Nature of Business, Basis of Presentation and Liquidity Risk	12 Months Ended
Dec. 31, 2025
Accounting Policies [Abstract]
Nature of Business, Basis of Presentation and Going Concern Uncertainty	1. NATURE OF BUSINESS, BASIS OF PRESENTATION AND GOING CONCERN UNCERTAINTY Achieve Life Sciences, Inc. (referred to as “Achieve,” “we,” “us,” or “our”) is a late-stage clinical specialty pharmaceutical company with the sole mission to address the global nicotine dependence epidemic through the development and commercialization of cytisinicline. We were incorporated in the state of Delaware, and operate out of Bothell, Washington and Vancouver, British Columbia. Going Concern Uncertainty The accompanying financial statements have been prepared assuming we will continue to operate as a going concern, which contemplates the realization of assets and settlement of liabilities and commitments in the normal course of business. We have historically experienced recurring losses from operations and have incurred an accumulated deficit of $260.2 million through December 31, 2025. As of December 31, 2025, we had cash, cash equivalents and marketable securities of $36.4 million and a positive working capital balance of $30.8 million. For the year ended December 31, 2025, we incurred a net loss of $54.6 million and net cash used in operating activities was $49.5 million. Substantial doubt exists as to our ability to continue as a going concern. Our ability to continue as a going concern is subject to material uncertainty and dependent on our ability to obtain additional financing. While we have historically financed our operations through equity offerings, debt financings, and government grants, the timing and amount of future financings may be impacted by macroeconomic conditions including uncertainty in the capital markets. There can be no assurance that financing from these or other sources will be available to us in the future. Without additional funds, we would be forced to delay, scale back or eliminate some of our commercialization and research and development, or R&D, activities or other operations and potentially delay product development in an effort to provide sufficient funds to continue our operations. If any of these events occurs, our ability to achieve our commercialization and development goals would be adversely affected. Our current resources are insufficient to fund our planned operations for the next 12 months. We will continue to require substantial additional capital to continue our clinical development and commercialization activities. Accordingly, we will need to raise substantial additional capital from the sale of our securities, debt, partnering arrangements, non-dilutive fundraising or other financing transactions in order to continue to fund our operations and finance the remaining development and commercialization of our product candidate. The amount and timing of our future funding requirements will depend on many factors, including the pace of our commercialization activities and the pace and results of our clinical development efforts. The uncertainty with respect to our operations and the market generally may also make it challenging to raise additional capital on favorable terms, if at all. In addition, current macroeconomic conditions have caused uncertainty in various sectors, including the capital markets. Failure to raise capital as and when needed, on favorable terms or at all, will have a negative impact on our financial condition and our ability to prepare for commercialization and develop our product candidate. We expect our expenses to substantially increase over time in connection with our ongoing activities, particularly as we prepare our commercialization activities and advance our product candidate in clinical development. We are required to keep substantially all of our cash and cash equivalents with a single financial institution, Silicon Valley Bank, or SVB, a division of First-Citizens Bank & Trust Company, or FCB, as required by the covenants of our New Debt Agreement (Note 3 – Financial Instruments and Risk - Concentration of Cash and Cash Equivalents Risk and Note 8 – Convertible Debt). Our commercial bank balances exceed federal insurance limits. We have not experienced any losses in our cash and cash equivalents for the years ended December 31, 2025 and 2024. These consolidated financial statements do not include any adjustments to the amounts and classification of assets and liabilities that might be necessary should we be unable to continue as a going concern. Such adjustments could be material. Basis of Presentation The consolidated financial statements include the accounts of Achieve and our wholly owned subsidiaries, Achieve Life Sciences Technologies Inc., Achieve Life Science, Inc., Extab Corporation, and Achieve Pharma UK Limited. All intercompany balances and transactions have been eliminated.

Nature of Business, Basis of Presentation and Liquidity Risk

12 Months Ended

Dec. 31, 2025

Nature of Business, Basis of Presentation and Going Concern Uncertainty

1. NATURE OF BUSINESS, BASIS OF PRESENTATION AND GOING CONCERN UNCERTAINTY

Achieve Life Sciences, Inc. (referred to as “Achieve,” “we,” “us,” or “our”) is a late-stage clinical specialty pharmaceutical company with the sole mission to address the global nicotine dependence epidemic through the development and commercialization of cytisinicline. We were incorporated in the state of Delaware, and operate out of Bothell, Washington and Vancouver, British Columbia.

Going Concern Uncertainty

The accompanying financial statements have been prepared assuming we will continue to operate as a going concern, which contemplates the realization of assets and settlement of liabilities and commitments in the normal course of business.

We have historically experienced recurring losses from operations and have incurred an accumulated deficit of $260.2 million through December 31, 2025. As of December 31, 2025, we had cash, cash equivalents and marketable securities of $36.4 million and a positive working capital balance of $30.8 million. For the year ended December 31, 2025, we incurred a net loss of $54.6 million and net cash used in operating activities was $49.5 million.

Substantial doubt exists as to our ability to continue as a going concern. Our ability to continue as a going concern is subject to material uncertainty and dependent on our ability to obtain additional financing. While we have historically financed our operations through equity offerings, debt financings, and government grants, the timing and amount of future financings may be impacted by macroeconomic conditions including uncertainty in the capital markets. There can be no assurance that financing from these or other sources will be available to us in the future. Without additional funds, we would be forced to delay, scale back or eliminate some of our commercialization and research and development, or R&D, activities or other operations and potentially delay product development in an effort to provide sufficient funds to continue our operations. If any of these events occurs, our ability to achieve our commercialization and development goals would be adversely affected.

Our current resources are insufficient to fund our planned operations for the next 12 months. We will continue to require substantial additional capital to continue our clinical development and commercialization activities. Accordingly, we will need to raise substantial additional capital from the sale of our securities, debt, partnering arrangements, non-dilutive fundraising or other financing transactions in order to continue to fund our operations and finance the remaining development and commercialization of our product candidate. The amount and timing of our future funding requirements will depend on many factors, including the pace of our commercialization activities and the pace and results of our clinical development efforts. The uncertainty with respect to our operations and the market generally may also make it challenging to raise additional capital on favorable terms, if at all. In addition, current macroeconomic conditions have caused uncertainty in various sectors, including the capital markets. Failure to raise capital as and when needed, on favorable terms or at all, will have a negative impact on our financial condition and our ability to prepare for commercialization and develop our product candidate. We expect our expenses to substantially increase over time in connection with our ongoing activities, particularly as we prepare our commercialization activities and advance our product candidate in clinical development.

We are required to keep substantially all of our cash and cash equivalents with a single financial institution, Silicon Valley Bank, or SVB, a division of First-Citizens Bank & Trust Company, or FCB, as required by the covenants of our New Debt Agreement (Note 3 – Financial Instruments and Risk - Concentration of Cash and Cash Equivalents Risk and Note 8 – Convertible Debt).

Our commercial bank balances exceed federal insurance limits. We have not experienced any losses in our cash and cash equivalents for the years ended December 31, 2025 and 2024.

These consolidated financial statements do not include any adjustments to the amounts and classification of assets and liabilities that might be necessary should we be unable to continue as a going concern. Such adjustments could be material.

Basis of Presentation

The consolidated financial statements include the accounts of Achieve and our wholly owned subsidiaries, Achieve Life Sciences Technologies Inc., Achieve Life Science, Inc., Extab Corporation, and Achieve Pharma UK Limited. All intercompany balances and transactions have been eliminated.