Intangible Assets and Goodwill (Details 1) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Goodwill [Line Items]
Income tax benefit (expense)	$ 330,093	$ 274,774	$ 904,475	$ 721,709
Increase to goodwill			649,400
Summary of roll forward of the changes in goodwill
Goodwill, beginning of period			1,760,249
Other			(700)
Goodwill, end of period	$ 2,408,854		2,408,854
TECFIDERA | Fumapharm AG
Goodwill [Line Items]
Income tax benefit (expense)			78,900
Increase to goodwill			$ 600,000