Organization and Accounting Pronouncements	6 Months Ended
Jun. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization and Accounting Pronouncements	1. Organization and Accounting Pronouncements Description of Business Equillium, Inc. (the Company) was incorporated in the state of Delaware on March 16, 2017. The Company is engaged in the research and development of products for severe autoimmune and inflammatory disorders with high unmet medical need. From inception through June 30, 2019, the Company has devoted substantially all of its efforts to organizing and staffing the company, business planning, raising capital, in-licensing rights to itolizumab, conducting preclinical research, filing two initial Investigational New Drug applications (INDs) and commencing clinical development of the Company’s initial product candidate, itolizumab (EQ001). In addition, the Company has a limited operating history, has not generated revenues from its principal operations, and the sales and income potential of its business is unproven. Liquidity As of June 30, 2019, the Company had $56.9 million in cash, cash equivalents and short-term investments. The Company has incurred significant operating losses and negative cash flows from operations. The Company expects to use its cash, cash equivalents and short-term investments to fund research and development of itolizumab and for working capital and other general corporate purposes. The Company does not expect to generate any revenues from product sales unless and until the Company successfully completes development and obtains regulatory approval of itolizumab or any future product candidate, which will not be for at least the next several years, if ever. Accordingly, until such time as the Company can generate significant revenue from sales of its product candidates, if ever, the Company expects to finance its cash needs through a combination of equity offerings, debt financings, and collaboration and license agreements. However, the Company may not be able to secure additional financing or enter into such other arrangements in a timely manner or on favorable terms, if at all. The Company’s failure to raise capital or enter into such other arrangements when needed would have a negative impact on the Company’s financial condition and could force the Company to delay, reduce or terminate its research and development programs or other operations, or grant rights to develop and market product candidates that the Company would otherwise prefer to develop and market itself. Management believes that the Company’s cash, cash equivalents and short-term investments as of June 30, 2019 will be sufficient to fund operations for more than a year from the date this Quarterly Report on Form 10-Q is filed with the Securities and Exchange Commission (SEC). Basis of Presentation The accompanying condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) and the rules and regulations of the SEC related to a quarterly report on Form 10-Q. Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Updates (ASU) promulgated by the Financial Accounting Standards Board (FASB). Certain information and note disclosures normally included in annual financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to those rules and regulations. The condensed consolidated financial statements reflect all adjustments which, in the opinion of management, are necessary for a fair statement of the results for the periods presented. All such adjustments are of a normal and recurring nature. The operating results presented in these condensed consolidated financial statements are not necessarily indicative of the results that may be expected for any future periods. These condensed consolidated financial statements should be read in conjunction with the audited financial statements and the notes thereto for the year ended December 31, 2018 included in the Company’s Annual Report on Form 10-K filed with the SEC on March 27, 2019. Principles of Consolidation In January 2019, the Company created a new wholly-owned subsidiary in Australia with the Company serving as the sole shareholder through the subscription of shares. The accompanying condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary. All intercompany transactions and balances have been eliminated in consolidation. Recently Issued Accounting Pronouncements In February 2015, the FASB issued ASU 2016-02, Leases (Topic 842), which amends the FASB ASC 840 and creates Topic 842, Leases. The new topic supersedes Topic 840, Leases, and increases transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and requires disclosures of key information about leasing arrangements. The guidance is effective for reporting periods beginning after December 15, 2019 due to the Company’s emerging growth company status. ASU 2016-02 mandates a modified retrospective transition method. The Company plans to adopt the provisions of ASU 2016-02 in the first quarter of 2020, and the Company is evaluating the impact on the condensed consolidated financial statements. In August 2016, the FASB issued ASU 2016-15, Classification of Certain Cash Receipts and Cash Payments (Topic 230). ASU 2016-15 addresses eight specific cash flow issues with the objective of reducing the existing diversity in practice for certain cash receipts and cash payments. The standard is effective for annual reporting periods beginning after December 15, 2018 and interim periods reporting within fiscal years beginning after December 15, 2019. The Company adopted this guidance as of January 1, 2019, which did not have a material effect on the condensed consolidated financial statements. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820) – Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement, which is designed to improve the effectiveness of disclosures by removing, modifying and adding disclosures related to fair value measurements. ASU 2018-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted. The Company plans to adopt the provisions of ASU 2018-13 in the first quarter of 2020, and the Company is currently evaluating the impact on the condensed consolidated financial statements.

Organization and Accounting Pronouncements

6 Months Ended

Jun. 30, 2019

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Organization and Accounting Pronouncements

1. Organization and Accounting Pronouncements

Description of Business

Equillium, Inc. (the Company) was incorporated in the state of Delaware on March 16, 2017. The Company is engaged in the research and development of products for severe autoimmune and inflammatory disorders with high unmet medical need.

From inception through June 30, 2019, the Company has devoted substantially all of its efforts to organizing and staffing the company, business planning, raising capital, in-licensing rights to itolizumab, conducting preclinical research, filing two initial Investigational New Drug applications (INDs) and commencing clinical development of the Company’s initial product candidate, itolizumab (EQ001). In addition, the Company has a limited operating history, has not generated revenues from its principal operations, and the sales and income potential of its business is unproven.

Liquidity

As of June 30, 2019, the Company had $56.9 million in cash, cash equivalents and short-term investments. The Company has incurred significant operating losses and negative cash flows from operations. The Company expects to use its cash, cash equivalents and short-term investments to fund research and development of itolizumab and for working capital and other general corporate purposes. The Company does not expect to generate any revenues from product sales unless and until the Company successfully completes development and obtains regulatory approval of itolizumab or any future product candidate, which will not be for at least the next several years, if ever. Accordingly, until such time as the Company can generate significant revenue from sales of its product candidates, if ever, the Company expects to finance its cash needs through a combination of equity offerings, debt financings, and collaboration and license agreements. However, the Company may not be able to secure additional financing or enter into such other arrangements in a timely manner or on favorable terms, if at all. The Company’s failure to raise capital or enter into such other arrangements when needed would have a negative impact on the Company’s financial condition and could force the Company to delay, reduce or terminate its research and development programs or other operations, or grant rights to develop and market product candidates that the Company would otherwise prefer to develop and market itself. Management believes that the Company’s cash, cash equivalents and short-term investments as of June 30, 2019 will be sufficient to fund operations for more than a year from the date this Quarterly Report on Form 10-Q is filed with the Securities and Exchange Commission (SEC).

Basis of Presentation

The accompanying condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) and the rules and regulations of the SEC related to a quarterly report on Form 10-Q. Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Updates (ASU) promulgated by the Financial Accounting Standards Board (FASB). Certain information and note disclosures normally included in annual financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to those rules and regulations. The condensed consolidated financial statements reflect all adjustments which, in the opinion of management, are necessary for a fair statement of the results for the periods presented. All such adjustments are of a normal and recurring nature. The operating results presented in these condensed consolidated financial statements are not necessarily indicative of the results that may be expected for any future periods. These condensed consolidated financial statements should be read in conjunction with the audited financial statements and the notes thereto for the year ended December 31, 2018 included in the Company’s Annual Report on Form 10-K filed with the SEC on March 27, 2019.

Principles of Consolidation

In January 2019, the Company created a new wholly-owned subsidiary in Australia with the Company serving as the sole shareholder through the subscription of shares. The accompanying condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary. All intercompany transactions and balances have been eliminated in consolidation.

Recently Issued Accounting Pronouncements

In February 2015, the FASB issued ASU 2016-02, Leases (Topic 842), which amends the FASB ASC 840 and creates Topic 842, Leases. The new topic supersedes Topic 840, Leases, and increases transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and requires disclosures of key information about leasing arrangements. The guidance is effective for reporting periods beginning after December 15, 2019 due to the Company’s emerging growth company status. ASU 2016-02 mandates a modified retrospective transition method. The Company plans to adopt the provisions of ASU 2016-02 in the first quarter of 2020, and the Company is evaluating the impact on the condensed consolidated financial statements.

In August 2016, the FASB issued ASU 2016-15, Classification of Certain Cash Receipts and Cash Payments (Topic 230). ASU 2016-15 addresses eight specific cash flow issues with the objective of reducing the existing diversity in practice for certain cash receipts and cash payments. The standard is effective for annual reporting periods beginning after December 15, 2018 and interim periods reporting within fiscal years beginning after December 15, 2019. The Company adopted this guidance as of January 1, 2019, which did not have a material effect on the condensed consolidated financial statements.

In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820) – Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement, which is designed to improve the effectiveness of disclosures by removing, modifying and adding disclosures related to fair value measurements. ASU 2018-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted. The Company plans to adopt the provisions of ASU 2018-13 in the first quarter of 2020, and the Company is currently evaluating the impact on the condensed consolidated financial statements.