Intangible Assets and Goodwill (Details 1) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Goodwill [Line Items]
Income tax benefit (expense)	$ 292,501	$ 268,521	$ 574,382	$ 446,935
Increase to goodwill			390,000
Summary of roll forward of the changes in goodwill
Goodwill, beginning of period			1,760,249
Other			4,100
Goodwill, end of period	$ 2,154,341		2,154,341
TECFIDERA | Fumapharm AG
Goodwill [Line Items]
Income tax benefit (expense)			38,300
Increase to goodwill			$ 300,000