Description of Operations and Summary of Significant Accounting Policies - Description of Operations and Variable Interest Entity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Description of Operations and Summary of Significant Accounting Policies
Cash balance	$ 351,981		$ 278,096	[1]
Total net revenue	78,678	$ 55,183
Total operating expenses	2,563	3,015
GSK
Description of Operations and Summary of Significant Accounting Policies
Total net revenue	$ 78,678	55,183
Long-Acting Beta2 Agonist (LABA) Collaboration | GSK
Description of Operations and Summary of Significant Accounting Policies
Percentage of economic interest in any future payments made under the agreements	15.00%
Long-Acting Beta2 Agonist (LABA) Collaboration | GSK | RELVAR/BREO
Description of Operations and Summary of Significant Accounting Policies
Royalty rate for first level of annual global net sales (as a percent)	15.00%
Annual global sales level used to determine royalty rate	$ 3,000,000
Royalty rate for sales above first level of annual global net sales (as a percent)	5.00%
Long-Acting Beta2 Agonist (LABA) Collaboration | GSK | ANORO | Minimum
Description of Operations and Summary of Significant Accounting Policies
Royalty rate for combination products (as a percent)	6.50%
Long-Acting Beta2 Agonist (LABA) Collaboration | GSK | ANORO | Maximum
Description of Operations and Summary of Significant Accounting Policies
Royalty rate for combination products (as a percent)	10.00%
TRC
Description of Operations and Summary of Significant Accounting Policies
Cash balance	$ 15,300
TRC | TRELEGY
Description of Operations and Summary of Significant Accounting Policies
Total net revenue	16,100	$ 7,300
TRC | Collaborative arrangement
Description of Operations and Summary of Significant Accounting Policies
Related-party receivables	16,100		$ 14,400
Theravance Biopharma | TRC
Description of Operations and Summary of Significant Accounting Policies
Total operating expenses	$ 300

[1] Consolidated balance sheet as of December 31, 2019 has been derived from audited consolidated financial statements.