Potbelly (PBPB) 10-Q 6 May 21 2021 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 28, 2021	Apr. 25, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 28, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	PBPB
Security Exchange Name	NASDAQ
Entity Registrant Name	Potbelly Corporation
Entity Central Index Key	0001195734
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-26
Entity Filer Category	Non-accelerated Filer
Entity Shell Company	false
Entity Bankruptcy Proceedings, Reporting Current	true
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		27,966,488
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 325
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 Quarterly Report	true
Document Transition Report	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 28, 2021	Dec. 27, 2020
Current assets
Cash and cash equivalents	$ 11,507	$ 11,126
Accounts receivable, net of allowances of $11 and $47 as of March 28, 2021 and December 27, 2020, respectively	4,636	4,354
Inventories	2,683	2,989
Prepaid expenses and other current assets	4,516	4,839
Total current assets	23,342	23,308
Property and equipment, net	55,670	61,193
Right-of-use assets for operating leases	181,165	189,141
Indefinite-lived intangible assets	3,404	3,404
Goodwill	2,222	2,222
Deferred expenses, net and other assets	4,215	4,089
Total assets	270,018	283,357
Current liabilities
Accounts payable	6,499	6,206
Accrued expenses	25,574	23,742
Short-term operating lease liabilities	32,098	35,325
Current portion of long-term debt	833	333
Total current liabilities	65,004	65,606
Long-term debt, net of current portion	11,953	15,953
Long-term operating lease liabilities	181,705	189,146
Other long-term liabilities	5,066	7,157
Total liabilities	263,728	277,862
Commitments and contingencies (Note 10)
Equity
Common stock, $0.01 par value—authorized 200,000 shares; outstanding 27,636 and 24,323 shares as of March 28, 2021 and December 27, 2020, respectively	372	339
Warrants	2,566
Additional paid-in-capital	450,708	438,174
Treasury stock, held at cost, 9,612 and 9,612 shares as of March 28, 2021, and December 27, 2020, respectively	(113,266)	(113,266)
Accumulated deficit	(333,949)	(319,477)
Total stockholders’ equity	6,431	5,770
Non-controlling interest	(141)	(275)
Total equity	6,290	5,495
Total liabilities and equity	$ 270,018	$ 283,357

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 28, 2021	Dec. 27, 2020
Statement Of Financial Position [Abstract]
Allowances on accounts receivable	$ 11	$ 47
Common stock, par value	$ 0.01	$ 0.01
Common stock, authorized	200,000,000	200,000,000
Common stock, outstanding	27,636,000	24,323,000
Treasury stock, shares	9,612,000	9,612,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2021	Mar. 29, 2020
Revenues
Total revenues	$ 78,063	$ 87,590
Sandwich shop operating expenses
Labor and related expenses	28,614	30,397
Occupancy expenses	13,599	15,028
Other operating expenses	13,335	12,765
Advertising	460	441
General and administrative expenses	7,423	9,834
Depreciation expense	4,174	5,456
Pre-opening costs		64
Impairment, loss on disposal of property and equipment and shop closures	3,122	6,416
Total expenses	92,196	104,575
Loss from operations	(14,133)	(16,958)
Interest expense, net	288	74
Loss before income taxes	(14,421)	(17,059)
Income tax expense (benefit)	53	(3,709)
Net loss	(14,474)	(13,350)
Net loss attributable to non-controlling interest	(2)	(14)
Net loss attributable to Potbelly Corporation	$ (14,472)	$ (13,336)
Net loss per common share attributable to common stockholders:
Basic	$ (0.56)	$ (0.56)
Diluted	$ (0.56)	$ (0.56)
Weighted average shares outstanding:
Basic	25,944	23,646
Diluted	25,944	23,646
Product [Member]
Revenues
Total revenues	$ 77,501	$ 86,961
Sandwich shop operating expenses
Cost of goods sold, excluding depreciation	21,469	24,174
Franchise Royalties And Fees [Member]
Revenues
Total revenues	$ 562	$ 629

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Equity (Unaudited) - USD ($)	Total	Cumulative Effect, Period of Adoption, Adjustment [Member]Revision of Prior Period, Adjustment [Member]	Common Stock [Member]	Treasury Stock [Member]	Warrants [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. 29, 2019	$ 69,169,000		$ 331,000	$ (112,680,000)		$ 435,278,000	$ (254,081,000)		$ 321,000
Beginning balance, common shares at Dec. 29, 2019			23,638,000
Cumulative impact (ASU 2016-13 (Topic 326) [Member]) at Dec. 29, 2019		$ (5,000)						$ (5,000)
Net loss	(13,350,000)						(13,336,000)		(14,000)
Shares issued under equity compensation plan, shares			68,000
Treasury shares used for stock-based plans	(71,000)			(71,000)
Treasury shares used for stock-based plans, shares			(22,000)
Distributions to non-controlling interest	(172,000)								(172,000)
Contributions from non-controlling interest	143,000								143,000
Stock-based compensation expense	490,000					490,000
Ending balance at Mar. 29, 2020	56,204,000		$ 331,000	(112,751,000)		435,768,000	(267,422,000)		278,000
Ending balance, common shares at Mar. 29, 2020			23,684,000
Beginning balance at Dec. 27, 2020	$ 5,495,000		$ 339,000	(113,266,000)		438,174,000	(319,477,000)		(275,000)
Beginning balance, common shares at Dec. 27, 2020	24,323,000		24,323,000
Cumulative impact at Dec. 27, 2020	$ (319,477,000)
Net loss	(14,474,000)						(14,472,000)		(2,000)
Shares issued under equity compensation plans			$ 1,000			(1,000)
Shares issued under equity compensation plan, shares			63,000
Issuance of common shares and warrants, net of fees	14,940,000		$ 32,000		$ 2,566,000	12,342,000
Issuance of common shares and warrants, net of fees, shares			3,250,000
Contributions from non-controlling interest	136,000								136,000
Stock-based compensation expense	193,000					193,000
Ending balance at Mar. 28, 2021	$ 6,290,000		$ 372,000	$ (113,266,000)	$ 2,566,000	$ 450,708,000	$ (333,949,000)		$ (141,000)
Ending balance, common shares at Mar. 28, 2021	27,636,000		27,636,000

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Equity (Unaudited) (Parenthetical) $ in Thousands	3 Months Ended
	Mar. 29, 2020USD ($)
ASU 2016-13 (Topic 326) [Member]
Cumulative impact tax	$ 2

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2021	Mar. 29, 2020
Cash flows from operating activities:
Net loss	$ (14,474)	$ (13,350)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation expense	4,174	5,456
Noncash lease expense	6,287	7,295
Deferred income tax	5	5
Stock-based compensation expense	193	490
Asset impairment, store closure and disposal of property and equipment	2,741	6,050
Other operating activities	85	20
Changes in operating assets and liabilities:
Accounts receivable, net	(282)	1,620
Inventories	306	228
Prepaid expenses and other assets	(12)	(3,252)
Accounts payable	228	(767)
Operating lease liabilities	(8,991)	(7,467)
Accrued expenses and other liabilities	40	(4,144)
Net cash (used in) provided by operating activities:	(9,700)	(7,816)
Cash flows from investing activities:
Purchases of property and equipment	(1,300)	(4,860)
Net cash used in investing activities:	(1,300)	(4,860)
Cash flows from financing activities:
Borrowings under credit facility	8,000	39,786
Repayments under credit facility	(11,500)
Payment of debt issuance costs	(195)
Proceeds from issuance of common shares and warrants, net of fees	14,940
Employee taxes on certain stock-based payment arrangements		(71)
Distributions to non-controlling interest		(172)
Contributions from non-controlling interest	136	143
Net cash provided by (used in) financing activities:	11,381	39,686
Net increase (decrease) in cash and cash equivalents	381	27,010
Cash and cash equivalents at beginning of period	11,126	18,806
Cash and cash equivalents at end of period	11,507	45,816
Supplemental cash flow information:
Income taxes paid	10	9
Interest paid	238	25
Supplemental non-cash investing and financing activities:
Unpaid liability for purchases of property and equipment	$ 421	$ 1,091

Organization and Other Matters

Organization and Other Matters	3 Months Ended
	Mar. 28, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization and Other Matters	(1) Organization and Other Matters Business Potbelly Corporation (the “Company”, “Potbelly”, “we”, “us” or “our”), through its wholly owned subsidiaries, owns and operates 399 company-owned shops in the United States. Additionally, Potbelly franchisees operate 45 shops in the United States. Basis of Presentation The unaudited condensed consolidated financial statements and notes herein should be read in conjunction with the audited consolidated financial statements of Potbelly Corporation and its subsidiaries and the notes thereto included in our Annual Report on Form 10-K for the year ended December 27, 2020. The unaudited condensed consolidated financial statements included herein have been prepared by us without audit, pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (the “SEC”) regarding interim financial reporting. Certain information and footnote disclosures normally included in financial statements prepared in accordance with generally accepted accounting principles in the United States of America (“U.S. GAAP”) have been condensed or omitted pursuant to the SEC rules and regulations. In the opinion of management, all adjustments, which are of a normal and recurring nature (except as otherwise noted), that are necessary to present fairly our balance sheet as of March 28, 2021 and December 27, 2020, our statement of operations for the 13 weeks ended March 28, 2021 and March 29, 2020, the statement of equity for the 13 weeks ended March 28, 2021 and March 29, 2020, and our statement of cash flows for the 13 weeks ended March 28, 2021 and March 29, 2020 have been included. The condensed consolidated statements of operations for the interim periods presented herein are not necessarily indicative of the results to be expected for the full year. Beginning with the third quarter of 2020, shop closure and lease termination expenses are being presented within impairment, loss on disposal of property and equipment and shop closures in our condensed 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. We do not have any components of other comprehensive income recorded within our consolidated financial statements and therefore, does not separately present a statement of comprehensive income in our condensed 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. 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. While the pandemic continues to have an impact on our business, the distribution of COVID-19 vaccines and a decline in positive cases and hospitalizations has resulted in a gradual improvement in our sales during the first quarter of 2021. Nearly all of our shops have reopened their dining rooms, many with continued 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 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, we cannot determine the ultimate impact that the COVID-19 pandemic will have on our consolidated financial condition, liquidity, and future results of operations, and therefore any prediction as to the ultimate impact on our consolidated financial condition, liquidity, and future results of operations is uncertain. P rinciples of Consolidation The unaudited condensed 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 (“PSW”); seven of PSW’s wholly owned subsidiaries and PSW’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. Potbelly has ownership interests ranging from 51-80% in these consolidated joint ventures. Fiscal Year We use a 52/53-week fiscal year that ends on the last Sunday of the calendar period. Approximately every five or six years a 53rd week is added. Fiscal year 2021 and 2020 both consist of 52 weeks. The fiscal quarters ended March 28, 2021 and March 29, 2020 each consisted of 13 weeks. Use of Estimates The preparation of financial statements in conformity with 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. Recent Accounting Pronouncements On December 28, 2020, we adopted Accounting Standard Update No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging— Contracts in Entity’s Own Equity (Subtopic 815-40)

Revenue

Revenue	3 Months Ended
	Mar. 28, 2021
Revenue From Contract With Customer [Abstract]
Revenue	(2) Revenue We primarily earn 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. We have other revenue generating activities outlined below. Franchise Revenue We earn an initial franchise fee, a franchise development agreement fee and ongoing royalty fees under our 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. We record 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 us 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 We sell gift cards to customers, record the sale as a contract liability and recognize 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 us 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. We recognized gift card breakage income of $0.1 million and $0.1 million for the 13 weeks ended March 28, 2021, and March 29, 2020, respectively, which is recorded within net sandwich shop sales in our condensed consolidated statements of operations. Loyalty Program During the second quarter of 2020, we 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 in addition to any active promotions, and the customer will earn a free entrée after earning 1,000 points. We defer 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, we recognize revenue for the redeemed product and reduces deferred revenue. For the 13 weeks ended March 28, 2021 revenue recognized from all revenue sources on point in time sales was $77.5 million, and revenue recognized from sales over time was $0.1 million. For the 13 weeks ended March 29, 2020, revenue recognized from all revenue sources on point in time sales was $87.5 million, and revenue recognized from sales over time was $0.1 million. Contract Liabilities As described above, we record current and noncurrent contract liabilities for upfront franchise fees, gift cards and the loyalty program. There are no other contract liabilities or contract assets recorded by us. The opening and closing balances of our 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 27, 2020 $ (3,138 ) $ (1,707 ) Ending balance as of March 28, 2021 (2,846 ) (1,634 ) Decrease in contract liability $ (292 ) $ (73 ) The aggregate value of remaining performance obligations on outstanding contracts was $4.5 million as of March 28, 2021. We expect to recognize revenue related to contract liabilities as follows (in thousands), which may vary based upon franchise activity as well as gift card redemption patterns: Years Ending Amount 2021 $ 1,500 2022 1,313 2023 216 2024 183 2025 331 Thereafter 937 Total revenue recognized $ 4,480 For the 13 weeks ended March 28, 2021, the amount of revenue recognized related to the December 27, 2020 liability ending balance was $0.6 million. For the 13 weeks ended March 29, 2020, the amount of revenue recognized related to the December 31, 2019 liability ending balance was $0.5 million. This revenue related to the recognition of gift card redemptions and upfront franchise fees. For the 13 weeks ended March 28, 2021 and March 29, 2020, we did not recognize any revenue from obligations satisfied (or partially satisfied) in prior periods.

Fair Value Measurement

Fair Value Measurement	3 Months Ended
	Mar. 28, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurement	(3) Fair Value Measurement The carrying amounts of cash and cash equivalents, accounts receivable, accounts payable and all other current liabilities approximate fair values due to the short maturities of these balances. We assess potential impairments to our long-lived assets, which includes property and equipment and lease right-of-use assets, on a quarterly basis or whenever events or circumstances indicate that the carrying amount of an asset may not be recoverable. Shop-level assets and right-of-use assets are grouped at the individual shop-level for the purpose of the impairment assessment. Recoverability of an asset group is measured by a comparison of the carrying amount of an asset group to its estimated undiscounted future cash flows expected to be generated by the asset group. If the carrying amount of the asset group exceeds its estimated undiscounted future cash flows, an impairment charge is recognized as the amount by which the carrying amount of the asset group exceeds the fair value of the asset group. The fair value of the shop assets is determined using the discounted future cash flow method of anticipated cash flows through the shop’s lease-end date using fair value measurement inputs classified as Level 3. The fair value of right-of-use assets is estimated using market comparative information for similar properties. Level 3 inputs are derived from valuation techniques in which one or more significant inputs or significant value drivers are unobservable. After performing a periodic review of our shops during the 13 weeks ended March 28, 2021, it was determined that indicators of impairment were present for certain shops as a result of continued underperformance. We performed an impairment analysis related to these shops and recorded an impairment charge of $148 thousand for the 13 weeks ended March 28, 2021. T he 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. The book value of the long-term debt under the Credit Agreement, subsequently amended most recently as of February 26, 2021 and further discussed in Note 7, is considered to approximate its fair value as of March 28, 2020 as the interest rates are considered in line with current market rates. Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis Assets recognized or disclosed at fair value on the consolidated financial statements on a nonrecurring basis include items such as leasehold improvements, property and equipment, operating lease assets, goodwill, and other intangible assets. These assets are measured at fair value if determined to be impaired. During the first quarter of 2021, we amended the lease for our corporate Support Center office in Chicago to relocate to a different office space within the same building. As a result of this relocation, the leasehold improvements of the original office space were disposed, resulting in a loss on disposal of $2.5 million based on the remaining net book value of those assets.

Loss Per Share

Loss Per Share	3 Months Ended
	Mar. 28, 2021
Earnings Per Share [Abstract]
Loss Per Share	(4) Loss Per Share Basic and diluted income per common share attributable to common stockholders are calculated using the weighted average number of common shares outstanding for the period. Diluted income 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 the 13 weeks ended March 28, 2021, we had a loss per share, and therefore potentially dilutive shares were excluded from the calculation. The following table summarizes the loss per share calculation: For the 13 Weeks Ended March 28, March 29, 2021 2020 Net loss attributable to Potbelly Corporation $ (14,472 ) $ (13,336 ) Weighted average common shares outstanding-basic 25,944 23,646 Plus: Effect of potential stock options exercise — — Weighted average common shares outstanding-diluted 25,944 23,646 Loss per share available to common stockholders-basic $ (0.56 ) $ (0.56 ) Loss per share available to common stockholders-diluted $ (0.56 ) $ (0.56 ) Potentially dilutive shares that are considered anti-dilutive: Common share options 2,544 2,294

Income Taxes

Income Taxes	3 Months Ended
	Mar. 28, 2021
Income Tax Disclosure [Abstract]
Income Taxes	(5) Income Taxes The interim tax provision is determined using an estimated annual effective tax rate and is adjusted for discrete taxable events that occur during the quarter. We regularly assess the need for a valuation allowance related to our 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 our deferred tax assets will not be realized. In our assessment, we consider recent financial operating results, projected future taxable income, the reversal of existing taxable differences, and tax planning strategies. We recorded a full valuation allowance against our net deferred tax assets during the first quarter of 2019, resulting in a non-cash charge to income tax expense of $13.6 million. We continue to maintain a valuation allowance against all of our deferred tax assets as of March 28, 2021. We did not provide for an income tax benefit on our pre-tax loss for the 13 weeks ended March 28, 2021 and March 29, 2020. We assess the likelihood of the realization of our deferred tax assets each quarter and the valuation allowance is adjusted accordingly. 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, we estimated that we will be able to obtain a tax refund of $6.7 million from the carryback of NOLs and a refund of prior AMT credits. We received the entire amount of the refund during fiscal year 2020. We recognized $3.7 million of this income tax benefit during the first quarter of 2020.

Leases

Leases	3 Months Ended
	Mar. 28, 2021
Leases [Abstract]
Leases	(6) Leases We determine if a contract contains a lease at inception. We lease retail shops, warehouse and office space under operating leases. For leases with renewal periods at our option, we determine the expected lease period based on whether the renewal of any options are reasonably assured at the inception of the lease. Operating lease assets and liabilities are recognized at the lease commencement date. Operating lease liabilities represent the present value of lease payments not yet paid. Operating lease assets represent our right to use an underlying asset and are based upon the operating lease liabilities adjusted for prepayments or accrued lease payments, initial direct costs, lease incentives, and impairment of operating lease assets. To determine the present value of lease payments not yet paid, we estimate incremental secured borrowing rates corresponding to the maturities of the leases. We estimate this rate based on prevailing financial market conditions, comparable company and credit analysis, and management judgment. We recognize expense for these leases on a straight-line basis over the lease term. Additionally, tenant incentives used to fund leasehold improvements are recognized when earned and reduce our right-of-use asset related to the lease. These are amortized through the right-of-use asset as reductions of expense over the lease term. Beginning in fiscal year 2020, as a result of COVID-19, we held discussions with landlords regarding restructuring of our leases in light of various contractual and legal defenses and have subsequently entered into a total of 339 amendments with our respective landlords as of March 28, 2021. Under these amendments, certain rent payments have been abated, deferred or modified without penalty for various periods, generally covering two to four months of rent payments. During the 13 weeks ended March 28, 2021, we received concessions from certain landlords in the form of rent deferrals and abatements which were not substantial, and we have elected to not account for these rent concessions as lease modifications. During the 13 weeks ended March 28, 2021, we terminated 2 leases. We incurred $0.2 million in lease termination fees related to these leases for the 13 weeks ended March 28, 2021. Upon termination of leases during the 13 weeks ended March 28, 2021, we derecognized ROU assets of $0.6 million and lease liabilities of $0.7 million that resulted in a net gain of $0.1 million that is recorded in impairment, loss on disposal of property and equipment and shop closures. During the first quarter of 2021, we amended the lease for our corporate Support Center office in Chicago to relocate to a different office space within the same building. We accounted for this amendment as a lease modification which resulted in a decrease in the related right-of-use asset and lease liability of $2.7 million. Operating lease term and discount rate were as follows: March 28, March 29, 2021 2020 Weighted average remaining lease term (years) 7.65 8.33 Weighted average discount rate 7.83 % 7.90 % Certain of our 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: 13 weeks ended March 28, March 29, Classification 2021 2020 Operating lease cost Occupancy and General and administrative expenses 10,411 11,770 Variable lease cost Occupancy 3,239 3,322 Total lease cost $ 13,650 $ 15,092 Supplemental disclosures of cash flow information related to leases were as follows: 13 weeks ended March 28, March 29, 2021 2020 Operating cash flows rent paid for operating lease liabilities 12,914 11,979 Operating right-of-use assets obtained in exchange for new operating lease liabilities 1,718 5,534 Reduction in operating right-of-use assets due to lease terminations and modifications 3,294 1,439 As of March 28, 2021, we had no real estate leases entered into that had not yet commenced. Maturities of lease liabilities were as follows as of March 28, 2021: Operating Leases Remainder of 2021 36,613 2022 39,353 2023 37,229 2024 34,706 2025 31,823 2026 28,224 Thereafter 82,198 Total lease payments 290,146 Less: imputed interest (76,343 ) Present value of lease liabilities $ 213,803

Debt and Credit Facilities

Debt and Credit Facilities	3 Months Ended
	Mar. 28, 2021
Debt Disclosure [Abstract]
Debt and Credit Facilities	(7) Debt and Credit Facilities The components of long-term debt were as follows: March 28, December 27, 2021 2020 Revolving credit facility $ 2,786 $ 6,286 Paycheck Protection Program loan 10,000 10,000 Less: current portion of long-term debt (833 ) (333 ) Total long-term debt $ 11,953 $ 15,953 Current portion of debt $ 833 $ 333 Revolving credit facility On August 7, 2019, we 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 As disclosed in our Annual Report on Form 10-K for the fiscal year ended December 27, 2020, we drew on the credit facility to increase our cash position and preserve financial flexibility in light of the uncertainty resulting from the COVID-19 pandemic, and we amended the Credit Agreement throughout fiscal year 2020. Most recently, we entered into Amendment No. 5 (the “Fifth Amendment”) to the Credit Agreement on February 26, 2021. As a result of the Amendment (i) the maturity date was extended from March 31, 2022 to January 31, 2023, (ii) the revolving credit commitment decreased from $40 million to $25 million, (iii) the interest rate margin with respect to any Commercial Bank Floating Rate Loan increased to 2.75%, (iv) the interest rate margin with respect to any Eurodollar Loan increased to 5.00%, (v) the definition of EBITDA was amended to exclude non-cash charges/gains in connection with certain equity interests of the Company, (vi) certain borrowing conditions relating to the Company’s Consolidated Cash Balance were instituted, (vii) the Company is permitted to repurchase/redeem its equity interests under certain conditions and (viii) the minimum monthly EBITDA and Liquidity thresholds the Company must maintain were revised. As of March 28, 2021, we had $2.8 million outstanding under the Credit Agreement. As of March 29, 2020, we had $39.8 million outstanding under the Credit Agreement. We are currently in compliance with all financial debt covenants. 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 our ongoing operations 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. We have used all of the PPP proceeds toward qualifying expenses and intend to pursue forgiveness of the Loan amount, but we are not able to determine the likelihood or the amount of forgiveness that will be obtained. We have recorded the amount of the Loan as long-term debt in our condensed consolidated balance sheet as of March 28, 2021 and related interest has been recorded to interest expense in our condensed consolidated statement of operations for the 13 weeks ended March 28, 2021.

Restructuring

Restructuring	3 Months Ended
	Mar. 28, 2021
Restructuring And Related Activities [Abstract]
Restructuring	(8) Restructuring On November 3, 2020, as part of our COVID-related cost reduction efforts and to better align our general and administrative expenses with future strategy, we made the determination to reorganize and restructure our corporate team. We expect 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. We substantially completed our 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 March 28, 2021 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 27, 2020 $ 1,489 Charges incurred — Payments made (478 ) Balance as of March 28, 2021 $ 1,011

Capital Stock

Capital Stock	3 Months Ended
	Mar. 28, 2021
Equity [Abstract]
Capital Stock	(9) Capital Stock On May 8, 2018, we announced that our Board of Directors authorized a stock repurchase program for up to $65.0 million of our outstanding common stock. The program permits us, 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. For the 13 weeks ended March 28, 2021, we did not repurchase any shares of its common stock. In light of the COVID-19 pandemic, we do not have plans to repurchase any common stock under our stock repurchase program at this time. On February 9, 2021, we closed on a Securities Purchase Agreement (the “SPA”) for the sale by us of 3,249,668 shares of our common stock at a par value of $ 0.01 per share and the issuance of warrants to purchase 1,299,861 shares of common stock at an exercise price of $ 5.45 per warrant for gross proceeds of $ million , before deducting placement agent fees and offering expenses of approximately $ 1.0 million . The warrants are initially exercisable commencing August 13, 2021 through their expiration date of August 12, 2026 . The proceeds received from the SPA were allocated between shares and warrants was based on their relative fair values at closing. The warrants were valued utilizing the Black-Scholes method.

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 28, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	(10) Stock-Based Compensation Stock options We have awarded stock options to certain employees and certain non-employee members on our Board of Directors. The grants generally vest over a four-year A summary of stock option activity for the 13 weeks ended March 28, 2021 is as follows: Options Shares (Thousands) Weighted Average Exercise Price Aggregate Intrinsic Value (Thousands) Weighted Average Remaining Term (Years) Outstanding—December 27, 2020 1,233 $ 10.68 $ — 2.49 Granted — — Exercised — — Canceled (307 ) 12.61 Outstanding—March 28, 2021 926 10.04 $ — 1.81 Exercisable—March 28, 2021 922 $ 10.03 $ — 1.79 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 13 weeks ended March 28, 2021, we recognized stock-based compensation expense related to stock options of $0.1 million. For the 13 weeks ended March 29, 2020, we recognized stock-based compensation expense related to stock options of $0.2 million. As of March 28, 2021, unrecognized stock-based compensation expense for stock options was $0.1 million, which will be recognized through fiscal year 2022. We record stock-based compensation expense within general and administrative expenses in the condensed consolidated statements of operations. Restricted stock units We award restricted stock units (“RSUs”) to certain employees and certain non-employee members on our 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 A summary of RSU activity for the 13 weeks ended March 28, 2021 is as follows: RSUs Number of RSUs (Thousands) Weighted Average Fair Value per Share Non-vested as of December 27, 2020 994 $ 3.35 Granted 179 5.60 Vested (22 ) 6.02 Canceled (13 ) — Non-vested as of March 28, 2021 1,138 $ 3.59 Performance stock units We award performance share units (“PSUs”) to certain of its employees. The PSUs have certain vesting conditions based upon our financial performance or our stock price. We have granted PSUs 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 our common stock contingent on achievement of a stock return on our 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 13 weeks ended March 28, 2021, we recognized stock-based compensation expense for PSUs with market vesting conditions of $0.1 million. A summary of activity for PSUs with market vesting conditions for the 13 weeks ended March 28, 2021 is as follows: PSUs Number of PSUs (Thousands) Weighted Average Fair Value per Share Non-vested as of December 27, 2020 502 1.38 Granted — — Vested (41 ) 5.66 Canceled — — Non-vested as of March 28, 2021 461 $ 1.37

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 28, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	(11) Commitments and Contingencies We are 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. In the opinion of management, the amount of ultimate liability with respect to those actions should not have a material adverse impact on our financial position or results of operations and cash flows .

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 28, 2021
Related Party Transactions [Abstract]
Related Party Transactions	(12) Related Party Transactions In connection with our sale of common stock and warrants to purchase common stock in February 2021 in a private placement, certain of our stockholders that owned greater than 5% of our outstanding shares prior to the closing of the private placement purchased shares of common stock and warrants to purchase common stock on the same terms as the other shares and warrants that were offered and sold in the offering. The purchasers included the following stockholders, none of which owned more than 8.5% of our outstanding common stock prior to the closing of the private placement: 201,514 shares of common stock and warrants to purchase 80,605 shares of common stock were purchased by 180 Degree Capital Corp., for an aggregate purchase price of approximately $1.0 million and 164,875 shares of common stock and warrants to purchase 65,950 shares of common stock were purchased by B&W Pension Trust (of which 180 Degree Capital Corp. is the investment advisor and may be deemed to be a beneficial owner of such shares), for an aggregate purchase price of approximately $0.8 million; 223,904 shares of common stock and warrants to purchase 89,561 shares of common stock were purchased by Agman Investments LLC, for an aggregate purchase price of approximately $1.1 million; 366,389 shares of common stock and warrants to purchase 146,555 shares of common stock were purchased by funds controlled by Ancora Holdings Inc., for an aggregate purchase price of approximately $1.8 million; 193,372 shares of common stock and warrants to purchase 77,348 shares of common stock were purchased by Chain of Lakes Investment Fund, LLC, for an aggregate purchase price of approximately $0.9 million; and 407,099 shares of common stock were purchased by Intrinsic Investment Holdings, LLC, for an aggregate purchase price of approximately $2.0 million.

Organization and Other Matters

Organization and Other Matters (Policies)	3 Months Ended
	Mar. 28, 2021
Accounting Policies [Abstract]
Business	Business Potbelly Corporation (the “Company”, “Potbelly”, “we”, “us” or “our”), through its wholly owned subsidiaries, owns and operates 399 company-owned shops in the United States. Additionally, Potbelly franchisees operate 45 shops in the United States.
Basis of Presentation	Basis of Presentation The unaudited condensed consolidated financial statements and notes herein should be read in conjunction with the audited consolidated financial statements of Potbelly Corporation and its subsidiaries and the notes thereto included in our Annual Report on Form 10-K for the year ended December 27, 2020. The unaudited condensed consolidated financial statements included herein have been prepared by us without audit, pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (the “SEC”) regarding interim financial reporting. Certain information and footnote disclosures normally included in financial statements prepared in accordance with generally accepted accounting principles in the United States of America (“U.S. GAAP”) have been condensed or omitted pursuant to the SEC rules and regulations. In the opinion of management, all adjustments, which are of a normal and recurring nature (except as otherwise noted), that are necessary to present fairly our balance sheet as of March 28, 2021 and December 27, 2020, our statement of operations for the 13 weeks ended March 28, 2021 and March 29, 2020, the statement of equity for the 13 weeks ended March 28, 2021 and March 29, 2020, and our statement of cash flows for the 13 weeks ended March 28, 2021 and March 29, 2020 have been included. The condensed consolidated statements of operations for the interim periods presented herein are not necessarily indicative of the results to be expected for the full year. Beginning with the third quarter of 2020, shop closure and lease termination expenses are being presented within impairment, loss on disposal of property and equipment and shop closures in our condensed 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. We do not have any components of other comprehensive income recorded within our consolidated financial statements and therefore, does not separately present a statement of comprehensive income in our condensed consolidated financial statements.
COVID-19	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. 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. While the pandemic continues to have an impact on our business, the distribution of COVID-19 vaccines and a decline in positive cases and hospitalizations has resulted in a gradual improvement in our sales during the first quarter of 2021. Nearly all of our shops have reopened their dining rooms, many with continued 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 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, we cannot determine the ultimate impact that the COVID-19 pandemic will have on our consolidated financial condition, liquidity, and future results of operations, and therefore any prediction as to the ultimate impact on our consolidated financial condition, liquidity, and future results of operations is uncertain.
Principles of Consolidation	P rinciples of Consolidation The unaudited condensed 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 (“PSW”); seven of PSW’s wholly owned subsidiaries and PSW’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. Potbelly has ownership interests ranging from 51-80% in these consolidated joint ventures.
Fiscal Year	Fiscal Year We use a 52/53-week fiscal year that ends on the last Sunday of the calendar period. Approximately every five or six years a 53rd week is added. Fiscal year 2021 and 2020 both consist of 52 weeks. The fiscal quarters ended March 28, 2021 and March 29, 2020 each consisted of 13 weeks.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with 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.
Recent Accounting Pronouncements	Recent Accounting Pronouncements On December 28, 2020, we adopted Accounting Standard Update No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging— Contracts in Entity’s Own Equity (Subtopic 815-40)

Revenue (Tables)

Revenue (Tables)	3 Months Ended
	Mar. 28, 2021
Revenue From Contract With Customer [Abstract]
Summary of Current and Noncurrent Contract Liabilities from Contracts with Customers	The opening and closing balances of our 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 27, 2020 $ (3,138 ) $ (1,707 ) Ending balance as of March 28, 2021 (2,846 ) (1,634 ) Decrease in contract liability $ (292 ) $ (73 )
Summary of Expected Revenue Recognition Related to Contract Liabilities	We expect to recognize revenue related to contract liabilities as follows (in thousands), which may vary based upon franchise activity as well as gift card redemption patterns: Years Ending Amount 2021 $ 1,500 2022 1,313 2023 216 2024 183 2025 331 Thereafter 937 Total revenue recognized $ 4,480

Loss Per Share (Tables)

Loss Per Share (Tables)	3 Months Ended
	Mar. 28, 2021
Earnings Per Share [Abstract]
Summary of Loss Per Share Calculation	The following table summarizes the loss per share calculation: For the 13 Weeks Ended March 28, March 29, 2021 2020 Net loss attributable to Potbelly Corporation $ (14,472 ) $ (13,336 ) Weighted average common shares outstanding-basic 25,944 23,646 Plus: Effect of potential stock options exercise — — Weighted average common shares outstanding-diluted 25,944 23,646 Loss per share available to common stockholders-basic $ (0.56 ) $ (0.56 ) Loss per share available to common stockholders-diluted $ (0.56 ) $ (0.56 ) Potentially dilutive shares that are considered anti-dilutive: Common share options 2,544 2,294

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 28, 2021
Leases [Abstract]
Operating Lease Term and Discount Rate	Operating lease term and discount rate were as follows: March 28, March 29, 2021 2020 Weighted average remaining lease term (years) 7.65 8.33 Weighted average discount rate 7.83 % 7.90 %
Components of Lease Cost	The components of lease cost were as follows: 13 weeks ended March 28, March 29, Classification 2021 2020 Operating lease cost Occupancy and General and administrative expenses 10,411 11,770 Variable lease cost Occupancy 3,239 3,322 Total lease cost $ 13,650 $ 15,092
Supplemental Disclosures of Cash Flow Information Related to Leases	Supplemental disclosures of cash flow information related to leases were as follows: 13 weeks ended March 28, March 29, 2021 2020 Operating cash flows rent paid for operating lease liabilities 12,914 11,979 Operating right-of-use assets obtained in exchange for new operating lease liabilities 1,718 5,534 Reduction in operating right-of-use assets due to lease terminations and modifications 3,294 1,439
Maturities of Lease Liabilities	Maturities of lease liabilities were as follows as of March 28, 2021: Operating Leases Remainder of 2021 36,613 2022 39,353 2023 37,229 2024 34,706 2025 31,823 2026 28,224 Thereafter 82,198 Total lease payments 290,146 Less: imputed interest (76,343 ) Present value of lease liabilities $ 213,803

Debt and Credit Facilities (Ta

Debt and Credit Facilities (Tables)	3 Months Ended
	Mar. 28, 2021
Debt Disclosure [Abstract]
Component of Long-term Debt	The components of long-term debt were as follows: March 28, December 27, 2021 2020 Revolving credit facility $ 2,786 $ 6,286 Paycheck Protection Program loan 10,000 10,000 Less: current portion of long-term debt (833 ) (333 ) Total long-term debt $ 11,953 $ 15,953 Current portion of debt $ 833 $ 333

Restructuring (Tables)

Restructuring (Tables)	3 Months Ended
	Mar. 28, 2021
Restructuring And Related Activities [Abstract]
Schedule Future Cash Payments Required to Satisfy Our Remaining Obligations	The accrued restructuring balances as of March 28, 2021 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 27, 2020 $ 1,489 Charges incurred — Payments made (478 ) Balance as of March 28, 2021 $ 1,011

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 28, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock Option Activity	A summary of stock option activity for the 13 weeks ended March 28, 2021 is as follows: Options Shares (Thousands) Weighted Average Exercise Price Aggregate Intrinsic Value (Thousands) Weighted Average Remaining Term (Years) Outstanding—December 27, 2020 1,233 $ 10.68 $ — 2.49 Granted — — Exercised — — Canceled (307 ) 12.61 Outstanding—March 28, 2021 926 10.04 $ — 1.81 Exercisable—March 28, 2021 922 $ 10.03 $ — 1.79
Summary of RSU Activity	A summary of RSU activity for the 13 weeks ended March 28, 2021 is as follows: RSUs Number of RSUs (Thousands) Weighted Average Fair Value per Share Non-vested as of December 27, 2020 994 $ 3.35 Granted 179 5.60 Vested (22 ) 6.02 Canceled (13 ) — Non-vested as of March 28, 2021 1,138 $ 3.59
Summary of PSU Activity	A summary of activity for PSUs with market vesting conditions for the 13 weeks ended March 28, 2021 is as follows: PSUs Number of PSUs (Thousands) Weighted Average Fair Value per Share Non-vested as of December 27, 2020 502 1.38 Granted — — Vested (41 ) 5.66 Canceled — — Non-vested as of March 28, 2021 461 $ 1.37

Organization and Other Matter_2

Organization and Other Matters - Additional Information (Detail)	3 Months Ended
	Mar. 28, 2021ShopSubsidiaryJointVenture
Nature Of Business And Basis Of Presentation [Line Items]
Number of shops franchisees operate	45
Number of wholly owned subsidiaries | Subsidiary	7
Number of joint ventures | JointVenture	7
Minimum [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Number of shops Potbelly Corporation owns or operates	399
Ownership interest rate	51.00%
Maximum [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Ownership interest rate	80.00%

Revenue - Additional Informatio

Revenue - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 28, 2021	Mar. 29, 2020
Disaggregation Of Revenue [Line Items]
Revenue recognized related to prior periods	$ 100,000	$ 100,000
Amount of revenue recognized	78,063,000	87,590,000
Aggregate value of remaining performance obligation on outstanding contracts	4,480,000
Revenue recognized related to prior periods	0	0
December 27, 2020 and December 31, 2019 Liability Ending Balance [Member]
Disaggregation Of Revenue [Line Items]
Amount of revenue recognized	600,000	500,000
Point in Time Sales [Member]
Disaggregation Of Revenue [Line Items]
Amount of revenue recognized	77,500,000	87,500,000
Over Time Sales [Member]
Disaggregation Of Revenue [Line Items]
Amount of revenue recognized	$ 100,000	$ 100,000

Revenue - Summary of Current an

Revenue - Summary of Current and Noncurrent Contract Liabilities from Contracts with Customers (Detail) $ in Thousands	3 Months Ended
	Mar. 28, 2021USD ($)
Revenue From Contract With Customer [Abstract]
Beginning balance of current contract liability	$ (3,138)
Ending balance of current contract liability	(2,846)
Decrease in contract liability	(292)
Beginning balance of noncurrent contract liability	(1,707)
Ending balance of noncurrent contract liability	(1,634)
Decrease in contract liability	$ (73)

Revenue - Summary of Expected R

Revenue - Summary of Expected Revenue Recognition Related to Contract Liabilities (Detail1) $ in Thousands	Mar. 28, 2021USD ($)
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, remaining performance obligations	$ 4,480
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	$ 1,500
Revenue, remaining performance obligation, expected timing of satisfaction, period	9 months
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	$ 1,313
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	$ 216
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	$ 183
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	$ 331
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	$ 937
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year

Revenue - Summary of Expected_2

Revenue - Summary of Expected Revenue Recognition Related to Contract Liabilities (Detail) $ in Thousands	Mar. 28, 2021USD ($)
Revenue From Contract With Customer [Abstract]
Revenue, remaining performance obligations	$ 4,480

Fair Value Measurement - Additi

Fair Value Measurement - Additional Information (Detail) $ in Thousands	3 Months Ended
	Mar. 28, 2021USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impairment charge	$ 148
Leasehold Improvements [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Losses on disposal of property and equipment	$ 2,500

Loss Per Share - Additional Inf

Loss Per Share - Additional Information (Detail)	3 Months Ended
	Mar. 28, 2021shares
Common Share Options [Member]
Loss Per Share [Line Items]
Potential common shares included in diluted shares outstanding	0

Loss Per Share - Summary of Los

Loss Per Share - Summary of Loss Per Share Calculation (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 28, 2021	Mar. 29, 2020
Loss Per Share [Line Items]
Net loss attributable to Potbelly Corporation	$ (14,472)	$ (13,336)
Weighted average common shares outstanding-basic	25,944	23,646
Weighted average common shares outstanding-diluted	25,944	23,646
Loss per share available to common stockholders-basic	$ (0.56)	$ (0.56)
Loss per share available to common stockholders-diluted	$ (0.56)	$ (0.56)
Common Share Options [Member]
Loss Per Share [Line Items]
Potentially dilutive shares that are considered anti-dilutive	2,544	2,294

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2021	Mar. 29, 2020	Mar. 27, 2020	Mar. 31, 2019
Deferred tax assets, valuation allowance				$ 13,600
Income tax expense (benefit)	$ 53	$ (3,709)
COVID 19 [Member]
Tax refund from net operating loss carry back			$ 6,700
Income tax expense (benefit)		$ 3,700

Leases - Additional Information

Leases - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 28, 2021USD ($)Termination
Leases [Abstract]
Leases of terminated | Termination	2
Lease termination fees	$ 0.2
Right-of-use assets derecognized upon lease termination	0.6
Lease liabilities derecognized upon lease termination	0.7
Gain recognized upon lease termination	0.1
Decrease in the right-of-use asset and lease Liability	2.7
Additional operating leases payments related to shops not yet open, amount	$ 0

Leases - Operating Lease Term a

Leases - Operating Lease Term and Discount Rate (Detail)	Mar. 28, 2021	Mar. 29, 2020
Leases [Abstract]
Weighted average remaining lease term (years)	7 years 7 months 24 days	8 years 3 months 29 days
Weighted average discount rate	7.83%	7.90%

Leases - Components of Lease Co

Leases - Components of Lease Cost (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2021	Mar. 29, 2020
Lessee Lease Description [Line Items]
Total lease cost	$ 13,650	$ 15,092
Occupancy and General and Administrative Expenses [Member]
Lessee Lease Description [Line Items]
Operating lease cost	10,411	11,770
Occupancy Expenses [Member]
Lessee Lease Description [Line Items]
Variable lease cost	$ 3,239	$ 3,322

Leases - Supplemental Disclosur

Leases - Supplemental Disclosures of Cash Flow Information Related to Leases (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2021	Mar. 29, 2020
Leases [Abstract]
Operating cash flows rent paid for operating lease liabilities	$ 12,914	$ 11,979
Operating right-of-use assets obtained in exchange for new operating lease liabilities	1,718	5,534
Reduction in operating right-of-use assets due to lease terminations and modifications	$ 3,294	$ 1,439

Leases - Maturities of Lease Li

Leases - Maturities of Lease Liabilities (Detail) $ in Thousands	Mar. 28, 2021USD ($)
Operating Leases
Remainder of 2021	$ 36,613
2022	39,353
2023	37,229
2024	34,706
2025	31,823
2026	28,224
Thereafter	82,198
Total lease payments	290,146
Less: imputed interest	(76,343)
Present value of lease liabilities	$ 213,803

Debt and Credit Facilities - Co

Debt and Credit Facilities - Component of Long-term Debt (Detail) - USD ($) $ in Thousands	Mar. 28, 2021	Dec. 27, 2020
Debt Instrument [Line Items]
Long-term debt	$ 11,953	$ 15,953
Less: current portion of long-term debt	(833)	(333)
Current portion of debt	833	333
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long-term debt	2,786	6,286
Paycheck Protection Program Loan [Member]
Debt Instrument [Line Items]
Long-term debt	$ 10,000	$ 10,000

Debt and Credit Facilities - Ad

Debt and Credit Facilities - Additional Information (Detail) - USD ($)	Feb. 26, 2021	Aug. 10, 2020	Aug. 07, 2019	Mar. 28, 2021	Mar. 29, 2020
CARES Act Of 2020 [Member] | Fifth Credit Agreement Amendment [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt Instrument, maturity date	Mar. 31, 2022
CARES Act Of 2020 [Member] | Fifth Credit Agreement Amendment [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt Instrument, maturity date	Jan. 31, 2023
JPMorgan Chase Bank, N.A. [Member]
Debt Instrument [Line Items]
Commitment fee, percentage			0.20%
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] | Maximum [Member]
Debt Instrument [Line Items]
Credit facility agreement, future increases			$ 20,000,000
Paycheck Protection Program Loan [Member] | CARES Act Of 2020 [Member] | Potbelly Sandwich Works, LLC [Member]
Debt Instrument [Line Items]
Loan maturity period		5 years
Credit facility agreement, interest rate		1.00%
Paycheck Protection Program Loan [Member] | Harvest Small Business Finance L L C | Commercial Loan [Member] | Potbelly Sandwich Works, LLC [Member]
Debt Instrument [Line Items]
Loan amount		$ 10,000,000
Paycheck Protection Program Loan [Member] | Harvest Small Business Finance L L C | CARES Act Of 2020 [Member] | Fifth Credit Agreement Amendment [Member]
Debt Instrument [Line Items]
Credit facility agreement, amount outstanding				$ 2,800,000	$ 39,800,000
Revolving Credit Commitment [Member] | CARES Act Of 2020 [Member] | Fifth Credit Agreement Amendment [Member] | Minimum [Member]
Debt Instrument [Line Items]
Credit facility agreement, future increases	$ 40,000,000
Revolving Credit Commitment [Member] | CARES Act Of 2020 [Member] | Fifth Credit Agreement Amendment [Member] | Maximum [Member]
Debt Instrument [Line Items]
Credit facility agreement, future increases	$ 25,000,000
Eurodollar Loan [Member] | CARES Act Of 2020 [Member] | Fifth Credit Agreement Amendment [Member]
Debt Instrument [Line Items]
Debt instrument, increase in interest rate	5.00%
CBFR Loan [Member] | CARES Act Of 2020 [Member] | Fifth Credit Agreement Amendment [Member]
Debt Instrument [Line Items]
Debt instrument, increase in interest rate	2.75%

Restructuring - Additional Info

Restructuring - Additional Information (Detail)	1 Months Ended	3 Months Ended
	Nov. 03, 2020USD ($)	Mar. 28, 2021USD ($)Employee	Mar. 29, 2020USD ($)
Number of employee reduce | Employee		35
General and administrative expenses		$ 7,423,000	$ 9,834,000
Minimum [Member]
General and administrative expenses	$ 3,500,000
Maximum [Member]
General and administrative expenses	$ 4,000,000

Restructuring - Schedule Future

Restructuring - Schedule Future Cash Payments Required to Satisfy Our Remaining Obligations (Detail) $ in Thousands	3 Months Ended
	Mar. 28, 2021USD ($)
Restructuring Reserve Roll Forward
Beginning balance	$ 1,489
Payments made	(478)
Ending balance	$ 1,011

Capital Stock - Additional Info

Capital Stock - Additional Information (Detail) - USD ($)	Feb. 09, 2021	Mar. 28, 2021	Dec. 27, 2020	May 08, 2018
Equity Class Of Treasury Stock [Line Items]
Stock repurchase program, authorized amount				$ 65,000,000
Common stock, par value		$ 0.01	$ 0.01
Warrants [Member]
Equity Class Of Treasury Stock [Line Items]
Placement agent fees and offering expenses	$ 1,000,000
Securities Purchase Agreement [Member]
Equity Class Of Treasury Stock [Line Items]
Issuance of common stock	3,249,668
Common stock, par value	$ 0.01
Warrants exercisable commencement date	Aug. 13, 2021
Warrants expiration date	Aug. 12, 2026
Securities Purchase Agreement [Member] | Warrants [Member]
Equity Class Of Treasury Stock [Line Items]
Issuance of common stock	1,299,861
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 5.45
Proceeds From Securities Purchase Agreement	$ 16,000,000
Stock Repurchase Program [Member]
Equity Class Of Treasury Stock [Line Items]
Common stock shares repurchased		0

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2021	Mar. 29, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized stock-based compensation expense	$ 193	$ 490
Common Share Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized stock-based compensation expense	100	200
Unrecognized stock compensation expense	$ 100
Unrecognized stock compensation expense, recognition period	2022
Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants vesting period	5 years
Performance Stock Units [Member] | Market Vesting Conditions [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized stock-based compensation expense	$ 100
Employee and Non Employee Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants vesting period	4 years
Method used to determine fair value of the options	Black-Scholes option pricing model
Stock options granted	0
Non-Employee Board Of Directors [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants vesting period	3 years
Recognized stock-based compensation expense	$ 100	$ 300
Unrecognized stock compensation expense	$ 1,900
Unrecognized stock compensation expense, recognition period	2023
Vesting description	The employee grants vest in one-third increments over a three-year period.
Non-Employee Board Of Directors [Member] | Restricted Stock Units (RSUs) [Member] | First Anniversary [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	50.00%
Non-Employee Board Of Directors [Member] | Restricted Stock Units (RSUs) [Member] | Second Anniversary [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	50.00%

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option Activity (Detail) - $ / shares shares in Thousands	3 Months Ended	12 Months Ended
	Mar. 28, 2021	Dec. 27, 2020	Mar. 28, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options outstanding shares, beginning balance	1,233
Options, canceled	(307)
Options outstanding shares, ending balance	926	1,233
Options outstanding shares, exercisable			922
Options outstanding weighted average exercise price, beginning balance	$ 10.68
Options, weighted average exercise price, canceled	12.61
Options outstanding weighted average exercise price, ending balance	$ 10.68	$ 10.68	$ 10.04
Options outstanding weighted average exercise price, exercisable			$ 10.03
Option outstanding weighted average remaining term	1 year 9 months 21 days	2 years 5 months 26 days
Options exercisable weighted average remaining term	1 year 9 months 14 days

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of RSU Activity (Detail) - Restricted Stock Units (RSUs) [Member] shares in Thousands	3 Months Ended
	Mar. 28, 2021$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of RSUs, Non-vested, beginning balance | shares | shares	994
Number of shares, Granted	179
Number of RSUs, Vested	(22)
Number of RSUs, Canceled	(13)
Number of RSUs, Non-vested, ending balance | shares | shares	1,138
Weighted Average Fair Value per Share, Non-vested, beginning balance | $ / shares	$ 3.35
Weighted Average Fair Value per Share, Granted | $ / shares	5.60
Weighted Average Fair Value per Share, Vested | $ / shares	6.02
Weighted Average Fair Value per Share, Non-vested, ending balance | $ / shares	$ 3.59

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of PSU Activity (Detail) - Performance Stock Units [Member] shares in Thousands	3 Months Ended
	Mar. 28, 2021$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of RSUs, Non-vested, beginning balance | shares | shares | shares	502
Number of RSUs, Vested | shares	(41)
Number of RSUs, Non-vested, ending balance | shares | shares | shares	461
Weighted Average Fair Value per Share, Non-vested, beginning balance | $ / shares	$ 1.38
Weighted Average Fair Value per Share, Vested | $ / shares	5.66
Weighted Average Fair Value per Share, Non-vested, ending balance | $ / shares	$ 1.37

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended
	Feb. 28, 2021	Mar. 28, 2021
Related Party Transaction [Line Items]
Stock Issued During Period, Value, New Issues		$ 14,940,000
Warrants [Member]
Related Party Transaction [Line Items]
Stock Issued During Period, Value, New Issues		$ 2,566,000
Private Placement [Member] | Minimum [Member]
Related Party Transaction [Line Items]
Ownership percentage related party	5.00%
Private Placement [Member] | Maximum [Member]
Related Party Transaction [Line Items]
Ownership percentage related party	8.50%
Private Placement [Member] | 180 Degree Capital Corp [Member]
Related Party Transaction [Line Items]
Issuance of common stock	201,514
Private Placement [Member] | 180 Degree Capital Corp [Member] | Warrants [Member]
Related Party Transaction [Line Items]
Issuance of common stock	80,605
Stock Issued During Period, Value, New Issues	$ 1,000,000
Private Placement [Member] | B&W Pension Trust [Member]
Related Party Transaction [Line Items]
Issuance of common stock	164,875
Private Placement [Member] | B&W Pension Trust [Member] | Warrants [Member]
Related Party Transaction [Line Items]
Issuance of common stock	65,950
Stock Issued During Period, Value, New Issues	$ 800,000
Private Placement [Member] | Agman Investments LLC [Member]
Related Party Transaction [Line Items]
Issuance of common stock	223,904
Private Placement [Member] | Agman Investments LLC [Member] | Warrants [Member]
Related Party Transaction [Line Items]
Issuance of common stock	89,561
Stock Issued During Period, Value, New Issues	$ 1,100,000
Private Placement [Member] | Ancora Holdings Inc [Member]
Related Party Transaction [Line Items]
Issuance of common stock	366,389
Private Placement [Member] | Ancora Holdings Inc [Member] | Warrants [Member]
Related Party Transaction [Line Items]
Issuance of common stock	146,555
Stock Issued During Period, Value, New Issues	$ 1,800,000
Private Placement [Member] | Lakes Investment Fund, LLC [Member]
Related Party Transaction [Line Items]
Issuance of common stock	193,372
Private Placement [Member] | Lakes Investment Fund, LLC [Member] | Warrants [Member]
Related Party Transaction [Line Items]
Issuance of common stock	77,348
Stock Issued During Period, Value, New Issues	$ 900,000
Private Placement [Member] | Intrinsic Investment Holdings, LLC [Member]
Related Party Transaction [Line Items]
Issuance of common stock	407,099
Stock Issued During Period, Value, New Issues	$ 2,000,000