Government Contracts	12 Months Ended
Dec. 31, 2019
Contractors [Abstract]
Government Contracts	13. Government Contracts BARDA In July 2018, the Company was awarded a contract from BARDA of up to $44.2 million to develop tebipenem HBr for the treatment of complicated urinary tract infections (“cUTIs”) 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 $2.5 million for SPR 994, increasing the amount of initial committed funding from $15.7 million to $18.1 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 $34.1 million. The balance of the award is 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. As part of an inter-agency collaboration between BARDA and the Defense Threat Reduction Agency (“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 by the U.S. Army Medical Research Institute of Infectious Diseases (“USAMRIID”) under the direction of Spero. Because the FDA requires data from a human pneumonic disease as supportive of use of an antibiotic to treat a biothreat infection, the scope of the BARDA award includes the assessment of tebipenem HBr levels in the lung of healthy volunteers as well as a proof of concept clinical trial in pneumonia patients. During the years ended December 31, 2019 and 2018, the Company recorded $12.1 million and $1.4 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 will support the further clinical development of SPR206. The award commits 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 non-human primate toxicology study, and microbiological surveillance studies that would be required for a potential New Drug Application, or NDA, submission with the U.S. Food and Drug Administration for SPR206. During the year ended December 31, 2019, the Company recorded less than $0.1 million in revenue under this agreement. In September 2016, the Company was awarded a cooperative agreement with the DoD to further develop anti-infective agents to combat Gram-negative bacteria. The agreement is structured as a single, two-year $1.5 million award. The Company is eligible for the full funding from the DoD, and there are no options to be exercised at a later date. The DoD funding supports next-generation potentiator discovery and screening of SPR741 partners. The Company recognizes revenue under this agreement as qualifying expenses are incurred. During the years ended December 31, 2019 and 2018, the Company recorded $0.2 million and $0.3 million in revenue under this agreement, respectively. NIAID In February 2017, the Company was awarded a grant from NIAID to conduct additional preclinical studies of SPR720, the Company’s novel oral bacterial gyrase inhibitor, for the treatment of non-tuberculous mycobacterial infections. The award is structured as a 12-month $0.6 million base period and $0.4 million option period. In February 2018 NIAID exercised the $0.4 million 12-month option period. In January 2019, the period of performance for this award was extended for an additional 12-month period. During the years ended December 31, 2019 and 2018, the Company recorded $0.1 million and $0.5 million of revenue under this agreement, 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 assign the then CAI-held NIAID contract to Spero, which was finalized in December 2017. The NIAID contract provides for development funding of up to $6.5 million over a base period and three option periods. As of December 31, 2018, funding for the base period and the first two option periods totaling $5.9 million have been committed. Spero shall pay PBB a percentage of funds received from NIAID up to a maximum of $1.3 million, of which $0.3 million was paid upfront to PBB as part of the agreement. During the years ended December 31, 2019 and 2018, the Company recorded $1.0 million and $1.4 million in revenue under this agreement, respectively. CARB-X In April 2017, the Company was awarded a grant from CARB-X, a public-private partnership funded by BARDA within the U.S. Department of Health and Human Services to be used to screen, identify and complete Phase 1 trials with at least one partner compound for SPR741. The award committed to funding of $1.5 million over a 12-month period. On March 12, 2018, CARB-X committed an additional $0.4 million related to the first option for a period from December 1, 2017 to March 31, 2018. There will be no additional options exercised under the CARB-X award. The Company recognized zero and $0.5 million of revenue in the years ended December 31, 2019 and 2018, respectively, under this agreement.

Government Contracts

12 Months Ended

Dec. 31, 2019

13. Government Contracts

BARDA

In July 2018, the Company was awarded a contract from BARDA of up to $44.2 million to develop tebipenem HBr for the treatment of complicated urinary tract infections (“cUTIs”) 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 $2.5 million for SPR 994, increasing the amount of initial committed funding from $15.7 million to $18.1 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 $34.1 million. The balance of the award is 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.

As part of an inter-agency collaboration between BARDA and the Defense Threat Reduction Agency (“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 by the U.S. Army Medical Research Institute of Infectious Diseases (“USAMRIID”) under the direction of Spero. Because the FDA requires data from a human pneumonic disease as supportive of use of an antibiotic to treat a biothreat infection, the scope of the BARDA award includes the assessment of tebipenem HBr levels in the lung of healthy volunteers as well as a proof of concept clinical trial in pneumonia patients. During the years ended December 31, 2019 and 2018, the Company recorded $12.1 million and $1.4 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 will support the further clinical development of SPR206. The award commits 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 non-human primate toxicology study, and microbiological surveillance studies that would be required for a potential New Drug Application, or NDA, submission with the U.S. Food and Drug Administration for SPR206. During the year ended December 31, 2019, the Company recorded less than $0.1 million in revenue under this agreement.

In September 2016, the Company was awarded a cooperative agreement with the DoD to further develop anti-infective agents to combat Gram-negative bacteria. The agreement is structured as a single, two-year $1.5 million award. The Company is eligible for the full funding from the DoD, and there are no options to be exercised at a later date. The DoD funding supports next-generation potentiator discovery and screening of SPR741 partners. The Company recognizes revenue under this agreement as qualifying expenses are incurred. During the years ended December 31, 2019 and 2018, the Company recorded $0.2 million and $0.3 million in revenue under this agreement, respectively.

NIAID

In February 2017, the Company was awarded a grant from NIAID to conduct additional preclinical studies of SPR720, the Company’s novel oral bacterial gyrase inhibitor, for the treatment of non-tuberculous mycobacterial infections. The award is structured as a 12-month $0.6 million base period and $0.4 million option period. In February 2018 NIAID exercised the $0.4 million 12-month option period. In January 2019, the period of performance for this award was extended for an additional 12-month period. During the years ended December 31, 2019 and 2018, the Company recorded $0.1 million and $0.5 million of revenue under this agreement, 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 assign the then CAI-held NIAID contract to Spero, which was finalized in December 2017. The NIAID contract provides for development funding of up to $6.5 million over a base period and three option periods. As of December 31, 2018, funding for the base period and the first two option periods totaling $5.9 million have been committed. Spero shall pay PBB a percentage of funds received from NIAID up to a maximum of $1.3 million, of which $0.3 million was paid upfront to PBB as part of the agreement. During the years ended December 31, 2019 and 2018, the Company recorded $1.0 million and $1.4 million in revenue under this agreement, respectively.

CARB-X

In April 2017, the Company was awarded a grant from CARB-X, a public-private partnership funded by BARDA within the U.S. Department of Health and Human Services to be used to screen, identify and complete Phase 1 trials with at least one partner compound for SPR741. The award committed to funding of $1.5 million over a 12-month period. On March 12, 2018, CARB-X committed an additional $0.4 million related to the first option for a period from December 1, 2017 to March 31, 2018. There will be no additional options exercised under the CARB-X award. The Company recognized zero and $0.5 million of revenue in the years ended December 31, 2019 and 2018, respectively, under this agreement.