The Company and Basis of Presentation	9 Months Ended
Sep. 30, 2016
Organization Consolidation And Presentation Of Financial Statements [Abstract]
The Company and Basis of Presentation	1. The Company and Basis of Presentation Aeglea BioTherapeutics, Inc. (“Aeglea” or the “Company”) is an early-stage biotechnology company committed to developing enzyme-based therapeutics in the field of amino acid metabolism that it believes will transform the lives of patients with cancer and inborn errors of metabolism, a subset of rare genetic metabolic diseases. The Company was formed as a Limited Liability Company (LLC) in Delaware on December 16, 2013 under the name Aeglea BioTherapeutics Holdings, LLC (“Aeglea LLC”) and was converted from a Delaware LLC to a Delaware corporation (the “LLC Conversion”) on March 10, 2015. The Company operates in one segment and has its principal offices in Austin, Texas. Initial Public Offering On April 6, 2016, the Company’s Registration Statement on Form S-1 (File No. 333-205001) relating to the initial public offering (“IPO”) of its common stock was declared effective by the Securities and Exchange Commission (“SEC”). The IPO closed on April 12, 2016, and 5,481,940 shares of common stock were sold at a public offering price of $10.00 per share, including 481,940 shares of common stock issued upon the partial exercise by the underwriters of their option to purchase additional shares. The Company received $47.3 million in aggregate cash proceeds, net of underwriting discounts and commissions of $3.8 million and offering costs of $3.7 million incurred by the Company. Immediately prior to the closing of the IPO, all shares of outstanding convertible preferred stock were automatically converted, at a ratio of one share of common stock for each share of convertible preferred stock, into 7,172,496 shares of common stock with the related carrying value of $58.3 million reclassified to common stock and additional paid-in capital. In connection with the IPO, the Company amended its Restated Certificate of Incorporation (the “Public Certificate”) to change the authorized capital stock to 510,000,000 shares of which 500,000,000 shares are designated as common stock and 10,000,000 shares are designated as preferred stock, all with a par value of $0.0001 per share. There are no shares of preferred stock outstanding as of September 30, 2016. Reverse Stock Split The Company’s Board of Directors and stockholders approved a 1-for-10.5 reverse stock split of the Company’s common stock and preferred stock. The reverse stock split became effective on March 28, 2016 upon filing an amended Restated Certificate of Incorporation (the “Split Certificate”). The Split Certificate remained in effect until closing of the IPO, at which time the company amended the Restated Certificate of Incorporation and filed the Public Certificate. All share and per share amounts in the condensed consolidated financial statements and notes thereto have been retroactively adjusted for all periods presented to give effect to this reverse stock split, including reclassifying an amount equal to the reduction in par value of common stock to additional paid-in capital. Liquidity As of September 30, 2016, the Company had working capital of $67.8 million, an accumulated deficit of $39.8 million, and cash, cash equivalents, and marketable securities of $68.0 million. The Company has not generated any product revenues and has not achieved profitable operations. There is no assurance that profitable operations will ever be achieved, and, if achieved, could be sustained on a continuing basis. In addition, development activities, clinical and nonclinical testing, and commercialization of the Company’s products will require significant additional financing. The Company believes that its existing cash, cash equivalents, and marketable securities will be sufficient to enable the Company to continue as a going concern for at least 12 months beyond September 30, 2016. However, the Company will need to secure additional funding in the future, in order to carry out all of its planned research and development activities. If the Company is unable to obtain additional financing or generate license or product revenue, the lack of liquidity could have a material adverse effect on the Company’s future prospects. Unaudited Interim Financial Information The interim condensed consolidated financial statements included in this document are unaudited. The unaudited interim financial statements have been prepared on the same basis as the annual financial statements and reflect, in the opinion of management, all adjustments of a normal and recurring nature that are necessary for a fair statement of the Company’s financial position as of September 30, 2016, and its results of operations for the three months and nine months ended September 30, 2016 and 2015, and cash flows for the nine months ended September 30, 2016 and 2015. The results of operations for the nine months ended September 30, 2016 are not necessarily indicative of the results to be expected for the year ending December 31, 2016 or for any other future annual or interim period. The December 31, 2015 balance sheet was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States (“U.S. GAAP”). These financial statements should be read in conjunction with the audited financial statements included in the Company’s Prospectus dated April 6, 2016 filed with the SEC pursuant to Rule 424(b)(4) (the “Prospectus”).

1. The Company and Basis of Presentation

Aeglea BioTherapeutics, Inc. (“Aeglea” or the “Company”) is an early-stage biotechnology company committed to developing enzyme-based therapeutics in the field of amino acid metabolism that it believes will transform the lives of patients with cancer and inborn errors of metabolism, a subset of rare genetic metabolic diseases. The Company was formed as a Limited Liability Company (LLC) in Delaware on December 16, 2013 under the name Aeglea BioTherapeutics Holdings, LLC (“Aeglea LLC”) and was converted from a Delaware LLC to a Delaware corporation (the “LLC Conversion”) on March 10, 2015. The Company operates in one segment and has its principal offices in Austin, Texas.

Initial Public Offering

On April 6, 2016, the Company’s Registration Statement on Form S-1 (File No. 333-205001) relating to the initial public offering (“IPO”) of its common stock was declared effective by the Securities and Exchange Commission (“SEC”). The IPO closed on April 12, 2016, and 5,481,940 shares of common stock were sold at a public offering price of $10.00 per share, including 481,940 shares of common stock issued upon the partial exercise by the underwriters of their option to purchase additional shares. The Company received $47.3 million in aggregate cash proceeds, net of underwriting discounts and commissions of $3.8 million and offering costs of $3.7 million incurred by the Company.

Immediately prior to the closing of the IPO, all shares of outstanding convertible preferred stock were automatically converted, at a ratio of one share of common stock for each share of convertible preferred stock, into 7,172,496 shares of common stock with the related carrying value of $58.3 million reclassified to common stock and additional paid-in capital.

In connection with the IPO, the Company amended its Restated Certificate of Incorporation (the “Public Certificate”) to change the authorized capital stock to 510,000,000 shares of which 500,000,000 shares are designated as common stock and 10,000,000 shares are designated as preferred stock, all with a par value of $0.0001 per share. There are no shares of preferred stock outstanding as of September 30, 2016.

Reverse Stock Split

The Company’s Board of Directors and stockholders approved a 1-for-10.5 reverse stock split of the Company’s common stock and preferred stock. The reverse stock split became effective on March 28, 2016 upon filing an amended Restated Certificate of Incorporation (the “Split Certificate”). The Split Certificate remained in effect until closing of the IPO, at which time the company amended the Restated Certificate of Incorporation and filed the Public Certificate.

All share and per share amounts in the condensed consolidated financial statements and notes thereto have been retroactively adjusted for all periods presented to give effect to this reverse stock split, including reclassifying an amount equal to the reduction in par value of common stock to additional paid-in capital.

Liquidity

As of September 30, 2016, the Company had working capital of $67.8 million, an accumulated deficit of $39.8 million, and cash, cash equivalents, and marketable securities of $68.0 million. The Company has not generated any product revenues and has not achieved profitable operations. There is no assurance that profitable operations will ever be achieved, and, if achieved, could be sustained on a continuing basis. In addition, development activities, clinical and nonclinical testing, and commercialization of the Company’s products will require significant additional financing.

The Company believes that its existing cash, cash equivalents, and marketable securities will be sufficient to enable the Company to continue as a going concern for at least 12 months beyond September 30, 2016. However, the Company will need to secure additional funding in the future, in order to carry out all of its planned research and development activities. If the Company is unable to obtain additional financing or generate license or product revenue, the lack of liquidity could have a material adverse effect on the Company’s future prospects.

Unaudited Interim Financial Information

The interim condensed consolidated financial statements included in this document are unaudited. The unaudited interim financial statements have been prepared on the same basis as the annual financial statements and reflect, in the opinion of management, all adjustments of a normal and recurring nature that are necessary for a fair statement of the Company’s financial position as of September 30, 2016, and its results of operations for the three months and nine months ended September 30, 2016 and 2015, and cash flows for the nine months ended September 30, 2016 and 2015. The results of operations for the nine months ended September 30, 2016 are not necessarily indicative of the results to be expected for the year ending December 31, 2016 or for any other future annual or interim period. The December 31, 2015 balance sheet was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States (“U.S. GAAP”). These financial statements should be read in conjunction with the audited financial statements included in the Company’s Prospectus dated April 6, 2016 filed with the SEC pursuant to Rule 424(b)(4) (the “Prospectus”).