The Company and Basis of Presentation	12 Months Ended
Dec. 31, 2017
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 a clinical-stage biotechnology company committed to developing enzyme-based therapeutics in the field of amino acid metabolism to treat rare genetic diseases and cancer. 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 LLC Conversion was effective January 1, 2015 for tax purposes and as such, the Company filed a consolidated tax return for the full year ended December 31, 2015. The Company operates in one segment and has its principal offices in Austin, Texas. Stock Offerings Initial Public Offering On April 12, 2016, the Company closed an initial public offering (“IPO”) of its common stock, which resulted in the sale of 5,481,940 shares of its common stock 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. Follow-on Public Offering In June 2017, the Company issued and sold 3,000,000 shares of common stock in an underwritten public offering pursuant to a shelf registration statement on Form S-3 at a public offering price of $4.10 per share. The net proceeds to the Company from this public offering was approximately $11.4 million, after deducting underwriting discounts and commissions of $615,000 and offering costs of $306,000. Liquidity As of December 31, 2017, the Company had working capital of $49.4 million, an accumulated deficit of $72.5 million, and cash, cash equivalents, and marketable securities of $50.3 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 is subject to a number of risks similar to other life science companies, including, but not limited to, risks related to the successful discovery and development of product candidates, raising additional capital, development of competing drugs and therapies, protection of proprietary technology and market acceptance of the Company’s products. As a result of these and other factors and the related uncertainties, there can be no assurance of the Company’s future success. Based upon the Company’s current operating plan, the Company believes that it has sufficient resources to fund operations through September 30, 2019 with its existing cash, cash equivalents, and marketable securities. 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. Basis of Presentation The consolidated financial statements have been prepared in conformity with generally accepted accounting principles in the United States (“U.S. GAAP”) as defined by the Financial Accounting Standards Board (“FASB”) and include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.

1. The Company and Basis of Presentation

Aeglea BioTherapeutics, Inc. (“Aeglea” or the “Company”) is a clinical-stage biotechnology company committed to developing enzyme-based therapeutics in the field of amino acid metabolism to treat rare genetic diseases and cancer. 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 LLC Conversion was effective January 1, 2015 for tax purposes and as such, the Company filed a consolidated tax return for the full year ended December 31, 2015. The Company operates in one segment and has its principal offices in Austin, Texas.

Stock Offerings

Initial Public Offering

On April 12, 2016, the Company closed an initial public offering (“IPO”) of its common stock, which resulted in the sale of 5,481,940 shares of its common stock 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.

Follow-on Public Offering

In June 2017, the Company issued and sold 3,000,000 shares of common stock in an underwritten public offering pursuant to a shelf registration statement on Form S-3 at a public offering price of $4.10 per share. The net proceeds to the Company from this public offering was approximately $11.4 million, after deducting underwriting discounts and commissions of $615,000 and offering costs of $306,000.

Liquidity

As of December 31, 2017, the Company had working capital of $49.4 million, an accumulated deficit of $72.5 million, and cash, cash equivalents, and marketable securities of $50.3 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 is subject to a number of risks similar to other life science companies, including, but not limited to, risks related to the successful discovery and development of product candidates, raising additional capital, development of competing drugs and therapies, protection of proprietary technology and market acceptance of the Company’s products. As a result of these and other factors and the related uncertainties, there can be no assurance of the Company’s future success.

Based upon the Company’s current operating plan, the Company believes that it has sufficient resources to fund operations through September 30, 2019 with its existing cash, cash equivalents, and marketable securities. 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.

Basis of Presentation

The consolidated financial statements have been prepared in conformity with generally accepted accounting principles in the United States (“U.S. GAAP”) as defined by the Financial Accounting Standards Board (“FASB”) and include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.