Organization and Business	6 Months Ended
Jun. 30, 2026
Accounting Policies [Abstract]
Organization and Business	1. Organization and Business Acadia Pharmaceuticals Inc. (the Company), is a biopharmaceutical company focused on turning scientific promise into meaningful innovation that makes the difference for underserved neurological and rare disease communities around the world. In April 2016, the U.S. Food and Drug Administration (FDA) approved the Company’s first drug, NUPLAZID® (pimavanserin), for the treatment of hallucinations and delusions associated with Parkinson’s disease psychosis (PDP). NUPLAZID became available for prescription in the United States in May 2016. In March 2023, the FDA approved the Company’s second drug, DAYBUE® (trofinetide), for the treatment of Rett syndrome. DAYBUE became available for prescription in the United States in April 2023. In October 2024, Health Canada granted marketing authorization of DAYBUE® (trofinetide) for the treatment of Rett syndrome in adult and pediatric patients 2 years of age and older. In December 2025, the FDA approved DAYBUE® STIX (trofinetide), a dye- and preservative-free powder formulation, for the treatment of Rett syndrome in adult and pediatric patients 2 years and older. DAYBUE STIX was available on a limited basis starting in the first quarter of 2026 followed by a broader launch early in the second quarter of 2026. In December 2025, the Ministry of Health in Israel approved DAYBUE® (trofinetide) for the treatment of Rett syndrome in adults and pediatric patients 2 years of age and older and weighing at least 9 kg.

Organization and Business

6 Months Ended

Jun. 30, 2026

1. Organization and Business

Acadia Pharmaceuticals Inc. (the Company), is a biopharmaceutical company focused on turning scientific promise into meaningful innovation that makes the difference for underserved neurological and rare disease communities around the world.

In April 2016, the U.S. Food and Drug Administration (FDA) approved the Company’s first drug, NUPLAZID® (pimavanserin), for the treatment of hallucinations and delusions associated with Parkinson’s disease psychosis (PDP). NUPLAZID became available for prescription in the United States in May 2016.

In March 2023, the FDA approved the Company’s second drug, DAYBUE® (trofinetide), for the treatment of Rett syndrome. DAYBUE became available for prescription in the United States in April 2023.

In October 2024, Health Canada granted marketing authorization of DAYBUE® (trofinetide) for the treatment of Rett syndrome in adult and pediatric patients 2 years of age and older.

In December 2025, the FDA approved DAYBUE® STIX (trofinetide), a dye- and preservative-free powder formulation, for the treatment of Rett syndrome in adult and pediatric patients 2 years and older. DAYBUE STIX was available on a limited basis starting in the first quarter of 2026 followed by a broader launch early in the second quarter of 2026.

In December 2025, the Ministry of Health in Israel approved DAYBUE® (trofinetide) for the treatment of Rett syndrome in adults and pediatric patients 2 years of age and older and weighing at least 9 kg.