Collaborations (Details 3)	12 Months Ended
	Dec. 31, 2011
Sobi rate to Biogen on net sales in the Sobi Territory [Member]
Mechanism for reimbursement, under the amended agreement amounts payable
Reimbursement, under the amended agreement, Method	Royalty
Rate during the reimbursement period	Base Rate plus 5%
Sobi rate to Biogen on net sales in the Sobi Territory [Member] | Sobi Territory [Member] | Maximum [Member]
Mechanism for reimbursement, under the amended agreement amounts payable
Base rate following first commercial sale in the territory	12.00%
Sobi rate to Biogen on net sales in the Sobi Territory [Member] | Sobi Territory [Member] | Minimum [Member]
Mechanism for reimbursement, under the amended agreement amounts payable
Base rate following first commercial sale in the territory	10.00%
Biogen rate to sobi on net sales in the Biogen North America Territory [Member]
Mechanism for reimbursement, under the amended agreement amounts payable
Reimbursement, under the amended agreement, Method	Royalty
Rate during the reimbursement period	Base Rate less 5%
Biogen rate to sobi on net sales in the Biogen North America Territory [Member] | Sobi Territory [Member]
Mechanism for reimbursement, under the amended agreement amounts payable
Rate prior to first commercial sale in the territory	2.00%
Biogen rate to sobi on net sales in the Biogen North America Territory [Member] | Sobi Territory [Member] | Maximum [Member]
Mechanism for reimbursement, under the amended agreement amounts payable
Base rate following first commercial sale in the territory	12.00%
Biogen rate to sobi on net sales in the Biogen North America Territory [Member] | Sobi Territory [Member] | Minimum [Member]
Mechanism for reimbursement, under the amended agreement amounts payable
Base rate following first commercial sale in the territory	10.00%
Biogen rate to sobi on net sales in the Biogen direct Territory [Member]
Mechanism for reimbursement, under the amended agreement amounts payable
Reimbursement, under the amended agreement, Method	Royalty
Rate during the reimbursement period	Base Rate less 5%
Biogen rate to sobi on net sales in the Biogen direct Territory [Member] | Sobi Territory [Member]
Mechanism for reimbursement, under the amended agreement amounts payable
Rate prior to first commercial sale in the territory	2.00%
Biogen rate to sobi on net sales in the Biogen direct Territory [Member] | Sobi Territory [Member] | Maximum [Member]
Mechanism for reimbursement, under the amended agreement amounts payable
Base rate following first commercial sale in the territory	17.00%
Biogen rate to sobi on net sales in the Biogen direct Territory [Member] | Sobi Territory [Member] | Minimum [Member]
Mechanism for reimbursement, under the amended agreement amounts payable
Base rate following first commercial sale in the territory	15.00%
Biogen rate to Sobi on net revenue from the Biogen distributor Territory [Member]
Mechanism for reimbursement, under the amended agreement amounts payable
Reimbursement, under the amended agreement, Method	Net Revenue Share
Rate during the reimbursement period	Base Rate less 15%
Biogen rate to Sobi on net revenue from the Biogen distributor Territory [Member] | Sobi Territory [Member]
Mechanism for reimbursement, under the amended agreement amounts payable
Rate prior to first commercial sale in the territory	10.00%
Biogen rate to Sobi on net revenue from the Biogen distributor Territory [Member] | Sobi Territory [Member] | Maximum [Member]
Mechanism for reimbursement, under the amended agreement amounts payable
Base rate following first commercial sale in the territory	50.00%
Biogen rate to Sobi on net revenue from the Biogen distributor Territory [Member] | Sobi Territory [Member] | Minimum [Member]
Mechanism for reimbursement, under the amended agreement amounts payable
Base rate following first commercial sale in the territory	0.00%