DESCRIPTION OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Use of Management’s Estimates

The preparation of consolidated financial statements in conformity with U.S. Generally Accepted Accounting Principles (“GAAP”) requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ materially from those estimates. Management evaluates its significant accounting policies and estimates on an ongoing basis. We base our estimates on historical experience and other relevant assumptions that we believe to be reasonable under the circumstances. These estimates also form the basis for making judgments about the carrying values of assets and liabilities when these values are not readily apparent from other sources.

Segment Reporting

We operate in a single segment, which is to provide capital return to stockholders by maximizing the potential value of our respiratory assets partnered with GSK. Revenues are generated from our collaborative arrangements and royalty payments from GSK, located in Great Britain. Our facilities are located within the United States.

Cash and Cash Equivalents

We consider all highly liquid investments purchased with a maturity of three months or less on the date of purchase to be cash equivalents. Cash equivalents are carried at cost, which approximates fair value.

Fair Value of Financial Instruments

We define fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date.

Our valuation techniques are based on observable and unobservable inputs. Observable inputs reflect readily obtainable data from independent sources, while unobservable inputs reflect our market assumptions. We classify these inputs into the following hierarchy:

Level 1—Quoted prices for identical instruments in active markets.

Level 2—Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations whose inputs are observable or whose significant value drivers are observable.

Level 3—Unobservable inputs and little, if any, market activity for the assets.

Financial instruments include cash equivalents, marketable securities, receivables from collaborative arrangements, accounts payable, and accrued liabilities. Cash equivalents and marketable securities are carried at estimated fair value. The carrying values of receivables from collaborative arrangements, accounts payable, and accrued liabilities approximate their estimated fair value due to the relatively short-term nature of these instruments.

Capitalized Fees Paid to a Related Party

We capitalize fees paid to licensors related to agreements for approved products or commercialized products. We capitalize these fees as capitalized fees paid to a related party (“Capitalized Fees”) and amortize these Capitalized Fees on a straight-line basis over their estimated useful lives upon the commercial launch of the product, which has been shortly after regulatory approval of such product. The estimated useful lives of these Capitalized Fees are based on a country-by-country and product-by-product basis, as the later of the expiration or termination of the last patent right covering the compound in such product in such country and 15 years from first commercial sale of such product in such country, unless the Collaboration Agreement is terminated earlier. Consistent with our policy for classification of costs under the research and development collaborative arrangements, the amortization of these Capitalized Fees is recognized as a reduction of royalty revenue. We review our Capitalized Fees for impairment on a product-by-product basis for each major geographic area when events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. The recoverability of Capitalized Fees is measured by comparing the asset’s carrying amount to the expected undiscounted future cash flows that the asset is expected to generate. The determination of recoverability typically requires various estimates and assumptions, including estimating the useful life over which cash flows will occur, their amount, and the asset’s residual value, if any. We derive the required cash flow estimates from near-term forecasted product sales and long-term projected sales in the corresponding market.

Fair Value of Stock-Based Compensation Awards

We use the Black-Scholes-Merton option pricing model to estimate the fair value of options granted under our equity incentive plans and rights to acquire stock granted under our employee stock purchase plan (“ESPP”). The Black-Scholes-Merton option valuation model requires the use of assumptions, including the expected term of the award and the expected stock price volatility. We use the “simplified” method as described in Staff Accounting Bulletin No. 107, “Share-Based Payment,” for the expected option term. We use our historical volatility to estimate expected stock price volatility.

Restricted stock units (“RSUs”) and restricted stock awards (“RSAs”) are measured based on the fair market values of the underlying stock on the dates of grant.

1. DESCRIPTION OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Continued)

Stock-based compensation expense is calculated based on awards ultimately expected to vest and was reduced for estimated forfeitures at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differed from those estimates. Our estimated annual forfeiture rates for stock options, RSUs and RSAs are based on our historical forfeiture experience.

The estimated fair value of stock options, RSUs and RSAs is expensed on a ratable or straight-line basis over the expected term of the grant or expected term of the vesting, and the estimated fair value of performance-contingent RSUs and RSAs is expensed using an accelerated method over the term of the award once we have determined that it is probable that performance milestones will be achieved. Compensation expense for RSUs and RSAs that contain performance conditions is based on the grant date fair value of the award. Compensation expense is recorded over the requisite service period based on management’s best estimate as to whether it is probable that the shares awarded are expected to vest. We assess the probability of the performance milestones being met on a continuous basis. The grant date fair value of the RSUs and RSAs with a market condition is determined using a Monte Carlo valuation model and the compensation expense is recognized over the implied service period.

Compensation expense for purchases under the ESPP is recognized based on the fair value of the common stock on the date of offering, less the purchase discount percentage provided for in the plan.

Comprehensive Income

Comprehensive income is comprised of net income and other comprehensive income (loss). Other comprehensive income (loss) consists of changes in unrealized and realized gains and losses on our marketable securities and the related tax impact of these changes.

Recently Adopted Accounting Standards Updates

In February 2016, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standard Update ASU 2016-02, Leases, which supersedes the lease recognition requirements in ASC Topic 840, Leases. The standard requires an entity to recognize right-of-use assets and lease liabilities arising from a lease for both financing and operating leases in the consolidated balance sheets but recognize the impact on the consolidated statement of operations and cash flows in a similar manner under previous GAAP. The

1. DESCRIPTION OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Continued)

standard also requires additional qualitative and quantitative disclosures. We adopted the standard in 2019 and recognized a right-of-use asset and lease liabilities in the amount of $0.3 million, respectively, for the operating lease on our current corporate headquarters at December 31, 2019.

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 this rule and added a Consolidated Statement of Changes in Stockholders’ Equity (Deficit) in its Form 10-Qs filed during the year ended December 31, 2019, which presented a reconciliation in a single statement showing the changes in stockholders equity for each interim period, as well as each comparable period.