Acquisition of Assets	12 Months Ended
Acquisition of Assets	Dec. 31, 2023
Business Combination and Asset Acquisition [Abstract]
Acquisition of Assets	Acquisition of Assets On February 6, 2023, the Company acquired Cerveau. Cerveau holds the rights under a license agreement to develop and commercialize MK-6240, an investigational second-generation F 18-labeled positron emission tomography (“PET”) imaging agent that targets Tau tangles in Alzheimer’s disease. The Company determined that upon review of the Cerveau acquisition, the transaction did not meet the definition of a business combination and is therefore treated as an asset acquisition. In February 2023, the Company made an upfront payment of approximately $35.3 million to the stockholders of Cerveau (the “Selling Stockholders”) and paid the Selling Stockholders an additional $10.0 million in May 2023 upon the successful completion of a technology transfer. The Company could pay up to an additional $51.0 million in milestone payments upon achievement of specified U.S. regulatory milestones related to MK-6240. The Selling Stockholders are also eligible to receive up to $1.2 billion in sales milestone payments upon the achievement of specified annual commercial sales thresholds of MK-6240 in the event the Company pursues commercialization, as well as up to $13.5 million in research revenue milestones upon achievement of specified annual research revenue thresholds. Additionally, the Company will pay to the Selling Stockholders up to double-digit royalty payments for research revenue and commercial sales. Research revenue is derived from existing partnerships with pharmaceutical companies that use MK-6240 in clinical trials and includes milestone and dose-related payments. The purchase agreement pursuant to which the Company purchased Cerveau specifies, among other things, that certain members of the Selling Stockholders will also provide transition and clinical development services for a prescribed time following the closing of the transaction. In December 2022, the Company made upfront payments of $260.0 million to POINT as a part of an asset acquisition with the potential for additional milestone payments of approximately $1.8 billion between the two licensed assets based on U.S. Food and Drug Administration (“FDA”) approval and net sales and commercial milestones. Under the terms of the PNT2002 License Agreement, Lantheus Two paid POINT an upfront cash payment of $250.0 million, and could pay up to an additional $281.0 million in milestone payments upon the achievement of specified U.S. and ex-U.S. regulatory milestones related to PNT2002. POINT is also eligible to receive up to $1.3 billion in sales milestone payments upon the achievement of specified annual sales thresholds of PNT2002. Under the terms of the PNT2003 License Agreement, Lantheus Three paid POINT an upfront cash payment of $10.0 million, and could pay up to an additional $34.5 million in milestone payments upon the achievement of specified U.S. and ex-U.S. regulatory milestones related to PNT2003. POINT is also eligible to receive up to $275.0 million in sales milestone payments upon the achievement of specified annual sales thresholds of PNT2003. Additionally, the Company will pay POINT royalties on net sales, beyond certain financial thresholds and subject to conditions, of 20% for PNT2002 and 15% for PNT2003. Costs of IPR&D projects acquired as part of an asset acquisition that have no alternative future use are expensed when incurred, and therefore, a charge of $260.0 million was recognized in research and development expenses during the year ended December 31, 2022.