Description of Business, Organization and Liquidity	3 Months Ended
Mar. 31, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Description of Business, Organization and Liquidity	1. DESCRIPTION OF BUSINESS, ORGANIZATION AND LIQUIDITY Business and Organization Galecto, Inc., together with its consolidated subsidiaries, or the Company or Galecto, is a clinical-stage biotechnology company developing therapeutics that are designed to target the biological processes that lie at the heart of fibrosis and impact a broad range of fibrotic and related diseases, including cancer. The Company’s initial focus is on the development of small-molecule inhibitors of galectin-3 and lysyl oxidase-like 2, or LOXL2, which play key roles in regulating fibrosis and cancer. As of March 31, 2021, the Company’s wholly owned subsidiaries were PharmAkea, Inc. or PharmAkea, Galecto Securities Corporation and Galecto Biotech AB, a Swedish company. Galecto Biotech ApS, a Danish operating company, was Galecto Biotech AB’s wholly owned subsidiary. Risks and uncertainties The Company is subject to risks common to companies in the biotechnology industry including, but not limited to, new technological innovations, protection of proprietary technology, dependence on key personnel, compliance with government regulations and the need to obtain additional financing. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel infrastructure and extensive compliance reporting capabilities. The Company’s product candidates are in development. There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s intellectual property will be obtained, that any products developed will obtain necessary government regulatory approval or that any approved products will be commercially viable. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will generate significant revenue from product sales. The Company operates in an environment of rapid change in technology and substantial competition from pharmaceutical and biotechnology companies. In addition, the Company is dependent upon the services of its employees and consultants. Liquidity and management plans The accompanying condensed consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles (“U.S. GAAP”). The accompanying interim condensed consolidated financial statements as of March 31, 2021 and for the three months ended March 31, 2021 and 2020, and related interim information contained within the notes to the condensed consolidated financial statements, are unaudited. In management’s opinion, the unaudited interim condensed consolidated financial statements have been prepared on the same basis as the Company’s audited consolidated financial statements and include all adjustments (including normal recurring adjustments) necessary for the fair presentation of the Company’s financial position as of March 31, 2021, results of operations, statement of convertible preferred stock and stockholders’ equity and its cash flows for the three months ended March 31, 2021 and 2020. These interim condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and accompanying notes contained in the Company’s The coronavirus disease 2019, or COVID-19, pandemic, which began in December 2019 and has spread worldwide, has caused many governments to implement measures to slow the spread of the outbreak through quarantines, travel restrictions, heightened border scrutiny and other measures. The outbreak and government measures taken in response have also had a significant impact, both directly and indirectly, on businesses and commerce, as worker shortages have occurred; supply chains have been disrupted; facilities and production have been suspended; and demand for certain goods and services, such as medical services and supplies, has spiked, while demand for other goods and services, such as travel, has fallen. The future progression of the outbreak and its effects on the Company’s business and operations are uncertain. In response to the impact of COVID-19, the Company has implemented certain measures intended to help the Company manage its impact and position the Company to resume operations quickly and efficiently once these restrictions are lifted, such as executing a work-from-home strategy for administrative functions and operations. The Company continues to monitor the impact of COVID-19 and assess its strategy accordingly. Despite the Company’s implementation of such measures, the actual and perceived impact of the COVID-19 pandemic is changing daily, and its ultimate effect on the Company cannot be predicted. As a result, there can be no assurance that the Company will not experience additional negative impacts associated with COVID-19, which could be significant. The COVID-19 pandemic may negatively impact the Company’s business, financial condition and results of operations by decreasing or delaying the enrollment of patients in the Company’s clinical trials or otherwise causing interruptions or delays in the Company’s programs and services. On March 27, 2020, the United States enacted the Coronavirus Aid, Relief and Economic Security Act, or CARES Act. The CARES Act is an emergency economic stimulus package that includes spending and tax breaks to strengthen the United States economy and fund a nationwide effort to curtail the effect of COVID-19. The CARES Act provides sweeping tax changes in response to the COVID-19 pandemic, some of the more significant provisions include removing certain limitations on the utilization of net operating losses, increasing the loss carryback period for certain losses to five years, increasing the ability to deduct interest expense, and deferring social security payments, as well as amending certain provisions of the previously enacted Tax Cuts and Jobs Act of 2017. The Company does not believe the CARES Act will have a material impact on its financial position and results of operations.

Description of Business, Organization and Liquidity

3 Months Ended

Mar. 31, 2021

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Description of Business, Organization and Liquidity

1. DESCRIPTION OF BUSINESS, ORGANIZATION AND LIQUIDITY

Business and Organization

Galecto, Inc., together with its consolidated subsidiaries, or the Company or Galecto, is a clinical-stage biotechnology company developing therapeutics that are designed to target the biological processes that lie at the heart of fibrosis and impact a broad range of fibrotic and related diseases, including cancer. The Company’s initial focus is on the development of small-molecule inhibitors of galectin-3 and lysyl oxidase-like 2, or LOXL2, which play key roles in regulating fibrosis and cancer.

As of March 31, 2021, the Company’s wholly owned subsidiaries were PharmAkea, Inc. or PharmAkea, Galecto Securities Corporation and Galecto Biotech AB, a Swedish company. Galecto Biotech ApS, a Danish operating company, was Galecto Biotech AB’s wholly owned subsidiary.

Risks and uncertainties

The Company is subject to risks common to companies in the biotechnology industry including, but not limited to, new technological innovations, protection of proprietary technology, dependence on key personnel, compliance with government regulations and the need to obtain additional financing. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel infrastructure and extensive compliance reporting capabilities.

The Company’s product candidates are in development. There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s intellectual property will be obtained, that any products developed will obtain necessary government regulatory approval or that any approved products will be commercially viable. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will generate significant revenue from product sales. The Company operates in an environment of rapid change in technology and substantial competition from pharmaceutical and biotechnology companies. In addition, the Company is dependent upon the services of its employees and consultants.

Liquidity and management plans

The accompanying condensed consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles (“U.S. GAAP”).

The accompanying interim condensed consolidated financial statements as of March 31, 2021 and for the three months ended March 31, 2021 and 2020, and related interim information contained within the notes to the condensed consolidated financial statements, are unaudited. In management’s opinion, the unaudited interim condensed consolidated financial statements have been prepared on the same basis as the Company’s audited consolidated financial statements and include all adjustments (including normal recurring adjustments) necessary for the fair presentation of the Company’s financial position as of March 31, 2021, results of operations, statement of convertible preferred stock and stockholders’ equity and its cash flows for the three months ended March 31, 2021 and 2020. These interim condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and accompanying notes contained in the Company’s The coronavirus disease 2019, or COVID-19, pandemic, which began in December 2019 and has spread worldwide, has caused many governments to implement measures to slow the spread of the outbreak through quarantines, travel restrictions, heightened border scrutiny and other measures. The outbreak and government measures taken in response have also had a significant impact, both directly and indirectly, on businesses and commerce, as worker shortages have occurred; supply chains have been disrupted; facilities and production have been suspended; and demand for certain goods and services, such as medical services and supplies, has spiked, while demand for other goods and services, such as travel, has fallen. The future progression of the outbreak and its effects on the Company’s business and operations are uncertain.

In response to the impact of COVID-19, the Company has implemented certain measures intended to help the Company manage its impact and position the Company to resume operations quickly and efficiently once these restrictions are lifted, such as executing a work-from-home strategy for administrative functions and operations. The Company continues to monitor the impact of COVID-19 and assess its strategy accordingly.

Despite the Company’s implementation of such measures, the actual and perceived impact of the COVID-19 pandemic is changing daily, and its ultimate effect on the Company cannot be predicted. As a result, there can be no assurance that the Company will not experience additional negative impacts associated with COVID-19, which could be significant. The COVID-19 pandemic may negatively impact the Company’s business, financial condition and results of operations by decreasing or delaying the enrollment of patients in the Company’s clinical trials or otherwise causing interruptions or delays in the Company’s programs and services.

On March 27, 2020, the United States enacted the Coronavirus Aid, Relief and Economic Security Act, or CARES Act. The CARES Act is an emergency economic stimulus package that includes spending and tax breaks to strengthen the United States economy and fund a nationwide effort to curtail the effect of COVID-19. The CARES Act provides sweeping tax changes in response to the COVID-19 pandemic, some of the more significant provisions include removing certain limitations on the utilization of net operating losses, increasing the loss carryback period for certain losses to five years, increasing the ability to deduct interest expense, and deferring social security payments, as well as amending certain provisions of the previously enacted Tax Cuts and Jobs Act of 2017. The Company does not believe the CARES Act will have a material impact on its financial position and results of operations.