Property, Plant and Equipment Property, Plant and Equipment (Details) - Eisai $ in Millions	3 Months Ended
	Sep. 30, 2015 USD ($)
Property, Plant and Equipment [Line Items]
Research Triangle Park facility purchase	$ 104.8
Building
Property, Plant and Equipment [Line Items]
Research Triangle Park facility purchase	58.6
Machinery and Equipment
Property, Plant and Equipment [Line Items]
Research Triangle Park facility purchase	25.9
Land
Property, Plant and Equipment [Line Items]
Research Triangle Park facility purchase	$ 20.3