Description of Operations and Summary of Significant Accounting Policies (Policies)	3 Months Ended
Mar. 31, 2020
Description of Operations and Summary of Significant Accounting Policies
Basis of Presentation	Basis of Presentation The accompanying unaudited 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 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, 2020 or any other period. The accompanying unaudited 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, 2019 filed with the Securities and Exchange Commission (“SEC”) on February 19, 2020, and as amended on February 21, 2020 (“2019 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 March 31, 2020, and December 31, 2019, $16.1 million and $14.4 million, respectively, of the related party receivables from collaborative arrangements were attributable to TRC. The cash balance attributable to TRC as of March 31, 2020 was $15.3 million. The primary source of revenue for TRC is the royalties generated from the net sales of TRELEGY^® ELLIPTA^® by GSK. Total revenue for TRC related to TRELEGY® ELLIPTA® was $16.1 million and $7.3 million for the three months ended March 31, 2020 and 2019, respectively. Total operating expenses were $0.3 million for the three months ended March 31, 2020, compared to minimal amounts for the same period in 2019.
Equity Investments	Equity Investments We invest from time to time in equity securities of private or public companies. If we determine that we do not have control over these companies under either voting or VIE models, we then determine if we have an ability to exercise significant influence via voting interests, board representation or other business relationships. We may account for the equity investments where we exercise significant influence using either an equity method of accounting or at fair value by electing the fair value option. If the fair value option is applied to an investment that would otherwise be accounted for under the equity method, we apply it to all our financial interests in the same entity (equity and debt, including guarantees) that are eligible items. All gains and losses from fair value changes, unrealized and realized, are presented as changes in fair values of equity investments, net on the consolidated statements of income. If we conclude that we do not have an ability to exercise significant influence over an investee, we may elect to account for an equity security without a readily determinable fair value at its cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer. As of March 31, 2020, we accounted for our equity investments in common stock and warrants of Armata Pharmaceuticals, Inc. (NYSE American: ARMP) (“Armata”) at fair value by electing the fair value option and presented the investments as equity investments on the consolidated balance sheets.
Accounting Pronouncement Adopted by the Company	Accounting Pronouncement Adopted by the Company In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-13 Financial Instruments-Credit Losses: Measurement of Credit Losses on Financial Instruments, as clarified in subsequent amendments to the initial guidance (collectively, Topic 326). Topic 326 requires measurement and recognition of expected credit losses for financial assets held at the reporting date based on historical experience, current conditions and reasonable and supportable forecast. ASC 326 must be adopted using a modified retrospective approach with a cumulative effect adjustment as of the beginning of the reporting period in which the guidance is adopted. Topic 326 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019, with early adoption permitted. We adopted Topic 326 effective January 1, 2020. The adoption did not have a material impact on our consolidated financial statements.

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

3 Months Ended

Mar. 31, 2020

Description of Operations and Summary of Significant Accounting Policies

The accompanying unaudited 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 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, 2020 or any other period.

The accompanying unaudited 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, 2019 filed with the Securities and Exchange Commission (“SEC”) on February 19, 2020, and as amended on February 21, 2020 (“2019 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 March 31, 2020, and December 31, 2019, $16.1 million and $14.4 million, respectively, of the related party receivables from collaborative arrangements were attributable to TRC. The cash balance attributable to TRC as of March 31, 2020 was $15.3 million. The primary source of revenue for TRC is the royalties generated from the net sales of TRELEGY^® ELLIPTA^® by GSK. Total revenue for TRC related to TRELEGY® ELLIPTA® was $16.1 million and $7.3 million for the three months ended March 31, 2020 and 2019, respectively. Total operating expenses were $0.3 million for the three months ended March 31, 2020, compared to minimal amounts for the same period in 2019.

Equity Investments

We invest from time to time in equity securities of private or public companies. If we determine that we do not have control over these companies under either voting or VIE models, we then determine if we have an ability to exercise significant influence via voting interests, board representation or other business relationships. We may account for the equity investments where we exercise significant influence using either an equity method of accounting or at fair value by electing the fair value option. If the fair value option is applied to an investment that would otherwise be accounted for under the equity method, we apply it to all our financial interests in the same entity (equity and debt, including guarantees) that are eligible items. All gains and losses from fair value changes, unrealized and realized, are presented as changes in fair values of equity investments, net on the consolidated statements of income.

If we conclude that we do not have an ability to exercise significant influence over an investee, we may elect to account for an equity security without a readily determinable fair value at its cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer.

As of March 31, 2020, we accounted for our equity investments in common stock and warrants of Armata Pharmaceuticals, Inc. (NYSE American: ARMP) (“Armata”) at fair value by electing the fair value option and presented the investments as equity investments on the consolidated balance sheets.

Accounting Pronouncement Adopted by the Company

In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-13 Financial Instruments-Credit Losses: Measurement of Credit Losses on Financial Instruments, as clarified in subsequent amendments to the initial guidance (collectively, Topic 326). Topic 326 requires measurement and recognition of expected credit losses for financial assets held at the reporting date based on historical experience, current conditions and reasonable and supportable forecast. ASC 326 must be adopted using a modified retrospective approach with a cumulative effect adjustment as of the beginning of the reporting period in which the guidance is adopted. Topic 326 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019, with early adoption permitted. We adopted Topic 326 effective January 1, 2020. The adoption did not have a material impact on our consolidated financial statements.