Commitments and Contingencies	3 Months Ended
Mar. 31, 2025
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Matters Stockholder Litigation On November 12, 2021, Sothinathan Sinnathurai filed a purported securities class action in the U.S. District Court for the District of Maryland (the “Maryland Court”) 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”). The parties ultimately negotiated a settlement, which the Maryland Court approved on May 23, 2024. The Maryland Court closed the Sinnathurai Action on May 24, 2024. After the Sinnathurai Action was filed, eight derivative lawsuits were filed: (i) Robert E. Meyer v. Stanley C. Erck, et al., No. 8:21-cv-02996-TDC (the “Meyer Action”), (ii) Shui Shing Yung v. Stanley C. Erck, et al., No. 8:21-cv-03248-TDC (the “Yung Action”), (iii) William Kirst, et al. v. Stanley C. Erck, et al., No. C-15-CV-21-000618 (the “Kirst Action”), (iv) Amy Snyder v. Stanley C. Erck, et al., No. 8:22-cv-01415-TDC (the “Snyder Action”), (v) Charles R. Blackburn, et al. v. Stanley C. Erck, et al., No. 1:22-cv-01417-TDC (the “Blackburn Action”), (vi) Diego J. Mesa v. Stanley C. Erck, et al., No. 2022-0770-NAC (the “Mesa Action”), (vii) Sean Acosta v. Stanley C. Erck, et al., No. 2022-1133-NAC (the “Acosta Action”), and (viii) Jared Needelman v. Stanley C. Erck, et al., No. C-15-CV-23-001550 (the “Needelman Action”). The Meyer, Yung, Snyder, and Blackburn Actions were filed in the Maryland Court. The Kirst Action was filed in the Circuit Court for Montgomery County, Maryland, and shortly thereafter removed to the Maryland Court by the defendants. The Needelman Action was also filed in the Circuit Court for Montgomery County, Maryland. The Mesa and Acosta Actions were filed in the Delaware Court of Chancery (the “Delaware Court”). The derivative lawsuits name members of the Company’s 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 February 7, 2022, the Maryland Court entered an order consolidating the Meyer and Yung Actions (the “First Consolidated Derivative Action”). The plaintiffs in the First Consolidated Derivative Action filed their consolidated derivative complaint on April 25, 2022. On May 10, 2022, the Maryland Court entered an order 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. On June 10, 2022, the Snyder and Blackburn Actions were filed. On October 5, 2022, the Maryland Court entered an order granting a request by the plaintiffs in the First Consolidated Derivative Action and the Snyder and Blackburn Actions to consolidate all three actions and appoint co-lead plaintiffs and co-lead and liaison counsel (the “Second Consolidated Derivative Action”). The co-lead plaintiffs in the Second Consolidated Derivative Action filed a consolidated amended complaint on November 21, 2022. On February 10, 2023, defendants filed a motion to dismiss the Second Consolidated Derivative Action. The plaintiffs filed their opposition to the motion to dismiss on April 11, 2023. Defendants filed their reply brief in further support of their motion to dismiss on May 11, 2023. On August 21, 2023, the court entered an order granting in part and denying in part the motion to dismiss. On September 5, 2023, the Company filed an Answer to the consolidated amended complaint. On September 6, 2023, the court entered an order granting the individual defendants an extension of time to file their answer until November 6, 2023. On October 6, 2023, the Board of Directors of the Company formed a Special Litigation Committee (“SLC”) with full and exclusive power and authority of the Board to, among other things, investigate, review, and analyze the facts and circumstances surrounding the claims asserted in the pending derivative actions, including the claims that remain following the court’s order on the motion to dismiss in the Second Consolidated Derivative Action. On November 7, 2023, the court entered an order granting the parties’ request to stay the Second Consolidated Derivative Action for up to six months from the date of entry of the order, and, on April 15, 2024, the court entered a further order extending the stay until June 6, 2024. On June 7, 2024, the court entered another order extending the stay until August 5, 2024. On August 19, 2024, the court entered another order extending the stay until November 4, 2024, to allow the SLC and the parties to continue then-ongoing mediation efforts. On November 1, 2024, the parties notified the court that a settlement in principle had been reached and requested the stay to be extended until the definitive settlement agreement was filed. On November 22, 2024, the SLC filed its Unopposed Motion for Preliminary Approval of Derivative Settlement, Approval of Form and Manner of Notice, and Setting Hearing Date on Final Approval of Settlement and supporting documents. Under the terms of the proposed settlement, individual defendants Erck and Herrmann agreed to pay or cause their insurers to pay $6.8 million to Novavax in exchange for a release of claims. In addition, Novavax and its Board of Directors agreed to adopt and implement certain governance provisions identified in the settlement stipulation. On December 12, 2024, the court entered an order granting preliminary approval of the derivative settlement and setting a date for a hearing on the final approval of the settlement. On March 7, 2025, the court held a hearing and entered a Final Judgment and Order Approving Derivative Settlement (the “Final Judgment and Order”). As part of the Final Judgment and Order, the court granted the motion for attorneys’ fees and awarded plaintiffs’ counsel fees and expenses in the amount of $2.0 million to be paid by the Company following its receipt of the $6.8 million settlement funds. During the three months ended, March 31, 2025, the Company recorded a net gain on the settlement of $4.8 million in Other income (expense), net. The Kirst Action was filed on December 28, 2021, and the defendants immediately removed the case to the Maryland Court. On July 21, 2022, the Maryland Court issued a memorandum opinion and order remanding the Kirst Action to state court. The plaintiffs filed an amended complaint on December 30, 2022. On January 23, 2023, defendants filed a motion to stay the Kirst action. On February 22, 2023, the parties in the Kirst Action filed for the Court’s approval of a stipulation staying the Kirst Action pending the resolution of defendants’ motion to dismiss in the Second Consolidated Derivative Action. On March 22, 2023, the Court entered the parties’ stipulated stay of the Kirst Action pending resolution of the motion to dismiss in the Second Consolidated Derivative Action. On August 30, 2022, the Mesa Action was filed. On October 3, 2022, the Delaware Court entered an order granting the parties’ request to stay all proceedings and deadlines in the Mesa Action pending the earlier of dismissal of the Sinnathurai Action or the filing of an answer to the operative complaint in the Sinnathurai Action. On January 9, 2023, following the ruling on the motion to dismiss the Sinnathurai Action, the Delaware Court entered an order granting the Mesa Action parties’ request to set a briefing schedule in connection with a motion to stay by defendants. On February 28, 2023, the court granted the defendants’ motion and stayed the Mesa Action pending the entry of a final, non-appealable judgment in the Second Consolidated Derivative Action. On August 31, 2023, the Mesa plaintiffs filed a motion to lift the stay in the Mesa Action. On October 6, 2023, the Company filed an opposition to plaintiff’s motion to lift the stay. Plaintiff filed his reply on October 17, 2023. On December 27, 2023, the parties filed a letter informing the Court that the Second Consolidated Derivative Action had been stayed for a period of six months and asked the Court to stay further proceedings in the Mesa Action until expiration of that stay. On December 7, 2022, the Acosta Action was filed. On February 6, 2023, defendants accepted service of the complaint and summons in the Acosta Action. On March 9, 2023, the court entered an order granting the parties’ request to stay the Acosta Action pending the entry of a final, non-appealable judgment in the Second Consolidated Derivative Action. On October 13, 2023, the parties filed, and the Delaware Court entered, a stipulated order providing that (i) if the Delaware Court declines to lift the stay in the Mesa Action, the Acosta Action will also remain stayed, and (ii) if the Delaware Court lifts the stay in the Mesa Action, the stay in the Acosta Action will also be lifted. On April 28, 2025, the parties filed a joint status report with the Delaware Court in which they indicated that plaintiffs intend to dismiss the Mesa Action and Acosta Action in light of the Derivative Settlement. On May 2, 2025, the Delaware Court granted the stipulated order of voluntary dismissal, and the Mesa Action was dismissed with prejudice. On April 17, 2023, the Needelman Action was filed. On July 12, 2023, the parties filed a stipulation and proposed order to stay the Needelman Action pending the Maryland Court’s decision on the motion to dismiss in the Second Consolidated Derivative Action. The court entered that order on July 17, 2023. On November 30, 2023, the court entered an order consolidating the Kirst and Needelman Actions. On December 14, 2023, the parties filed a stipulation (i) extending the plaintiffs’ deadline to file a consolidated complaint until January 29, 2024, and (ii) otherwise staying all other proceedings in the case (including the defendants’ deadline to respond to the consolidated complaint) until February 12, 2024. On May 3, 2024, the plaintiffs filed a consolidated complaint. On May 14, 2024, the parties filed a stipulation staying the action until June 6, 2024. On July 12, 2024, the court entered an order staying the action until August 5, 2024. On September 24, 2024, the court entered another order staying the action until November 4, 2024. On November 4, 2024, the parties filed a stipulation requesting a status conference with the court and further requesting that the action remain stayed until such status conference takes place. On April 15, 2025, the parties filed a Stipulated Notice of Dismissal dismissing the Kirst and Needelman Actions in light of the Derivative Action. The Company is also involved in various other legal proceedings arising in the normal course of business. Although the outcomes of these other legal proceedings are inherently difficult to predict, the Company does not expect the resolution of these other legal proceedings to have a material adverse effect on its financial position, results of operations, or cash flows.

After the Sinnathurai Action was filed, eight derivative lawsuits were filed: (i) Robert E. Meyer v. Stanley C. Erck, et al., No. 8:21-cv-02996-TDC (the “Meyer Action”), (ii) Shui Shing Yung v. Stanley C. Erck, et al., No. 8:21-cv-03248-TDC (the “Yung Action”), (iii) William Kirst, et al. v. Stanley C. Erck, et al., No. C-15-CV-21-000618 (the “Kirst Action”), (iv) Amy Snyder v. Stanley C. Erck, et al., No. 8:22-cv-01415-TDC (the “Snyder Action”), (v) Charles R. Blackburn, et al. v. Stanley C. Erck, et al., No. 1:22-cv-01417-TDC (the “Blackburn Action”), (vi) Diego J. Mesa v. Stanley C. Erck, et al., No. 2022-0770-NAC (the “Mesa Action”), (vii) Sean Acosta v. Stanley C. Erck, et al., No. 2022-1133-NAC (the “Acosta Action”), and (viii) Jared Needelman v. Stanley C. Erck, et al., No. C-15-CV-23-001550 (the “Needelman Action”). The Meyer, Yung, Snyder, and Blackburn Actions were filed in the Maryland Court. The Kirst Action was filed in the Circuit Court for Montgomery County, Maryland, and shortly thereafter removed to the Maryland Court by the defendants. The Needelman Action was also filed in the Circuit Court for Montgomery County, Maryland. The Mesa and Acosta Actions were filed in the Delaware Court of Chancery (the “Delaware Court”). The derivative lawsuits name members of the Company’s 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 February 7, 2022, the Maryland Court entered an order consolidating the Meyer and Yung Actions (the “First Consolidated Derivative Action”). The plaintiffs in the First Consolidated Derivative Action filed their consolidated derivative complaint on April 25, 2022. On May 10, 2022, the Maryland Court entered an order 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. On June 10, 2022, the Snyder and Blackburn Actions were filed. On October 5, 2022, the Maryland Court entered an order granting a request by the plaintiffs in the First Consolidated Derivative Action and the Snyder and Blackburn Actions to consolidate all three actions and appoint co-lead plaintiffs and co-lead and liaison counsel (the “Second Consolidated Derivative Action”). The co-lead plaintiffs in the Second Consolidated Derivative Action filed a consolidated amended complaint on November 21, 2022. On February 10, 2023, defendants filed a motion to dismiss the Second Consolidated Derivative Action. The plaintiffs filed their opposition to the motion to dismiss on April 11, 2023. Defendants filed their reply brief in further support of their motion to dismiss on May 11, 2023. On August 21, 2023, the court entered an order granting in part and denying in part the motion to dismiss. On September 5, 2023, the Company filed an Answer to the consolidated amended complaint. On September 6, 2023, the court entered an order granting the individual defendants an extension of time to file their answer until November 6, 2023. On October 6, 2023, the Board of Directors of the Company formed a Special Litigation Committee (“SLC”) with full and exclusive power and authority of the Board to, among other things, investigate, review, and analyze the facts and circumstances surrounding the claims asserted in the pending derivative actions, including the claims that remain following the court’s order on the motion to dismiss in the Second Consolidated Derivative Action. On November 7, 2023, the court entered an order granting the parties’ request to stay the Second Consolidated Derivative Action for up to six months from the date of entry of the order, and, on April 15, 2024, the court entered a further order extending the stay until June 6, 2024. On June 7, 2024, the court entered another order extending the stay until August 5, 2024. On August 19, 2024, the court entered another order extending the stay until November 4, 2024, to allow the SLC and the parties to continue then-ongoing mediation efforts. On November 1, 2024, the parties notified the court that a settlement in principle had been reached and requested the stay to be extended until the definitive settlement agreement was filed. On November 22, 2024, the SLC filed its Unopposed Motion for Preliminary Approval of Derivative Settlement, Approval of Form and Manner of Notice, and Setting Hearing Date on Final Approval of Settlement and supporting documents. Under the terms of the proposed settlement, individual defendants Erck and Herrmann agreed to pay or cause their insurers to pay $6.8 million to Novavax in exchange for a release of claims. In addition, Novavax and its Board of Directors agreed to adopt and implement certain governance provisions identified in the settlement stipulation. On December 12, 2024, the court entered an order granting preliminary approval of the derivative settlement and setting a date for a hearing on the final approval of the settlement. On March 7, 2025, the court held a hearing and entered a Final Judgment and Order Approving Derivative Settlement (the “Final Judgment and Order”). As part of the Final Judgment and Order, the court granted the motion for attorneys’ fees and awarded plaintiffs’ counsel fees and expenses in the amount of $2.0 million to be paid by the Company following its receipt of the $6.8 million settlement funds. During the three months ended, March 31, 2025, the Company recorded a net gain on the settlement of $4.8 million in Other income (expense), net.

On August 30, 2022, the Mesa Action was filed. On October 3, 2022, the Delaware Court entered an order granting the parties’ request to stay all proceedings and deadlines in the Mesa Action pending the earlier of dismissal of the Sinnathurai Action or the filing of an answer to the operative complaint in the Sinnathurai Action. On January 9, 2023, following the ruling on the motion to dismiss the Sinnathurai Action, the Delaware Court entered an order granting the Mesa Action parties’ request to set a briefing schedule in connection with a motion to stay by defendants. On February 28, 2023, the court granted the defendants’ motion and stayed the Mesa Action pending the entry of a final, non-appealable judgment in the Second Consolidated Derivative Action. On August 31, 2023, the Mesa plaintiffs filed a motion to lift the stay in the Mesa Action. On October 6, 2023, the Company filed an opposition to plaintiff’s motion to lift the stay. Plaintiff filed his reply on October 17, 2023. On December 27, 2023, the parties filed a letter informing the Court that the Second Consolidated Derivative Action had been stayed for a period of six months and asked the Court to stay further proceedings in the Mesa Action until expiration of that stay.

On December 7, 2022, the Acosta Action was filed. On February 6, 2023, defendants accepted service of the complaint and summons in the Acosta Action. On March 9, 2023, the court entered an order granting the parties’ request to stay the Acosta Action pending the entry of a final, non-appealable judgment in the Second Consolidated Derivative Action. On October 13, 2023, the parties filed, and the Delaware Court entered, a stipulated order providing that (i) if the Delaware Court declines to lift the stay in the Mesa Action, the Acosta Action will also remain stayed, and (ii) if the Delaware Court lifts the stay in the Mesa Action, the stay in the Acosta Action will also be lifted. On April 28, 2025, the parties filed a joint status report with the Delaware Court in which they indicated that plaintiffs intend to dismiss the Mesa Action and Acosta Action in light of the Derivative Settlement. On May 2, 2025, the Delaware Court granted the stipulated order of voluntary dismissal, and the Mesa Action was dismissed with prejudice.

On November 30, 2023, the court entered an order consolidating the Kirst and Needelman Actions. On December 14, 2023, the parties filed a stipulation (i) extending the plaintiffs’ deadline to file a consolidated complaint until January 29, 2024, and (ii) otherwise staying all other proceedings in the case (including the defendants’ deadline to respond to the consolidated complaint) until February 12, 2024. On May 3, 2024, the plaintiffs filed a consolidated complaint. On May 14, 2024, the parties filed a stipulation staying the action until June 6, 2024. On July 12, 2024, the court entered an order staying the action until August 5, 2024. On September 24, 2024, the court entered another order staying the action until November 4, 2024. On November 4, 2024, the parties filed a stipulation requesting a status conference with the court and further requesting that the action remain stayed until such status conference takes place. On April 15, 2025, the parties filed a Stipulated Notice of Dismissal dismissing the Kirst and Needelman Actions in light of the Derivative Action.