Description of Operations and Summary of Significant Accounting Policies (Policies)	6 Months Ended
Jun. 30, 2019
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“US GAAP”) for interim financial information. Accordingly, they do not include all of the information and notes required by US GAAP for complete financial statements. In our opinion, the unaudited condensed consolidated financial statements have been prepared on the same basis as audited consolidated financial statements and include all adjustments, consisting of only normal recurring adjustments, necessary for the fair presentation of our financial position, results of operations, comprehensive income and cash flows. The interim results are not necessarily indicative of the results of operations to be expected for the year ending December 31, 2019 or any other period. The accompanying unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2018 filed with the Securities and Exchange Commission (“SEC”) on February 19, 2019 (“2018 Form 10-K”).
Variable Interest Entity	Variable Interest Entity We evaluate our ownership, contractual and other interest in entities to determine if they are variable interest entities (“VIE”), whether we have a variable interest in those entities and the nature and extent of those interests. Based on our evaluation, if we determine we are the primary beneficiary of a VIE, we consolidate the entity into our financial statements. We consolidate the financial results of TRC, which we have determined to be a VIE, because we have the power to direct the economically significant activities of TRC and the obligation to absorb losses of, or the right to receive benefits from, TRC. As of June 30, 2019 and December 31, 2018, $9.8 million and $6.4 million, respectively, of the related party receivables from collaborative arrangements were attributable to TRC. The cash balance attributable to TRC as of June 30, 2019 was $13.8 million. Total revenue for TRC related to TRELEGY® ELLIPTA® was $9.8 million and $2.4 million for the three months ended June 30, 2019 and 2018, respectively, and $17.2 million and $3.3 million for the six months ended June 30, 2019 and 2018, respectively.
Accounting Pronouncement Adopted by the Company	Accounting Pronouncement Adopted by the Company In February 2016, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) 2016 02, Leases (Topic 842), which requires an entity to recognize right of use assets representing its right to use the underlying asset for the lease term and lease liabilities representing the present value of the future lease payments for both financing and operating leases on its consolidated balance sheets. For a lease with a term of 12 months or less, the standard allows an entity to elect not to recognize a right-of-use asset and a lease liability and recognize the lease expense on a straight-line basis. We adopted the standard on the effective date of January 1, 2019 using the alternative transition approach. This approach is similar to a prospective transition, which requires the application of ASC 842 at the effective date with a cumulative-effect adjustment recognized through retained earnings. Under this approach, we do not present the adjusted comparative periods. Our pro-rata share of common area expenses are recorded as lease expense when incurred since they are variable and considered nonlease components under the standard. The most significant impact of the adoption to us is that we recognized a right of use asset in the amount of $1.5 million and lease liabilities in the total amount of $1.6 million at January 1, 2019 for the operating lease on our corporate headquarters. The adoption did not have a material impact on our retained earnings and consolidated statements of operations and cash flows. In August 2018, the U.S. Securities and Exchange Commission (the “SEC”) adopted the final rule under SEC Release No. 33-10532, Disclosure Update and Simplification, amending certain disclosure requirements that were redundant, duplicative, overlapping, outdated or superseded. In addition, the amendments expanded the disclosure requirements relating to the analysis of stockholders’ equity for interim financial statements. Under the amendments, an analysis of changes in each caption of stockholders’ equity presented in the balance sheet must be provided in a note or separate statement. The analysis should present a reconciliation of the beginning balance to the ending balance of each period for which a statement of income is required to be filed. This final rule is effective on November 5, 2018. Effective January 1, 2019, the Company adopted SEC Release No. 33-10532. In accordance with the new guidance, the Company has added a Condensed Consolidated Statement of Changes in Stockholders’ Equity (Deficit) in its Form 10-Q and elected to present a reconciliation in a single statement that shows the changes in stockholders equity for each interim period, as well as each comparable period.

Description of Operations and Summary of Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2019

The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“US GAAP”) for interim financial information. Accordingly, they do not include all of the information and notes required by US GAAP for complete financial statements. In our opinion, the unaudited condensed consolidated financial statements have been prepared on the same basis as audited consolidated financial statements and include all adjustments, consisting of only normal recurring adjustments, necessary for the fair presentation of our financial position, results of operations, comprehensive income and cash flows. The interim results are not necessarily indicative of the results of operations to be expected for the year ending December 31, 2019 or any other period.

The accompanying unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2018 filed with the Securities and Exchange Commission (“SEC”) on February 19, 2019 (“2018 Form 10-K”).

Variable Interest Entity

We evaluate our ownership, contractual and other interest in entities to determine if they are variable interest entities (“VIE”), whether we have a variable interest in those entities and the nature and extent of those interests. Based on our evaluation, if we determine we are the primary beneficiary of a VIE, we consolidate the entity into our financial statements. We consolidate the financial results of TRC, which we have determined to be a VIE, because we have the power to direct the economically significant activities of TRC and the obligation to absorb losses of, or the right to receive benefits from, TRC. As of June 30, 2019 and December 31, 2018, $9.8 million and $6.4 million, respectively, of the related party receivables from collaborative arrangements were attributable to TRC. The cash balance attributable to TRC as of June 30, 2019 was $13.8 million. Total revenue for TRC related to TRELEGY® ELLIPTA® was $9.8 million and $2.4 million for the three months ended June 30, 2019 and 2018, respectively, and $17.2 million and $3.3 million for the six months ended June 30, 2019 and 2018, respectively.

Accounting Pronouncement Adopted by the Company

In February 2016, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) 2016 02, Leases (Topic 842), which requires an entity to recognize right of use assets representing its

right to use the underlying asset for the lease term and lease liabilities representing the present value of the future lease payments for both financing and operating leases on its consolidated balance sheets. For a lease with a term of 12 months or less, the standard allows an entity to elect not to recognize a right-of-use asset and a lease liability and recognize the lease expense on a straight-line basis. We adopted the standard on the effective date of January 1, 2019 using the alternative transition approach. This approach is similar to a prospective transition, which requires the application of ASC 842 at the effective date with a cumulative-effect adjustment recognized through retained earnings. Under this approach, we do not present the adjusted comparative periods. Our pro-rata share of common area expenses are recorded as lease expense when incurred since they are variable and considered nonlease components under the standard. The most significant impact of the adoption to us is that we recognized a right of use asset in the amount of $1.5 million and lease liabilities in the total amount of $1.6 million at January 1, 2019 for the operating lease on our corporate headquarters. The adoption did not have a material impact on our retained earnings and consolidated statements of operations and cash flows.

In August 2018, the U.S. Securities and Exchange Commission (the “SEC”) adopted the final rule under SEC Release No. 33-10532, Disclosure Update and Simplification, amending certain disclosure requirements that were redundant, duplicative, overlapping, outdated or superseded. In addition, the amendments expanded the disclosure requirements relating to the analysis of stockholders’ equity for interim financial statements. Under the amendments, an analysis of changes in each caption of stockholders’ equity presented in the balance sheet must be provided in a note or separate statement. The analysis should present a reconciliation of the beginning balance to the ending balance of each period for which a statement of income is required to be filed. This final rule is effective on November 5, 2018. Effective January 1, 2019, the Company adopted SEC Release No. 33-10532. In accordance with the new guidance, the Company has added a Condensed Consolidated Statement of Changes in Stockholders’ Equity (Deficit) in its Form 10-Q and elected to present a reconciliation in a single statement that shows the changes in stockholders equity for each interim period, as well as each comparable period.