Description of Operations and Summary of Significant Accounting Policies - Description of Operations and Variable Interest Entity (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Description of Operations and Summary of Significant Accounting Policies
Cash balance	$ 172,946		$ 172,946		$ 62,417	[1]
Net revenue	65,755	$ 61,680	185,045	$ 181,146
Total operating expenses	4,962	4,019	12,324	20,115
GSK
Description of Operations and Summary of Significant Accounting Policies
Net revenue	65,755	61,680	$ 185,045	181,146
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	11,200		$ 11,200
TRC | TRELEGY
Description of Operations and Summary of Significant Accounting Policies
Net revenue	11,200	$ 3,600	28,400	$ 6,900
TRC | Collaborative arrangement
Description of Operations and Summary of Significant Accounting Policies
Related-party receivables	11,200		11,200		$ 6,400
Theravance Biopharma | TRC
Description of Operations and Summary of Significant Accounting Policies
Total operating expenses	$ 2,800		$ 2,900

[1] Condensed consolidated balance sheet as of December 31, 2018 has been derived from audited consolidated financial statements.