Collaborative and License Agreements ( Narrative) (Details) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2012 Amgen Inc. USD ($)	Jun. 30, 2011 Amgen Inc. USD ($)	Jun. 30, 2012 Amgen Inc. USD ($)	Jun. 30, 2011 Amgen Inc. USD ($)	Jun. 30, 2012 GlaxoSmithKline USD ($)	Jun. 30, 2012 Kyowa Hakko Kirin USD ($)	Jun. 30, 2011 Kyowa Hakko Kirin USD ($)	Jun. 30, 2012 Kyowa Hakko Kirin USD ($)	Jun. 30, 2011 Kyowa Hakko Kirin USD ($)	Jun. 30, 2012 Nycomed Teduglutide USD ($)	Jun. 30, 2011 Nycomed Teduglutide USD ($)	Jun. 30, 2012 Nycomed Teduglutide USD ($)	Jun. 30, 2011 Nycomed Teduglutide USD ($)	Jun. 30, 2012 Nycomed Preotact USD ($)	Jun. 30, 2011 Nycomed Preotact USD ($)	Jun. 30, 2012 Nycomed Preotact USD ($)	Jun. 30, 2011 Nycomed Preotact USD ($)	Jun. 30, 2012 Nycomed Preotact EUR (€)	Jun. 30, 2012 Janssen Pharmaceuticals, Inc. USD ($)	Jun. 30, 2011 Janssen Pharmaceuticals, Inc. USD ($)	Jun. 30, 2012 Janssen Pharmaceuticals, Inc. USD ($)	Jun. 30, 2011 Janssen Pharmaceuticals, Inc. USD ($)	Jun. 30, 2012 Hoffman-La Roche Inc. and F. Hoffmann-La Roche Ltd. USD ($)	Jun. 30, 2011 Hoffman-La Roche Inc. and F. Hoffmann-La Roche Ltd. USD ($)	Jun. 30, 2012 Hoffman-La Roche Inc. and F. Hoffmann-La Roche Ltd. USD ($)	Jun. 30, 2011 Hoffman-La Roche Inc. and F. Hoffmann-La Roche Ltd. USD ($)	Jun. 30, 2012 In-License and Purchase Agreements USD ($)
Year of agreement	1996		1996		2011	1995		1995		2007		2007						2004 and 2007	2006		2006		2008		2008
Number of days to terminate upon written notice to the Company	90		90			90		90		180 or 365		180 or 365						180	60		60		30		30
Percentage of Company costs to develop product	0.00%		0.00%			0.00%		0.00%		50.00%		50.00%							0.00%		0.00%		0.00%		0.00%
Nonrefundable license fee received	$ 10.0		$ 10.0			$ 5.0		$ 5.0		$ 35.0		$ 35.0							$ 8.0		$ 8.0		$ 2.0		$ 2.0
Total milestone payments under the agreement payable to the Company	26.0		26.0		11.5	13.0		13.0		170.0		170.0						22.0
Company payments to licensor to date										6.6		6.6
Research support payments under the agreement						7.0		7.0
Future milestone payments outside the Company's control	5.0		5.0		1.0					5.0		5.0						14.8
Next future milestone payment outside the Company's control	5.0		5.0															0.3
Total milestone payments paid to the Company to date	21.0		21.0		0	13.0		13.0		40.0		40.0						7.1					0.3		0.3
Research support payments paid to the Company to date						7.0		7.0
Milestone payments received by the Company	0	0	0	0		0	0	0	0	0	0	0	5.0
Recognized royalties from product sales received by the Company	23.6	22.6	42.3	36.9		2.3	1.9	4.1	3.5					1.9	2.3	3.7	4.5		0.8	0.5	1.4	0.9	0	0	0	0
Sale of royalty rights	25.0		25.0
Company payments to licensor											2.4		2.4
Company maximum royalties to be paid on sales of cinacalcet HCl																											15.0
Royalties payable accrued on sales of cinacalcet HCl, to date																											15.0
Royalties paid on sales of cinacalcet HCl, to date																											8.4
Annual upper limit of royalty payments on sales of cinacalcet HCl																											1.0
Royalties recorded in other liabilites on sales of cinacalcet HCl																											5.6
Royalties recorded in accrued expenses and other liabilites on sales of cinacalcet HCl																											$ 1.0