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, 2013 USD ($)	Sep. 30, 2012 USD ($)	Sep. 30, 2013 USD ($)	Sep. 30, 2012 USD ($)	Feb. 29, 2012 Samsung Biosimilar Agreement [Member] USD ($)	Feb. 29, 2012 Samsung Biosimilar Agreement [Member] KRW	Sep. 30, 2013 Samsung Biosimilar Agreement [Member] USD ($)	Sep. 30, 2013 Samsung Biosimilar Agreement [Member] KRW	Sep. 30, 2012 Samsung Biosimilar Agreement [Member] USD ($)	Sep. 30, 2013 Samsung Biosimilar Agreement [Member] USD ($)	Sep. 30, 2012 Samsung Biosimilar Agreement [Member] USD ($)	Dec. 31, 2012 Samsung Biosimilar Agreement [Member] USD ($)	Dec. 31, 2012 Samsung Biosimilar Agreement [Member] KRW
Schedule of Equity Method Investments [Line Items]
Contribution from Samsung to develop, manufacture and market biosimilar 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					45,000,000	49,500,000,000	26,500,000	28,500,000,000		26,500,000		27,800,000	29,700,000,000
Percentage of stake in entity minimum					15.00%	15.00%
Percentage of stake in entity maximum					49.90%	49.90%
Cash contributions to Samsung Bioepis							5,800,000	6,500,000,000
Recognized loss	(6,170,000)	(1,258,000)	(12,270,000)	(1,769,000)			(6,200,000)		(1,300,000)	(12,300,000)	(1,800,000)
Revenue related to technical development and technology transfer services	$ 71,016,000	$ 58,652,000	$ 174,497,000	$ 150,147,000			$ 4,300,000		$ 4,300,000	$ 18,500,000	$ 9,900,000