
Ownership percentage related party	2.69%

Subsequent Events - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	Feb. 12, 2021	Feb. 09, 2021	Dec. 27, 2020	Dec. 29, 2019
Subsequent Event [Line Items]
Common stock, par value			$ 0.01	$ 0.01
Subsequent Event [Member] \| Securities Purchase Agreement [Member]
Subsequent Event [Line Items]
Issuance of common stock		3,249,668
Common stock, par value		$ 0.01
Proceeds From Securities Purchase Agreement	$ 15.9
Placement Agent Fees	$ 1.0
Subsequent Event [Member] \| Securities Purchase Agreement [Member] \| Warrant [Member]
Subsequent Event [Line Items]
Issuance of common stock		1,299,861
Stock Issued During Period, Value, New Issues		$ 15.9
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 5.45