The purpose of this study is to measure the safety and decrease in daytime sleepiness in subjects with Idiopathic Hypersomnia when taking ALKS 2680 tablets compared with placebo tablets

Inclusion Criteria:

• Is willing and able, in the opinion of the Investigator, to understand and comply with protocol requirements, including: lifestyle considerations and restrictions, adherence to contraception guidance, adherence to actigraphy and diary requirements, if receiving treatment for OSA, adherence to primary OSA therapy over the 30 days prior to Visit 1, and throughout the study, including during overnight visits.
• Meets the diagnostic criteria of Idiopathic Hypersomnia according to ICSD-3-TR guidelines, confirmed by the diagnostic evaluations (PSG/MSLT/actigraphy) within the previous 10 years

Exclusion Criteria:

• Has another comorbid sleep disorder or condition that may influence the sleep-wake cycle
• Has a history or presence at Visit 1 of other clinically significant (treated or untreated) illness, disease, abnormality, or surgical procedure that, in the opinion of the Investigator, might compromise subject safety, interfere with any study assessment, or affect the subject's ability to complete the study
• Is currently enrolled in another clinical study or used any investigational drug or device within 30 days prior to Visit 1
• Is currently pregnant, breastfeeding, or is planning to become pregnant during the study