Collaboration Arrangements (Details) (USD $)	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended			6 Months Ended		6 Months Ended	3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended			6 Months Ended						6 Months Ended				3 Months Ended	6 Months Ended		1 Months Ended							3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012 GSK	Jun. 30, 2011 GSK	Jun. 30, 2012 GSK	Jun. 30, 2011 GSK	Jun. 30, 2012 VIBATIV	Jun. 30, 2012 VIBATIV Maximum	Jun. 30, 2012 Long-acting beta agonist (LABA) collaboration GSK product	Jun. 30, 2012 Long-acting beta agonist (LABA) collaboration LAMA/LABA GSK Maximum	Jun. 30, 2012 Long-acting beta agonist (LABA) collaboration LABA collaboration GSK	Jun. 30, 2011 Long-acting beta agonist (LABA) collaboration LABA collaboration GSK	Jun. 30, 2012 Long-acting beta agonist (LABA) collaboration LABA collaboration GSK	Jun. 30, 2011 Long-acting beta agonist (LABA) collaboration LABA collaboration GSK	Jun. 30, 2012 2004 Strategic alliance LAMA GSK	Jun. 30, 2012 2004 Strategic alliance MABA GSK	Jun. 30, 2011 2004 Strategic alliance MABA GSK	Jun. 30, 2012 2004 Strategic alliance MABA GSK product	Jun. 30, 2011 2004 Strategic alliance MABA GSK	Jun. 30, 2012 2004 Strategic alliance MABA containing '081 GSK	Jun. 30, 2012 2004 Strategic alliance MABA containing '081 - single-agent GSK	Jun. 30, 2012 2004 Strategic alliance MABA containing '081 - single-agent GSK Maximum	Jun. 30, 2012 2004 Strategic alliance MABA containing '081 - single-agent GSK Minimum	Jun. 30, 2012 2004 Strategic alliance MABA containing '081 - combination product GSK	Jun. 30, 2012 2004 Strategic alliance MABA containing additional MABA GSK product	Jun. 30, 2012 2004 Strategic alliance MABA containing additional MABA GSK Maximum	Jun. 30, 2012 2004 Strategic alliance MABA containing additional MABA - single-agent GSK	Jun. 30, 2012 2004 Strategic alliance MABA containing additional MABA - single-agent GSK Maximum	Jun. 30, 2012 2004 Strategic alliance MABA containing additional MABA - single-agent GSK Minimum	Jun. 30, 2012 2004 Strategic alliance MABA containing additional MABA - combination product GSK	Jun. 30, 2011 2004 Strategic alliance Non-license specific GSK	Jun. 30, 2011 2004 Strategic alliance Non-license specific GSK	Jun. 30, 2012 2004 Strategic alliance Non-license specific GSK	Feb. 29, 2012 Governance agreement Common stock GSK	Nov. 30, 2011 Governance agreement Common stock GSK	Aug. 31, 2011 Governance agreement Common stock GSK	May 31, 2011 Governance agreement Common stock GSK	Feb. 28, 2011 Governance agreement Common stock GSK	Jul. 31, 2011 Governance agreement Class A common stock GSK	Apr. 02, 2012 Common stock purchase agreement Common stock GSK	Mar. 31, 2012 License, Development and Commercialization Agreement With Astellas VIBATIV Astellas	Jun. 30, 2011 License, Development and Commercialization Agreement With Astellas VIBATIV Astellas	Jun. 30, 2012 License, Development and Commercialization Agreement With Astellas VIBATIV Astellas	Jun. 30, 2011 License, Development and Commercialization Agreement With Astellas VIBATIV Astellas
Information related to collaboration arrangements
Maximum obligation for milestone payments to GSK											$ 220,000,000
Number of combination products											2
Period over which portion of potential milestone payments could be payable to GSK															2 years
Royalty rate for first level of annual global net sales (as a percent)															15.00%									20.00%	10.00%					15.00%	10.00%
Royalty rate for combination products as a percentage of the rate applied to single products																										70.00%						50.00%
Royalty rate for sales above first level of annual global net sales (as a percent)															5.00%								7.50%						10.00%
Percentage of royalties receivable												10.00%
Percentage of royalties payable to Astellas																																													2.00%
Amount of purchase agreements for pharmaceutical ingredient and raw materials										6,200,000
Amount of purchase agreements for finished goods inventory										4,200,000
Purchases of active pharmaceutical ingredient and other raw materials									4,300,000
Liability recorded due to termination agreement																																													150,000
Annual global sales level used to determine royalty rate															3,000,000,000								3,500,000,000						3,500,000,000
Number of products which Company is obligated to use diligent efforts to discover after license of a program																											6
Number of combination products to be developed and commercialized																				1
Potential upfront license and milestone payments that Company could receive																							125,000,000
Potential upfront license and milestone payments that Company could receive in respect of combination medicines																						250,000,000
Potential milestone payments that Company could receive																												129,000,000
Agreement to issue stock, number of shares																																										10,000,000
Agreement to issue stock, price per share																																										$ 21.2887
Agreement to issue stock, total investment in the Company's stock																																										212,887,000
Entity's common stock information
Issuance of common stock for cash in private placement to a related party (in shares)																																				88,468	58,411	102,466	261,299	152,278
Issuance of common stock for cash in private placement to a related party																																				1,603,000	1,298,000	2,020,000	6,689,000	3,609,000
Shares of Class A common stock converted into common stock																																									9,401,499
Number of shares of Class A stock convertible into one share of common stock																																									1
Number of shares of common stock into which one share of Class A stock can be converted																																									1
GSK Upfront License Fees, Milestone Payments and Revenue
Upfront License Fees					41,000,000		41,000,000				10,000,000						5,000,000	6,000,000		6,000,000															20,000,000
Milestone Payments					69,000,000		69,000,000				50,000,000						3,000,000	16,000,000		16,000,000
Total					110,000,000		110,000,000				60,000,000						8,000,000	22,000,000		22,000,000															20,000,000
Term of royalty payment																																													10 years
License, Development and Commercialization Agreement with Astellas
Upfront license, milestone and other fees received																																													191,000,000
Net revenue recognized under the collaboration
Revenue	1,430,000	6,389,000	128,529,000	12,719,000	1,430,000	2,456,000	2,860,000	4,913,000					907,000	1,270,000	1,814,000	2,540,000		523,000	502,000	1,046,000	1,004,000												684,000	1,369,000										3,932,000	125,669,000	7,806,000
Recognition of remaining deferred revenue																																											125,800,000		125,819,000
Amortization of deferred revenue																																												3,244,000		6,488,000
Royalties from net sales of VIBATIV																																												694,000		1,324,000
Proceeds from VIBATIV delivered to Astellas																																												1,171,000		1,171,000
Cost of VIBATIV delivered to Astellas																																												(1,177,000)		(1,177,000)
Astellas-labeled product sales allowance																																													$ (150,000)