Jazz Pharmaceuticals (NSDQ:JAZZ) has announced that its Xywav (calcium, magnesium, potassium and sodium oxybates) oral solution has won FDA approval for treating idiopathic hypersomnia in adults. Idiopathic hypersomnia is a rare chronic disorder involving chronic excessive daytime sleepiness. Previously, the drug was FDA approved for treating cataplexy or excessive daytime sleepiness (EDS) in patients seven years…