Available-for-Sale Securities and Fair Value Measurements (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2015
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	$ 281,644	$ 176,776
U.S. government securities
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	30,043
U.S. government agency securities
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	34,750	14,405
Corporate notes
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	80,775	2,701
Commercial paper
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	34,469	10,997
Equity securities | Theravance Biopharma
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	6,517
Recognized losses	3,800
Money market funds
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	95,090	148,673
Recurring basis
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	281,644	176,776
Recurring basis | U.S. government securities
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	30,043
Recurring basis | U.S. government agency securities
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	34,750	14,405
Recurring basis | Corporate notes
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	80,775	2,701
Recurring basis | Commercial paper
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	34,469	10,997
Recurring basis | Equity securities | Theravance Biopharma
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	6,517
Recurring basis | Money market funds
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	95,090	148,673
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	148,673
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
Recurring basis | Quoted Prices in Active Markets for Identical Assets, Level 1 | U.S. government agency securities
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	0	0
Recurring basis | Quoted Prices in Active Markets for Identical Assets, Level 1 | Corporate notes
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	0	0
Recurring basis | Quoted Prices in Active Markets for Identical Assets, Level 1 | Commercial paper
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	0	0
Recurring basis | Quoted Prices in Active Markets for Identical Assets, Level 1 | Equity securities | Theravance Biopharma
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	6,517
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	148,673
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	28,103
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
Recurring basis | Significant Other Observable Inputs, Level 2 | U.S. government agency securities
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	34,750	14,405
Recurring basis | Significant Other Observable Inputs, Level 2 | Corporate notes
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	80,775	2,701
Recurring basis | Significant Other Observable Inputs, Level 2 | Commercial paper
Estimated fair values of entity's financial assets and liabilities
Total assets measured at fair value	34,469	10,997
Recurring basis | Significant Other Observable Inputs, Level 2 | Equity securities | 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
Recurring basis | Significant Unobservable Inputs, Level 3 | U.S. government agency 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 | 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 | 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 | Equity securities | 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
Nonrecurring basis
Estimated fair values of entity's financial assets and liabilities
Total fair value of liabilities	653,506	660,070
Nonrecurring basis | Convertible Subordinated Notes Due 2023
Estimated fair values of entity's financial assets and liabilities
Convertible subordinated notes due 2023	197,095	189,100
Nonrecurring basis | 9% fixed rate term notes due 2029
Estimated fair values of entity's financial assets and liabilities
Non-recourse notes due 2029	456,411	470,970
Nonrecurring basis | Quoted Prices in Active Markets for Identical Assets, Level 1
Estimated fair values of entity's financial assets and liabilities
Total fair value of liabilities	0	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
Convertible subordinated notes due 2023	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	0
Nonrecurring basis | Significant Other Observable Inputs, Level 2
Estimated fair values of entity's financial assets and liabilities
Total fair value of liabilities	653,506	660,070
Nonrecurring basis | Significant Other Observable Inputs, Level 2 | Convertible Subordinated Notes Due 2023
Estimated fair values of entity's financial assets and liabilities
Convertible subordinated notes due 2023	197,095	189,100
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	470,970
Nonrecurring basis | Significant Unobservable Inputs, Level 3
Estimated fair values of entity's financial assets and liabilities
Total fair value of liabilities	0	0
Nonrecurring basis | Significant Unobservable Inputs, Level 3 | Convertible Subordinated Notes Due 2023
Estimated fair values of entity's financial assets and liabilities
Convertible subordinated notes due 2023	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	$ 0