Capitalized Fees Paid to a Related Party (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Capitalized Fees Paid To Related Party [Line Items]
Net Carrying Value	$ 208,191,000	$ 124,257,000
Amortization Of Capitalized Fees Paid To A Related Party	11,066,000	743,000	0
Estimated amortization expense for the year 2015	13,800,000
Estimated amortization expense for the year 2016	13,800,000
Estimated amortization expense for the year 2017	13,800,000
Estimated amortization expense for the year 2018	13,800,000
Estimated amortization expense for the year 2019	13,800,000
Estimated amortization expense thereafter	139,200,000
GSK
Capitalized Fees Paid To Related Party [Line Items]
Amortization Of Capitalized Fees Paid To A Related Party	11,066,000	743,000	0
LABA Collaboration | GSK
Capitalized Fees Paid To Related Party [Line Items]
Weighted Average Remaining Amortization Period	15 years 1 month 6 days
Gross Carrying Value	220,000,000	125,000,000
Accumulated Amortization	(11,809,000)	(743,000)
Net Carrying Value	208,191,000	124,257,000
Amortization Of Capitalized Fees Paid To A Related Party	$ 11,100,000	$ 700,000	$ 0