Commitments and Contingencies	12 Months Ended
Dec. 31, 2016
Commitments and Contingencies [Abstract]
Commitments and Contingencies	10. Commitments and Contingencies Purchase Obligations The Company enters into various purchase obligations in the ordinary course of business, generally of a short term nature. Those that are binding primarily relate to commitments for food purchases and supplies, amounts owed under contractor and subcontractor agreements, orders submitted for equipment for restaurants under construction, and marketing initiatives and corporate sponsorships. Litigation Receipt of Grand Jury Subpoenas On January 28, 2016, the Company was served with a Federal Grand Jury Subpoena from the U.S. District Court for the Central District of California in connection with an official criminal investigation being conducted by the U.S. Attorney’s Office for the Central District of California, in conjunction with the U.S. Food and Drug Administration’s Office of Criminal Investigations. The subpoena requires the production of documents and information related to company-wide food safety matters dating back to January 1, 2013. The Company intends to continue to fully cooperate in the investigation. It is not possible at this time to determine whether the Company will incur, or to reasonably estimate the amount of, any fines or penalties in connection with the investigation pursuant to which the subpoena was issued. Shareholder Class Action On January 8, 2016, Susie Ong filed a complaint in the U.S. District Court for the Southern District of New York on behalf of a purported class of purchasers of shares of the Company’s common stock between February 4, 2015 and January 5, 2016. The complaint purports to state claims against the Company, each of its co-Chief Executive Officers and its Chief Financial Officer under Sections 10(b) and 20(a) of the Exchange Act and related rules, based on the Company’s alleged failure during the claimed class period to disclose material information about the Company’s quality controls and safeguards in relation to consumer and employee health. The complaint asserts that those failures and related public statements were false and misleading and that, as a result, the market price of the Company’s stock was artificially inflated during the claimed class period. The complaint seeks damages on behalf of the purported class in an unspecified amount, interest, and an award of reasonable attorneys’ fees, expert fees and other costs. The Company intends to defend this case vigorously, but it is not possible at this time to reasonably estimate the outcome of or any potential liability from the case. Shareholder Derivative Actions On March 21, 2016, Jessica Oldfather filed a shareholder derivative action in the Court of Chancery of the State of Delaware alleging that the Company’s Board of Directors and officers breached their fiduciary duties in connection with allegedly excessive compensation awarded from 2011 to 2015 under the Company’s stock incentive plan. On December 8, 2016, the Court of Chancery dismissed the complaint, with prejudice. On April 6, 2016, Uri Skorski filed a shareholder derivative action in Colorado state court in Denver, Colorado, making largely the same allegations as the Oldfather complaint and also alleging that the Company’s Board of Directors and officers breached their fiduciary duties in connection with the Company’s alleged failure to disclose material information about the Company’s food safety policies and procedures. On April 14, 2016, Mark Arnold and Zachary Arata filed a shareholder derivative action in Colorado state court in Denver, Colorado, making largely the same allegations as the Skorski complaint. On May 26, 2016, the court issued an order consolidating the Skorski and Arnold/Arata actions into a single case. On August 8, 2016, Sean Gubricky filed a shareholder derivative action the U.S. District Court for the District of Colorado, alleging that the Company’s Board of Directors and certain officers failed to institute proper food safety controls and policies, issued materially false and misleading statements in violation of federal securities laws, and otherwise breached their fiduciary duties to the Company. On September 1, 2016, Ross Weintraub filed a shareholder derivative action in Colorado state court in Denver, Colorado, making largely the same allegations as the Gubricky complaint. On December 27, 2016, Cyrus Lashkari filed a shareholder derivative action the U.S. District Court for the District of Colorado, making largely the same allegations as the foregoing shareholder derivative complaints. Each of these actions purports to state a claim for damages on behalf of the Company, and is based on statements in the Company’s SEC filings and related public disclosures, as well as media reports and Company records. The Company intends to defend these cases vigorously, but it is not possible at this time to reasonably estimate the outcome of or any potential liability from these cases. Notices of Inspection of Work Authorization Documents and Related Civil and Criminal Investigations Following an inspection during 2010 by the U.S. Department of Homeland Security, or DHS, of the work authorization documents of the Company’s restaurant employees in Minnesota, the Immigration and Customs Enforcement arm of DHS, or ICE, issued to the Company a Notice of Suspect Documents identifying a large number of employees who, according to ICE and notwithstanding the Company’s review of work authorization documents for each employee at the time they were hired, appeared not to be authorized to work in the U.S. The Company approached each of the named employees to explain ICE’s determination and afforded each employee an opportunity to confirm the validity of their original work eligibility documents, or provide valid work eligibility documents. Employees who were unable to provide valid work eligibility documents were terminated in accordance with the law. In December 2010, the Company was also requested by DHS to provide the work authorization documents of restaurant employees in the District of Columbia and Virginia, and the Company provided the requested documents in January 2011. The Company subsequently received requests from the office of the U.S. Attorney for the District of Columbia for work authorization documents covering all of the Company’s employees since 2007, plus employee lists and other documents concerning work authorization. In May 2012, the U.S. Securities and Exchange Commission notified the Company that it was conducting a civil investigation of the Company’s compliance with employee work authorization verification requirements and its related disclosures and statements, and the office of the U.S. Attorney for the District of Columbia advised the Company that its investigation had broadened to include a parallel criminal and civil investigation of the Company’s compliance with federal securities laws. During the fourth quarter of 2016, the Company entered into an agreement with the office of the U.S. Attorney for the District of Columbia to resolve the DHS and ICE investigations. Miscellaneous The Company is involved in various other claims and legal actions that arise in the ordinary course of business. The Company does not believe that the ultimate resolution of these actions will have a material adverse effect on the Company’s financial position, results of operations, liquidity or capital resources. However, a significant increase in the number of these claims, or one or more successful claims under which the Company incurs greater liabilities than the Company currently anticipates, could materially and adversely affect the Company’s business, financial condition, results of operations and cash flows.

10. Commitments and Contingencies

Purchase Obligations

The Company enters into various purchase obligations in the ordinary course of business, generally of a short term nature. Those that are binding primarily relate to commitments for food purchases and supplies, amounts owed under contractor and subcontractor agreements, orders submitted for equipment for restaurants under construction, and marketing initiatives and corporate sponsorships.

Litigation

Receipt of Grand Jury Subpoenas

On January 28, 2016, the Company was served with a Federal Grand Jury Subpoena from the U.S. District Court for the Central District of California in connection with an official criminal investigation being conducted by the U.S. Attorney’s Office for the Central District of California, in conjunction with the U.S. Food and Drug Administration’s Office of Criminal Investigations. The subpoena requires the production of documents and information related to company-wide food safety matters dating back to January 1, 2013. The Company intends to continue to fully cooperate in the investigation. It is not possible at this time to determine whether the Company will incur, or to reasonably estimate the amount of, any fines or penalties in connection with the investigation pursuant to which the subpoena was issued.

Shareholder Class Action

On January 8, 2016, Susie Ong filed a complaint in the U.S. District Court for the Southern District of New York on behalf of a purported class of purchasers of shares of the Company’s common stock between February 4, 2015 and January 5, 2016. The complaint purports to state claims against the Company, each of its co-Chief Executive Officers and its Chief Financial Officer under Sections 10(b) and 20(a) of the Exchange Act and related rules, based on the Company’s alleged failure during the claimed class period to disclose material information about the Company’s quality controls and safeguards in relation to consumer and employee health. The complaint asserts that those failures and related public statements were false and misleading and that, as a result, the market price of the Company’s stock was artificially inflated during the claimed class period. The complaint seeks damages on behalf of the purported class in an unspecified amount, interest, and an award of reasonable attorneys’ fees, expert fees and other costs. The Company intends to defend this case vigorously, but it is not possible at this time to reasonably estimate the outcome of or any potential liability from the case.

Shareholder Derivative Actions

On March 21, 2016, Jessica Oldfather filed a shareholder derivative action in the Court of Chancery of the State of Delaware alleging that the Company’s Board of Directors and officers breached their fiduciary duties in connection with allegedly excessive compensation awarded from 2011 to 2015 under the Company’s stock incentive plan. On December 8, 2016, the Court of Chancery dismissed the complaint, with prejudice.

On April 6, 2016, Uri Skorski filed a shareholder derivative action in Colorado state court in Denver, Colorado, making largely the same allegations as the Oldfather complaint and also alleging that the Company’s Board of Directors and officers breached their fiduciary duties in connection with the Company’s alleged failure to disclose material information about the Company’s food safety policies and procedures. On April 14, 2016, Mark Arnold and Zachary Arata filed a shareholder derivative action in Colorado state court in Denver, Colorado, making largely the same allegations as the Skorski complaint. On May 26, 2016, the court issued an order consolidating the Skorski and Arnold/Arata actions into a single case. On August 8, 2016, Sean Gubricky filed a shareholder derivative action the U.S. District Court for the District of Colorado, alleging that the Company’s Board of Directors and certain officers failed to institute proper food safety controls and policies, issued materially false and misleading statements in violation of federal securities laws, and otherwise breached their fiduciary duties to the Company. On September 1, 2016, Ross Weintraub filed a shareholder derivative action in Colorado state court in Denver, Colorado, making largely the same allegations as the Gubricky complaint. On December 27, 2016, Cyrus Lashkari filed a shareholder derivative action the U.S. District Court for the District of Colorado, making largely the same allegations as the foregoing shareholder derivative complaints. Each of these actions purports to state a claim for damages on behalf of the Company, and is based on statements in the Company’s SEC filings and related public disclosures, as well as media reports and Company records. The Company intends to defend these cases vigorously, but it is not possible at this time to reasonably estimate the outcome of or any potential liability from these cases.

Notices of Inspection of Work Authorization Documents and Related Civil and Criminal Investigations

Following an inspection during 2010 by the U.S. Department of Homeland Security, or DHS, of the work authorization documents of the Company’s restaurant employees in Minnesota, the Immigration and Customs Enforcement arm of DHS, or ICE, issued to the Company a Notice of Suspect Documents identifying a large number of employees who, according to ICE and notwithstanding the Company’s review of work authorization documents for each employee at the time they were hired, appeared not to be authorized to work in the U.S. The Company approached each of the named employees to explain ICE’s determination and afforded each employee an opportunity to confirm the validity of their original work eligibility documents, or provide valid work eligibility documents. Employees who were unable to provide valid work eligibility documents were terminated in accordance with the law. In December 2010, the Company was also requested by DHS to provide the work authorization documents of restaurant employees in the District of Columbia and Virginia, and the Company provided the requested documents in January 2011. The Company subsequently received requests from the office of the U.S. Attorney for the District of Columbia for work authorization documents covering all of the Company’s employees since 2007, plus employee lists and other documents concerning work authorization. In May 2012, the U.S. Securities and Exchange Commission notified the Company that it was conducting a civil investigation of the Company’s compliance with employee work authorization verification requirements and its related disclosures and statements, and the office of the U.S. Attorney for the District of Columbia advised the Company that its investigation had broadened to include a parallel criminal and civil investigation of the Company’s compliance with federal securities laws. During the fourth quarter of 2016, the Company entered into an agreement with the office of the U.S. Attorney for the District of Columbia to resolve the DHS and ICE investigations.

Miscellaneous

The Company is involved in various other claims and legal actions that arise in the ordinary course of business. The Company does not believe that the ultimate resolution of these actions will have a material adverse effect on the Company’s financial position, results of operations, liquidity or capital resources. However, a significant increase in the number of these claims, or one or more successful claims under which the Company incurs greater liabilities than the Company currently anticipates, could materially and adversely affect the Company’s business, financial condition, results of operations and cash flows.