Organization	12 Months Ended
Dec. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization	1. Organization Graybug Vision, Inc., the Company or Graybug, is a clinical-stage biopharmaceutical company developing medicines for the treatment of diseases of the retina and optic nerve. The Company presently devotes substantially all of its resources to conducting research and development and raising capital. The Company was founded in May 2011 and maintains facilities in Redwood City, California and Baltimore, Maryland. The Company is subject to risks common to clinical stage companies in the biopharmaceutical industry, including dependence on the clinical success of its product candidates, ability to obtain regulatory approvals of its product candidates, compliance with regulatory requirements, the need for substantial additional financing and protection of its proprietary technology. Initial Public Offering In September 2020, the Company completed its initial public offering, or IPO, of shares of its common stock, pursuant to the Company’s registration statement on Form S-1, which was declared effective by the Securities and Exchange Commission, or the SEC, on September 24, 2020. The shares of the Company’s common stock began trading on the Nasdaq Global Market on September 25, 2020 and the IPO closed on September 29, 2020. As a result of the IPO, the Company issued and sold an aggregate of 6,468,750 shares of common stock (inclusive of 843,750 shares issued and sold pursuant to the exercise of the underwriters’ option to purchase additional shares on October 22, 2020) at a price of $16.00 per share for net proceeds of $92.0 million, after deducting underwriting discounts, commissions and offering expenses. Prior to the completion of the IPO, all 117,809,883 shares of convertible preferred stock then outstanding were converted into 13,085,913 shares of common stock. Reverse Stock Split On September 18, 2020, the Company effected a 9.0058:1 reverse stock split of its issued and outstanding common stock. Upon the effectiveness of the reverse stock split, (i) all shares of outstanding common stock were adjusted; (ii) the conversion prices of the convertible preferred stock were adjusted; (iii) the number of shares of common stock for which each outstanding option and warrant to purchase common stock is exercisable were adjusted; and (iv) the exercise price of each outstanding option and warrant to purchase common stock was adjusted. All of the outstanding common stock share numbers (including shares of common stock subject to the Company’s options, warrants and as-converted for the outstanding convertible preferred stock), share prices, exercise prices and per share amounts contained in the financial statements have been retroactively adjusted to reflect this reverse stock split for all periods presented. The par value per share and the authorized number of shares of common stock were not adjusted as a result of the reverse stock split. Going Concern Considerations The Company incurred losses from operations and had negative cash flows from operating activities for the years ended December 31, 2020 and 2019, and the Company’s accumulated deficit at December 31, 2020 is $133.4 million. The Company’s current operating plan indicates it will continue to incur losses from operations and generate negative cash flows from operating activities, given ongoing expenditures related to extensive research and development and the Company’s lack of revenue-generating activities at this point in its life cycle. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. These events and conditions raise substantial doubt about the Company’s ability to continue as a going concern. Based upon the Company’s current operating plan, the Company believes existing cash, cash equivalents and short-term investments will enable the Company to fund its operating expenses and capital expenditure requirements into the first quarter of 2022 but not at least 12 months from the issuance date of these financial statements. The Company bases this estimate on assumptions that may prove to be wrong, and it could utilize the available capital resources sooner than it currently expects. The Company currently plans to initiate two Phase 3 clinical trials for GB-102 in the second half of 2021. As such, the Company expects its cash and cash equivalents of $33.4 million and short-term investments of $61.6 million as of December 31, 2020, will be insufficient to fund its operating expenses and capital expenditure requirements for 12 months beyond the date of issuance of these financial statements. As a result, these conditions have raised substantial doubt about the Company’s ability to continue as a going concern. The future viability of the Company is dependent on its ability to raise additional capital to finance its operations and ultimately achieve profitable operations. The Company will seek to raise additional funds in order to further advance its research and development programs, operate its business and meet its obligations as they come due. The Company is pursuing financing alternatives, such as partnering and equity financing. Such sources of capital may not, however, be available to the Company in the necessary time frame, in the amounts that the Company requires, on terms that are acceptable to the Company, or at all. If the Company is unable to raise the necessary funds when needed or reduce spending on currently planned activities, it may not be able to continue the development of its products or the Company could be required to delay, scale back, or eliminate some or all of its research and development programs and other operations and will materially harm its business, financial position and results of operations. Coronavirus Outbreak In March 2020 the World Health Organization declared the global novel coronavirus disease 2019, or COVID-19, outbreak a pandemic. As of December 31, 2020, the Company’s operations have not been significantly impacted by the COVID-19 pandemic. However, the Company cannot at this time predict the specific extent, duration, or full impact that the COVID-19 pandemic will have on its financial condition and operations, including ongoing and planned clinical trials. The impact of the COVID-19 pandemic on the financial performance of the Company will depend on future developments, including the duration and spread of the pandemic and related governmental advisories and restrictions. These developments and the impact of the COVID-19 pandemic on the financial markets, the life sciences sector, and the overall economy are highly uncertain and cannot be predicted. If the financial markets, the life sciences sector, and/or the overall economy are impacted for an extended period, the Company’s results may be materially adversely affected. In March 2020, the Families First Coronavirus Response Act, or FFCR Act, and the Coronavirus Aid, Relief and Economic Security Act, or CARES Act, were signed into law in response to the COVID-19 pandemic. The FFCR Act and CARES Act include provisions related to refundable payroll tax credits, deferment of employer side social security payments, and retroactively and temporarily (for taxable years beginning before January 1, 2021) suspending the application of the 80%-of-income limitation on the use of net operating losses, which was enacted as part of the Tax Cuts and Jobs Act of 2017. The CARES Act also provides that net operating losses arising in any taxable year beginning after December 31, 2017 and before January 1, 2021 are generally eligible to be carried back up to five years. In June 2020, Assembly Bill 85, or A.B. 85, was signed into California law. A.B. 85 provides for a three-year suspension of the use of net operating losses for medium and large businesses and a three-year cap on the use of business incentive tax credits to offset no more than $5.0 million of tax per year. A.B. 85 suspends the use of net operating losses for taxable years 2020, 2021 and 2022 for certain taxpayers with taxable income of $1.0 million or more. The carryover period for any net operating losses that are suspended under this provision will be extended. A.B. 85 also requires that business incentive tax credits including carryovers may not reduce the applicable tax by more than $5.0 million for taxable years 2020, 2021 and 2022. In December 2020, the Consolidated Appropriations Act, 2021 was signed into law. The provisions within the law include the extension of the Investment Tax Credit for solar facilities, the extension and expansion of the CARES Act employee retention tax credit for the period from January 1, 2021 through June 30, 2021, including increasing the credit rate from 50 percent to 70 percent of qualified wages, and increasing the per-employee creditable wages limit from $10,000 per year to $10,000 for each quarter. The enactment of the FFCR Act, CARES Act, A.B. 85, and Consolidated Appropriations Act, 2021, did not result in any material adjustments to the Company’s income tax provision for the year ended December 31, 2020 or to the Company’s net deferred tax assets as of December 31, 2020. Given the Company’s history of losses, the provisions of the FFCR Act, CARES Act, A.B. 85 and Consolidated Appropriations Act, 2021, did not have a material impact on the Company’s annual effective tax rate or financial statements in 2020; however, the Company will continue to evaluate the impact of tax legislation and will update its disclosures as additional information and interpretive guidance becomes available.

Organization

12 Months Ended

Dec. 31, 2020

Organization Consolidation And Presentation Of Financial Statements [Abstract]

1. Organization

Graybug Vision, Inc., the Company or Graybug, is a clinical-stage biopharmaceutical company developing medicines for the treatment of diseases of the retina and optic nerve. The Company presently devotes substantially all of its resources to conducting research and development and raising capital. The Company was founded in May 2011 and maintains facilities in Redwood City, California and Baltimore, Maryland.

The Company is subject to risks common to clinical stage companies in the biopharmaceutical industry, including dependence on the clinical success of its product candidates, ability to obtain regulatory approvals of its product candidates, compliance with regulatory requirements, the need for substantial additional financing and protection of its proprietary technology.

Initial Public Offering

In September 2020, the Company completed its initial public offering, or IPO, of shares of its common stock, pursuant to the Company’s registration statement on Form S-1, which was declared effective by the Securities and Exchange Commission, or the SEC, on September 24, 2020. The shares of the Company’s common stock began trading on the Nasdaq Global Market on September 25, 2020 and the IPO closed on September 29, 2020. As a result of the IPO, the Company issued and sold an aggregate of 6,468,750 shares of common stock (inclusive of 843,750 shares issued and sold pursuant to the exercise of the underwriters’ option to purchase additional shares on October 22, 2020) at a price of $16.00 per share for net proceeds of $92.0 million, after deducting underwriting discounts, commissions and offering expenses. Prior to the completion of the IPO, all 117,809,883 shares of convertible preferred stock then outstanding were converted into 13,085,913 shares of common stock.

Reverse Stock Split

On September 18, 2020, the Company effected a 9.0058:1 reverse stock split of its issued and outstanding common stock. Upon the effectiveness of the reverse stock split, (i) all shares of outstanding common stock were adjusted; (ii) the conversion prices of the convertible preferred stock were adjusted; (iii) the number of shares of common stock for which each outstanding option and warrant to purchase common stock is exercisable were adjusted; and (iv) the exercise price of each outstanding option and warrant to purchase common stock was adjusted. All of the outstanding common stock share numbers (including shares of common stock subject to the Company’s options, warrants and as-converted for the outstanding convertible preferred stock), share prices, exercise prices and per share amounts contained in the financial statements have been retroactively adjusted to reflect this reverse stock split for all periods presented. The par value per share and the authorized number of shares of common stock were not adjusted as a result of the reverse stock split.

Going Concern Considerations

The Company incurred losses from operations and had negative cash flows from operating activities for the years ended December 31, 2020 and 2019, and the Company’s accumulated deficit at December 31, 2020 is $133.4 million. The Company’s current operating plan indicates it will continue to incur losses from operations and generate negative cash flows from operating activities, given ongoing expenditures related to extensive research and development and the Company’s lack of revenue-generating activities at this point in its life cycle. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. These events and conditions raise substantial doubt about the Company’s ability to continue as a going concern.

Based upon the Company’s current operating plan, the Company believes existing cash, cash equivalents and short-term investments will enable the Company to fund its operating expenses and capital expenditure requirements into the first quarter of 2022 but not at least 12 months from the issuance date of these financial statements. The Company bases this estimate on assumptions that may prove to be wrong, and it could utilize the available capital resources sooner than it currently expects. The Company currently plans to initiate two Phase 3 clinical trials for GB-102 in the second half of 2021. As such, the Company expects its cash and cash equivalents of $33.4 million and short-term investments of $61.6 million as of December 31, 2020, will be insufficient to fund its operating expenses and capital expenditure requirements for 12 months beyond the date of issuance of these financial statements. As a result, these conditions have raised substantial doubt about the Company’s ability to continue as a going concern. The future viability of the Company is dependent on its ability to raise additional capital to finance its operations and ultimately achieve profitable operations.

The Company will seek to raise additional funds in order to further advance its research and development programs, operate its business and meet its obligations as they come due. The Company is pursuing financing alternatives, such as partnering and equity financing. Such sources of capital may not, however, be available to the Company in the necessary time frame, in the amounts that the Company requires, on terms that are acceptable to the Company, or at all. If the Company is unable to raise the necessary funds when needed or reduce spending on currently planned activities, it may not be able to continue the development of its products or the Company could be required to delay, scale back, or eliminate some or all of its research and development programs and other operations and will materially harm its business, financial position and results of operations.

Coronavirus Outbreak

In March 2020 the World Health Organization declared the global novel coronavirus disease 2019, or COVID-19, outbreak a pandemic. As of December 31, 2020, the Company’s operations have not been significantly impacted by the COVID-19 pandemic. However, the Company cannot at this time predict the specific extent, duration, or full impact that the COVID-19 pandemic will have on its financial condition and operations, including ongoing and planned clinical trials. The impact of the COVID-19 pandemic on the financial performance of the Company will depend on future developments, including the duration and spread of the pandemic and related governmental advisories and restrictions. These developments and the impact of the COVID-19 pandemic on the financial markets, the life sciences sector, and the overall economy are highly uncertain and cannot be predicted. If the financial markets, the life sciences sector, and/or the overall economy are impacted for an extended period, the Company’s results may be materially adversely affected.

In March 2020, the Families First Coronavirus Response Act, or FFCR Act, and the Coronavirus Aid, Relief and Economic Security Act, or CARES Act, were signed into law in response to the COVID-19 pandemic. The FFCR Act and CARES Act include provisions related to refundable payroll tax credits, deferment of employer side social security payments, and retroactively and temporarily (for taxable years beginning before January 1, 2021) suspending the application of the 80%-of-income limitation on the use of net operating losses, which was enacted as part of the Tax Cuts and Jobs Act of 2017. The CARES Act also provides that net operating losses arising in any taxable year beginning after December 31, 2017 and before January 1, 2021 are generally eligible to be carried back up to five years.

In June 2020, Assembly Bill 85, or A.B. 85, was signed into California law. A.B. 85 provides for a three-year suspension of the use of net operating losses for medium and large businesses and a three-year cap on the use of business incentive tax credits to offset no more than $5.0 million of tax per year. A.B. 85 suspends the use of net operating losses for taxable years 2020, 2021 and 2022 for certain taxpayers with taxable income of $1.0 million or more. The carryover period for any net operating losses that are suspended under this provision will be extended. A.B. 85 also requires that business incentive tax credits including carryovers may not reduce the applicable tax by more than $5.0 million for taxable years 2020, 2021 and 2022.

In December 2020, the Consolidated Appropriations Act, 2021 was signed into law. The provisions within the law include the extension of the Investment Tax Credit for solar facilities, the extension and expansion of the CARES Act employee retention tax credit for the period from January 1, 2021 through June 30, 2021, including increasing the credit rate from 50 percent to 70 percent of qualified wages, and increasing the per-employee creditable wages limit from $10,000 per year to $10,000 for each quarter.

The enactment of the FFCR Act, CARES Act, A.B. 85, and Consolidated Appropriations Act, 2021, did not result in any material adjustments to the Company’s income tax provision for the year ended December 31, 2020 or to the Company’s net deferred tax assets as of December 31, 2020. Given the Company’s history of losses, the provisions of the FFCR Act, CARES Act, A.B. 85 and Consolidated Appropriations Act, 2021, did not have a material impact on the Company’s annual effective tax rate or financial statements in 2020; however, the Company will continue to evaluate the impact of tax legislation and will update its disclosures as additional information and interpretive guidance becomes available.