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Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Dec. 27, 2015	Feb. 19, 2016	Jun. 28, 2015
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 27, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY
Trading Symbol	PBPB
Entity Registrant Name	Potbelly Corporation
Entity Central Index Key	0001195734
Current Fiscal Year End Date	--12-27
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		26,308,631
Entity Public Float			$ 293.2

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 27, 2015	Dec. 28, 2014
Current assets
Cash and cash equivalents	$ 32,006	$ 63,005
Accounts receivable, net of allowances of $14 and $19 as of December 27, 2015 and December 28, 2014, respectively	4,461	4,016
Inventories	3,159	2,768
Deferred income taxes, current		507
Prepaid expenses and other current assets	10,155	9,922
Total current assets	49,781	80,218
Property and equipment, net	97,434	85,704
Indefinite-lived intangible assets	3,404	3,404
Goodwill	1,428	1,428
Deferred income taxes, non-current	18,439	17,860
Deferred expenses, net and other assets	4,021	3,333
Total assets	174,507	191,947
Current liabilities
Accounts payable	5,762	3,301
Accrued expenses	19,277	16,349
Accrued income taxes	143	226
Current portion of long-term debt		1,008
Total current liabilities	25,182	20,884
Deferred rent and landlord allowances	17,820	14,012
Other long-term liabilities	1,292	726
Total liabilities	44,294	35,622
Equity
Common stock, $0.01 par value—authorized, 200,000,000 shares; outstanding 26,304,261 and 28,934,700 shares as of December 27, 2015 and December 28, 2014, respectively	303	298
Warrants	909	909
Additional paid-in-capital	399,458	391,972
Treasury stock, held at cost, 4,033,910 and 827,090 shares as of December 27, 2015, and December 28, 2014, respectively	(50,000)	(10,246)
Accumulated deficit	(221,246)	(226,874)
Total stockholders’ equity	129,424	156,059
Non-controlling interest	789	266
Total equity	130,213	156,325
Total liabilities and equity	$ 174,507	$ 191,947

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2015	Dec. 28, 2014	Dec. 29, 2013
Revenues
Sandwich shop sales, net	$ 370,954	$ 325,464	$ 298,574
Franchise royalties and fees	1,895	1,515	1,138
Total revenues	372,849	326,979	299,712
Sandwich shop operating expenses
Cost of goods sold, excluding depreciation	105,614	93,688	87,380
Labor and related expenses	106,628	93,165	83,579
Occupancy expenses	46,762	41,389	36,394
Other operating expenses	39,869	34,669	30,781
General and administrative expenses	37,322	32,420	39,656
Depreciation expense	21,476	19,615	17,875
Pre-opening costs	2,160	1,634	1,437
Impairment and loss on disposal of property and equipment	3,589	3,128	1,135
Total expenses	363,420	319,708	298,237
Income from operations	9,429	7,271	1,475
Interest expense	221	179	387
Other expense			2
Income before income taxes	9,208	7,092	1,086
Income tax expense (benefit)	3,466	2,748	(204)
Net income	5,742	4,344	1,290
Net income (loss) attributable to non-controlling interest	114	(14)	32
Net income attributable to Potbelly Corporation	5,628	4,358	1,258
Dividend declared to common and preferred stockholders			(49,854)
Accretion of redeemable convertible preferred stock to maximum redemption value			(15,097)
Net income (loss) attributable to common stockholders	$ 5,628	$ 4,358	$ (63,693)
Net income (loss) per common share attributable to common stockholders:
Basic	$ 0.20	$ 0.15	$ (6.29)
Diluted	$ 0.20	$ 0.14	$ (6.29)
Weighted average shares outstanding:
Basic	28,002,005	29,209,298	10,132,805
Diluted	28,634,396	30,275,061	10,132,805

Consolidated Statements of Redeemable Convertible Preferred Stock and Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Warrants [Member]	Additional Paid-in-Capital [Member]	Accumulated Deficit [Member]	Non-Controlling Interest [Member]	Series A [Member]	Series B [Member]	Series C [Member]	Series D [Member]	Series E [Member]	Series F [Member]	Redeemable Convertible Preferred Stock [Member]
Beginning Balance at Dec. 30, 2012	$ (168,728)	$ 42		$ 1,552		$ (170,518)	$ 196	$ 52,796	$ 46,983	$ 23,715	$ 18,319	$ 79,861	$ 28,669	$ 250,343
Beginning Balance, Preferred Shares at Dec. 30, 2012								3,697,377	3,290,294	1,646,595	1,250,000	4,194,366	2,007,743	16,086,375
Net income	1,290					1,258	32
Beneficial conversion change					$ 50	(50)
Cash dividends declared	(49,854)				(49,854)
Common stock issuance, net of fees	108,321	$ 87			108,234
Common stock issuance, net of fees, Shares		8,709,785
Changes in redemption value of preferred stock	(15,097)				46,825	(61,922)		$ 3,582	$ 3,188	$ 1,609	$ 1,251	$ 3,523	$ 1,944	$ 15,097
Conversion of preferred stock to common stock	265,440	$ 160			265,280			$ (56,378)	$ (50,171)	$ (25,324)	$ (19,570)	$ (83,384)	$ (30,613)	$ (265,440)
Conversion of preferred stock to common stock, Shares		16,086,375						(3,697,377)	(3,290,294)	(1,646,595)	(1,250,000)	(4,194,366)	(2,007,743)	(16,086,375)
Shares cancelled in lieu of payment of payroll taxes	(165)				(165)
Exercise of stock options	$ 147	$ 1
Exercise of stock options, Shares	99,000
Exercise of stock options, additional paid in capital					146
Excess tax benefits associated with exercise of stock options	$ 308				308
Exercise of stock warrants	1	$ 1
Exercise of stock warrants, Shares		117,892
Exercise of stock warrants, additional paid in capital				(643)	643
Stock-based compensation	11,610				11,610
Ending Balance at Dec. 29, 2013	153,273	$ 291		909	383,077	(231,232)	228
Beginning Balance, Common Shares at Dec. 30, 2012		4,233,977
Ending Balance, Common Shares at Dec. 29, 2013		29,148,029
Net income	4,344					4,358	(14)
Common stock issuance, net of fees	432				432
Common stock issuance, net of fees, Shares		28,240
Exercise of stock options	$ 5,059	$ 7			5,052
Exercise of stock options, Shares	586,000	585,521
Repurchases of common stock	$ (10,246)		$ (10,246)
Repurchases of common stock, Shares		(827,090)
Contributions from non-controlling interest	98						98
Distribution to non-controlling interest	(46)						(46)
Excess tax benefits associated with exercise of stock options	1,300				1,300
Stock-based compensation	2,111				2,111
Ending Balance at Dec. 28, 2014	$ 156,325	$ 298	(10,246)	909	391,972	(226,874)	266
Ending Balance, Common Shares at Dec. 28, 2014	28,934,700	28,934,700
Net income	$ 5,742					5,628	114
Exercise of stock options	$ 4,784	$ 5			4,779
Exercise of stock options, Shares	576,000	576,381
Repurchases of common stock	$ (39,754)		(39,754)
Repurchases of common stock, Shares	(3,206,820)	(3,206,820)
Contributions from non-controlling interest	$ 607						607
Distribution to non-controlling interest	(198)						(198)
Excess tax benefits associated with exercise of stock options	308				308
Stock-based compensation	2,399				2,399
Ending Balance at Dec. 27, 2015	$ 130,213	$ 303	$ (50,000)	$ 909	$ 399,458	$ (221,246)	$ 789
Ending Balance, Common Shares at Dec. 27, 2015	26,304,261	26,304,261

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2015	Dec. 28, 2014	Dec. 29, 2013
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 5,742	$ 4,344	$ 1,290
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	21,476	19,615	17,875
Deferred income tax	(72)	(289)	(1,969)
Deferred rent and landlord allowances	3,808	1,787	440
Stock-based compensation	2,399	2,543	11,610
Excess tax benefit from stock-based compensation	(308)	(1,300)	(308)
Asset impairment, store closure and disposal of property and equipment	3,818	3,679	1,142
Amortization of debt issuance costs	11	70	64
Changes in operating assets and liabilities:
Accounts receivable, net	(445)	(1,013)	285
Inventories	(388)	(505)	(353)
Prepaid expenses and other assets	(1,155)	(4,216)	(2,076)
Accounts payable	1,876	1,301	(176)
Accrued and other liabilities	3,558	538	2,056
Net cash provided by operating activities	40,320	26,554	29,880
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisition of franchise shop	(333)
Purchases of property and equipment	(35,725)	(29,209)	(28,098)
Net cash (used in) investing activities	(36,058)	(29,209)	(28,098)
CASH FLOWS FROM FINANCING ACTIVITIES:
Payments on debt			(14,000)
Payments on note payable	(1,008)	(84)	(79)
Proceeds from exercise of stock options	5,825	6,137	147
Proceeds from exercise of stock warrants			1
Shares cancelled in lieu of payment of payroll taxes			(165)
Payment of payroll taxes related to stock-based compensation awards	(1,041)	(1,078)
Excess tax benefit from stock-based compensation	308	1,300	308
Treasury stock repurchase	(39,754)	(10,246)
Issuance of common stock, net of underwriting fees			110,343
Payment of costs associated with initial public offering			(1,499)
Cash dividend on preferred and common stock			(49,854)
Contributions from non-controlling interest	607	98
Distribution to non-controlling interest	(198)	(46)
Net cash (used in) provided by financing activities	(35,261)	(3,919)	45,202
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(30,999)	(6,574)	46,984
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	63,005	69,579	22,595
CASH AND CASH EQUIVALENTS AT END OF PERIOD	32,006	63,005	69,579
Supplemental cash flow information :
Income taxes paid	2,376	3,232	1,808
Interest paid	183	179	332
Supplemental non-cash investing and financing activities :
Unpaid liability for purchases of property and equipment	$ 3,395	$ 2,690	2,636
Accretion of redeemable convertible preferred stock to maximum redemption value			$ 15,097

Organization and Other Matters

12 Months Ended

Dec. 27, 2015

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Organization and Other Matters

(1) Organization and Other Matters

Business

Potbelly Corporation (the “Company” or “Potbelly”), through its wholly-owned subsidiaries, operates Potbelly Sandwich Works sandwich shops in 28 states and the District of Columbia. The Company also sells and administers franchises of Potbelly Sandwich Works sandwich shops. The first franchise locations administered by the Company opened during February 2011, and in July 2015, the Company opened its first franchise shop in the United Kingdom. Additionally, during July 2015, the Company purchased a franchise shop, converting it into a company-operated shop at a cost of $0.3 million. The Company did not record any goodwill related to the transaction.

The table below sets forth a rollforward of company-operated and franchise-operated activities:

	Company-			Franchise-Operated									Total
	Operated			Domestic			International			Total			Company
Shops as of December 30, 2012		264			5			10			15			279
Shops opened		34			6			2			8			42
Shops closed		(2	)		—			—			—			(2	)
Shops as of December 29, 2013		296			11			12			23			319
Shops opened		39			6			1			7			46
Shop closed		(1	)		—			(1	)		(1	)		(2	)
Shops as of December 28, 2014		334			17			12			29			363
Shops opened		43			8			2			10			53
Shop purchased from franchisee		1			(1	)		—			(1	)		—
Shops closed		(6	)		—			(2	)		(2	)		(8	)
Shops as of December 27, 2015		372			24			12			36			408

Initial Public Offering

On October 9, 2013, the Company completed an initial public offering (“IPO”) of 8,625,000 shares of common stock, which included 1,125,000 shares of common stock issued upon the exercise in full of the underwriters’ option to purchase additional shares. The Company sold 8,474,869 shares of common stock and certain stockholders sold 150,131 shares of common stock. The Company received net proceeds from the offering of approximately $108.8 million, after deducting the underwriting discount and other offering expenses. The Company did not receive any proceeds from the shares sold by the selling stockholders.

The Company used the net proceeds received from the sale of its shares to pay a previously-declared one-time cash dividend of $49.9 million on shares outstanding on October 8, 2013 and also to repay borrowings of approximately $14.0 million under its senior credit facility. During fiscal year 2014, the Company used approximately $10.2 million of the net proceeds to repurchase common stock pursuant to the share repurchase program authorized by the Company’s Board of Directors on August 1, 2014. The remaining proceeds were used in fiscal year 2015 for share repurchases, working capital, and general corporate purposes.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 27, 2015

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

(2) Summary of Significant Accounting Policies

(a) Principles of Consolidation

The consolidated financial statements include the accounts of Potbelly Corporation; its wholly owned subsidiary, Potbelly Illinois, Inc. (“PII”); PII’s wholly owned subsidiaries, Potbelly Franchising, LLC and Potbelly Sandwich Works LLC (“LLC”); 17 of LLC’s wholly owned subsidiaries and LLC’s four joint ventures, collectively, the “Company.” All significant 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 four joint venture investments. The Company has ownership interests ranging from 65-80% in these consolidated joint ventures.

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

(b) Reporting Period

The Company uses a 52/53-week fiscal year that ends on the last Sunday of the calendar year. Approximately every five or six years a 53rd week is added. Fiscal years 2013, 2014 and 2015 each consisted of 52 weeks.

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

(d) Use of Estimates

The preparation of financial statements in conformity with generally accepted accounting principles in the United States (“GAAP”) requires management to make estimates and assumptions, primarily related to the long-lived assets and income taxes, that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

(e) Fair Value Measurements

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

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

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

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

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

(f) Financial Instruments

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

(g) Cash and Cash Equivalents

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

(h) Accounts Receivable, net

Accounts receivable, net consists of credit card receivables, amounts owed from vendors and miscellaneous receivables. The Company had credit card receivables of $1.9 million and $2.0 million as of December 28, 2014 and December 27, 2015, respectively.

(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 market. No adjustment is deemed necessary to reduce inventory to the lower of cost or market value due to the rapid turnover and high utilization of inventory.

(j) Property and Equipment

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

Direct costs and expenditures for refurbishments and improvements that significantly add to the productive capacity or extend the useful life of an asset are capitalized, whereas the costs of repairs and maintenance are expensed when incurred. The Company capitalizes certain internal costs associated with the development, design, and construction of new shop locations as these costs have a future benefit to the Company. The Company capitalized costs of $0.7 million, $0.9 million and $0.6 million for the fiscal years ended December 29, 2013, December 28, 2014 and December 27, 2015, respectively. 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.

The Company assesses potential impairments to its long-lived assets, which includes property and equipment, on a quarterly basis or whenever events or circumstances indicate that the carrying amount of an asset may not be recoverable. Shop-level assets are grouped together for the purpose of the impairment assessment. Recoverability of an asset is measured by a comparison of the carrying amount of an asset group to its estimated undiscounted future cash flows expected to be generated by the asset. If the carrying amount of the asset group exceeds its estimated undiscounted future cash flows, an impairment charge is recognized as the amount by which the carrying amount of the asset exceeds the fair value of the asset. After performing periodic reviews of the company-operated shops during each quarter of 2013, 2014 and 2015, it was determined that indicators of impairment were present for certain shops as a result of underperformance of shop profitability. The Company performed an impairment analysis related to these shops and recorded impairment charges of $1.1 million, $2.9 million and $3.4 million for the fiscal years 2013, 2014 and 2015, respectively, which is included in impairment and loss on disposal of property and equipment in the consolidated statements of operations. The fair value of the shop assets was determined using the discounted future cash flow method of anticipated cash flows through the shop’s lease-end date using fair value measurement inputs classified as Level 3. Level 3 inputs are derived from valuation techniques in which one or more significant inputs or significant value drivers are unobservable. The Company used a weighted average cost of capital to discount the future cash flows.

(k) 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 both an income-based approach and a market 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 market approach measures fair value by comparison to the observed fair values of comparable companies, adjusted for the relative size and profitability of these comparable companies. 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.

(l) Pre-opening Costs

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

(m) Advertising Expenses

Advertising costs are expensed as incurred and are included in general and administrative expenses in the consolidated statements of operations. Advertising expenses were $1.6 million, $2.2 million and $2.9 million in fiscal years 2013, 2014 and 2015, respectively.

(n) Income Taxes

Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are attributable 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 realizability of deferred tax assets, the Company considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. The Company considers the scheduled reversal of deferred tax liabilities, projected future taxable income, and tax planning strategies in making this assessment. Deferred tax liabilities are recognized for temporary differences that will be taxable in future years’ tax returns.

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

(o) Stock-Based Compensation

The Company has granted stock options under its 2001 Equity Incentive Plan (the “2001 Plan”), 2004 Equity Incentive Plan (the “2004 Plan”) and 2013 Long-Term Incentive Plan (the “2013 Plan” and together with the 2004 Plan and 2001 Plan, the “Plans”). 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 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. In September 2011, the 2001 Plan expired with options outstanding under the plan still available for exercise. On July 31, 2013, the Company’s board of directors approved the adoption of the 2013 Plan, which replaced the 2004 Plan in conjunction with the Company’s IPO. Upon approval of the 2013 Plan, the Company no longer issued awards under the 2004 Plan. The 2004 Plan expired in February 2014, but will continue to govern outstanding awards granted prior to its termination.

The Company accounts for its stock-based employee compensation in accordance with Accounting Standards Codification (“ASC”) 718, Stock Based Compensation. The Company’s stock option plan contained a performance condition that restricted certain option holders’ ability to exercise vested options until the consummation of an IPO under the Securities Act, or at the discretion of the Company’s board of directors. As a result, compensation cost related to vested employee stock options with these performance conditions was not recognized until October 2013 when the performance conditions were met as a result of the IPO. The Company recorded a $7.6 million charge associated with vested options, which was determined using the Black-Scholes option pricing valuation model. For stock options granted without performance conditions, the Company records stock compensation expense on a straight-line basis over the vesting period based on the grant-date fair value of the option, determined using the Black-Scholes option pricing valuation model.

(p) Leases

The Company leases retail shops, warehouse and office space under operating leases. Most lease agreements contain tenant improvement allowances, rent holidays, lease premiums, rent escalation clauses, and/or contingent rent provisions. For purposes of recognizing incentives, premiums, and minimum rental expenses on a straight-line basis over the terms of the leases, the Company uses the date it takes possession of the leased space for construction purposes as the beginning of the term, which is generally two to three months prior to a shop’s opening date. 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. In addition to rental expense, certain leases require the Company to pay a portion of real estate taxes, utilities, building operating expenses, insurance and other charges in addition to rent.

For tenant improvement allowances, rent escalations, and rent holidays, the Company records a deferred rent liability in its consolidated balance sheets and amortizes the deferred rent over the terms of the leases as reductions to occupancy expense in the consolidated statements of operations.

(q) Revenue Recognition

Revenue from retail shops are presented net of discounts and recognized when food and beverage products are sold. 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.

Revenues from the Company’s gift cards are deferred and were previously recognized upon redemption or after a period of 36 months of inactivity on gift card balances (“gift card breakage”) and the Company does not have a legal obligation to remit the value of the unredeemed gift cards to the relevant jurisdictions. The Company monitors its actual patterns of redemption and updates its estimates and assumptions regarding redemption as the actual pattern changes. The Company estimates and records gift card breakage income based on its historical redemption pattern. During fiscal 2014, the Company updated its analysis of historical gift card redemptions based on historical data and changed its estimate to record gift card breakage income from 36 months to 24 months after the date of issuance for all gift cards that have not been redeemed. In accordance with ASC 250, “Accounting Changes and Error Corrections,” the Company recorded a cumulative adjustment of $0.2 million, which is included in other operating expenses, representing the effect of this change in accounting estimate. The Company recognized an immaterial amount of gift card breakage income for the fiscal years ended 2013, 2014 and 2015, which is recorded within other operating expenses 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 fee revenue is recognized at the point a franchise shop opens for business to the public, as this is the point in time when the Company has substantially performed all initial services required under the franchise agreement. The Company recognized franchise fee revenue of $0.3 million, $0.3 million and $0.4 million in fiscal year 2013, 2014 and 2015, respectively. Initial franchise fee payments received by the Company before the shop opens are recorded as deferred revenue in the consolidated balance sheet. The Company had deferred revenue related to initial franchise fees of $0.2 million and $0.5 million included in accrued expenses as of December 28, 2014 and December 27, 2015, respectively. Franchise development agreement fee represents 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. The Company had deferred revenue related to franchise development agreement fees of $0.2 million and $0.4 million recorded as accrued expenses as of December 28, 2014 and December 27, 2015, respectively. 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. The Company recognized royalty fees revenue of $0.8 million, $1.2 million and $1.5 million for fiscal years 2013, 2014, and 2015, respectively.

(r) Recent Accounting Pronouncements

In May 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers.” The pronouncement was issued to clarify the principles for recognizing revenue and to develop a common revenue standard and disclosure requirements for U.S. GAAP and IFRS. The FASB has approved a one-year deferral of the effective date of ASU 2014-09, such that it will become effective for the annual period beginning after December 15, 2017. The Company is evaluating the effect this guidance will have on the Company’s consolidated financial statements and related disclosures. The Company has not yet selected a transition method nor has it determined the effect of the standard on its ongoing financial reporting.

In August 2014, the FASB issued ASU No. 2014-15, “Presentation of Financial Statements – Going Concern (Subtopic 205-40)—Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern.” The pronouncement requires the Company’s management to evaluate whether there is substantial doubt about the Company’s ability to continue as a going concern. The pronouncement is effective for the annual period ending after December 15, 2016, and for annual periods and interim periods thereafter. Early adoption is permitted. The adoption of ASU 2014-15 is not expected to have a material effect on the Company’s consolidated balance sheet or consolidated statement of operations.

In November 2015, the FASB issued ASU No. 2015-17, “Income Taxes (Topic 740) —Balance Sheet Classification of Deferred Taxes.” ASU 2015-17 requires deferred tax assets and liabilities to be presented as noncurrent in a classified balance sheet. The provisions of ASU 2015-17 are effective for interim and fiscal years beginning after December 15, 2016, with early adoption permitted. The Company has elected to early adopt ASU 2015-17 as of December 27, 2015 on a prospective basis. As a result of adopting the standard, the Company reclassified its net current deferred tax assets and liabilities to net noncurrent deferred tax assets and liabilities, respectively, in its consolidated financial statements for the year ended December 27, 2015. As the Company adopted on a prospective basis, the prior periods have not been restated.

(s) 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. 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, results of operations or cash flows.

Many of the food products the Company purchases are subject to changes in the price and availability of food commodities, including, among other things, beef, poultry, grains, dairy and produce. The Company works with its suppliers and uses a mix of forward pricing protocols for certain items including agreements with its supplier on fixed prices for deliveries at some time in the future and agreements on a fixed price with its supplier for the duration of that protocol. 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. The Company does not enter into futures contracts or other derivative instruments.

Earnings per Share

12 Months Ended

Dec. 27, 2015

Earnings Per Share [Abstract]

Earnings per Share

(4) Earnings per share

Basic and diluted income (loss) per common share attributable to common stockholders are calculated using the weighted average number of common shares outstanding for the period. Diluted income (loss) per common share attributable to common stockholders is computed by dividing the income (loss) allocated to common stockholders utilizing the two-class method by the weighted average number of fully diluted common shares outstanding. The Company’s redeemable convertible preferred stock were all considered participating securities requiring the two-class method to calculate basic and diluted earnings per share. In periods of a net loss attributable to common stockholders, the redeemable convertible preferred stock were excluded from the computation of basic earnings per share due to the fact that they are not required to fund losses and the redemption amount is not reduced as a result of losses.

	Fiscal Year
	2015		2014		2013
Calculation of undistributed income (loss) for basic and diluted shares:
Net income attributable to Potbelly Corporation	$	5,628	$	4,358	$	1,258
Less: Dividend paid to common and preferred stockholders		—		—		(49,854	)
Less: Accretion of redeemable convertible preferred stock to maximum redemption value		—		—		(15,097	)
Undistributed income (loss) for basic and diluted shares	$	5,628	$	4,358	$	(63,693	)

Allocation of undistributed income (losses) to participating securities:
Common shares	$	5,628	$	4,358	$	(63,693	)
Undistributed income (loss)	$	5,628	$	4,358	$	(63,693	)

Weighted average common shares outstanding-basic		28,002,005		29,209,298		10,132,805
Plus: Effect of potential stock options exercise		577,156		949,142		—
Plus: Effect of potential warrant exercise		55,235		116,621		—
Weighted average common shares outstanding-diluted		28,634,396		30,275,061		10,132,805
Income (loss) per share available to common stockholders-basic	$	0.20	$	0.15	$	(6.29	)
Income (loss) per share available to common stockholders-diluted	$	0.20	$	0.14	$	(6.29	)
Potentially dilutive shares that are considered anti-dilutive:
Common share options		898,966		622,879		5,029,576
Warrants		—		—		247,704

Income Taxes

12 Months Ended

Dec. 27, 2015

Income Tax Disclosure [Abstract]

Income Taxes

(7) Income Taxes

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

	Fiscal Year
	2015		2014		2013
Domestic operations	$	8,660	$	6,627	$	605
Foreign operations		548		465		481
Total	$	9,208	$	7,092	$	1,086

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

	Fiscal Year
	2015			2014			2013
Federal:
Current	$	2,450		$	2,386		$	—
Deferred		209			(467	)		(818	)
		2,659			1,919			(818	)
State and Local:
Current		1,047			622			1,394
Deferred		(281	)		178			(838	)
		766			800			556
Foreign:
Current		41			29			58
Deferred		—			—			—
		41			29			58
Income tax expense (benefit)	$	3,466		$	2,748		$	(204	)

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

	Fiscal Year
	2015			2014			2013
Computed “expected” tax (benefit) expense	$	3,223		$	2,411		$	380
Increase (reduction) resulting from:
Minority interest		(45	)		—			—
Permanent differences		51			97			63
State and local income taxes, net of federal income tax effect		533			460			145
FICA and other tax credits		(392	)		(222	)		(113	)
Non-deductible IPO costs		—			—			195
Rate change and true-ups		164			2			(874	)
Change in valuation allowance		(68	)		—			0
	$	3,466		$	2,748		$	(204	)

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

	December 27,			December 28,
	2015			2014
Deferred tax assets:
Accrued liabilities	$	2,074		$	1,047
Deferred revenue on gift certificates and gift cards		141			70
Net operating loss carryforwards		—			336
Stock-based compensation		8,261			8,317
Property and equipment depreciation		5,805			6,760
Deferred rent and start-up amortization		4,650			3,930
Other timing differences		273			345
FICA and other tax credits		43			116
Total deferred tax assets		21,247			20,921
Less: valuation allowance		—			(68	)
Net deferred tax assets		21,247			20,853
Deferred tax liabilities:
Prepaids		(547	)		(610	)
Intangible asset		(1,226	)		(1,126	)
Smallwares		(733	)		(668	)
Other timing differences		(302	)		(82	)
Total gross deferred tax liabilities		(2,808	)		(2,486	)
Net deferred tax assets (liabilities)	$	18,439		$	18,367

Recognized in the balance sheet as:
Deferred tax assets - current		—			507
Deferred tax assets - noncurrent		18,439			17,860
Net deferred tax assets (liabilities)	$	18,439		$	18,367

Consistent with the Company’s early adoption of ASU 2015-17 on a prospective basis, the deferred tax assets and deferred tax liabilities in the table above have been classified as noncurrent deferred taxes on the consolidated balance sheet. Since the Company adopted the ASU on a prospective basis, the 2014 balances above have not been restated.

For the year ended December 27, 2015, the Company recorded a net valuation allowance release of $0.1 million related to Illinois tax credits on the basis of management’s reassessment of the amount of its deferred tax assets that are 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 28, 2014 and December 27, 2015, the Company had no interest or penalties accrued.

The tax years prior to 2012 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. Our last IRS examination was for the 2012 tax year; no other IRS audits are currently ongoing. State statutes are generally open for audit for the 2011 to 2015 tax years. Additionally, the tax years from 2004 to 2010 are open for examination by certain state tax authorities due to net operating losses generated at the state level.

Capital Stock and Warrants	12 Months Ended
Capital Stock and Warrants	Dec. 27, 2015
Equity [Abstract]
Capital Stock and Warrants	(9) Capital Stock and Warrants As of December 27, 2015 and December 28, 2014, the Company had authorized an aggregate of 210,000,000 shares of capital stock, of which 200,000,000 shares were designated as common stock and 10,000,000 shares were designated as preferred stock. As of December 27, 2015, the Company had issued and outstanding 30,338,171 and 26,304,261 shares of common stock, respectively. As of December 28, 2014, the Company had issued and outstanding 29,761,790 and 28,934,700 shares of common stock, respectively. Common Stock On October 9, 2013, the Company completed an initial public offering. Effective upon the closing of such offering, all shares of preferred stock and non-voting common stock converted into common stock. The terms of the non-voting common stock provided that all shares of non-voting common stock would convert into voting common stock on a 1:1 basis immediately prior to the closing of an underwritten IPO or sale of the Company. The redeemable convertible preferred stock included down-round provisions which would adjust the conversion price for any additional stock issued without consideration or for a consideration per share less than the respective conversion price for one or more of the series of preferred stock in effect immediately prior to the issuance of such additional stock. See “Preferred Stock” below for further information regarding the preferred stock and the conversion of preferred stock upon completion of the IPO. As of December 27, 2015, 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 September 8, 2015, the Company’s Board of Directors authorized a share repurchase program of up to $35.0 million of the Company’s common stock. This program replaces the previously authorized share repurchase program, which was completed in the third quarter of 2015. Under the current program, the Company may, from time to time, 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 Exchange Act of 1934, as amended) or in privately negotiated transactions. During the fiscal year ended December 27, 2015, the Company repurchased 3,206,820 shares of its common stock for approximately $39.8 million, including cost and commission, in open market transactions. As of December 27, 2015, the remaining dollar value of authorization under the share repurchase program was $20.0 million, which does not include commission. Repurchased shares are included as treasury stock in the consolidated balance sheets and the consolidated statements of redeemable convertible preferred stock and equity (deficit). Preferred Stock All series of preferred stock were subject to substantially the same general terms and conditions. Dividends accrued (whether or not declared) on each share of preferred stock at a rate of 6% per annum of the applicable liquidation value until the first to occur of (1) the date on which the applicable liquidation value of such share is paid to the holder in connection with a significant event, (2) the date on which such share is converted into common stock, or (3) the date on which such share is acquired by the Company. Dividends were cumulative, but were payable only upon their redemption or the occurrence of a significant event that would result in a distribution to their holders of less than 110% of the shares’ liquidation value (generally the applicable gross issuance price of the shares). A significant event includes a merger, sale of substantially all assets, change of control, or liquidation of the Company, but it did not include an IPO. The terms of the preferred stock provided that unpaid dividends would be forfeited upon any conversion of preferred stock into common stock. The terms of the preferred stock provided that all shares of preferred stock would automatically convert to common stock in the event of a qualified IPO, as defined; the election of the holders of a majority of the shares of preferred stock; or the conversion of at least a majority of the shares of issued preferred stock. None of the shares of preferred stock were mandatorily redeemable. Subsequent to December 24, 2014, preferred stock may have been redeemed upon a majority vote of the preferred stockholders for a period of 12 months (the “Redemption Election Period”). If the holders of at least a majority of the preferred stock then outstanding did not approve the redemption of preferred shares outstanding during the Redemption Election Period, the Company would have had no further obligation to redeem any shares of preferred stock. As of December 30, 2012 and through the date of the IPO, the Company classified the preferred stock outside of permanent equity on the balance sheet as redemption of the preferred stock was outside the control of the Company. The Company recognized changes in the redemption value immediately as they occurred via direct charges to additional paid-in capital and then to accumulated deficit, and adjusted the carrying value of the preferred stock to equal its maximum redemption value at the end of each reporting period. In the event of a redemption, the price paid by the Company for the preferred stock would be the greater of (a) the liquidation value of the preferred stock series being redeemed, plus any accrued and unpaid dividends, or (b) the amount in respect of such share of preferred stock that such holder would have been entitled to receive on an as-converted basis assuming all the shares have been converted into common stock. The form of consideration in the event of liquidation would be the same for the common stockholders as would be provided to the preferred stockholders. The redemption and conversion features did not require bifurcation and separate measurement in the financial statements since neither of the features meet the net settlement criteria under ASC Topic 815, Derivatives and Hedging. The redeemable convertible preferred stock include down-round provisions which would adjust the conversion price for any additional stock issued without consideration or for a consideration per share less than the respective conversion price for one or more of the series of preferred stock in effect immediately prior to the issuance of such additional stock. The Company measured its redeemable convertible preferred stock at its maximum redemption value at each reporting period. The fair value of the Company, used to calculate the maximum redemption value of the redeemable convertible preferred stock and to measure the value of the common stock as a key assumption in the determination of the compensation expense associated with the Company’s stock options, was determined with assistance from an independent third-party valuation specialist utilizing Level 3 inputs. The valuations of the Company and its common stock were determined based on valuation methodologies and assumptions selected in accordance with the guidelines outlined in the American Institute of Certified Public Accountants Practice Aid, Valuation of Privately-Held-Companies Equity Securities Issued as Compensation. In the absence of observable market data regarding the value of the Company’s stock, the valuation of the Company and its common stock was estimated using multiple valuation approaches, primarily an income and market approach. The income approach is based on the present value of estimated future cash flows, and relies upon significant assumptions and estimates, including those related to the selected discount rate and forecasted revenues and expenses. The market approach is based on a comparison to observed fair values of comparable peer companies and recent market transactions, adjusted for the relative size and profitability of these peer companies relative to the Company. On October 9, 2013, the Company completed an initial public offering. Effective upon the closing of such offering, all shares of preferred stock converted into common stock and all dividends accrued on the shares of preferred stock were forfeited. Additionally, the Company paid the one-time cash dividend on October 9, 2013 from the net proceeds of the Company’s initial public offering. Warrants As of December 28, 2014 and December 27, 2015, the Company had 241,704 warrants outstanding. During 2013, the Company modified 241,704 of warrants issued to Oxford Capital Partners, Inc. that were set to expire upon the consummation of an IPO to extend the expiration date of such warrants to five years from the date of the consummation of an IPO. In accordance with ASC Topic 718, Compensation—Stock Compensation, the Company recorded a charge of approximately $0.1 million related to the incremental value associated with the extension of the expiration date.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(d),(e))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21484-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB TOPIC 4.E)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74512-122707

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21488-112644

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29-31)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
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-Paragraph 4
-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
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-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
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-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6405834&loc=d3e23285-112656

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Preferred Stock
-URI http://asc.fasb.org/extlink&oid=6521494

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21564-112644

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section E

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section C

+ Details

Stock Based Compensation

12 Months Ended

Dec. 27, 2015

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock Based Compensation

(12) Stock Based Compensation

Stock Based Compensation Granted Under the 2001 and 2004 Equity Incentive Plans and 2013 Long-Term Incentive Plan

Under the 2001 Plan, the Company had 746,749 shares reserved for issuance. In 2007, the Company entered into a Stock Option Agreement (the “Agreement”), which granted a certain key executive 500,000 options of non-voting common stock. In September 2011, the 2001 Plan expired with options outstanding under the plan still available for exercise. As a result of the IPO, all shares of the non-voting common stock converted into voting common stock on a 1:1 basis upon exercise.

On July 31, 2013, the Company’s board of directors approved the adoption of the 2013 Plan, which replaced the 2004 Plan in conjunction with the Company’s IPO. Upon approval of the 2013 Plan, the Company no longer issued awards under the 2004 Plan. The 2004 Plan expired in February 2014, but will continue to govern outstanding awards granted prior to its termination. As of December 27, 2015, there have been 1,278,202 options, 28,240 shares of unrestricted common stock and 36,077 shares of restricted stock units (“RSUs”) granted under the 2013 Plan and 380,564 shares are reserved for future issuance.

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. Certain options have been issued to key executives. Options issued and outstanding expire on various dates through the year 2025. The range of exercise prices of options outstanding as of December 27, 2015, is $7.00 to $20.53 per option, and the options vest over a range of immediately to five-year periods.

Activity under the Plans and the Agreement is as follows:

Options	Shares (Thousands)			Weighted Average Exercise Price		Aggregate Intrinsic Value (Thousands)		Weighted Average Remaining Term (Years)
Outstanding—December 30, 2012		4,213		$	9.30	$	5,348		5.93
Granted		1,243			11.32
Exercised		(99	)		7.97
Canceled		(327	)		8.40
Outstanding—December 29, 2013		5,030		$	9.41	$	78,575		6.31
Granted		318			19.16
Exercised		(586	)		8.67
Canceled		(149	)		11.68
Outstanding—December 28, 2014		4,613		$	10.10	$	12,731		5.62
Granted		565			13.21
Exercised		(576	)		8.30
Canceled		(234	)		13.89
Outstanding—December 27, 2015		4,368		$	10.53	$	9,742		5.10
Vested and expected to vest—December 27, 2015		3,244			9.54	$	9,327		3.78
Exercisable—December 27, 2015		3,232		$	9.55	$	8,976		3.92

The following table reflects the average assumptions utilized in the Black-Scholes option-pricing model to value the options granted for each year:

	2015			2014			2013
Risk-free interest rate		1.9	%		1.3	%		1.2	%
Expected life (years)		7.00			7.00			6.05
Expected dividend yield		—			—			—
Volatility		45.3	%		49.2	%		46.9	%
Weighted average common stock fair value	$	13.21		$	19.16		$	11.32

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. Beginning October 2015, expected volatility of the options was calculated using the Company’s historical data since its initial public offering. Prior to October 2015, the Company calculated expected volatility of the options based on historical data from selected peer public company restaurants.

During fiscal year 2014, the Company issued 28,240 shares of unrestricted common stock to certain non-employee members of its Board of Directors. The unrestricted stock had a weighted average grant-date share price of $15.29 upon issuance. The Company recorded $0.4 million in stock-based compensation expense, with a corresponding increase to additional paid-in capital, related to the issuance of the common stock.

In May 2015, the Company issued 30,856 RSUs to certain non-employee members of its Board of Directors. The RSUs had a grant-date fair value of $14.26 upon issuance and have a vesting schedule of 50% on the first anniversary of the grant date and 50% on the second anniversary of the grant date. In August 2015, the Company issued 5,221 RSUs to the new non-employee member of its Board of Directors. The RSUs had a grant-date fair value of $11.88 upon issuance and have a vesting schedule of 50% on the first anniversary of the grant date and 50% on the second anniversary of the grant date.

Stock-based Compensation Expense

In accordance with ASC Topic 718, Compensation—Stock Compensation, stock-based compensation is measured at the grant date, based on the calculated fair value of the award, and is recognized as an expense over the requisite employee service period (generally the vesting period of the grant). The Company recognized $11.6 million, $2.5 million and $2.4 million for the fiscal years 2013, 2014 and 2015, respectively, with a corresponding increase to additional paid-in-capital. Fiscal year 2013 stock-based compensation expense reflects the $7.6 million in cost recorded upon consummation of the IPO associated with vested options that were subject to the performance condition. Fiscal year 2014 stock-based compensation expense includes $0.4 million related to unrestricted common stock granted during 2014. As of December 27, 2015, the unrecognized stock-based compensation expense was $5.7 million, which will be recognized through fiscal year 2019. The Company records stock-based compensation expense within general and administrative expenses in the consolidated statements of operations.

Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 27, 2015

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 a fair presentation of the information shown. 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 2015 (1)
	March 29		June 28		September 27		December 27
Total revenues	$	85,768	$	95,949	$	96,039	$	95,093
Income from operations		948		4,084		2,379		2,018
Net income attributable to Potbelly Corporation		531		2,461		1,401		1,235
Income per share available to common stockholders-basic		0.02		0.09		0.05		0.05
Income per share available to common stockholders-diluted		0.02		0.08		0.05		0.05

	Fiscal Year 2014 (1)
	March 30 (2)			June 29		September 28		December 28
Total revenues	$	73,881		$	83,620	$	84,675	$	84,803
(Loss) income from operations		(441	)		3,454		3,254		1,004
Net (loss) income attributable to Potbelly Corporation		(301	)		2,010		1,947		702
(Loss) income per share available to common stockholders-basic		(0.01	)		0.07		0.07		0.02
(Loss) income per share available to common stockholders-diluted		(0.01	)		0.07		0.06		0.02

(1)	Fiscal years 2015 and 2014 were 52-week years. Each quarter of the fiscal year consists of 13 weeks.

(2)	The 13 weeks ended March 30, 2014 were impacted by significantly adverse weather.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 27, 2015

Accounting Policies [Abstract]

Principles of Consolidation

(a) Principles of Consolidation

Reporting Period

(b) Reporting Period

Segment Reporting

Use of Estimates

(d) Use of Estimates

Fair Value Measurements

(e) Fair Value Measurements

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

Financial Instruments

(f) Financial Instruments

Cash and Cash Equivalents

(g) Cash and Cash Equivalents

Accounts Receivable, net

(h) Accounts Receivable, net

Inventories

(i) Inventories

Property and Equipment

(j) Property and Equipment

Intangible Assets

(k) Intangible Assets

Pre-opening Costs

(l) Pre-opening Costs

Advertising Expenses

(m) Advertising Expenses

Income Taxes

(n) Income Taxes

Stock-Based Compensation

(o) Stock-Based Compensation

Leases

(p) Leases

Revenue Recognition

(q) Revenue Recognition

Recent Accounting Pronouncements

(r) Recent Accounting Pronouncements

Commitments and Contingencies

(s) Commitments and Contingencies

Organization and Other Matters (Tables)

12 Months Ended

Dec. 27, 2015

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Summary of Company-Operated and Franchise-Operated Activities

The table below sets forth a rollforward of company-operated and franchise-operated activities:

	Company-			Franchise-Operated									Total
	Operated			Domestic			International			Total			Company
Shops as of December 30, 2012		264			5			10			15			279
Shops opened		34			6			2			8			42
Shops closed		(2	)		—			—			—			(2	)
Shops as of December 29, 2013		296			11			12			23			319
Shops opened		39			6			1			7			46
Shop closed		(1	)		—			(1	)		(1	)		(2	)
Shops as of December 28, 2014		334			17			12			29			363
Shops opened		43			8			2			10			53
Shop purchased from franchisee		1			(1	)		—			(1	)		—
Shops closed		(6	)		—			(2	)		(2	)		(8	)
Shops as of December 27, 2015		372			24			12			36			408

Earnings per Share (Tables)

12 Months Ended

Dec. 27, 2015

Earnings Per Share [Abstract]

Schedule of the Calculation of Weighted Average Common Shares Outstanding for Basic and Diluted Earnings per Share Available to Common Stockholders

	Fiscal Year
	2015		2014		2013
Calculation of undistributed income (loss) for basic and diluted shares:
Net income attributable to Potbelly Corporation	$	5,628	$	4,358	$	1,258
Less: Dividend paid to common and preferred stockholders		—		—		(49,854	)
Less: Accretion of redeemable convertible preferred stock to maximum redemption value		—		—		(15,097	)
Undistributed income (loss) for basic and diluted shares	$	5,628	$	4,358	$	(63,693	)

Allocation of undistributed income (losses) to participating securities:
Common shares	$	5,628	$	4,358	$	(63,693	)
Undistributed income (loss)	$	5,628	$	4,358	$	(63,693	)

Weighted average common shares outstanding-basic		28,002,005		29,209,298		10,132,805
Plus: Effect of potential stock options exercise		577,156		949,142		—
Plus: Effect of potential warrant exercise		55,235		116,621		—
Weighted average common shares outstanding-diluted		28,634,396		30,275,061		10,132,805
Income (loss) per share available to common stockholders-basic	$	0.20	$	0.15	$	(6.29	)
Income (loss) per share available to common stockholders-diluted	$	0.20	$	0.14	$	(6.29	)
Potentially dilutive shares that are considered anti-dilutive:
Common share options		898,966		622,879		5,029,576
Warrants		—		—		247,704

Accrued Expenses (Tables)

12 Months Ended

Dec. 27, 2015

Accrued Liabilities Current [Abstract]

Summary of Accrued Expenses

Accrued expenses consisted of the following (in thousands):

	December 27,		December 28,
	2015		2014
Accrued labor and related expenses	$	7,482	$	3,942
Deferred gift card revenue		1,843		1,456
Accrued occupancy expenses		672		775
Deferred rent—current		813		950
Accrued corporate and shop expenses		1,961		1,663
Accrued utilities		1,035		1,003
Accrued sales and use tax		1,820		2,304
Accrued construction		2,271		2,133
Accrued contract termination costs (a)		21		801
Accrued professional fees		136		215
Accrued other		1,223		1,107
Total	$	19,277	$	16,349

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

	December 27,			December 28,
	2015			2014
Accrued contract termination costs—beginning balance	$	801		$	93
Contract termination costs incurred (1)		—			749
Contract termination costs settled and paid		(780	)		(41	)
Accrued contract termination costs—ending balance	$	21		$	801

__________________

(1)	Fiscal year ended December 28, 2014 includes costs associated with the plans to move the Company’s corporate headquarters.

Summary of Accrued Contract Termination Costs

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

	December 27,			December 28,
	2015			2014
Accrued contract termination costs—beginning balance	$	801		$	93
Contract termination costs incurred (1)		—			749
Contract termination costs settled and paid		(780	)		(41	)
Accrued contract termination costs—ending balance	$	21		$	801

__________________

(1)	Fiscal year ended December 28, 2014 includes costs associated with the plans to move the Company’s corporate headquarters.

Income Taxes (Tables)

12 Months Ended

Dec. 27, 2015

Income Tax Disclosure [Abstract]

Schedule of Income Before Income Taxes

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

	Fiscal Year
	2015		2014		2013
Domestic operations	$	8,660	$	6,627	$	605
Foreign operations		548		465		481
Total	$	9,208	$	7,092	$	1,086

Components of Income Tax Expense (Benefit)

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

	Fiscal Year
	2015			2014			2013
Federal:
Current	$	2,450		$	2,386		$	—
Deferred		209			(467	)		(818	)
		2,659			1,919			(818	)
State and Local:
Current		1,047			622			1,394
Deferred		(281	)		178			(838	)
		766			800			556
Foreign:
Current		41			29			58
Deferred		—			—			—
		41			29			58
Income tax expense (benefit)	$	3,466		$	2,748		$	(204	)

Reconciliation of Differences Between Federal Statutory and Effective Income Tax Rate

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

	Fiscal Year
	2015			2014			2013
Computed “expected” tax (benefit) expense	$	3,223		$	2,411		$	380
Increase (reduction) resulting from:
Minority interest		(45	)		—			—
Permanent differences		51			97			63
State and local income taxes, net of federal income tax effect		533			460			145
FICA and other tax credits		(392	)		(222	)		(113	)
Non-deductible IPO costs		—			—			195
Rate change and true-ups		164			2			(874	)
Change in valuation allowance		(68	)		—			0
	$	3,466		$	2,748		$	(204	)

Schedule of Deferred Tax Assets and Liabilities

	December 27,			December 28,
	2015			2014
Deferred tax assets:
Accrued liabilities	$	2,074		$	1,047
Deferred revenue on gift certificates and gift cards		141			70
Net operating loss carryforwards		—			336
Stock-based compensation		8,261			8,317
Property and equipment depreciation		5,805			6,760
Deferred rent and start-up amortization		4,650			3,930
Other timing differences		273			345
FICA and other tax credits		43			116
Total deferred tax assets		21,247			20,921
Less: valuation allowance		—			(68	)
Net deferred tax assets		21,247			20,853
Deferred tax liabilities:
Prepaids		(547	)		(610	)
Intangible asset		(1,226	)		(1,126	)
Smallwares		(733	)		(668	)
Other timing differences		(302	)		(82	)
Total gross deferred tax liabilities		(2,808	)		(2,486	)
Net deferred tax assets (liabilities)	$	18,439		$	18,367

Recognized in the balance sheet as:
Deferred tax assets - current		—			507
Deferred tax assets - noncurrent		18,439			17,860
Net deferred tax assets (liabilities)	$	18,439		$	18,367

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 27, 2015

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Activity Under Plans and Agreement

Activity under the Plans and the Agreement is as follows:

Options	Shares (Thousands)			Weighted Average Exercise Price		Aggregate Intrinsic Value (Thousands)		Weighted Average Remaining Term (Years)
Outstanding—December 30, 2012		4,213		$	9.30	$	5,348		5.93
Granted		1,243			11.32
Exercised		(99	)		7.97
Canceled		(327	)		8.40
Outstanding—December 29, 2013		5,030		$	9.41	$	78,575		6.31
Granted		318			19.16
Exercised		(586	)		8.67
Canceled		(149	)		11.68
Outstanding—December 28, 2014		4,613		$	10.10	$	12,731		5.62
Granted		565			13.21
Exercised		(576	)		8.30
Canceled		(234	)		13.89
Outstanding—December 27, 2015		4,368		$	10.53	$	9,742		5.10
Vested and expected to vest—December 27, 2015		3,244			9.54	$	9,327		3.78
Exercisable—December 27, 2015		3,232		$	9.55	$	8,976		3.92

Schedule of Average Assumptions to Value Options

The following table reflects the average assumptions utilized in the Black-Scholes option-pricing model to value the options granted for each year:

	2015			2014			2013
Risk-free interest rate		1.9	%		1.3	%		1.2	%
Expected life (years)		7.00			7.00			6.05
Expected dividend yield		—			—			—
Volatility		45.3	%		49.2	%		46.9	%
Weighted average common stock fair value	$	13.21		$	19.16		$	11.32

Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 27, 2015

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 2015 (1)
	March 29		June 28		September 27		December 27
Total revenues	$	85,768	$	95,949	$	96,039	$	95,093
Income from operations		948		4,084		2,379		2,018
Net income attributable to Potbelly Corporation		531		2,461		1,401		1,235
Income per share available to common stockholders-basic		0.02		0.09		0.05		0.05
Income per share available to common stockholders-diluted		0.02		0.08		0.05		0.05

	Fiscal Year 2014 (1)
	March 30 (2)			June 29		September 28		December 28
Total revenues	$	73,881		$	83,620	$	84,675	$	84,803
(Loss) income from operations		(441	)		3,454		3,254		1,004
Net (loss) income attributable to Potbelly Corporation		(301	)		2,010		1,947		702
(Loss) income per share available to common stockholders-basic		(0.01	)		0.07		0.07		0.02
(Loss) income per share available to common stockholders-diluted		(0.01	)		0.07		0.06		0.02

(1)	Fiscal years 2015 and 2014 were 52-week years. Each quarter of the fiscal year consists of 13 weeks.

(2)	The 13 weeks ended March 30, 2014 were impacted by significantly adverse weather.

Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 27, 2015 USD ($) Subsidiary JointVenture Segment	Dec. 28, 2014 USD ($)	Dec. 29, 2013 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of wholly owned subsidiaries \| Subsidiary	17
Number of joint ventures \| JointVenture	4
Number of operating segments \| Segment	1
Number of reportable segments \| Segment	1
Credit card receivables	$ 2,000,000	$ 1,900,000
Capitalized costs	600,000	900,000	$ 700,000
Impairment charges	3,400,000	2,900,000	1,100,000
Recognized impairment for intangible assets	0	0	0
Advertising expenses	2,900,000	2,200,000	1,600,000
Cost related to vested stock options	2,399,000	2,543,000	11,610,000
Cumulative adjustment		200,000
Initial franchise fee	400,000	300,000	300,000
Royalty fees revenue	1,500,000	1,200,000	800,000
Initial Franchise Fees [Member]
Summary Of Significant Accounting Policies [Line Items]
Deferred revenue	500,000	200,000
Franchise Development Agreement [Member]
Summary Of Significant Accounting Policies [Line Items]
Deferred revenue	$ 400,000	$ 200,000
IPO [Member]
Summary Of Significant Accounting Policies [Line Items]
Cost related to vested stock options			$ 7,600,000
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Ownership interest rate	65.00%
Estimated period of time between Company's possession of leased space and shop opening date	2 months
Gift card breakage, period		24 months
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%
Estimated period of time between Company's possession of leased space and shop opening date	3 months
Gift card breakage, period		36 months
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

Earnings Per Share - Schedule of the Calculation of Weighted Average Common Shares Outstanding for Basic and Diluted Earnings per Share Available to Common Stockholders (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 27, 2015	Sep. 27, 2015	Jun. 28, 2015	Mar. 29, 2015	Dec. 28, 2014	Sep. 28, 2014	Jun. 29, 2014	Mar. 30, 2014	Dec. 27, 2015	Dec. 28, 2014	Dec. 29, 2013
Calculation of undistributed income (loss) for basic and diluted shares:
Net income attributable to Potbelly Corporation	$ 1,235	$ 1,401	$ 2,461	$ 531	$ 702	$ 1,947	$ 2,010	$ (301)	$ 5,628	$ 4,358	$ 1,258
Dividend declared to common and preferred stockholders											(49,854)
Accretion of redeemable convertible preferred stock to maximum redemption value											(15,097)
Undistributed income (loss) for basic and diluted shares									5,628	4,358	(63,693)
Allocation of undistributed income (losses) to participating securities:
Undistributed income (loss)									$ 5,628	$ 4,358	$ (63,693)
Weighted average common shares outstanding-basic									28,002,005	29,209,298	10,132,805
Plus: Effect of potential stock options exercise									577,156	949,142
Plus: Effect of potential warrant exercise									55,235	116,621
Weighted average common shares outstanding-diluted									28,634,396	30,275,061	10,132,805
Income (loss) per share available to common stockholders-basic	$ 0.05	$ 0.05	$ 0.09	$ 0.02	$ 0.02	$ 0.07	$ 0.07	$ (0.01)	$ 0.20	$ 0.15	$ (6.29)
Income (loss) per share available to common stockholders-diluted	$ 0.05	$ 0.05	$ 0.08	$ 0.02	$ 0.02	$ 0.06	$ 0.07	$ (0.01)	$ 0.20	$ 0.14	$ (6.29)
Common Share Options [Member]
Allocation of undistributed income (losses) to participating securities:
Potentially dilutive shares that are considered anti-dilutive									898,966	622,879	5,029,576
Common Stock [Member]
Allocation of undistributed income (losses) to participating securities:
Undistributed income (loss)									$ 5,628	$ 4,358	$ (63,693)
Warrants [Member]
Allocation of undistributed income (losses) to participating securities:
Potentially dilutive shares that are considered anti-dilutive									0	0	247,704

Accrued Expenses - Summary of Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 27, 2015	Dec. 28, 2014	Dec. 29, 2013
Accrued Liabilities And Other Liabilities [Abstract]
Accrued labor and related expenses	$ 7,482	$ 3,942
Deferred gift card revenue	1,843	1,456
Accrued occupancy expenses	672	775
Deferred rent—current	813	950
Accrued corporate and shop expenses	1,961	1,663
Accrued utilities	1,035	1,003
Accrued sales and use tax	1,820	2,304
Accrued construction	2,271	2,133
Accrued contract termination costs	21	801	$ 93
Accrued professional fees	136	215
Accrued other	1,223	1,107
Total	$ 19,277	$ 16,349

Income Taxes - Components of Income Tax Expense (Benefit) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2015	Dec. 28, 2014	Dec. 29, 2013
Income Tax Disclosure [Abstract]
Federal, Current	$ 2,450	$ 2,386
Federal, Deferred	209	(467)	$ (818)
Federal, Total	2,659	1,919	(818)
State and Local, Current	1,047	622	1,394
State and Local, Deferred	(281)	178	(838)
State and Local, Total	766	800	556
Foreign, Current	41	29	58
Foreign, Total	41	29	58
Income tax expense (benefit)	$ 3,466	$ 2,748	$ (204)

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 27, 2015	Dec. 28, 2014
Deferred tax assets:
Accrued liabilities	$ 2,074	$ 1,047
Deferred revenue on gift certificates and gift cards	141	70
Net operating loss carryforwards		336
Stock-based compensation	8,261	8,317
Property and equipment depreciation	5,805	6,760
Deferred rent and start-up amortization	4,650	3,930
Other timing differences	273	345
FICA and other tax credits	43	116
Total deferred tax assets	21,247	20,921
Less: valuation allowance		(68)
Net deferred tax assets	21,247	20,853
Deferred tax liabilities:
Prepaids	(547)	(610)
Intangible asset	(1,226)	(1,126)
Smallwares	(733)	(668)
Other timing differences	(302)	(82)
Total gross deferred tax liabilities	(2,808)	(2,486)
Net deferred tax assets (liabilities)	18,439	18,367
Deferred income taxes, current		507
Deferred income taxes, non-current	$ 18,439	$ 17,860

Long-term Debt - Additional Information (Detail) - USD ($)		12 Months Ended
	Dec. 09, 2015	Dec. 27, 2015	Dec. 28, 2014	Dec. 29, 2013
J P Morgan Chase Bank N A [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Percentage of commitment fees based on credit facility		0.125%
J P Morgan Chase Bank N A [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Percentage of commitment fees based on credit facility		0.20%
J P Morgan Chase Bank N A [Member] \| Senior Credit Facility [Member]
Debt Instrument [Line Items]
Revolving credit facility agreement term period	5 years
Revolving credit facility agreement expiration date		Nov. 30, 2020
Credit facility, Maximum borrowing capacity	$ 50,000,000
Credit facility, possible future maximum borrowing capacity	$ 75,000,000
Credit facility outstanding amount		$ 0
Credit facility, remaining borrowing capacity		$ 49,400,000
J P Morgan Chase Bank N A [Member] \| Senior Credit Facility [Member] \| LIBOR [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		1.00%
J P Morgan Chase Bank N A [Member] \| Senior Credit Facility [Member] \| LIBOR [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		1.75%
J P Morgan Chase Bank N A [Member] \| Senior Credit Facility [Member] \| Prime Rate [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		0.00%
J P Morgan Chase Bank N A [Member] \| Senior Credit Facility [Member] \| Prime Rate [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		0.50%
Note Payable [Member]
Debt Instrument [Line Items]
Interest rate on notes payable under effective interest rate method			6.20%	6.20%
Interest expense on note payable			$ 100,000	$ 100,000
Final repayment of interest and principal		Apr. 01, 2015

Capital Stock and Warrants - Additional Information (Detail) - USD ($)		12 Months Ended
	Dec. 29, 2013	Dec. 27, 2015	Dec. 28, 2014	Sep. 08, 2015
Equity [Abstract]
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		30,338,171	29,761,790
Common stock, outstanding		26,304,261	28,934,700
Terms of non-voting Common stock conversion basis ratio		The terms of the non-voting common stock provided that all shares of non-voting common stock would convert into voting common stock on a 1:1 basis immediately prior to the closing of an underwritten IPO or sale of the Company.
Non-voting Common stock conversion basis ratio		100.00%	100.00%
Stock repurchase program, authorized amount				$ 35,000,000
Common stock shares repurchased		3,206,820
Common stock repurchased value		$ 39,754,000	$ 10,246,000
Remaining dollar value of authorization under the share repurchase program		$ 20,000,000
Preferred stock dividend rate		6.00%
Percentage of liquidation value to be paid		Dividends were cumulative, but were payable only upon their redemption or the occurrence of a significant event that would result in a distribution to their holders of less than 110% of the shares’ liquidation value
Minimum percentage of liquidation value to be paid		110.00%
Redemption election period		12 months
Company warrants outstanding		241,704	241,704
Modification of warrants issued	241,704
Expiration date of warrants		5 years
Recognized stock compensation expense		$ 100,000

Stock Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended		12 Months Ended
	Oct. 09, 2013	Aug. 31, 2015	May 31, 2015	Dec. 27, 2015	Dec. 28, 2014	Dec. 29, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-voting Common stock conversion basis ratio				100.00%	100.00%
Weighted average share value of unrestricted common stock				$ 100
Recognized stock-based compensation expense				2,399	$ 2,543	$ 11,610
Unrecognized stock compensation expense				$ 5,700
Unrecognized stock compensation expense, recognition period				Through 2019
IPO [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of unrestricted common stock	8,625,000
Recognized stock-based compensation expense						$ 7,600
Non-Employee Board Of Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of unrestricted common stock					28,240
Weighted average grant-date share price					$ 15.29
Weighted average share value of unrestricted common stock					$ 400
Restricted Stock Units (RSUs) [Member] \| Non-Employee Board Of Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units issued		5,221	30,856
Restricted stock units issued, grant-date fair value		$ 11.88	$ 14.26
Restricted Stock Units (RSUs) [Member] \| First Anniversary [Member] \| Non-Employee Board Of Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		50.00%	50.00%
Restricted Stock Units (RSUs) [Member] \| Second Anniversary [Member] \| Non-Employee Board Of Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		50.00%	50.00%
Unrestricted Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized stock-based compensation expense					$ 400
2001 Equity Incentive Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for issuance				746,749
2001 Equity Incentive Plans [Member] \| Non-Voting Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock issued to key executive				500,000
2013 Long-Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for issuance				380,564
Options granted				1,278,202
2013 Long-Term Incentive Plan [Member] \| Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units issued				36,077
2013 Long-Term Incentive Plan [Member] \| Unrestricted Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of unrestricted common stock				28,240
2001 and 2004 Equity Incentive Plans and 2013 Long-Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of options outstanding, lower limit				$ 7.00
Exercise price of options outstanding, higher limit				$ 20.53
2001 and 2004 Equity Incentive Plans and 2013 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, 2025
Options vesting period				5 years

Stock Based Compensation - Summary of Activity Under Plans and Agreement (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 27, 2015	Dec. 28, 2014	Dec. 29, 2013	Dec. 30, 2012
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options Outstanding shares, Beginning balance	4,613	5,030	4,213
Options, Granted	565	318	1,243
Options, Exercised	(576)	(586)	(99)
Options, Canceled	(234)	(149)	(327)
Options Outstanding shares, Ending balance	4,368	4,613	5,030	4,213
Options Outstanding shares, Vested and expected to vest	3,244
Options Outstanding shares, Exercisable	3,232
Options outstanding weighted average exercise price, Beginning balance	$ 10.10	$ 9.41	$ 9.30
Options, Weighted Average Exercise Price, Granted	13.21	19.16	11.32
Options, Weighted Average Exercise Price, Exercised	8.30	8.67	7.97
Options, Weighted Average Exercise Price, Canceled	13.89	11.68	8.40
Options outstanding weighted average exercise price, Ending balance	10.53	$ 10.10	$ 9.41	$ 9.30
Options outstanding weighted average exercise price, vested and expected to vest	9.54
Options outstanding weighted average exercise price, Exercisable	$ 9.55
Options Outstanding Aggregate Intrinsic value	$ 9,742	$ 12,731	$ 78,575	$ 5,348
Options Vested and Expected to Vest Aggregate Intrinsic Value	9,327
Options Exercisable Aggregate Intrinsic Value	$ 8,976
Option Outstanding Weighted Average Remaining Term	5 years 1 month 6 days	5 years 7 months 13 days	6 years 3 months 22 days	5 years 11 months 5 days
Options Vested and Expected to Vest Weighted Average Remaining Term	3 years 9 months 11 days
Options Exercisable Weighted Average Remaining Term	3 years 11 months 1 day

Fair Value Measurement	12 Months Ended
Fair Value Measurement	Dec. 27, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurement	(3) Fair Value Measurement The carrying amounts of cash and cash equivalents, accounts receivable, accounts payable and all other current liabilities approximate fair values due to the short maturities of these balances. The Company assesses potential impairments to its long-lived assets, which includes property and equipment, on a quarterly basis, or whenever events or circumstances indicate that the carrying amount of an asset may not be recoverable. Shop-level assets are grouped at the individual shop-level for the purpose of the impairment assessment. Recoverability of an asset is measured by a comparison of the carrying amount of an asset to its estimated undiscounted future cash flows expected to be generated by the asset. If the carrying amount of the asset group exceeds its estimated undiscounted future cash flows, an impairment charge is recognized as the amount by which the carrying amount of the asset exceeds the fair value of the asset. The fair value of the shop assets was determined using the discounted future cash flow method of anticipated cash flows through the shop’s lease-end date using fair value measurement inputs classified as Level 3. Level 3 inputs are derived from valuation techniques in which one or more significant inputs or significant value drivers are unobservable. After performing a periodic review of the Company’s shops during each quarter of 2013, 2014 and 2015, it was determined that indicators of impairment were present for certain shops as a result of continued underperformance of shop profitability. The Company performed an impairment analysis related to these shops and recorded impairment charges of $1.1 million, $2.9 million and $3.4 million for the fiscal years 2013, 2014 and 2015, respectively, related to the excess of the carrying amounts recorded on the Company’s consolidated balance sheet over the identified shops’ estimated fair values. In fiscal 2014, the Company established a non-qualified deferred compensation plan, “Potbelly Non-Qualified Deferred Compensation Plan,” which allows highly compensated employees to defer a portion of their base salary and variable compensation each plan year. The Company maintains a rabbi trust to fund obligations under the deferred compensation plan. Amounts in the rabbi trust are invested in mutual funds. The investments in the rabbi trust are designated as trading securities and carried at fair value. Fair market value of investments in the rabbi trust is measured using Level 1 inputs (quoted prices for identical assets in active markets). As of December 28, 2014 and December 27, 2015, the fair value of the investments in the rabbi trust was $35 thousand and $128 thousand, respectively, which is included in other assets in the consolidated balance sheet. The associated liability is recorded within other long-term liabilities in the consolidated balance sheet. The Company records trading gains and losses in general and administrative expenses in the consolidated statement of operations, along with the offsetting amount related to the increase or decrease in deferred compensation to reflect its exposure to liabilities for payment under the deferred plan. For the fiscal years ended December 28, 2014 and December 27, 2015, the Company recorded an immaterial amount of unrealized losses on investments held in the rabbi trust.

Employee Benefit Plan	12 Months Ended
Employee Benefit Plan	Dec. 27, 2015
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 $0.3 million for fiscal years 2013 and 2014 and $0.4 million for fiscal year 2015.

Organization and Other Matters - Additional Information (Detail) $ in Thousands			1 Months Ended	12 Months Ended
	Oct. 09, 2013 USD ($) shares	Oct. 08, 2013 USD ($)	Jul. 31, 2015 USD ($)	Dec. 27, 2015 USD ($) State	Dec. 28, 2014 USD ($)	Dec. 29, 2013 USD ($)
Nature Of Business And Basis Of Presentation [Line Items]
Number of sandwich works and shops operation states \| State				28
Purchase of franchise shop			$ 300	$ 333
Net proceeds from IPO						$ 110,343
Cash dividend paid from proceeds from IPO		$ 49,900				$ 49,854
Public offering proceeds used for repayments of debt		$ 14,000
Net Proceeds to repurchase of common stock				$ 39,754	$ 10,246
IPO [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Public offering shares of common stock \| shares	8,625,000
Share sold by company \| shares	8,474,869
Net proceeds from IPO	$ 108,800
IPO [Member] \| Underwritten Public Offering [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Public offering shares of common stock \| shares	1,125,000
IPO [Member] \| Shareholders' Equity [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Share sold by stock holders through public offering \| shares	150,131

Fair Value Measurement - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2015	Dec. 28, 2014	Dec. 29, 2013
Fair Value Disclosures [Abstract]
Impairment charges	$ 3,400	$ 2,900	$ 1,100
Fair value of investments in rabbi trust	$ 128	$ 35

Property and Equipment - Components of Property and Equipment (Detail) - USD ($) $ in Thousands	Dec. 27, 2015	Dec. 28, 2014
Property Plant And Equipment [Abstract]
Leasehold improvements	$ 157,556	$ 142,184
Machinery and equipment	42,840	38,431
Furniture and fixtures	28,605	25,131
Computer equipment and software	20,077	17,242
Construction in progress	3,074	3,700
Property and equipment, gross	252,152	226,688
Less: Accumulated depreciation	(154,718)	(140,984)
Property and equipment, net	$ 97,434	$ 85,704

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 27, 2015	Dec. 28, 2014
Statement Of Financial Position [Abstract]
Allowances on accounts receivable	$ 14	$ 19
Common stock, par value	$ 0.01	$ 0.01
Common stock, authorized	200,000,000	200,000,000
Common stock, outstanding	26,304,261	28,934,700
Treasury stock, shares	4,033,910	827,090

Long-term Debt - Summary of Long-Term Debt (Detail) $ in Thousands	Dec. 28, 2014 USD ($)
Debt Disclosure [Abstract]
Note payable	$ 1,008
Total long-term debt	1,008
Less: Current portion	$ 1,008

Operating Leases - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 27, 2015 USD ($) Option	Dec. 28, 2014 USD ($)	Dec. 29, 2013 USD ($)
Leases Operating [Abstract]
Initial operating lease period	10 years
Number of renewal options under operating leases \| Option	2
Operating lease rent increment term	5 years
Operating lease period for expiration or renewal	2016 to 2028
Letters of credit in lieu of rent deposits \| $	$ 0.6	$ 0.6	$ 0.6
Letters of credit annual fee percentage	1.50%

Operating Leases - Schedule of Future Minimum Rental Payments Under Operating Leases (Detail) $ in Thousands	Dec. 27, 2015 USD ($)
Leases [Abstract]
2016	$ 38,817
2017	36,754
2018	32,846
2019	29,272
2020	27,281
Thereafter	85,253
Total minimum payments required	$ 250,223

Operating Leases - Schedule of Future Minimum Rental Payments Under Operating Leases (Parenthetical) (Detail) $ in Millions	Dec. 27, 2015 USD ($)
Leases [Abstract]
Minimum sublease rentals due in future	$ 0.4