Note 1 - Corporate Information	3 Months Ended
Mar. 31, 2024
Notes to Financial Statements
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	1. Corporate Information Pieris Pharmaceuticals, Inc., or the Company or Pieris, was founded in May 2013, and acquired 100% interest in Pieris Pharmaceuticals GmbH (formerly Pieris AG, a German company which was founded in 2001) in December 2014. Pieris Pharmaceuticals, Inc. and its wholly-owned subsidiaries, hereinafter collectively Pieris, or the Company, is a biopharmaceutical company that, prior to July of 2023, discovered and developed Anticalin-based drugs to target validated disease pathways in unique and transformative ways. Pieris’ clinical pipeline consists of immuno-oncology, or IO, programs partnered with several major multi-national pharmaceutical companies. Pieris' corporate headquarters is located in Boston, Massachusetts. Pieris also maintains office space in Hallbergmoos, Germany. The Company’s core Anticalin technology and platform was developed in Germany. On July 18, 2023, the Company announced its intention to explore engaging in one or more strategic transactions, including mergers, reverse mergers, acquisitions, other business combinations or sales of assets, or other strategic transactions. This decision was related to events that impacted the Company’s inhaled respiratory franchise in connection with AstraZeneca's discontinuation of enrollment of the Phase 2a study for elarekibep, an inhaled IL-4Rα antagonist Anticalin protein to treat uncontrolled asthma. As part of this initiative, the Company engaged Stifel, Nicolaus & Company, Incorporated to serve as its advisor in its review of strategic transactions. Also on July 18, 2023, the Company’s Board of Directors approved a reduction in the Company’s workforce by approximately 70%. Since July of 2023, and through March 31, 2024, the Company took additional steps to reduce its operating footprint including terminating its remaining lease obligations in Germany and winding down its proprietary inhaled respiratory programs. The Company also has opted out and terminated programs where possible to reduce operating costs. Further reductions in the workforce have occurred based upon these actions. As a result, the Company has incurred approximately $7.5 million of severance costs and other related termination benefits in 2023 as the service period to earn such benefits is considered complete. The Company expects termination benefits to be paid through the end of 2024. On March 27, 2024, the Company announced the implementation of a new strategy along with relevant cost-saving measures that are expected to extend its cash runway into at least 2027, while maximizing its ability to capture the potential milestones from its partnered 4-1BB bispecific Mabcalin™ protein IO assets. The Company may be entitled to aggregate milestones of up to approximately $20.0 million upon first patient dosed in the Phase 2 trials for SGN-BB228, S095012 (formerly PRS-344) and BOS-342, which are all currently in Phase 1 clinical development, and up to approximately $55.0 million upon first patient dosed in pivotal clinical trials for SGN-BB228, S095012 and BOS-342. To support this new strategy, the Company plans to discontinue all of its research and development efforts which it expects to complete by the middle of 2024, implement a workforce reduction that will impact additional employees and the executive leadership team which is expected to be implemented in the second quarter of 2024, and reduce the size of its Board of Directors, which is also expected to be implemented in the second quarter of 2024. In addition to the alliance management activities for its partnered programs, the Company remains committed to obtaining value for its products in prior development, including cinrebafusp alfa, as well as its proprietary platform capabilities by pursuing potential out-licensing or sales transactions. In addition to these potential transactions, the Company may also, from time-to-time, consider strategic opportunities that it believes may increase stockholder value. As of March 31, 2024, cash and cash equivalents were $19.1 million. For the three months ended March 31, 2024 and 2023, the Company had net losses of $4.9 million and $13.2 million, respectively. The Company has incurred net losses since inception and had an accumulated deficit of $319.9 million as of March 31, 2024. Net losses and negative cash flows from operations have had, and will continue to have, an adverse effect on the Company’s stockholders’ equity and working capital. The Company expects to continue to incur operating losses for the foreseeable future. The Company has historically devoted substantially all of its financial resources and efforts to research and development and general and administrative expenses to support the discovery and development of Anticalin-based drugs. Going forward, as part of the Company's decision to implement measures to maximize its ability to capture potential milestones from its partnered programs with Pfizer, Boston Pharmaceuticals, and Servier (all as defined in Note 3 below), the Company plans to discontinue all research and development efforts and reduce discretionary expenditures and other fixed or variable personnel costs. The Company believes that its currently available funds will be sufficient to fund its operations through at least the next twelve months from the issuance of this Quarterly Report on Form 10-Q. The Company's belief with respect to its ability to fund operations is based on estimates that are subject to risks and uncertainties. If actual results are different from management’s estimates, the Company may need to seek additional funding.

Note 1 - Corporate Information

3 Months Ended

Mar. 31, 2024

Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]

1. Corporate Information

Pieris Pharmaceuticals, Inc., or the Company or Pieris, was founded in May 2013, and acquired 100% interest in Pieris Pharmaceuticals GmbH (formerly Pieris AG, a German company which was founded in 2001) in December 2014. Pieris Pharmaceuticals, Inc. and its wholly-owned subsidiaries, hereinafter collectively Pieris, or the Company, is a biopharmaceutical company that, prior to July of 2023, discovered and developed Anticalin-based drugs to target validated disease pathways in unique and transformative ways. Pieris’ clinical pipeline consists of immuno-oncology, or IO, programs partnered with several major multi-national pharmaceutical companies. Pieris' corporate headquarters is located in Boston, Massachusetts. Pieris also maintains office space in Hallbergmoos, Germany.

The Company’s core Anticalin technology and platform was developed in Germany.

On July 18, 2023, the Company announced its intention to explore engaging in one or more strategic transactions, including mergers, reverse mergers, acquisitions, other business combinations or sales of assets, or other strategic transactions. This decision was related to events that impacted the Company’s inhaled respiratory franchise in connection with AstraZeneca's discontinuation of enrollment of the Phase 2a study for elarekibep, an inhaled IL-4Rα antagonist Anticalin protein to treat uncontrolled asthma. As part of this initiative, the Company engaged Stifel, Nicolaus & Company, Incorporated to serve as its advisor in its review of strategic transactions.

Also on July 18, 2023, the Company’s Board of Directors approved a reduction in the Company’s workforce by approximately 70%. Since July of 2023, and through March 31, 2024, the Company took additional steps to reduce its operating footprint including terminating its remaining lease obligations in Germany and winding down its proprietary inhaled respiratory programs. The Company also has opted out and terminated programs where possible to reduce operating costs. Further reductions in the workforce have occurred based upon these actions. As a result, the Company has incurred approximately $7.5 million of severance costs and other related termination benefits in 2023 as the service period to earn such benefits is considered complete. The Company expects termination benefits to be paid through the end of 2024.

On March 27, 2024, the Company announced the implementation of a new strategy along with relevant cost-saving measures that are expected to extend its cash runway into at least 2027, while maximizing its ability to capture the potential milestones from its partnered 4-1BB bispecific Mabcalin™ protein IO assets. The Company may be entitled to aggregate milestones of up to approximately $20.0 million upon first patient dosed in the Phase 2 trials for SGN-BB228, S095012 (formerly PRS-344) and BOS-342, which are all currently in Phase 1 clinical development, and up to approximately $55.0 million upon first patient dosed in pivotal clinical trials for SGN-BB228, S095012 and BOS-342. To support this new strategy, the Company plans to discontinue all of its research and development efforts which it expects to complete by the middle of 2024, implement a workforce reduction that will impact additional employees and the executive leadership team which is expected to be implemented in the second quarter of 2024, and reduce the size of its Board of Directors, which is also expected to be implemented in the second quarter of 2024. In addition to the alliance management activities for its partnered programs, the Company remains committed to obtaining value for its products in prior development, including cinrebafusp alfa, as well as its proprietary platform capabilities by pursuing potential out-licensing or sales transactions. In addition to these potential transactions, the Company may also, from time-to-time, consider strategic opportunities that it believes may increase stockholder value.

As of March 31, 2024, cash and cash equivalents were $19.1 million. For the three months ended March 31, 2024 and 2023, the Company had net losses of $4.9 million and $13.2 million, respectively. The Company has incurred net losses since inception and had an accumulated deficit of $319.9 million as of March 31, 2024. Net losses and negative cash flows from operations have had, and will continue to have, an adverse effect on the Company’s stockholders’ equity and working capital. The Company expects to continue to incur operating losses for the foreseeable future.

The Company has historically devoted substantially all of its financial resources and efforts to research and development and general and administrative expenses to support the discovery and development of Anticalin-based drugs. Going forward, as part of the Company's decision to implement measures to maximize its ability to capture potential milestones from its partnered programs with Pfizer, Boston Pharmaceuticals, and Servier (all as defined in Note 3 below), the Company plans to discontinue all research and development efforts and reduce discretionary expenditures and other fixed or variable personnel costs. The Company believes that its currently available funds will be sufficient to fund its operations through at least the next twelve months from the issuance of this Quarterly Report on Form 10-Q. The Company's belief with respect to its ability to fund operations is based on estimates that are subject to risks and uncertainties. If actual results are different from management’s estimates, the Company may need to seek additional funding.