Acquisition, Divestitures, Licensing Arrangements, Collaborative Arrangements and Privately Held Investment - Biogen (Details) - Disposed of by Sale [Member] - Phase 2b Ready AMPA Receptor Potentiator For CIAS [Member] $ in Millions	1 Months Ended
	Apr. 30, 2018 USD ($)
Indefinite-lived Intangible Assets [Line Items]
Proceeds from sale of Phase 2b Ready AMPA Receptor Potentiator for CIAS to Biogen	$ 75
Potential development and commercialization milestones	515
Other (Income)/Deductions, Net [Member]
Indefinite-lived Intangible Assets [Line Items]
Proceeds from sale of Phase 2b Ready AMPA Receptor Potentiator for CIAS to Biogen	$ 75