Available-for-Sale Securities and Fair Value Measurements (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	$ 281,644,000	$ 502,831,000
U.S. government securities
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	30,043,000	42,158,000
U.S. government agencies
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	34,750,000	141,331,000
U.S. corporate notes
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	80,775,000	94,977,000
U.S. commercial paper
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	34,469,000	102,022,000
Ordinary shares of Theravance Biopharma
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	6,517,000
Recognized losses	3,800,000
Money market funds
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	95,090,000	122,343,000
Recurring basis | Quoted Prices in Active Markets for Identical Assets, Level 1
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	131,650,000	327,827,000
Fair value measurements transfer to Level 1 From Level 2		8,000,000
Recurring basis | Quoted Prices in Active Markets for Identical Assets, Level 1 | U.S. government securities
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	30,043,000	42,158,000
Recurring basis | Quoted Prices in Active Markets for Identical Assets, Level 1 | U.S. government agencies
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	0	98,236,000
Recurring basis | Quoted Prices in Active Markets for Identical Assets, Level 1 | U.S. corporate notes
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	0	61,591,000
Recurring basis | Quoted Prices in Active Markets for Identical Assets, Level 1 | U.S. commercial paper
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	0	3,499,000
Recurring basis | Quoted Prices in Active Markets for Identical Assets, Level 1 | Ordinary shares of Theravance Biopharma
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	6,517,000
Recurring basis | Quoted Prices in Active Markets for Identical Assets, Level 1 | Money market funds
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	95,090,000	122,343,000
Recurring basis | Significant Other Observable Inputs, Level 2
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	149,994,000	175,004,000
Fair value measurements transfer to Level 1 From Level 2	8,000,000
Recurring basis | Significant Other Observable Inputs, Level 2 | U.S. government securities
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	0	0
Recurring basis | Significant Other Observable Inputs, Level 2 | U.S. government agencies
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	34,750,000	43,095,000
Recurring basis | Significant Other Observable Inputs, Level 2 | U.S. corporate notes
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	80,775,000	33,386,000
Recurring basis | Significant Other Observable Inputs, Level 2 | U.S. commercial paper
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	34,469,000	98,523,000
Recurring basis | Significant Other Observable Inputs, Level 2 | Ordinary shares of Theravance Biopharma
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	0
Recurring basis | Significant Other Observable Inputs, Level 2 | Money market funds
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	0	0
Recurring basis | Significant Unobservable Inputs, Level 3
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	0	0
Recurring basis | Significant Unobservable Inputs, Level 3 | U.S. government securities
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	0	0
Recurring basis | Significant Unobservable Inputs, Level 3 | U.S. government agencies
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	0	0
Recurring basis | Significant Unobservable Inputs, Level 3 | U.S. corporate notes
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	0	0
Recurring basis | Significant Unobservable Inputs, Level 3 | U.S. commercial paper
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	0	0
Recurring basis | Significant Unobservable Inputs, Level 3 | Ordinary shares of Theravance Biopharma
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	0
Recurring basis | Significant Unobservable Inputs, Level 3 | Money market funds
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	0	0
Recurring basis | Total
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	281,644,000	502,831,000
Recurring basis | Total | U.S. government securities
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	30,043,000	42,158,000
Recurring basis | Total | U.S. government agencies
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	34,750,000	141,331,000
Recurring basis | Total | U.S. corporate notes
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	80,775,000	94,977,000
Recurring basis | Total | U.S. commercial paper
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	34,469,000	102,022,000
Recurring basis | Total | Ordinary shares of Theravance Biopharma
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	6,517,000
Recurring basis | Total | Money market funds
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	95,090,000	122,343,000
Nonrecurring basis | Quoted Prices in Active Markets for Identical Assets, Level 1
Estimated fair values of entity's financial assets and liabilities
Total debt measured at fair value	0
Nonrecurring basis | Quoted Prices in Active Markets for Identical Assets, Level 1 | Convertible Subordinated Notes Due 2023
Estimated fair values of entity's financial assets and liabilities
Total debt measured at fair value	0	0
Nonrecurring basis | Quoted Prices in Active Markets for Identical Assets, Level 1 | 9% fixed rate term notes due 2029
Estimated fair values of entity's financial assets and liabilities
Non-recourse notes due 2029	0
Nonrecurring basis | Significant Other Observable Inputs, Level 2
Estimated fair values of entity's financial assets and liabilities
Total debt measured at fair value	653,506,000
Nonrecurring basis | Significant Other Observable Inputs, Level 2 | Convertible Subordinated Notes Due 2023
Estimated fair values of entity's financial assets and liabilities
Total debt measured at fair value	197,095,000	408,250,000
Nonrecurring basis | Significant Other Observable Inputs, Level 2 | 9% fixed rate term notes due 2029
Estimated fair values of entity's financial assets and liabilities
Non-recourse notes due 2029	456,411,000
Nonrecurring basis | Significant Unobservable Inputs, Level 3
Estimated fair values of entity's financial assets and liabilities
Total debt measured at fair value	0
Nonrecurring basis | Significant Unobservable Inputs, Level 3 | Convertible Subordinated Notes Due 2023
Estimated fair values of entity's financial assets and liabilities
Total debt measured at fair value	0	0
Nonrecurring basis | Significant Unobservable Inputs, Level 3 | 9% fixed rate term notes due 2029
Estimated fair values of entity's financial assets and liabilities
Non-recourse notes due 2029	0
Nonrecurring basis | Total
Estimated fair values of entity's financial assets and liabilities
Total debt measured at fair value	653,506,000
Nonrecurring basis | Total | Convertible Subordinated Notes Due 2023
Estimated fair values of entity's financial assets and liabilities
Total debt measured at fair value	197,095,000	408,250,000
Nonrecurring basis | Total | 9% fixed rate term notes due 2029
Estimated fair values of entity's financial assets and liabilities
Non-recourse notes due 2029	$ 456,411,000