This study is looking at how safe and effective a new medicine, called ALKS 2680, is for people with a condition called Idiopathic Hypersomnia (IH). IH makes people feel very sleepy during the day for no clear reason. The study compares ALKS 2680 tablets with placebo tablets (tablets that don't contain medicine).

Key Points:

• Duration: The study involves multiple visits, including overnight stays.
• Requirements: Participants must follow guidelines like keeping a sleep diary and possibly using a device to track sleep.
• Eligibility: You cannot join if you have other sleep disorders, certain health conditions, or are pregnant.

To be part of the study, you must understand and follow the rules set by the researchers, like using birth control if needed and sticking to your usual sleep treatments if you have Obstructive Sleep Apnea (OSA). You also need to have been diagnosed with IH in the last 10 years. You can't join if you're in another study or have used test medicines recently.