Description of Business	6 Months Ended
Jun. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	1. Description of Business Organization Icosavax, Inc. (the “Company”) was incorporated in the state of Delaware on November 1, 2017, and is located in Seattle, Washington. The Company is focused on the research and development of vaccines against infectious diseases. The Company was founded on computationally designed virus-like particle technology, exclusively licensed for a variety of infectious disease indications from the Institute for Protein Design at the University of Washington. The Company’s business involves inherent risks. These risks include, among others, dependence on key personnel, licensors and third-party service providers, patentability of the Company’s products and processes, the immunogenicity, efficacy and safety of the Company’s vaccine candidates and the potential of the Company’s novel vaccine technology platform. In addition, any of the Company’s vaccine candidates, and the Company’s vaccine technology platform, could become obsolete or diminished in value by discoveries and developments at other organizations. Liquidity The Company had an accumulated deficit of $236.9 million, and cash, cash equivalents, and short-term investments of $246.9 million at June 30, 2023. Management believes the Company has sufficient capital to execute its strategic plan and fund operations through at least the next twelve months from the date these condensed financial statements are issued. The Company has devoted substantially all its resources to organizing and staffing the Company, business planning, raising capital, in-licensing intellectual property rights, developing vaccine candidates, scaling up manufacturing of vaccine candidates, and preparing for and conducting preclinical studies and clinical trials. The Company has a limited operating history, and the sales and income potential of its business is unproven. The Company has incurred net losses and negative cash flows from operating activities since its inception and expects to continue to incur net losses into the foreseeable future as it continues the development of its vaccine candidates. From inception to June 30, 2023, the Company has funded its operations primarily through the sale of its convertible preferred stock and common stock. The Company has an Equity Distribution Agreement with Oppenheimer & Co. Inc., pursuant to which the Company may offer and sell shares of the Company’s common stock having an aggregate offering price of up to $150.0 million from time to time, in “at the market” offerings. As of June 30, 2023, approximately $10.0 million of shares have been sold through the Equity Distribution Agreement, all of which were sold in 2022. In the second quarter of 2023, the Company issued 8,369,754 shares of common stock in a registered direct offering for net proceeds of $67.5 million, net of offering costs of $0.3 million, which were included in accrued and other current liabilities at June 30, 2023. As the Company continues to pursue its business plan, it expects to finance its operations through equity offerings, debt financings or other capital sources, including potential strategic collaborations, licenses, and other similar arrangements. However, there can be no assurance that any additional financing or strategic transactions will be available to the Company on acceptable terms, if at all. If events or circumstances occur such that the Company does not obtain additional funding, it may need to delay, reduce or eliminate its product development or future commercialization efforts, which could have a material adverse effect on the Company’s business, results of operations or financial condition. The accompanying financial statements do not include any adjustments that might be necessary if the Company were unable to continue as a going concern.

Description of Business

6 Months Ended

Jun. 30, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

1. Description of Business

Organization

Icosavax, Inc. (the “Company”) was incorporated in the state of Delaware on November 1, 2017, and is located in Seattle, Washington. The Company is focused on the research and development of vaccines against infectious diseases. The Company was founded on computationally designed virus-like particle technology, exclusively licensed for a variety of infectious disease indications from the Institute for Protein Design at the University of Washington.

The Company’s business involves inherent risks. These risks include, among others, dependence on key personnel, licensors and third-party service providers, patentability of the Company’s products and processes, the immunogenicity, efficacy and safety of the Company’s vaccine candidates and the potential of the Company’s novel vaccine technology platform. In addition, any of the Company’s vaccine candidates, and the Company’s vaccine technology platform, could become obsolete or diminished in value by discoveries and developments at other organizations.

Liquidity

The Company had an accumulated deficit of $236.9 million, and cash, cash equivalents, and short-term investments of $246.9 million at June 30, 2023.

Management believes the Company has sufficient capital to execute its strategic plan and fund operations through at least the next twelve months from the date these condensed financial statements are issued.

The Company has devoted substantially all its resources to organizing and staffing the Company, business planning, raising capital, in-licensing intellectual property rights, developing vaccine candidates, scaling up manufacturing of vaccine candidates, and preparing for and conducting preclinical studies and clinical trials. The Company has a limited operating history, and the sales and income potential of its business is unproven. The Company has incurred net losses and negative cash flows from operating activities since its inception and expects to continue to incur net losses into the foreseeable future as it continues the development of its vaccine candidates. From inception to June 30, 2023, the Company has funded its operations primarily through the sale of its convertible preferred stock and common stock. The Company has an Equity Distribution Agreement with Oppenheimer & Co. Inc., pursuant to which the Company may offer and sell shares of the Company’s common stock having an aggregate offering price of up to $150.0 million from time to time, in “at the market” offerings. As of June 30, 2023, approximately $10.0 million of shares have been sold through the Equity Distribution Agreement, all of which were sold in 2022. In the second quarter of 2023, the Company issued 8,369,754 shares of common stock in a registered direct offering for net proceeds of $67.5 million, net of offering costs of $0.3 million, which were included in accrued and other current liabilities at June 30, 2023.

As the Company continues to pursue its business plan, it expects to finance its operations through equity offerings, debt financings or other capital sources, including potential strategic collaborations, licenses, and other similar arrangements. However, there can be no assurance that any additional financing or strategic transactions will be available to the Company on acceptable terms, if at all. If events or circumstances occur such that the Company does not obtain additional funding, it may need to delay, reduce or eliminate its product development or future commercialization efforts, which could have a material adverse effect on the Company’s business, results of operations or financial condition. The accompanying financial statements do not include any adjustments that might be necessary if the Company were unable to continue as a going concern.