Collaborative and Other Relationships Collaborative and Other Relationships - Equity Method Investments (Details)	3 Months Ended		9 Months Ended			1 Months Ended		3 Months Ended	9 Months Ended
	Sep. 30, 2012 USD ($)	Sep. 30, 2011 USD ($)	Sep. 30, 2012 USD ($)	Sep. 30, 2012 KRW	Sep. 30, 2011 USD ($)	Feb. 29, 2012 Samsung Biosimilar Agreement [Member] USD ($)	Feb. 29, 2012 Samsung Biosimilar Agreement [Member] KRW	Sep. 30, 2012 Samsung Biosimilar Agreement [Member] USD ($)	Sep. 30, 2012 Samsung Biosimilar Agreement [Member] USD ($)	Sep. 30, 2012 Samsung Biosimilar Agreement [Member] KRW
Schedule of Equity Method Investments [Line Items]
Contribution from Samsung to develop, manufacture and market bio-similar pharmaceuticals						$ 250,000,000	280,500,000,000
Variable interest entity, qualitative or quantitative information, ownership percentage						85.00%	85.00%
Contribution from Biogen Idec to develop, manufacture and market biosimilar pharmaceuticals	29,500,000		29,500,000	32,600,000,000		45,000,000	49,500,000,000
Percentage of stake in entity minimum						15.00%	15.00%
Percentage of stake in entity maximum						49.90%	49.90%
Payments to Acquire Equity Method Investments			32,100,000	36,000,000,000
Remaining obligation of financing arrangements								12,200,000	12,200,000	13,500,000,000
Remaining obligation of financing arrangements due within the next year								6,400,000	6,400,000	7,100,000,000
Recognized loss	(1,258,000)	0	(1,769,000)		0
Revenue related to technical development and technology transfer services								4,300,000	9,900,000
Revenue related to manufacturing agreement									$ 0