Government Contracts	12 Months Ended
Dec. 31, 2022
Contractors [Abstract]
Government Contracts	13. Government Contracts BARDA In July 2018, the Company was awarded a contract from Biomedical Advanced Research and Development Authority (“BARDA”) of up to $44.2 million to develop tebipenem HBr for the treatment of complicated urinary tract infections (“cUTI”) caused by antibiotic resistant Gram-negative bacteria and for assessment against biodefense pathogens. The award committed initial funding of $15.7 million over a three-year base period from July 1, 2018 to June 30, 2021 for cUTI development activities. In May 2019, the contract was modified to include additional funding of approximately $2.5 million for the development of tebipenem HBr, increasing the amount of the initial committed funding from $15.7 million to approximately $18.2 million and increasing the overall potential award to $46.8 million. In January 2020, BARDA exercised its first contract option for additional committed funding of $15.9 million, increasing the total committed funding to $34.0 million and extended the period of performance through November 1, 2021. In October 2022, BARDA extended the period of performance for the first contract option through December 15, 2023. As of December 31, 2022, the balance of the award was subject to BARDA exercising a second option which would entail funding of $12.7 million and is exercisable by BARDA subject to, among other things, satisfactory progress and results from the biodefense studies described below. On January 19, 2022, the Company announced that BARDA exercised a new option under the contract. The new option increases the total amount of committed funding by $12.9 million to approximately $46.9 million, increasing the total potential contract value to $59.7 million. In September 2022, remaining funding from the $12.9 million option was reprogrammed to support clinical trials for patients with cUTIs, including acute pyelonephritis. The period of performance for this new option extends through December 31, 2025 and does not change the total amount of committed funding or potential contract value. As part of an inter-agency collaboration between BARDA and the DTRA, a series of studies to assess the efficacy of tebipenem HBr in the treatment of infections caused by biodefense threats such as anthrax, plague and melioidosis will be conducted under the direction of Spero. DTRA provides up to $10.0 million, in addition to the total potential award from BARDA, to cover the cost of the nonclinical biodefense aspects of the collaborative program for tebipenem HBr. Together, BARDA and DTRA will provide up to $69.7 million in total funding for the clinical development and biodefense assessment of tebipenem HBr, of which $12.7 million is subject to the exercise of options by BARDA and Spero’s achievement of specified milestones. During the years ended December 31, 2022 and 2021, the Company recognized $2.2 million and $9.9 million of revenue under this agreement, respectively. U.S. Department of Defense On July 1, 2019, the Company received a $5.9 million award from the DoD Congressionally Directed Medical Research Programs (“CDMRP”) Joint Warfighter Medical Research Program. The funding supported the further clinical development of SPR206. The award committed non-dilutive funding of $5.9 million over a four-year period to cover the costs of select Phase 1 pharmacology studies, a 28-day GLP NHP toxicology study, and microbiological surveillance studies that would be required for a potential NDA submission with the FDA for SPR206. During the years ended December 31, 2022 and 2021, the Company recognized $1.0 million and $4.5 million in revenue under this agreement, respectively. As of December 31, 2022, all activities under this award were completed and this award was closed out. NIAID In May 2021, the Company was awarded a five-year contract from the U.S. National Institute of Allergy and Infectious Diseases (“NIAID”) under the Agency’s Omnibus Broad Agency Announcement No. HHS-NIH-NIAID-BAA2020-1 award mechanism to support further development of SPR206. Funding will be used to offset certain expenses related to manufacturing, clinical, non-clinical and regulatory activities. The Company can receive up to $23.4 million over a base period and five option periods. As of December 31, 2022, funding for the base period totaling $6.2 million has been committed. In December 2022, the contract was modified to include additional funding of approximately $0.1 million increasing the amount of base period committed funding from $2.1 million to $2.2 million. This increased the total potential contract value to $23.5 million. In October 2022, NIAID exercised its first option under the contract, committing $4.0 million for SPR206 through April 2025. The Company recognized $1.7 million and $0.4 million under this agreement during the years ended December 31, 2022 and 2021, respectively. In June 2016, the Company entered into agreements with Pro Bono Bio PLC (“PBB”), a corporation organized under the laws of England, and certain of its affiliates, including PBB Distributions Limited and Cantab Anti-Infectives Limited (“CAI”), in order to acquire certain intellectual property and government funding arrangements relating to SPR206. Under these agreements, CAI agreed to submit a request to NIAID to novate the then CAI-held NIAID contract to Spero, which was finalized in December 2017. The NIAID contract provided development funding of up to $6.5 million over a base period and three option periods. In March 2021, a contract modification was executed and the performance period for this award was extended through June 15, 2021. As of December 31, 2021, funding for the base period and the first two option periods totaling $5.9 million had been committed. The Company did not recognize revenue under this agreement during the year ended December 31, 2022 and recognized $0.4 million in revenue under this agreement, during the year ended December 31, 2021.

Government Contracts

12 Months Ended

Dec. 31, 2022

13. Government Contracts

BARDA

In July 2018, the Company was awarded a contract from Biomedical Advanced Research and Development Authority (“BARDA”) of up to $44.2 million to develop tebipenem HBr for the treatment of complicated urinary tract infections (“cUTI”) caused by antibiotic resistant Gram-negative bacteria and for assessment against biodefense pathogens. The award committed initial funding of $15.7 million over a three-year base period from July 1, 2018 to June 30, 2021 for cUTI development activities. In May 2019, the contract was modified to include additional funding of approximately $2.5 million for the development of tebipenem HBr, increasing the amount of the initial committed funding from $15.7 million to approximately $18.2 million and increasing the overall potential award to $46.8 million. In January 2020, BARDA exercised its first contract option for additional committed funding of $15.9 million, increasing the total committed funding to $34.0 million and extended the period of performance through November 1, 2021. In October 2022, BARDA extended the period of performance for the first contract option through December 15, 2023. As of December 31, 2022, the balance of the award was subject to BARDA exercising a second option which would entail funding of $12.7 million and is exercisable by BARDA subject to, among other things, satisfactory progress and results from the biodefense studies described below. On January 19, 2022, the Company announced that BARDA exercised a new option under the contract. The new option increases the total amount of committed funding by $12.9 million to approximately $46.9 million, increasing the total potential contract value to $59.7 million. In September 2022, remaining funding from the $12.9 million option was reprogrammed to support clinical trials for patients with cUTIs, including acute pyelonephritis. The period of performance for this new option extends through December 31, 2025 and does not change the total amount of committed funding or potential contract value.

As part of an inter-agency collaboration between BARDA and the DTRA, a series of studies to assess the efficacy of tebipenem HBr in the treatment of infections caused by biodefense threats such as anthrax, plague and melioidosis will be conducted under the direction of Spero. DTRA provides up to $10.0 million, in addition to the total potential award from BARDA, to cover the cost of the nonclinical biodefense aspects of the collaborative program for tebipenem HBr. Together, BARDA and DTRA will provide up to $69.7 million in total funding for the clinical development and biodefense assessment of tebipenem HBr, of which $12.7 million is subject to the exercise of options by BARDA and Spero’s achievement of specified milestones.

During the years ended December 31, 2022 and 2021, the Company recognized $2.2 million and $9.9 million of revenue under this agreement, respectively.

U.S. Department of Defense

On July 1, 2019, the Company received a $5.9 million award from the DoD Congressionally Directed Medical Research Programs (“CDMRP”) Joint Warfighter Medical Research Program. The funding supported the further clinical development of SPR206. The award committed non-dilutive funding of $5.9 million over a four-year period to cover the costs of select Phase 1 pharmacology studies, a 28-day GLP NHP toxicology study, and microbiological surveillance studies that would be required for a potential NDA submission with the FDA for SPR206. During the years ended December 31, 2022 and 2021, the Company recognized $1.0 million and $4.5 million in revenue under this agreement, respectively. As of December 31, 2022, all activities under this award were completed and this award was closed out.

NIAID

In May 2021, the Company was awarded a five-year contract from the U.S. National Institute of Allergy and Infectious Diseases (“NIAID”) under the Agency’s Omnibus Broad Agency Announcement No. HHS-NIH-NIAID-BAA2020-1 award mechanism to support further development of SPR206. Funding will be used to offset certain expenses related to manufacturing, clinical, non-clinical and regulatory activities. The Company can receive up to $23.4 million over a base period and five option periods. As of December 31, 2022, funding for the base period totaling $6.2 million has been committed. In December 2022, the contract was modified to include additional funding of approximately $0.1 million increasing the amount of base period committed funding from $2.1 million to $2.2 million. This increased the total potential contract value to $23.5 million. In October 2022, NIAID exercised its first option under the contract, committing $4.0 million for SPR206 through April 2025. The Company recognized $1.7 million and $0.4 million under this agreement during the years ended December 31, 2022 and 2021, respectively.

In June 2016, the Company entered into agreements with Pro Bono Bio PLC (“PBB”), a corporation organized under the laws of England, and certain of its affiliates, including PBB Distributions Limited and Cantab Anti-Infectives Limited (“CAI”), in order to acquire certain intellectual property and government funding arrangements relating to SPR206. Under these agreements, CAI agreed to submit a request to NIAID to novate the then CAI-held NIAID contract to Spero, which was finalized in December 2017. The NIAID contract provided development funding of up to $6.5 million over a base period and three option periods. In March 2021, a contract modification was executed and the performance period for this award was extended through June 15, 2021. As of December 31, 2021, funding for the base period and the first two option periods totaling $5.9 million had been committed. The Company did not recognize revenue under this agreement during the year ended December 31, 2022 and recognized $0.4 million in revenue under this agreement, during the year ended December 31, 2021.