Basis of Presentation (Policies)	3 Months Ended
Mar. 29, 2022
Accounting Policies [Abstract]
Basis of Presentation	The accompanying unaudited consolidated financial statements include the accounts of BJ’s Restaurants, Inc. (referred to herein as the “Company,” “we,” “us” and “our”) and our wholly owned subsidiaries. The consolidated financial statements presented herein include all material adjustments (consisting of normal recurring adjustments) which are, in the opinion of management, necessary for a fair presentation of our financial condition, results of operations, shareholders’ equity and cash flows for the periods presented. Our consolidated financial statements and accompanying notes have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Certain information and footnote disclosures normally included in consolidated financial statements in accordance with U.S. GAAP have been omitted pursuant to the U.S. Securities and Exchange Commission (“SEC”) rules. The preparation of financial statements in conformity with U.S. GAAP requires us to make certain estimates and assumptions for the reporting periods covered by the financial statements. These estimates and assumptions affect the reported amounts of assets, liabilities, revenues and expenses. Actual amounts could differ from these estimates. Our operating results for the thirteen weeks ended March 29, 2022 may not be indicative of operating results for the entire year. A description of our accounting policies and other financial information is included in our audited consolidated financial statements filed with the SEC on Form 10-K for the fiscal year ended December 28, 2021. The disclosures included in our accompanying interim consolidated financial statements and footnotes should be read in conjunction with our consolidated financial statements and notes thereto included in the Annual Report on Form 10-K and our other reports filed from time to time with the Securities and Exchange Commission.
COVID-19 Pandemic Update	COVID-19 Pandemic Update The COVID-19 pandemic has adversely affected, and is expected to continue to adversely affect, our operations and financial results for the foreseeable future. Currently, national, state and local jurisdictions have removed their capacity restrictions on businesses and therefore our restaurants are serving customers (referred to as “guests”) in our dining rooms without social distancing requirements. However, it is possible additional outbreaks could require us to reduce our capacity, implement social distancing, or further suspend our in-restaurant dining operations. In addition, our restaurant performance could be adversely affected if we are required by law to have guests present evidence of vaccination or negative tests in a significant number of jurisdictions. There is also no guarantee that state and local jurisdictions that ease restrictions will not later reverse or roll-back the restrictions, as many have done in the past. Additionally, our restaurant operations have been and could continue to be disrupted by employee (referred to as “team member”) staffing issues because of illness, exclusion, fear of contracting COVID-19 or caring for family members due to COVID-19, legal requirements for team member vaccinations or COVID testing, lack of labor supply, competitive labor pressures, or for other reasons. Furthermore, we remain in regular contact with our major suppliers and while to date we have not experienced material disruptions in our supply chain due to COVID-19, we could see material future disruptions should the impacts of COVID-19 continue. For more information regarding the risks to our business relating to the COVID-19 pandemic, see “Risk Factors” in Item 1A of our Annual Report on Form 10-K for the fiscal year ended December 28, 2021.
Net Income (Loss) Per Share	Basic and diluted net income (loss) per share is calculated by dividing net income (loss) by the weighted average number of common shares outstanding during the period. Potentially dilutive shares are excluded from the computation of diluted net (loss) per share since they have an anti-dilutive effect, yet potentially dilutive shares are included in the computation of diluted net income per share. The number of diluted shares reflects the potential dilution that could occur if holders of in-the-money options and warrants exercised their right to convert these instruments into common stock and the restrictions on restricted stock units (“RSUs”) lapse. Additionally, performance-based RSUs are considered contingent shares; therefore, at each reporting date we determine the probable number of shares that will vest and include these contingently issuable shares in our diluted share calculation unless they are antidilutive. Once these performance-based RSUs vest, they are included in our basic net income (loss) per share calculation.

Basis of Presentation (Policies)

3 Months Ended

Mar. 29, 2022

The accompanying unaudited consolidated financial statements include the accounts of BJ’s Restaurants, Inc. (referred to herein as the “Company,” “we,” “us” and “our”) and our wholly owned subsidiaries. The consolidated financial statements presented herein include all material adjustments (consisting of normal recurring adjustments) which are, in the opinion of management, necessary for a fair presentation of our financial condition, results of operations, shareholders’ equity and cash flows for the periods presented. Our consolidated financial statements and accompanying notes have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Certain information and footnote disclosures normally included in consolidated financial statements in accordance with U.S. GAAP have been omitted pursuant to the U.S. Securities and Exchange Commission (“SEC”) rules.

The preparation of financial statements in conformity with U.S. GAAP requires us to make certain estimates and assumptions for the reporting periods covered by the financial statements. These estimates and assumptions affect the reported amounts of assets, liabilities, revenues and expenses. Actual amounts could differ from these estimates. Our operating results for the thirteen weeks ended March 29, 2022 may not be indicative of operating results for the entire year.

A description of our accounting policies and other financial information is included in our audited consolidated financial statements filed with the SEC on Form 10-K for the fiscal year ended December 28, 2021. The disclosures included in our accompanying interim consolidated financial statements and footnotes should be read in conjunction with our consolidated financial statements and notes thereto included in the Annual Report on Form 10-K and our other reports filed from time to time with the Securities and Exchange Commission.

COVID-19 Pandemic Update

The COVID-19 pandemic has adversely affected, and is expected to continue to adversely affect, our operations and financial results for the foreseeable future. Currently, national, state and local jurisdictions have removed their capacity restrictions on businesses and therefore our restaurants are serving customers (referred to as “guests”) in our dining rooms without social distancing requirements. However, it is possible additional outbreaks could require us to reduce our capacity, implement social distancing, or further suspend our in-restaurant dining operations. In addition, our restaurant performance could be adversely affected if we are required by law to have guests present evidence of vaccination or negative tests in a significant number of jurisdictions. There is also no guarantee that state and local jurisdictions that ease restrictions will not later reverse or roll-back the restrictions, as many have done in the past. Additionally, our restaurant operations have been and could continue to be disrupted by employee (referred to as “team member”) staffing issues because of illness, exclusion, fear of contracting COVID-19 or caring for family members due to COVID-19, legal requirements for team member vaccinations or COVID testing, lack of labor supply, competitive labor pressures, or for other reasons. Furthermore, we remain in regular contact with our major suppliers and while to date we have not experienced material disruptions in our supply chain due to COVID-19, we could see material future disruptions should the impacts of COVID-19 continue. For more information regarding the risks to our business relating to the COVID-19 pandemic, see “Risk Factors” in Item 1A of our Annual Report on Form 10-K for the fiscal year ended December 28, 2021.

Net Income (Loss) Per Share

Basic and diluted net income (loss) per share is calculated by dividing net income (loss) by the weighted average number of common shares outstanding during the period. Potentially dilutive shares are excluded from the computation of diluted net (loss) per share since they have an anti-dilutive effect, yet potentially dilutive shares are included in the computation of diluted net income per share. The number of diluted shares reflects the potential dilution that could occur if holders of in-the-money options and warrants exercised their right to convert these instruments into common stock and the restrictions on restricted stock units (“RSUs”) lapse. Additionally, performance-based RSUs are considered contingent shares; therefore, at each reporting date we determine the probable number of shares that will vest and include these contingently issuable shares in our diluted share calculation unless they are antidilutive. Once these performance-based RSUs vest, they are included in our basic net income (loss) per share calculation.