Commitments and Contingencies	6 Months Ended
Commitments and Contingencies	Jun. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Matters On November 12, 2021, Sothinathan Sinnathurai filed a purported securities class action in the U.S. District Court for the District of Maryland against the Company and certain members of senior management, captioned Sothinathan Sinnathurai v. Novavax, Inc., et al., No. 8:21-cv-02910-TDC (the “Sinnathurai Action”). On January 26, 2022, the court entered an order designating David Truong, Nuggehalli Balmukund Nandkumar, and Jeffrey Gabbert as co-lead plaintiffs in the Sinnathurai Action. The co-lead plaintiffs filed a consolidated amended complaint on March 11, 2022, alleging that the defendants made certain purportedly false and misleading statements concerning the Company’s ability to manufacture NVX-CoV2373 on a commercial scale and to secure the vaccine’s regulatory approval. The amended complaint defines the purported class as those stockholders who purchased the Company’s securities between February 24, 2021 and October 19, 2021. On April 25, 2022, defendants filed a motion to dismiss the consolidated amended complaint. On June 9, 2022, the co-lead plaintiffs filed an opposition to the motion to dismiss and on July 11, 2022, the Company filed a reply brief. The matter is now fully briefed. The Court has not indicated whether it intends to schedule any hearing on the motion before issuing a ruling. After the Sinnathurai Action was filed, five derivative lawsuits were filed: Robert E. Meyer v. Stanley C. Erck, et al., No. 8:21-cv-02996-TDC (the “Meyer Action”), Shui Shing Yung v. Stanley C. Erck, et al., No. 8:21-cv-03248-TDC (the “Yung Action”), William Kirst, et al. v. Stanley C. Erck, et al., No. 8:22-cv-00024-TDC (the “Kirst Action”), Amy Snyder v. Stanley C. Erck, et al., No. 8:22-cv-01415-TDC (the “Snyder Action”), and Charles R. Blackburn, et al. v. Stanley C. Erck, et al., No. 1:22-cv-01417-TDC (the “Blackburn Action”). The Meyer, Yung, Snyder, and Blackburn Actions were filed in the U.S. District Court for the District of Maryland. The Kirst Action was filed in the Circuit Court for Montgomery County, Maryland, and shortly thereafter removed to the U.S. District Court for the District of Maryland by the defendants. The derivative lawsuits name members of the board of directors and certain members of senior management as defendants. The Company is deemed a nominal defendant. The plaintiffs assert derivative claims arising out of substantially the same alleged facts and circumstances as the Sinnathurai Action. Collectively, the derivative complaints assert claims for breach of fiduciary duty, insider selling, unjust enrichment, violation of federal securities law, abuse of control, waste, and mismanagement. Plaintiffs seek declaratory and injunctive relief, as well as an award of monetary damages and attorneys’ fees. On July 21, 2022, the Court issued a memorandum opinion and order remanding the Kirst Action to state court. On February 4, 2022, the Court entered an order consolidating the Meyer and Yung Actions (the “Consolidated Derivative Action”). The plaintiffs in the Consolidated Derivative Action filed their consolidated derivative complaint on April 25, 2022. On May 10, 2022, the Court entered an order in the Consolidated Derivative Action granting the parties’ request to stay all proceedings and deadlines pending the earlier of dismissal or the filing of an answer in the Sinnathurai Action. If a related derivative action is filed and is not stayed, the Meyer and Yung plaintiffs may seek to terminate the stay. On June 10, 2022, the Snyder and Blackburn Actions were filed. The Snyder and Blackburn plaintiffs have expressed their intent to move the court to consolidate all of the derivative actions pending in Maryland federal court and to appoint lead counsel. On July 21, 2022, the Court ordered the parties in the Consolidated Derivative Action, the Snyder Action, and the Blackburn Action to meet and confer concerning consolidation, the appointment of lead counsel, and the ongoing stay of proceedings in the Consolidated Derivative Action. Should the parties fail to reach agreement on those issues, the Snyder and Blackburn plaintiffs were granted leave to file a motion for consolidation and appointment of lead counsel by August 18, 2022. On March 29, 2022, Par Sterile Products, LLC (“Par”) submitted a demand for arbitration against the Company with the American Arbitration Association, alleging that the Company breached certain provisions of the Manufacturing and Services Agreement (“MSA”) that the Company entered into with Par in September 2020 to provide fill-finish manufacturing services for NVX-CoV2373. The matter is at a preliminary stage and therefore the potential loss is not reasonably estimable. While the Company maintains that no breach of the MSA has occurred and intends to vigorously defend the matter, if the final resolution of the matter is adverse to the Company, it could have a material impact on the Company’s financial position, results of operations, or cash flows. The Company is also involved in various legal proceedings arising in the normal course of business. Although the outcomes of these legal proceedings are inherently difficult to predict, management does not expect the resolution of these legal proceedings to have a material adverse effect on the Company’s financial position, results of operations, or cash flows.