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Summary of Significant Accounting Policies - Schedule of Impact on Consolidated Balance Sheet (Parenthetical) (Detail) - USD ($) $ / shares in Units, $ in Thousands	Dec. 29, 2019	Dec. 31, 2018	Dec. 30, 2018
Nature Of Business And Basis Of Presentation [Line Items]
Allowances on accounts receivable	$ 202		$ 113
Common stock, par value	$ 0.01		$ 0.01
Common stock, authorized	200,000,000		200,000,000
Common stock, outstanding	23,638,000		24,143,000
Treasury stock, shares	9,465,000		8,801,000
ASU 2016-02 (Topic 842) [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Net reduction to opening accumulated deficit		$ 500

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 29, 2019	Dec. 30, 2018
Current assets
Cash and cash equivalents	$ 18,806	$ 19,775
Accounts receivable, net of allowances of $202 and $113 as of December 29, 2019 and December 30, 2018, respectively	4,257	4,737
Inventories	3,473	3,482
Prepaid expenses and other current assets	5,687	11,426
Total current assets	32,223	39,420
Property and equipment, net	79,032	87,782
Right-of-use assets for operating leases	211,988
Indefinite-lived intangible assets	3,404	3,404
Goodwill	2,222	2,222
Deferred income taxes, non-current		13,385
Deferred expenses, net and other assets	4,010	7,002
Total assets	332,879	153,215
Current liabilities
Accounts payable	3,886	3,835
Accrued expenses	20,398	25,029
Short-term operating lease liabilities	29,319
Accrued income taxes	171	162
Total current liabilities	53,774	29,026
Deferred rent and landlord allowances		22,905
Long-term operating lease liabilities	206,726
Other long-term liabilities	3,210	5,751
Total liabilities	263,710	57,682
Commitments and contingencies (Note 14)
Equity
Common stock, $0.01 par value—authorized 200,000 shares; outstanding 23,638 and 24,143 shares as of December 29, 2019 and December 30, 2018, respectively	331	330
Additional paid-in-capital	435,278	432,771
Treasury stock, held at cost, 9,465 and 8,801 shares as of December 29, 2019, and December 30, 2018, respectively	(112,680)	(108,372)
Accumulated deficit	(254,081)	(229,558)
Total stockholders’ equity	68,848	95,171
Non-controlling interest	321	362
Total equity	69,169	95,533
Total liabilities and equity	$ 332,879	$ 153,215

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

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

Organization and Other Matters

12 Months Ended

Dec. 29, 2019

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 or operates more than 400 company-owned shops in the United States as of December 29, 2019. Additionally, Potbelly franchisees operate over 40 shops domestically.

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 29, 2019	Dec. 30, 2018	Dec. 31, 2017
Income Tax [Line Items]
U.S. federal corporate tax rate	21.00%	21.00%	35.00%
Deferred tax assets, valuation allowance	$ 16,116,000
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	$ 16,100,000	$ 0

Leases

12 Months Ended

Dec. 29, 2019

Leases [Abstract]

Leases

(8) Leases

Operating lease term and discount rate were as follows:

	December 29,
	2019
Weighted average remaining lease term (years)	8.52
Weighted average discount rate		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
	Classification	2019
Operating lease cost	Occupancy and general and administrative expenses	$	45,604
Variable lease cost	Occupancy and general and administrative expenses		13,692
Total lease cost		$	59,296

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

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

As of December 29, 2019, the Company has additional operating lease payments related to shops not yet open of $2.8 million. These operating leases will commence during the next fiscal year with an average lease term of 11 years.

Maturities of lease liabilities were as follows at December 29, 2019 (in thousands):

	Operating Leases
2020	$	46,581
2021		43,639
2022		38,096
2023		33,512
2024		30,427
Thereafter		141,456
Total lease payments		333,711
Less: imputed interest		(97,666	)
Present value of lease liabilities	$	236,045

As previously disclosed in our 2018 Annual Report on Form 10-K and under the previous lease accounting, maturities of lease liabilities were as follows at December 30, 2018 (in thousands):

	Operating Leases
2019	$	47,918
2020		45,828
2021		41,497
2022		36,120
2023		31,060
Thereafter		138,928
Total minimum lease payments	$	341,351

Commitment and Contingencies - Additional Information (Detail)		1 Months Ended
	Feb. 04, 2020	Oct. 31, 2017
Loss Contingencies [Line Items]
Purported collective and class action lawsuit filed date		October 2017
Subsequent Event [Member]
Loss Contingencies [Line Items]
Purported collective and class action lawsuit approval date	February 4, 2020

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

Revenue (Tables)

12 Months Ended

Dec. 29, 2019

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 31, 2018	$	(2,184	)	$	(1,631	)
Ending balance as of December 29, 2019		(1,594	)		(2,054	)
Decrease in contract liability	$	(590	)	$	423

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 as well as gift card redemption patterns:

Years Ending	Amount
2020	$	1,272
2021		325
2022		222
2023		201
2024		166
Thereafter		1,462
Total revenue recognized	$	3,648

Accrued Expenses - Summary of Accrued Contract Termination Costs (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 29, 2019	Dec. 30, 2018
Accrued Liabilities And Other Liabilities [Abstract]
Accrued contract termination costs—beginning balance	$ 392	$ 27
Contract termination costs incurred	3,449	1,461
Contract termination costs settled and paid	$ (3,841)	(1,096)
Accrued contract termination costs—ending balance		$ 392

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 29, 2019

ASU 2016-02 (Topic 842) [Member]

New Accounting Pronouncements Or Change In Accounting Principle [Line Items]

Schedule of Impact on Consolidated Balance Sheet

The impact on the consolidated balance sheet is as follows:

				Adjustments Due
	December 30,			to the Adoption of			December 31,
	2018			Topic 842			2018
Assets
Current assets
Cash and cash equivalents	$	19,775		$	—		$	19,775
Accounts receivable, net of allowances of $113 as of December 30, 2018		4,737			—			4,737
Inventories		3,482			—			3,482
Prepaid expenses and other current assets		11,426			—			11,426
Total current assets		39,420			—			39,420

Property and equipment, net		87,782			—			87,782
Right-of-use assets for operating leases		—			232,477			232,477
Indefinite-lived intangible assets		3,404			—			3,404
Goodwill		2,222			—			2,222
Deferred income taxes, noncurrent		13,385			195			13,580
Deferred expenses, net and other assets		7,002			—			7,002
Total assets	$	153,215		$	232,672		$	385,887

Liabilities and Equity
Current liabilities
Accounts payable	$	3,835		$	—		$	3,835
Accrued expenses⁽¹⁾		25,029			(1,124	)		23,905
Short-term operating lease liabilities		—			28,826			28,826
Accrued income taxes		162			—			162
Total current liabilities		29,026			27,702			56,728

Deferred rent and landlord allowances⁽¹⁾		22,905			(22,905	)		—
Long-term operating lease liabilities		—			228,406			228,406
Other long-term liabilities		5,751			—			5,751
Total liabilities		57,682			233,203			290,885

Stockholders’ equity
Common stock, $0.01 par value—authorized 200,000 shares; outstanding 24,143 shares as of December 30, 2018		330			—			330
Additional paid-in-capital		432,771			—			432,771
Treasury stock, held at cost, 8,801 shares as of December 30, 2018		(108,372	)		—			(108,372	)
Accumulated deficit⁽²⁾		(229,558	)		(531	)		(230,089	)
Total stockholders’ equity		95,171			(531	)		94,640
Non-controlling interest		362			—			362
Total stockholders' equity		95,533			(531	)		95,002

Total liabilities and equity	$	153,215		$	232,672		$	385,887

(1)	Adjustment to reclassify deferred rent and tenant improvement allowance to right-of-use assets for operating leases upon the adoption of Topic 842.

(2)	The Company recorded a net reduction of $0.5 million to opening accumulated deficit as of December 31, 2018, due to the cumulative impact of adopting Topic 842.

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 29, 2019	Dec. 30, 2018
Deferred tax assets:
Net operating loss carryforwards	$ 3,721	$ 576
Accrued liabilities	848	1,449
Deferred revenue	423	543
Stock-based compensation	2,516	2,685
Property and equipment	4,568	5,037
Operating lease liabilities	62,313
Deferred rent		4,373
Tax credits and charitable contribution carryforwards	1,538	981
Gross deferred tax assets	75,927	15,644
Valuation allowance	(16,116)
Net deferred tax assets	59,811	15,644
Deferred tax liabilities:
Prepaids	(492)	(466)
Right-of-use asset for operating leases	(57,717)
Intangible assets	(1,162)	(1,075)
Smallwares	(533)	(566)
Other	(134)	(152)
Total deferred tax liabilities	(60,038)	(2,259)
Net deferred tax liabilities	$ 227	$ 13,385

Leases - Maturities of Lease Liabilities (Detail) $ in Thousands	Dec. 29, 2019 USD ($)
Operating Leases
2020	$ 46,581
2021	43,639
2022	38,096
2023	33,512
2024	30,427
Thereafter	141,456
Total lease payments	333,711
Less: imputed interest	(97,666)
Present value of lease liabilities	$ 236,045

Leases - Maturities of Lease Liabilities Under the Previous Lease Accounting (Detail) $ in Thousands	Dec. 30, 2018 USD ($)
Operating Leases
2019	$ 47,918
2020	45,828
2021	41,497
2022	36,120
2023	31,060
Thereafter	138,928
Total minimum lease payments	$ 341,351

Income Taxes - Components of Income Tax Expense (Benefit) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 29, 2019	Dec. 30, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Federal, Current	$ 159	$ (339)	$ (3,728)
Federal, Deferred	9,379	(1,644)	8,792
Federal, Total	9,538	(1,983)	5,064
State and Local, Current	227	73	150
State and Local, Deferred	4,425	(305)	(584)
State and Local, Total	4,652	(232)	(434)
Foreign, Current		20	13
Foreign, Total		20	13
Income tax expense (benefit)	$ 14,190	$ (2,195)	$ 4,643

Stock-Based Compensation - Schedule of Average Assumptions to Value Options (Detail) - $ / shares	12 Months Ended
	Dec. 29, 2019	Dec. 30, 2018
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions And Methodology [Abstract]
Risk-free interest rate	3.00%	2.00%
Expected life (years)	6 years 3 months	6 years 3 months
Expected dividend yield	0.00%	0.00%
Volatility	35.00%	36.00%
Weighted average grant date fair value	$ 4.52	$ 4.76

Employee Benefit Plan

12 Months Ended

Dec. 29, 2019

Postemployment Benefits [Abstract]

Employee Benefit Plan

(11) 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 $0.5 million, $0.4 million, and $0.4 million for fiscal years 2019, 2018 and 2017, respectively.

Income Taxes - Reconciliation of Differences Between Federal Statutory and Effective Income (Loss) Tax Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 29, 2019	Dec. 30, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
U.S. federal statutory tax	21.00%	21.00%	35.00%
Computed “expected” tax expense (benefit)	$ (1,973)	$ (2,256)	$ (716)
Valuation allowance	16,116
Minority interest	(107)	(87)	(105)
Permanent differences	425	220	96
State and local income taxes, net of federal income tax effect	(361)	(436)	5
FICA and other tax credits	(504)	(522)	(502)
Equity compensation	577	1,089	2,112
Adjustments	(106)	(252)	(93)
Tax rate change	123	49	3,846
Income tax expense (benefit)	$ 14,190	$ (2,195)	$ 4,643

Accrued Expenses

12 Months Ended

Dec. 29, 2019

Accrued Liabilities Current [Abstract]

Accrued Expenses

(6) Accrued Expenses

Accrued expenses consisted of the following (in thousands):

	December 29,		December 30,
	2019		2018
Accrued labor and related expenses	$	7,403	$	10,324
Deferred gift card revenue		1,415		1,821
Accrued occupancy expenses		2,010		2,309
Deferred rent—current		—		1,250
Accrued corporate and shop expenses		1,859		1,446
Accrued utilities		1,137		1,304
Accrued sales and use tax		2,063		3,001
Accrued construction		293		147
Accrued contract termination costs ^(a)		—		392
Accrued legal and professional fees		716		128
Accrued other		3,502		2,907
Total	$	20,398	$	25,029

(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 29,			December 30,
	2019			2018
Accrued contract termination costs—beginning balance	$	392		$	27
Contract termination costs incurred		3,449			1,461
Contract termination costs settled and paid		(3,841	)		(1,096	)
Accrued contract termination costs—ending balance	$	—		$	392

Commitments and Contingencies

12 Months Ended

Dec. 29, 2019

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

(14) 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.

In October 2017, plaintiffs filed a purported collective and class action lawsuit (the “Complaint”) in the United States District Court for the Southern District of New York against the Company alleging violations of the Fair Labor Standards Act (FLSA) and New York Labor Law (NYLL). The plaintiffs allege that the Company violated the FLSA and NYLL by not paying overtime compensation to our assistant managers and violated NYLL by not paying spread-of-hours pay. The Complaint was brought as a nationwide “collective action” under the FLSA and as a “class action” under NYLL. Since the filing of the Complaint, the plaintiffs filed a proposed amended complaint removing the NYLL class claim, but adding a proposed Illinois state law class action. In May 2019, the parties participated in a mediation and resolved the claims, which received final court approval on February 4, 2020. All charges related to the claims are reflected in the statement of operations.

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.

Income Taxes

12 Months Ended

Dec. 29, 2019

Income Tax Disclosure [Abstract]

Income Taxes

(7) Income Taxes

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

	Fiscal Year
	2019			2018			2017
Domestic operations	$	(9,790	)	$	(11,381	)	$	(2,513	)
Foreign operations		395			637			466
Total	$	(9,395	)	$	(10,744	)	$	(2,047	)

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

	Fiscal Year
	2019		2018			2017
Federal:
Current	$	159	$	(339	)	$	(3,728	)
Deferred		9,379		(1,644	)		8,792
		9,538		(1,983	)		5,064
State and Local:
Current		227		73			150
Deferred		4,425		(305	)		(584	)
		4,652		(232	)		(434	)
Foreign:
Current		—		20			13
		—		20			13
Income tax expense (benefit)	$	14,190	$	(2,195	)	$	4,643

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
	2019			2018			2017
U.S. federal statutory tax		21.0	%		21.0	%		35.0	%
Computed “expected” tax expense (benefit)	$	(1,973	)	$	(2,256	)	$	(716	)
Increase (reduction) resulting from:
Valuation allowance		16,116			-			-
Minority interest		(107	)		(87	)		(105	)
Permanent differences		425			220			96
State and local income taxes, net of federal income tax effect		(361	)		(436	)		5
FICA and other tax credits		(504	)		(522	)		(502	)
Equity compensation		577			1,089			2,112
Adjustments		(106	)		(252	)		(93	)
Tax rate change		123			49			3,846
	$	14,190		$	(2,195	)	$	4,643

On December 22, 2017, the Tax Cuts and Jobs Act of 2017 (the “Tax Act”) was enacted into law making significant changes to the U.S. tax code, including: (1) reducing the U.S. federal corporate tax rate from 35 percent to 21 percent; (2) implementing bonus depreciation that will allow for full expensing of qualified property; (3) implementing limitations on the deductibility of certain executive compensation; and (4) changing rules related to uses and limitations of net operating loss carryforwards created in tax years beginning after December 31, 2017.

Due to the adoption of ASU 2016-09 in 2017, all excess tax benefits and deficiencies are recognized as income tax expense in the Company’s Consolidated Statement of Operations.

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 29,			December 30,
	2019			2018
Deferred tax assets:
Net operating loss carryforwards	$	3,721		$	576
Accrued liabilities		848			1,449
Deferred revenue		423			543
Stock-based compensation		2,516			2,685
Property and equipment		4,568			5,037
Operating lease liabilities		62,313			—
Deferred rent		—			4,373
Tax credits and charitable contribution carryforwards		1,538			981
Gross deferred tax assets		75,927			15,644
Valuation allowance		(16,116	)		—
Net deferred tax assets		59,811			15,644
Deferred tax liabilities:
Prepaids		(492	)		(466	)
Right-of-use asset for operating leases		(57,717	)		—
Intangible assets		(1,162	)		(1,075	)
Smallwares		(533	)		(566	)
Other		(134	)		(152	)
Total deferred tax liabilities		(60,038	)		(2,259	)
Net deferred tax liabilities	$	(227	)	$	13,385

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. During its assessment for the first quarter of 2019, the Company estimated it would be in a three-year cumulative loss position as of December 29, 2019. Therefore, the Company determined based on the available evidence that a full valuation allowance against its net deferred tax assets was required. As a result of this valuation allowance, the Company did not provide for an income tax benefit on the pre-tax loss recorded for the year ended December 29, 2019. This accounting treatment has no effect on the Company’s ability to utilize deferred tax assets to reduce future cash tax payments. The Company will continue to assess the likelihood of the realization of its deferred tax assets and the valuation allowance will be adjusted accordingly.

As of December 29, 2019, the Company has a valuation allowance related to its deferred tax assets of $16.1 million. As of December 30, 2018, the Company had no valuation allowance recorded based on management’s assessment of the amount that its deferred tax assets were more likely than not to be realized.

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 29, 2019 and December 30, 2018, the Company had no interest or penalties accrued. As of December 29, 2019 and December 30, 2018, 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 2018 tax years.

Leases - Additional Information (Detail) $ in Millions	Dec. 29, 2019 USD ($)
Leases [Abstract]
Additional operating leases payments related to shops not yet open, amount	$ 2.8
Additional operating leases related to shops not yet commence, average term	11 years

Revenue - Summary of Expected Revenue Recognition Related to Contract Liabilities (Detail) $ in Thousands	Dec. 29, 2019 USD ($)
Revenue From Contract With Customer [Abstract]
Revenue, remaining performance obligations	$ 3,648

Summary of Significant Accounting Policies - Schedule of Impact on Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	Dec. 29, 2019	Dec. 31, 2018	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016
Current assets
Cash and cash equivalents	$ 18,806		$ 19,775	$ 25,530	$ 23,379
Accounts receivable, net of allowances of $113 as of December 30, 2018	4,257		4,737
Inventories	3,473		3,482
Prepaid expenses and other current assets	5,687		11,426
Total current assets	32,223		39,420
Property and equipment, net	79,032		87,782
Right-of-use assets for operating leases	211,988
Indefinite-lived intangible assets	3,404		3,404
Goodwill	2,222		2,222
Deferred income taxes, non-current			13,385
Deferred expenses, net and other assets	4,010		7,002
Total assets	332,879		153,215
Current liabilities
Accounts payable	3,886		3,835
Accrued expenses	20,398		25,029
Short-term operating lease liabilities	29,319
Accrued income taxes	171		162
Total current liabilities	53,774		29,026
Deferred rent and landlord allowances			22,905
Long-term operating lease liabilities	206,726
Other long-term liabilities	3,210		5,751
Total liabilities	263,710		57,682
Equity
Common stock, $0.01 par value—authorized 200,000 shares; outstanding 23,638 and 24,143 shares as of December 29, 2019 and December 30, 2018, respectively	331		330
Additional paid-in-capital	435,278		432,771
Treasury stock, held at cost, 9,465 and 8,801 shares as of December 29, 2019, and December 30, 2018, respectively	(112,680)		(108,372)
Accumulated deficit	(254,081)		(229,558)
Total stockholders’ equity	68,848		95,171
Non-controlling interest	321		362
Total equity	69,169		95,533	$ 117,238	$ 124,236
Total liabilities and equity	$ 332,879		$ 153,215
ASU 2016-02 (Topic 842) [Member]
Current assets
Cash and cash equivalents		$ 19,775
Accounts receivable, net of allowances of $113 as of December 30, 2018		4,737
Inventories		3,482
Prepaid expenses and other current assets		11,426
Total current assets		39,420
Property and equipment, net		87,782
Right-of-use assets for operating leases		232,477
Indefinite-lived intangible assets		3,404
Goodwill		2,222
Deferred income taxes, non-current		13,580
Deferred expenses, net and other assets		7,002
Total assets		385,887
Current liabilities
Accounts payable		3,835
Accrued expenses		23,905
Short-term operating lease liabilities		28,826
Accrued income taxes		162
Total current liabilities		56,728
Long-term operating lease liabilities		228,406
Other long-term liabilities		5,751
Total liabilities		290,885
Equity
Common stock, $0.01 par value—authorized 200,000 shares; outstanding 23,638 and 24,143 shares as of December 29, 2019 and December 30, 2018, respectively		330
Additional paid-in-capital		432,771
Treasury stock, held at cost, 9,465 and 8,801 shares as of December 29, 2019, and December 30, 2018, respectively		(108,372)
Accumulated deficit		(230,089)
Total stockholders’ equity		94,640
Non-controlling interest		362
Total equity		95,002
Total liabilities and equity		385,887
Adjustments Due to the Adoption of Topic 842 \| ASU 2016-02 (Topic 842) [Member]
Current assets
Right-of-use assets for operating leases		232,477
Deferred income taxes, non-current		195
Total assets		232,672
Current liabilities
Accrued expenses		(1,124)
Short-term operating lease liabilities		28,826
Total current liabilities		27,702
Deferred rent and landlord allowances		(22,905)
Long-term operating lease liabilities		228,406
Total liabilities		233,203
Equity
Accumulated deficit		(531)
Total stockholders’ equity		(531)
Total equity		(531)
Total liabilities and equity		$ 232,672

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. 29, 2019	Sep. 29, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 30, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 29, 2019	Dec. 30, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Net loss attributable to Potbelly Corporation	$ (1,332)	$ (2,355)	$ (1,866)	$ (18,439)	$ (4,363)	$ (1,961)	$ (360)	$ (2,194)	$ (23,992)	$ (8,878)	$ (6,956)
Weighted average common shares outstanding-basic									23,850	25,173	25,045
Weighted average common shares outstanding-diluted									23,850	25,173	25,045
Loss per share available to common stockholders-basic	$ (0.06)	$ (0.10)	$ (0.08)	$ (0.76)	$ (0.17)	$ (0.08)	$ (0.01)	$ (0.09)	$ (1.01)	$ (0.35)	$ (0.28)
Loss per share available to common stockholders-diluted	$ (0.06)	$ (0.10)	$ (0.08)	$ (0.76)	$ (0.17)	$ (0.08)	$ (0.01)	$ (0.09)	$ (1.01)	$ (0.35)	$ (0.28)
Potentially dilutive shares that are considered anti-dilutive									2,334	2,499	3,376

- 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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+ Details

- Definition

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.

+ References

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+ Details

- Definition

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

+ References + Details

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 29, 2019	Jan. 26, 2020	Jun. 30, 2019
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 29, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Trading Symbol	PBPB
Entity Registrant Name	Potbelly Corporation
Entity Central Index Key	0001195734
Current Fiscal Year End Date	--12-29
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		23,638,157
Entity Public Float			$ 116.7
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 2020 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.

Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 29, 2019

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 2019
	March 31			June 30			September 29			December 29
Total revenues	$	98,087		$	105,630		$	104,238		$	101,752
Loss from operations		(4,723	)		(1,468	)		(2,143	)		(862	)
Net 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	)

	Fiscal Year 2018
	April 1,			July 1,			September 30			December 30
Total revenues	$	102,917		$	110,347		$	106,996		$	102,378
Income (loss) from operations		(2,630	)		95			(2,697	)		(5,370	)
Loss attributable to Potbelly Corporation		(2,194	)		(360	)		(1,961	)		(4,363	)
Loss per share attributable to common stockholders-basic		(0.09	)		(0.01	)		(0.08	)		(0.17	)
Loss per share attributable to common stockholders-diluted		(0.09	)		(0.01	)		(0.08	)		(0.17	)

Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 29, 2019

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Data (Unaudited)

(13) 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 2019
	March 31			June 30			September 29			December 29
Total revenues	$	98,087		$	105,630		$	104,238		$	101,752
Loss from operations		(4,723	)		(1,468	)		(2,143	)		(862	)
Net 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	)

	Fiscal Year 2018
	April 1,			July 1,			September 30			December 30
Total revenues	$	102,917		$	110,347		$	106,996		$	102,378
Income (loss) from operations		(2,630	)		95			(2,697	)		(5,370	)
Loss attributable to Potbelly Corporation		(2,194	)		(360	)		(1,961	)		(4,363	)
Loss per share attributable to common stockholders-basic		(0.09	)		(0.01	)		(0.08	)		(0.17	)
Loss per share attributable to common stockholders-diluted		(0.09	)		(0.01	)		(0.08	)		(0.17	)

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 29, 2019	Dec. 30, 2018
Statement Of Financial Position [Abstract]
Allowances on accounts receivable	$ 202	$ 113
Common stock, par value	$ 0.01	$ 0.01
Common stock, authorized	200,000,000	200,000,000
Common stock, outstanding	23,638,000	24,143,000
Treasury stock, shares	9,465,000	8,801,000

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 29, 2019	Dec. 30, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net income (loss)	$ (23,585)	$ (8,549)	$ (6,690)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation expense	22,103	23,142	25,680
Noncash lease expense	27,853
Deferred income tax	13,808	(3,016)	6,096
Deferred rent and landlord allowances		(82)	1,911
Stock-based compensation expense	2,335	2,882	4,676
Excess tax deficiency from stock-based compensation		1,089	2,112
Asset impairment, store closure and disposal of property and equipment	2,989	13,762	10,947
Amortization of debt issuance costs	55	37	37
Changes in operating assets and liabilities:
Accounts receivable, net	480	100	(650)
Inventories	9	43	(160)
Prepaid expenses and other assets	5,917	(694)	(3,190)
Accounts payable	(249)	177	286
Operating lease liabilities	(29,725)
Accrued expenses and other liabilities	(3,822)	2,097	764
Net cash provided by operating activities	18,168	30,988	41,819
Cash flows from investing activities:
Purchases of property and equipment	(14,365)	(21,395)	(34,684)
Net cash used in investing activities	(14,365)	(21,395)	(34,684)
Cash flows from financing activities:
Treasury stock repurchase	(4,217)	(22,916)	(12,941)
Debt issuance costs	(189)
Proceeds from exercise of stock options	173	8,244	6,487
Proceeds from exercise of stock warrants			1,972
Employee taxes on certain stock-based payment arrangements	(91)	(194)
Contributions from non-controlling interest	75	98	11
Distributions to non-controlling interest	(523)	(580)	(513)
Net cash used in financing activities	(4,772)	(15,348)	(4,984)
Net increase (decrease) in cash and cash equivalents	(969)	(5,755)	2,151
Cash and cash equivalents at beginning of period	19,775	25,530	23,379
Cash and cash equivalents at end of period	18,806	19,775	25,530
Supplemental cash flow information:
Income taxes paid	187	250	1,656
Interest paid	108	110	94
Supplemental non-cash investing and financing activities:
Unpaid liability for purchases of property and equipment	$ 1,198	$ 751	$ 1,741

Revenue - Summary of Expected Revenue Recognition Related to Contract Liabilities (Detail1) $ in Thousands	Dec. 29, 2019 USD ($)
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, remaining performance obligations	$ 3,648
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, remaining performance obligations	$ 1,272
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
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	$ 325
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	$ 222
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	$ 201
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	$ 166
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	$ 1,462
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year

Earnings (Loss) Per Share (Tables)

12 Months Ended

Dec. 29, 2019

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
	2019			2018			2017
Net loss attributable to Potbelly Corporation	$	(23,992	)	$	(8,878	)	$	(6,956	)
Weighted average common shares outstanding-basic		23,850			25,173			25,045
Plus: Effect of potential stock options exercise		—			—			—
Weighted average common shares outstanding-diluted		23,850			25,173			25,045
Loss per share available to common stockholders- basic	$	(1.01	)	$	(0.35	)	$	(0.28	)
Loss per share available to common stockholders- diluted	$	(1.01	)	$	(0.35	)	$	(0.28	)
Potentially dilutive shares that are considered anti-dilutive:
Shares		2,334			2,499			3,376

Summary of Significant Accounting Policies - Additional Information (Detail)	1 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 29, 2019 USD ($) Subsidiary Segment	Dec. 30, 2018 USD ($) JointVenture	Dec. 31, 2017 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		4,100,000	4,300,000	3,400,000
Impairment charges		2,600,000	$ 13,400,000	$ 10,600,000
ASU 2016-02 (Topic 842) [Member]
Summary Of Significant Accounting Policies [Line Items]
Operating Lease, Impairment Loss		$ 700,000
Performance Shares
Summary Of Significant Accounting Policies [Line Items]
Vesting description		The PSUs will vest fully on the third anniversary of the grant date. 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.
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Ownership interest rate		51.00%
Minimum [Member] \| Performance Shares
Summary Of Significant Accounting Policies [Line Items]
Vesting percentage of targeted number of shares	0.00%
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] \| Performance Shares
Summary Of Significant Accounting Policies [Line Items]
Vesting percentage of targeted number of shares	200.00%
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

Capital Stock

12 Months Ended

Dec. 29, 2019

Equity [Abstract]

Capital Stock

(10) Capital Stock

As of December 29, 2019 and December 30, 2018, 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 29, 2019, the Company had issued and outstanding 33,103 thousand and 23,638 thousand shares of common stock, respectively. As of December 30, 2018, the Company had issued and outstanding 32,944 thousand and 24,143 thousand shares of common stock, respectively.

Common Stock

As of December 29, 2019, 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. 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 29, 2019, 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.

Property and Equipment (Tables)

12 Months Ended

Dec. 29, 2019

Property Plant And Equipment [Abstract]

Components of Property and Equipment, Net

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

	December 29,			December 30,
	2019			2018
Leasehold improvements	$	171,586		$	169,300
Machinery and equipment		49,943			48,606
Furniture and fixtures		34,325			33,177
Computer equipment and software		38,881			35,159
Construction in progress		2,615			1,938
		297,350			288,180
Less: Accumulated depreciation		(218,318	)		(200,398	)
	$	79,032		$	87,782

Debt and Credit Facilities

12 Months Ended

Dec. 29, 2019

Debt Disclosure [Abstract]

Debt and Credit Facilities

(9) Debt and Credit Facilities

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. As of the year ended December 29, 2019, the Company had no amounts outstanding under the Credit Agreement.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 29, 2019

Accounting Policies [Abstract]

Principles of Consolidation

(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.

Reporting Period

(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 2019, 2018 and 2017 consisted of 52, 52 and 53 weeks, respectively.

Segment Reporting

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.

Use of Estimates

(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.

Fair Value Measurements

(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.

Financial Instruments

(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.

Cash and Cash Equivalents

(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.

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

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.

Property and Equipment

(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.

Indefinite-Lived Intangible Assets

(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 for any of the fiscal periods presented.

Pre-opening Costs

(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.

Advertising Expenses

(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 $4.1 million, $4.3 million and $3.4 million in fiscal years 2019, 2018 and 2017, respectively.

Income Taxes

(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.

Stock-Based Compensation

(o) Stock-Based Compensation

The Company has granted stock options under its 2004 Equity Incentive Plan (the “2004 Plan”), 2013 Long-Term Incentive Plan (the “2013 Plan”) and 2019 Long-Term Incentive Plan (the “2019 Plan”), as amended (the “2019 Plan” and together with the 2013 Plan and 2004 Plan, the “Plans”) and restricted stock units (“RSUs”) under its 2013 Plan and 2019 Plan. The Plans permit the granting of awards to employees and non-employee officers, consultants, agents, and independent contractors of the Company in the form of stock appreciation rights, stock awards and units, and stock options. The Plans give broad powers to the Company’s board of directors to administer and interpret the Plans, including the authority to select the individuals to be granted options and rights and to prescribe the particular form and conditions of each option 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. All remaining shares of common stock reserved for issuance under the 2013 Plan are available for issuance under the 2019 Plan and no future awards will be made under the 2013 Plan.

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 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 related to adjusted EBITDA and same store sales goals. The PSUs will vest fully on the third anniversary of the grant date. 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.

Leases

(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. As we have no outstanding debt nor committed credit facilities, secured or otherwise, 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.

Related to the adoption of Topic 842, our policy elections were as follows:

Separation of lease and non-lease components		We elected this expedient to account for lease and non-lease components as a single component for our entire population of operating lease assets.
Short-term policy		We have elected the short-term lease recognition exemption for all applicable classes of underlying assets. Short-term disclosures include only those leases with a term greater than one month and 12 months or less, and expense is recognized on a straight-line basis over the lease term. Leases with an initial term of 12 months or less, that do not include an option to purchase the underlying asset that we are reasonably certain to exercise, are not recorded on the balance sheet.

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.

Revenue Recognition

(q) Revenue Recognition

Revenue from retail shops is presented net of discounts and recognized when food and beverage products are tendered at the point of sale. 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 adopted ASC 606 as January 1, 2018 using the modified retrospective method applied to contracts that were not completed as of the date of adoption.

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 recognized gift card breakage income, which is recorded within gross sales in the consolidated statements of operations.

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.

Impairment of Long-Lived Assets

(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 company-operated shops during each quarter of 2019, 2018 and 2017, it was determined that indicators of impairment were present for certain shops as a result of continued underperformance. The Company performed an impairment analysis for these shops and recorded impairment charges of $2.6 million, $13.4 million, and $10.6 million for the fiscal years 2019, 2018, and 2017, respectively, which is included in impairment and loss on disposal of property and equipment 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.

Recent Accounting Pronouncements

(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.

Our practical expedients were as follows:

	Implications as of December 31, 2018
Practical expedient package	We have not reassessed whether any expired or existing contracts are, or contain, leases.
	We have not reassessed the lease classification for any expired or existing leases.
	We have not reassessed initial direct costs for any expired or existing leases.
Hindsight practical expedient	We have not elected the hindsight practical expedient, which permits the use of hindsight when determining lease term and impairment of operating lease assets.

The impact on the consolidated balance sheet is as follows:

				Adjustments Due
	December 30,			to the Adoption of			December 31,
	2018			Topic 842			2018
Assets
Current assets
Cash and cash equivalents	$	19,775		$	—		$	19,775
Accounts receivable, net of allowances of $113 as of December 30, 2018		4,737			—			4,737
Inventories		3,482			—			3,482
Prepaid expenses and other current assets		11,426			—			11,426
Total current assets		39,420			—			39,420

Property and equipment, net		87,782			—			87,782
Right-of-use assets for operating leases		—			232,477			232,477
Indefinite-lived intangible assets		3,404			—			3,404
Goodwill		2,222			—			2,222
Deferred income taxes, noncurrent		13,385			195			13,580
Deferred expenses, net and other assets		7,002			—			7,002
Total assets	$	153,215		$	232,672		$	385,887

Liabilities and Equity
Current liabilities
Accounts payable	$	3,835		$	—		$	3,835
Accrued expenses⁽¹⁾		25,029			(1,124	)		23,905
Short-term operating lease liabilities		—			28,826			28,826
Accrued income taxes		162			—			162
Total current liabilities		29,026			27,702			56,728

Deferred rent and landlord allowances⁽¹⁾		22,905			(22,905	)		—
Long-term operating lease liabilities		—			228,406			228,406
Other long-term liabilities		5,751			—			5,751
Total liabilities		57,682			233,203			290,885

Stockholders’ equity
Common stock, $0.01 par value—authorized 200,000 shares; outstanding 24,143 shares as of December 30, 2018		330			—			330
Additional paid-in-capital		432,771			—			432,771
Treasury stock, held at cost, 8,801 shares as of December 30, 2018		(108,372	)		—			(108,372	)
Accumulated deficit⁽²⁾		(229,558	)		(531	)		(230,089	)
Total stockholders’ equity		95,171			(531	)		94,640
Non-controlling interest		362			—			362
Total stockholders' equity		95,533			(531	)		95,002

Total liabilities and equity	$	153,215		$	232,672		$	385,887

(1)	Adjustment to reclassify deferred rent and tenant improvement allowance to right-of-use assets for operating leases upon the adoption of Topic 842.

(2)	The Company recorded a net reduction of $0.5 million to opening accumulated deficit as of December 31, 2018, due to the cumulative impact of adopting Topic 842.

In June 2016, the FASB issued Accounting Standard Update No. 2016-13, Financial Instruments—Credit Losses (Topic 326), which 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. This new guidance is effective for the Company prospectively beginning December 30, 2019 and is not expected to have a material impact on the Company’s consolidated financial statements.

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 29, 2019	Dec. 30, 2018	Dec. 31, 2017
Revenues
Total revenues	$ 409,707	$ 422,638	$ 428,111
Sandwich shop operating expenses
Labor and related expenses	128,403	127,962	126,337
Occupancy expenses	58,977	59,789	58,562
Other operating expenses	50,178	50,363	49,209
General and administrative expenses	47,949	46,862	44,618
Depreciation expense	22,103	23,142	25,680
Pre-opening costs	35	472	1,441
Impairment and loss on disposal of property and equipment	2,932	13,567	10,761
Total expenses	418,903	433,240	430,034
Loss from operations	(9,196)	(10,602)	(1,923)
Interest expense	199	142	124
Loss before income taxes	(9,395)	(10,744)	(2,047)
Income tax expense (benefit)	14,190	(2,195)	4,643
Net loss	(23,585)	(8,549)	(6,690)
Net income attributable to non-controlling interest	407	329	266
Net loss attributable to Potbelly Corporation	$ (23,992)	$ (8,878)	$ (6,956)
Net loss per common share attributable to common stockholders:
Basic	$ (1.01)	$ (0.35)	$ (0.28)
Diluted	$ (1.01)	$ (0.35)	$ (0.28)
Weighted average shares outstanding:
Basic	23,850	25,173	25,045
Diluted	23,850	25,173	25,045
Product [Member]
Revenues
Total revenues	$ 406,688	$ 419,426	$ 424,932
Sandwich shop operating expenses
Cost of goods sold, excluding depreciation	108,326	111,083	113,426
Franchise Royalties And Fees [Member]
Revenues
Total revenues	$ 3,019	$ 3,212	$ 3,179

Capital Stock - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 29, 2019	Dec. 30, 2018	Dec. 31, 2017	May 08, 2018
Equity Class Of Treasury Stock [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	33,103,000	32,944,000
Common stock, outstanding	23,638,000	24,143,000
Stock repurchase program, authorized amount				$ 65,000,000
Common stock repurchased value	$ 4,217,000	$ 22,916,000	$ 12,941,000
Remaining dollar value of authorization under the share repurchase program	$ 37,900,000
Stock Repurchase Program [Member]
Equity Class Of Treasury Stock [Line Items]
Common stock shares repurchased	648,000
Common stock repurchased value	$ 4,200,000

Stock-Based Compensation

12 Months Ended

Dec. 29, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation

(12) 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. As of December 29, 2019, there have been 209 thousand shares of restricted stock units granted under the 2019 Plan. There were no options or shares of common stock granted under the 2019 Plan. As of December 29, 2019, there are 1,560 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 29, 2019 is $9.37 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 25, 2016		4,013		$	10.61	$	13,455		4.78
Granted		464			12.09
Exercised		(653	)		9.94
Canceled		(515	)		12.18
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
Exercisable—December 29, 2019		1,546		$	11.06	$	—		3.83

There were no stock option grants in 2019. The following table reflects the average assumptions utilized in the Black-Scholes option-pricing model to value the options granted for 2018 and 2017:

	2018			2017
Risk-free interest rate		3.0	%		2.0	%
Expected life (years)		6.25			6.25
Expected dividend yield		—			—
Volatility		35.0	%		36.0	%
Weighted average grant date fair value	$	4.52		$	4.76

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 29, 2019, December 30, 2018 and December 31, 2017, the Company recognized stock-based compensation expense related to stock options of $0.8 million, $1.4 million and $3.0 million, respectively. The Company records stock-based compensation expense within general and administrative expenses in the condensed consolidated statements of operations. As of December 29, 2019, unrecognized stock-based compensation expense related to stock options was $0.8 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 25, 2016		71		$	13.43
Granted		241			11.63
Vested		(45	)		13.53
Canceled		—			—
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

For the years ended December 29, 2019, December 30, 2018 and December 31, 2017, the Company recognized stock-based compensation expense related to RSUs of $1.5 million, $1.5 million and $1.7 million, respectively. As of December 29, 2019, unrecognized stock-based compensation expense for RSUs was $1.7 million, which will be recognized though fiscal year 2022.

Performance stock units

The Company awards performance share units (“PSUs”) to eligible employees; the PSUs are subject to service and performance vesting conditions. In March of 2019 the Company issued 188 thousand PSUs with a grant date fair value of $8.46 per share. The PSUs will vest based on the Company’s achievement of certain targets related to adjusted EBITDA and same store sales goals. The PSUs will vest fully on the third anniversary of the grant date. 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 29, 2019, no expense was recognized related to PSUs.

Stock-Based Compensation - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 29, 2019	Dec. 30, 2018	Dec. 31, 2017	Jun. 10, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock units issued		402,000	131,000	241,000
Stock-based compensation expense		$ 2,335,000	$ 2,882,000	$ 4,676,000
Stock units issued, grant-date fair value		$ 6.47	$ 12.12	$ 11.63
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-based compensation expense		$ 1,500,000	$ 1,500,000	$ 1,700,000
Unrecognized stock compensation expense		$ 1,700,000
Unrecognized stock compensation expense, recognition period		2022
Restricted Stock Units (RSUs) [Member] \| Non-Employee Board Of Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting description		The employee grants vest in one-third increments over a three-year period
Restricted Stock Units (RSUs) [Member] \| Share Based Compensation Award Tranche One [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] \| Share Based Compensation Award Tranche Two [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		$ 800,000	$ 1,400,000	$ 3,000,000
Unrecognized stock compensation expense		$ 800,000
Unrecognized stock compensation expense, recognition period		2022
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock units issued	188,000
Stock-based compensation expense		$ 0
Vesting description		The PSUs will vest fully on the third anniversary of the grant date. 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.
Stock units issued, grant-date fair value	$ 8.46
Performance Shares \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage of targeted number of shares	200.00%
Performance Shares \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage of targeted number of shares	0.00%
2019 Long Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for issuance		1,560,000
Options granted		0
Exercise price of options outstanding, lower limit		$ 9.37
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]
Exercisable period from the date of grant		10 years
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		209,000

Income Taxes (Tables)

12 Months Ended

Dec. 29, 2019

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
	2019			2018			2017
Domestic operations	$	(9,790	)	$	(11,381	)	$	(2,513	)
Foreign operations		395			637			466
Total	$	(9,395	)	$	(10,744	)	$	(2,047	)

Components of Income Tax Expense (Benefit)

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

	Fiscal Year
	2019		2018			2017
Federal:
Current	$	159	$	(339	)	$	(3,728	)
Deferred		9,379		(1,644	)		8,792
		9,538		(1,983	)		5,064
State and Local:
Current		227		73			150
Deferred		4,425		(305	)		(584	)
		4,652		(232	)		(434	)
Foreign:
Current		—		20			13
		—		20			13
Income tax expense (benefit)	$	14,190	$	(2,195	)	$	4,643

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
	2019			2018			2017
U.S. federal statutory tax		21.0	%		21.0	%		35.0	%
Computed “expected” tax expense (benefit)	$	(1,973	)	$	(2,256	)	$	(716	)
Increase (reduction) resulting from:
Valuation allowance		16,116			-			-
Minority interest		(107	)		(87	)		(105	)
Permanent differences		425			220			96
State and local income taxes, net of federal income tax effect		(361	)		(436	)		5
FICA and other tax credits		(504	)		(522	)		(502	)
Equity compensation		577			1,089			2,112
Adjustments		(106	)		(252	)		(93	)
Tax rate change		123			49			3,846
	$	14,190		$	(2,195	)	$	4,643

Schedule of Deferred Tax Assets and Liabilities

	December 29,			December 30,
	2019			2018
Deferred tax assets:
Net operating loss carryforwards	$	3,721		$	576
Accrued liabilities		848			1,449
Deferred revenue		423			543
Stock-based compensation		2,516			2,685
Property and equipment		4,568			5,037
Operating lease liabilities		62,313			—
Deferred rent		—			4,373
Tax credits and charitable contribution carryforwards		1,538			981
Gross deferred tax assets		75,927			15,644
Valuation allowance		(16,116	)		—
Net deferred tax assets		59,811			15,644
Deferred tax liabilities:
Prepaids		(492	)		(466	)
Right-of-use asset for operating leases		(57,717	)		—
Intangible assets		(1,162	)		(1,075	)
Smallwares		(533	)		(566	)
Other		(134	)		(152	)
Total deferred tax liabilities		(60,038	)		(2,259	)
Net deferred tax liabilities	$	(227	)	$	13,385

Summary of Significant Accounting Policies

12 Months Ended

Dec. 29, 2019

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

(2) Summary of Significant Accounting Policies

(a) Principles of Consolidation

(b) Reporting Period

(d) Use of Estimates

(e) Fair Value Measurements

•

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

•

(f) Financial Instruments

(g) Cash and Cash Equivalents

(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

(j) Property and Equipment

(k) Indefinite-Lived Intangible Assets

(l) Pre-opening Costs

(m) Advertising Expenses

(n) Income Taxes

(o) Stock-Based Compensation

(p) Leases

Related to the adoption of Topic 842, our policy elections were as follows:

Separation of lease and non-lease components		We elected this expedient to account for lease and non-lease components as a single component for our entire population of operating lease assets.
Short-term policy		We have elected the short-term lease recognition exemption for all applicable classes of underlying assets. Short-term disclosures include only those leases with a term greater than one month and 12 months or less, and expense is recognized on a straight-line basis over the lease term. Leases with an initial term of 12 months or less, that do not include an option to purchase the underlying asset that we are reasonably certain to exercise, are not recorded on the balance sheet.

(q) Revenue Recognition

(r) Impairment of Long-Lived Assets

(s) Recent Accounting Pronouncements

Our practical expedients were as follows:

	Implications as of December 31, 2018
Practical expedient package	We have not reassessed whether any expired or existing contracts are, or contain, leases.
	We have not reassessed the lease classification for any expired or existing leases.
	We have not reassessed initial direct costs for any expired or existing leases.
Hindsight practical expedient	We have not elected the hindsight practical expedient, which permits the use of hindsight when determining lease term and impairment of operating lease assets.

The impact on the consolidated balance sheet is as follows:

				Adjustments Due
	December 30,			to the Adoption of			December 31,
	2018			Topic 842			2018
Assets
Current assets
Cash and cash equivalents	$	19,775		$	—		$	19,775
Accounts receivable, net of allowances of $113 as of December 30, 2018		4,737			—			4,737
Inventories		3,482			—			3,482
Prepaid expenses and other current assets		11,426			—			11,426
Total current assets		39,420			—			39,420

Property and equipment, net		87,782			—			87,782
Right-of-use assets for operating leases		—			232,477			232,477
Indefinite-lived intangible assets		3,404			—			3,404
Goodwill		2,222			—			2,222
Deferred income taxes, noncurrent		13,385			195			13,580
Deferred expenses, net and other assets		7,002			—			7,002
Total assets	$	153,215		$	232,672		$	385,887

Liabilities and Equity
Current liabilities
Accounts payable	$	3,835		$	—		$	3,835
Accrued expenses⁽¹⁾		25,029			(1,124	)		23,905
Short-term operating lease liabilities		—			28,826			28,826
Accrued income taxes		162			—			162
Total current liabilities		29,026			27,702			56,728

Deferred rent and landlord allowances⁽¹⁾		22,905			(22,905	)		—
Long-term operating lease liabilities		—			228,406			228,406
Other long-term liabilities		5,751			—			5,751
Total liabilities		57,682			233,203			290,885

Stockholders’ equity
Common stock, $0.01 par value—authorized 200,000 shares; outstanding 24,143 shares as of December 30, 2018		330			—			330
Additional paid-in-capital		432,771			—			432,771
Treasury stock, held at cost, 8,801 shares as of December 30, 2018		(108,372	)		—			(108,372	)
Accumulated deficit⁽²⁾		(229,558	)		(531	)		(230,089	)
Total stockholders’ equity		95,171			(531	)		94,640
Non-controlling interest		362			—			362
Total stockholders' equity		95,533			(531	)		95,002

Total liabilities and equity	$	153,215		$	232,672		$	385,887

(1)	Adjustment to reclassify deferred rent and tenant improvement allowance to right-of-use assets for operating leases upon the adoption of Topic 842.

(2)	The Company recorded a net reduction of $0.5 million to opening accumulated deficit as of December 31, 2018, due to the cumulative impact of adopting Topic 842.

Earnings (Loss) Per Share

12 Months Ended

Dec. 29, 2019

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 the year ended December 29, 2019, 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
	2019			2018			2017
Net loss attributable to Potbelly Corporation	$	(23,992	)	$	(8,878	)	$	(6,956	)
Weighted average common shares outstanding-basic		23,850			25,173			25,045
Plus: Effect of potential stock options exercise		—			—			—
Weighted average common shares outstanding-diluted		23,850			25,173			25,045
Loss per share available to common stockholders- basic	$	(1.01	)	$	(0.35	)	$	(0.28	)
Loss per share available to common stockholders- diluted	$	(1.01	)	$	(0.35	)	$	(0.28	)
Potentially dilutive shares that are considered anti-dilutive:
Shares		2,334			2,499			3,376

Employee Benefit Plan - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 29, 2019	Dec. 30, 2018	Dec. 31, 2017
Defined Benefit Plans And Other Postretirement Benefit Plans Disclosures [Abstract]
Contributions made to profit sharing plan	$ 0.5	$ 0.4	$ 0.4

Income Taxes - Schedule of Income (Loss) Before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 29, 2019	Dec. 30, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Domestic operations	$ (9,790)	$ (11,381)	$ (2,513)
Foreign operations	395	637	466
Loss before income taxes	$ (9,395)	$ (10,744)	$ (2,047)

Leases (Tables)

12 Months Ended

Dec. 29, 2019

Leases [Abstract]

Operating Lease Term and Discount Rate

Operating lease term and discount rate were as follows:

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

Components of Lease Cost

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

		Fiscal Year
	Classification	2019
Operating lease cost	Occupancy and general and administrative expenses	$	45,604
Variable lease cost	Occupancy and general and administrative expenses		13,692
Total lease cost		$	59,296

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
	2019
Operating cash flows rent paid for operating lease liabilities	$	47,335
Operating right-of-use assets obtained in exchange for new operating lease liabilities		15,765
Reduction in operating right-of-use assets due to lease terminations	$	(6,506	)

Maturities of Lease Liabilities

Maturities of lease liabilities were as follows at December 29, 2019 (in thousands):

	Operating Leases
2020	$	46,581
2021		43,639
2022		38,096
2023		33,512
2024		30,427
Thereafter		141,456
Total lease payments		333,711
Less: imputed interest		(97,666	)
Present value of lease liabilities	$	236,045

Maturities of Lease Liabilities Under the Previous Lease Accounting

As previously disclosed in our 2018 Annual Report on Form 10-K and under the previous lease accounting, maturities of lease liabilities were as follows at December 30, 2018 (in thousands):

	Operating Leases
2019	$	47,918
2020		45,828
2021		41,497
2022		36,120
2023		31,060
Thereafter		138,928
Total minimum lease payments	$	341,351

Debt and Credit Facilities - Additional Information (Detail) - USD ($)	Aug. 07, 2019	Dec. 29, 2019
London Interbank Offered Rate (LIBOR) [Member] \| Maximum [Member]
Short Term Debt [Line Items]
Credit facility agreement, interest rate	1.75%
London Interbank Offered Rate (LIBOR) [Member] \| Minimum [Member]
Short Term Debt [Line Items]
Credit facility agreement, interest rate	1.25%
JPMorgan Chase Bank, N.A. [Member]
Short Term Debt [Line Items]
Commitment fee, percentage	0.20%
Credit facility agreement, amount outstanding		$ 0
JPMorgan Chase Bank, N.A. [Member] \| Prime Rate [Member] \| Maximum [Member]
Short Term Debt [Line Items]
Credit facility agreement, interest rate	0.50%
JPMorgan Chase Bank, N.A. [Member] \| Prime Rate [Member] \| Minimum [Member]
Short Term Debt [Line Items]
Credit facility agreement, interest rate	0.00%
Revolving Credit Facility [Member] \| JPMorgan Chase Bank, N.A. [Member]
Short Term Debt [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]
Short Term Debt [Line Items]
Credit facility agreement, future increases	$ 20,000,000

Accrued Expenses (Tables)

12 Months Ended

Dec. 29, 2019

Accrued Liabilities Current [Abstract]

Summary of Accrued Expenses

Accrued expenses consisted of the following (in thousands):

	December 29,		December 30,
	2019		2018
Accrued labor and related expenses	$	7,403	$	10,324
Deferred gift card revenue		1,415		1,821
Accrued occupancy expenses		2,010		2,309
Deferred rent—current		—		1,250
Accrued corporate and shop expenses		1,859		1,446
Accrued utilities		1,137		1,304
Accrued sales and use tax		2,063		3,001
Accrued construction		293		147
Accrued contract termination costs ^(a)		—		392
Accrued legal and professional fees		716		128
Accrued other		3,502		2,907
Total	$	20,398	$	25,029

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 29,			December 30,
	2019			2018
Accrued contract termination costs—beginning balance	$	392		$	27
Contract termination costs incurred		3,449			1,461
Contract termination costs settled and paid		(3,841	)		(1,096	)
Accrued contract termination costs—ending balance	$	—		$	392

Consolidated Statements of Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Warrants [Member]	Additional Paid-in-Capital [Member]	Accumulated Deficit [Member]	Non-Controlling Interest [Member]
Beginning balance at Dec. 25, 2016	$ 124,236	$ 309	$ (72,321)	$ 909	$ 407,622	$ (213,034)	$ 751
Beginning balance, common shares at Dec. 25, 2016		25,139
Net income (loss)	(6,690)					(6,956)	266
Stock-based compensation plans	6,487	$ 7			6,480
Stock-based compensation plans, shares		697
Exercise of stock warrants	$ 1,972	$ 2		$ (909)	2,879
Exercise of stock warrants, shares	653	242
Repurchases of common stock	$ (12,941)		(12,941)
Repurchases of common stock, shares		(1,078)
Distributions to non-controlling interest	(513)						(513)
Contributions from non-controlling interest	11						11
Stock-based compensation expense	4,676				4,676
Ending balance at Dec. 31, 2017	117,238	$ 318	(85,262)		421,657	(219,990)	515
Ending balance, common shares at Dec. 31, 2017		25,000
Net income (loss)	(8,549)					(8,878)	329
Cumulative impact \| ASU 2014-09 (Topic 606) [Member]	(690)					(690)
Stock-based compensation plans	$ 8,244	$ 12			8,232
Stock-based compensation plans, shares		1,112
Exercise of stock warrants, shares	993
Treasury shares used for stock-based plans	$ (194)		(194)
Treasury shares used for stock-based plans, shares		(16)
Repurchases of common stock	(22,916)		(22,916)
Repurchases of common stock, shares		(1,953)
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	24,143
Net income (loss)	$ (23,585)					(23,992)	407
Cumulative impact \| ASU 2016-02 (Topic 842) [Member]	(531)					(531)
Stock-based compensation plans	$ 173	$ 1			172
Stock-based compensation plans, shares		159
Exercise of stock warrants, shares	22
Treasury shares used for stock-based plans	$ (91)		(91)
Treasury shares used for stock-based plans, shares		(16)
Repurchases of common stock	(4,217)		(4,217)
Repurchases of common stock, shares		(648)
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	23,638

Earnings (Loss) Per Share - Additional Information (Detail) - shares	12 Months Ended
	Dec. 29, 2019	Dec. 30, 2018	Dec. 31, 2017
Earnings (Loss) Per Share [Line Items]
Potential common shares included in diluted shares outstanding	2,334	2,499	3,376
Common Share Options [Member]
Earnings (Loss) Per Share [Line Items]
Potential common shares included in diluted shares outstanding	0

Organization and Other Matters - Additional Information (Detail)	Dec. 29, 2019 Shop
Nature Of Business And Basis Of Presentation [Line Items]
Number of shops franchisees operate	40
Minimum [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Number of shops Potbelly Corporation owns or operates	400

Property and Equipment - Components of Property and Equipment (Detail) - USD ($) $ in Thousands	Dec. 29, 2019	Dec. 30, 2018
Property Plant And Equipment [Abstract]
Leasehold improvements	$ 171,586	$ 169,300
Machinery and equipment	49,943	48,606
Furniture and fixtures	34,325	33,177
Computer equipment and software	38,881	35,159
Construction in progress	2,615	1,938
Property and equipment, gross	297,350	288,180
Less: Accumulated depreciation	(218,318)	(200,398)
Property and equipment, net	$ 79,032	$ 87,782

Quarterly Financial Data (Unaudited) - Summary of Unaudited Quarterly Financial Data (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 29, 2019	Sep. 29, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 30, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 29, 2019	Dec. 30, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Total revenues	$ 101,752	$ 104,238	$ 105,630	$ 98,087	$ 102,378	$ 106,996	$ 110,347	$ 102,917	$ 409,707	$ 422,638	$ 428,111
Income (Loss) from operations	(862)	(2,143)	(1,468)	(4,723)	(5,370)	(2,697)	95	(2,630)	(9,196)	(10,602)	(1,923)
Net loss attributable to Potbelly Corporation	$ (1,332)	$ (2,355)	$ (1,866)	$ (18,439)	$ (4,363)	$ (1,961)	$ (360)	$ (2,194)	$ (23,992)	$ (8,878)	$ (6,956)
Basic	$ (0.06)	$ (0.10)	$ (0.08)	$ (0.76)	$ (0.17)	$ (0.08)	$ (0.01)	$ (0.09)	$ (1.01)	$ (0.35)	$ (0.28)
Diluted	(0.06)	(0.10)	(0.08)	(0.76)	(0.17)	(0.08)	(0.01)	(0.09)	(1.01)	(0.35)	(0.28)
Loss per share available to common stockholders-basic	(0.06)	(0.10)	(0.08)	(0.76)	(0.17)	(0.08)	(0.01)	(0.09)	(1.01)	(0.35)	(0.28)
Loss per share available to common stockholders-diluted	$ (0.06)	$ (0.10)	$ (0.08)	$ (0.76)	$ (0.17)	$ (0.08)	$ (0.01)	$ (0.09)	$ (1.01)	$ (0.35)	$ (0.28)

- 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.

+ References + Details

Revenue - Additional Information (Detail) - USD ($)	3 Months Ended								12 Months Ended
Revenue - Additional Information (Detail) - USD ($)	Dec. 29, 2019	Sep. 29, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 30, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 29, 2019	Dec. 30, 2018	Dec. 31, 2017	Dec. 31, 2017
Disaggregation Of Revenue [Line Items]
Amount of revenue recognized	$ 101,752,000	$ 104,238,000	$ 105,630,000	$ 98,087,000	$ 102,378,000	$ 106,996,000	$ 110,347,000	$ 102,917,000	$ 409,707,000	$ 422,638,000		$ 428,111,000
Revenue recognized related to prior periods									200,000	300,000	$ 400,000
Aggregate value of remaining performance obligation on outstanding contracts	$ 3,648,000								3,648,000
Revenue recognized related to prior periods									0	0
January 1, 2018 Liability Ending Balance [Member]
Disaggregation Of Revenue [Line Items]
Amount of revenue recognized									2,200,000	2,100,000
Point in Time Sales [Member]
Disaggregation Of Revenue [Line Items]
Amount of revenue recognized									408,800,000	421,800,000
Over Time Sales [Member]
Disaggregation Of Revenue [Line Items]
Amount of revenue recognized									$ 900,000	$ 800,000

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

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. 29, 2019	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options outstanding shares, beginning balance	2,150	3,309	4,013
Options, granted		203	464
Options, exercised	(22)	(993)	(653)
Options, canceled	(354)	(369)	(515)
Options outstanding shares, ending balance	1,774	2,150	3,309	4,013
Options outstanding shares, exercisable	1,546
Options outstanding weighted average exercise price, beginning balance	$ 11.49	$ 10.71	$ 10.61
Options, weighted average exercise price, granted		11.27	12.09
Options, weighted average exercise price, exercised	7.93	8.30	9.94
Options, weighted average exercise price, canceled	12.45	13.63	12.18
Options outstanding weighted average exercise price, ending balance	11.34	$ 11.49	$ 10.71	$ 10.61
Options outstanding weighted average exercise price, exercisable	$ 11.06
Options outstanding aggregate intrinsic value		$ 378	$ 7,699	$ 13,455
Option outstanding weighted average remaining term	4 years 3 months 29 days	5 years 1 month 17 days	4 years 10 months 24 days	4 years 9 months 10 days
Options exercisable weighted average remaining term	3 years 9 months 29 days

Revenue

12 Months Ended

Dec. 29, 2019

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 due at the time of the customer’s purchase. The Company also receives royalties from franchisees on their respective sales, which are recognized at the point in time the sale is made and invoiced weekly. Potbelly also records revenue from sales over time related to initial franchise fees, gift card redemptions and breakage. 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. For the fiscal year ended December 30, 2018, revenue recognized from all revenue sources on point in time sales was $421.8 million, and revenue recognized from sales over time was $0.8 million.

Franchise Revenue

Potbelly licenses intellectual property and trademarks to franchisees through franchise agreements. As part of these franchise agreements, Potbelly receives an initial franchise fee from the franchisee, which the Company recognizes over the term of the franchise agreement. The Company records a contract liability for the unearned portion of the initial franchise fees.

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 recognized gift card breakage income of $0.2 million, $0.3 million and $0.4 million for the fiscal years ended 2019, 2018 and 2017, respectively, which is recorded within net sandwich shop sales in the consolidated statements of operations

Contract Liabilities

As described above, the Company records current and noncurrent contract liabilities for initial franchise fees as well as gift cards. 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 31, 2018	$	(2,184	)	$	(1,631	)
Ending balance as of December 29, 2019		(1,594	)		(2,054	)
Decrease in contract liability	$	(590	)	$	423

The aggregate value of remaining performance obligations on outstanding contracts was $3.6 million as of December 29, 2019. The decrease in the liability during the 52 weeks ended December 29, 2019 was a result of gift card redemptions offset by purchases of new gift cards and recognition of franchise fees. The Company expects 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
2020	$	1,272
2021		325
2022		222
2023		201
2024		166
Thereafter		1,462
Total revenue recognized	$	3,648

For the 52 weeks ended December 29, 2019, the amount of revenue recognized related to the December 31, 2018 liability ending balance was $2.2 million. For the 52 weeks ended December 30, 2018, the amount of revenue recognized related to the January 1, 2018 liability ending balance was $2.1 million. This revenue related to the recognition of gift card redemptions and upfront franchise fees. For the year ended December 29, 2019 and December 30, 2018, the Company did not recognize any revenue from obligations satisfied (or partially satisfied) in prior periods.

Revenue - Summary of Current and Noncurrent Contract Liabilities from Contracts with Customers (Detail) $ in Thousands	12 Months Ended
	Dec. 29, 2019 USD ($)
Revenue From Contract With Customer [Abstract]
Beginning balance of current contract liability	$ (2,184)
Ending balance of current contract liability	(1,594)
Decrease in contract liability	(590)
Beginning balance of noncurrent contract liability	(1,631)
Ending balance of noncurrent contract liability	(2,054)
Decrease in contract liability	$ 423

Stock-Based Compensation - Summary of RSU Activity (Detail) - $ / shares shares in Thousands	12 Months Ended
	Dec. 29, 2019	Dec. 30, 2018	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of RSUs, Non-vested, beginning balance	247	267	71
Stock units issued	402	131	241
Number of RSUs, Vested	(135)	(121)	(45)
Number of RSUs, Canceled	(51)	(30)
Number of RSUs, Non-vested, ending balance \| shares	463	247	267
Weighted Average Fair Value per Share, Non-vested, beginning balance	$ 11.99	$ 11.79	$ 13.43
Weighted Average Fair Value per Share, Granted	6.47	12.12	11.63
Weighted Average Fair Value per Share, Vested	11.94	11.92	13.53
Weighted Average Fair Value per Share, Canceled	8.48	11.05
Weighted Average Fair Value per Share, Non-vested, ending balance	$ 7.59	$ 11.99	$ 11.79

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 29, 2019

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 25, 2016		4,013		$	10.61	$	13,455		4.78
Granted		464			12.09
Exercised		(653	)		9.94
Canceled		(515	)		12.18
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
Exercisable—December 29, 2019		1,546		$	11.06	$	—		3.83

Schedule of Average Assumptions to Value Options

There were no stock option grants in 2019. The following table reflects the average assumptions utilized in the Black-Scholes option-pricing model to value the options granted for 2018 and 2017:

	2018			2017
Risk-free interest rate		3.0	%		2.0	%
Expected life (years)		6.25			6.25
Expected dividend yield		—			—
Volatility		35.0	%		36.0	%
Weighted average grant date fair value	$	4.52		$	4.76

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 25, 2016		71		$	13.43
Granted		241			11.63
Vested		(45	)		13.53
Canceled		—			—
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

Property and Equipment

12 Months Ended

Dec. 29, 2019

Property Plant And Equipment [Abstract]

Property and Equipment

(5) Property and Equipment

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

	December 29,			December 30,
	2019			2018
Leasehold improvements	$	171,586		$	169,300
Machinery and equipment		49,943			48,606
Furniture and fixtures		34,325			33,177
Computer equipment and software		38,881			35,159
Construction in progress		2,615			1,938
		297,350			288,180
Less: Accumulated depreciation		(218,318	)		(200,398	)
	$	79,032		$	87,782

Accrued Expenses - Summary of Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 29, 2019	Dec. 30, 2018	Dec. 31, 2017
Accrued Liabilities And Other Liabilities [Abstract]
Accrued labor and related expenses	$ 7,403	$ 10,324
Deferred gift card revenue	1,415	1,821
Accrued occupancy expenses	2,010	2,309
Deferred rent—current		1,250
Accrued corporate and shop expenses	1,859	1,446
Accrued utilities	1,137	1,304
Accrued sales and use tax	2,063	3,001
Accrued construction	293	147
Accrued contract termination costs		392	$ 27
Accrued legal and professional fees	716	128
Accrued other	3,502	2,907
Total	$ 20,398	$ 25,029