Commitments and Contingencies	9 Months Ended
Sep. 30, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	16. Commitments and Contingencies Spitfire Acquisition As disclosed in Note 8, the Company is obligated to make payments of up to $80.0 million upon the achievement of specified worldwide net sales of all products developed using the technology acquired from Spitfire Pharma Inc. within ten years following the approval of a new drug application filed with the FDA. PER.C6 License Agreement Expansion On April 2, 2020, the Company entered into Amendment No. 3 to the Second Restated License Agreement (the “Amendment”), by and between the Company and Janssen Vaccines & Prevention B.V. (formerly known as Crucell Holland B.V.) (as amended by Amendment No. 1 to Second Restated License Agreement and Amendment No. 2 to Second Restated License Agreement, together with the Amendment, the “License Agreement”). Pursuant to the Amendment, the field of licenses granted to the Company for the use of the PER.C6 cell line under the License Agreement is expanded to cover COVID-19 caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), in addition to the existing licenses related to Bacillus anthracis and influenza virus. All capitalized terms not defined herein shall have the meanings assigned to them in the Amendment or the License Agreement, as applicable. Pursuant to the Amendment, the Company agreed to pay certain additional development-based milestone payments through approval of licensed products by the FDA for the treatment or prevention of COVID-19, up to an aggregate amount of $1.2 million. The Company also agreed to pay royalty payments as a percentage of net sales of products to a royalty stacking reduction and minimum annual royalty payments, until the expiration of the term of the License Agreement, as amended. As of September 30, 2020, payments made under the License Agreement were de minimis. Litigation In December 2019, a complaint was filed by Dr. De-Chu Christopher Tang (“Plaintiff”) against the Company in United States District Court for the Eastern District of Texas. The Plaintiff amended the complaint in February 2020 to include Vipin K. Garg and David J. Drutz as defendants, in addition to the Company (Dr. Garg, Dr. Drutz, and the Company are collectively referred to as “Defendants”). In March 2020 the Defendants filed a motion to dismiss the complaint. The Court denied the motion without prejudice and allowed Plaintiff an opportunity to file an amended complaint. Plaintiff’s second amended complaint was filed on April 17, 2020, and Defendants filed a motion to dismiss that complaint on May 1, 2020. A hearing on Defendants’ motion to dismiss was held on May 20, 2020, and the motion is currently pending. Plaintiff, who is representing himself, alleges five causes of action as follows: (1) Defendants’ alleged retention of Plaintiff’s lab notebooks after the termination of his employment in 2012; (2) alleged plagiarism based on publishing an article without naming Plaintiff as an author; (3) use of the Adhigh System, which Plaintiff alleges he developed; (4) allegations that Defendants manipulated the Company’s stock and caused a decrease in value; and (5) allegations that the Defendants “wast[ed] government grant money and poison[ed] science by leaving data to rot.” On September 30, 2020, Plaintiff filed a motion titled “Motion to Proscribe Defendants’ Allegedly Illegal Use of Plaintiff’s AdHigh System in Altimmune’s Human Clinical Trials,” to which Defendants filed an opposition on October 13, 2020. The court has not yet ruled on that motion, which also remains pending. The Company believes the allegations in the complaint are without merit and intends to vigorously defend the litigation. However, the outcome of this legal proceeding is uncertain at this time and the Company cannot reasonably estimate a range of loss, if any. Accordingly, the Company has not accrued any liability associated with this action. The Company is a party in various other contractual disputes, litigation, and potential claims arising in the ordinary course of business none of which are currently reasonably possible or probable of material loss.

Commitments and Contingencies

9 Months Ended

Sep. 30, 2020

Commitments And Contingencies Disclosure [Abstract]

16. Commitments and Contingencies

Spitfire Acquisition

As disclosed in Note 8, the Company is obligated to make payments of up to $80.0 million upon the achievement of specified worldwide net sales of all products developed using the technology acquired from Spitfire Pharma Inc. within ten years following the approval of a new drug application filed with the FDA.

PER.C6 License Agreement Expansion

On April 2, 2020, the Company entered into Amendment No. 3 to the Second Restated License Agreement (the “Amendment”), by and between the Company and Janssen Vaccines & Prevention B.V. (formerly known as Crucell Holland B.V.) (as amended by Amendment No. 1 to Second Restated License Agreement and Amendment No. 2 to Second Restated License Agreement, together with the Amendment, the “License Agreement”). Pursuant to the Amendment, the field of licenses granted to the Company for the use of the PER.C6 cell line under the License Agreement is expanded to cover COVID-19 caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), in addition to the existing licenses related to Bacillus anthracis and influenza virus. All capitalized terms not defined herein shall have the meanings assigned to them in the Amendment or the License Agreement, as applicable.

Pursuant to the Amendment, the Company agreed to pay certain additional development-based milestone payments through approval of licensed products by the FDA for the treatment or prevention of COVID-19, up to an aggregate amount of $1.2 million. The Company also agreed to pay royalty payments as a percentage of net sales of products to a royalty stacking reduction and minimum annual royalty payments, until the expiration of the term of the License Agreement, as amended. As of September 30, 2020, payments made under the License Agreement were de minimis.

Litigation

In December 2019, a complaint was filed by Dr. De-Chu Christopher Tang (“Plaintiff”) against the Company in United States District Court for the Eastern District of Texas. The Plaintiff amended the complaint in February 2020 to include Vipin K. Garg and David J. Drutz as defendants, in addition to the Company (Dr. Garg, Dr. Drutz, and the Company are collectively referred to as “Defendants”). In March 2020 the Defendants filed a motion to dismiss the complaint. The Court denied the motion without prejudice and allowed Plaintiff an opportunity to file an amended complaint. Plaintiff’s second amended complaint was filed on April 17, 2020, and Defendants filed a motion to dismiss that complaint on May 1, 2020. A hearing on Defendants’ motion to dismiss was held on May 20, 2020, and the motion is currently pending. Plaintiff, who is representing himself, alleges five causes of action as follows: (1) Defendants’ alleged retention of Plaintiff’s lab notebooks after the termination of his employment in 2012; (2) alleged plagiarism based on publishing an article without naming Plaintiff as an author; (3) use of the Adhigh System, which Plaintiff alleges he developed; (4) allegations that Defendants manipulated the Company’s stock and caused a decrease in value; and (5) allegations that the Defendants “wast[ed] government grant money and poison[ed] science by leaving data to rot.” On September 30, 2020, Plaintiff filed a motion titled “Motion to Proscribe Defendants’ Allegedly Illegal Use of Plaintiff’s AdHigh System in Altimmune’s Human Clinical Trials,” to which Defendants filed an opposition on October 13, 2020. The court has not yet ruled on that motion, which also remains pending. The Company believes the allegations in the complaint are without merit and intends to vigorously defend the litigation. However, the outcome of this legal proceeding is uncertain at this time and the Company cannot reasonably estimate a range of loss, if any. Accordingly, the Company has not accrued any liability associated with this action. The Company is a party in various other contractual disputes, litigation, and potential claims arising in the ordinary course of business none of which are currently reasonably possible or probable of material loss.