Basis of Presentation and Summary of Significant Accounting Policies | NOTE 2 – BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation The accompanying unaudited condensed consolidated financial statements were prepared in accordance with U.S. generally accepted accounting principles, or GAAP, for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they may not include all of the information and footnotes required by GAAP for complete financial statements. All adjustments that are, in the opinion of management, of a normal recurring nature and are necessary for a fair presentation of these interim financial statements have been included. These interim financial statements should be read in conjunction with the audited consolidated financial statements contained in our Annual Report on Form 10-K for the year ended December 31, 2015. The results of operations for the three and six months ended June 30, 2016, are not necessarily indicative of the results that may be expected for the entire fiscal year or any other interim period. Principles of Consolidation The condensed consolidated financial statements include our financial statements and those of our wholly-owned subsidiaries. Intercompany transactions and balances have been eliminated in consolidation. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and judgments that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of these condensed consolidated financial statements and the reported amounts of revenues and expenses during the applicable reporting period. Actual results could differ from those estimates. Such differences could be material to these condensed consolidated financial statements. Cash and Cash Equivalents We consider liquid investments with original maturities of three months or less when purchased to be cash and cash equivalents. At June 30, 2016 and December 31, 2015, all of our cash and cash equivalents were held in either commercial bank accounts or money market funds. Inventory Inventory is stated at the lower of cost or estimated realizable value. We determine the cost of our inventory, which includes amounts related to materials, third-party contract manufacturing and packaging services, and manufacturing overhead, on a first-in, first-out basis. We capitalize inventory costs at our suppliers when, based on management’s judgment, the realization of future economic benefit is probable at each given supplier. We received FDA approval for Auryxia on September 5, 2014, and on that date began capitalizing inventory purchases of saleable product from certain suppliers. Prior to FDA approval, all saleable product purchased from such suppliers was included as a component of research and development expense. Accounts Receivable, Net We extend credit to our customers for U.S. Auryxia product sales resulting in accounts receivable. Customer accounts are monitored for past due amounts. Past due accounts receivable, determined to be uncollectible, are written off against the allowance for doubtful accounts. Allowances for doubtful accounts are estimated based upon past due amounts, historical losses and existing economic factors, and are adjusted periodically. We offer cash discounts to certain of our customers, generally 2% of the sales price, as an incentive for prompt payment. The estimate of cash discounts is recorded at the time of sale. We account for the cash discounts by reducing revenue and accounts receivable by the amount of the discounts we expect our customers to take. The accounts receivable are reported in the condensed consolidated balance sheets, net of the allowances for doubtful accounts and cash discounts. There was no allowance for doubtful accounts at June 30, 2016 and December 31, 2015. Revenue Recognition Our commercial launch of our only product, Auryxia, in the United States occurred in late December 2014. We sell product to a limited number of major wholesalers, our Distributors, as well as certain pharmacies, or collectively, our Customers. Our Distributors resell the product to retail pharmacies for purposes of the pharmacies reselling the product to fill patient prescriptions. In accordance with GAAP, our revenue recognition policy requires that: (i) there is persuasive evidence that an arrangement exists between us and the Customer, (ii) delivery has occurred, (iii) collectability is reasonably assured, and (iv) the price is fixed or determinable. Until we have the ability to reliably estimate returns of Auryxia from our Customers, revenue will be recognized based on the resale of Auryxia for the purposes of filling patient prescriptions, and not based on initial sales from us to our Customers. Consistent with industry practice, once we can reliably estimate returns based on sales to our Customers, we anticipate that our revenues will be recognized based on sales to our Customers. We currently defer Auryxia revenue recognition until the earlier of the product being resold for purposes of filling patient prescriptions and the expiration of the right of return (twelve months after the expiration date of the product). The deferred revenue is recorded net of discounts, rebates, and chargebacks. We also defer the related cost of product sales and record such amounts as finished goods inventory held by others, which is included in inventory on our condensed consolidated balance sheets, until revenue related to such product sales is recognized. We have written contracts with our Customers and delivery occurs when a Customer receives Auryxia. We evaluate the creditworthiness of each of our Customers to determine whether revenues can be recognized upon delivery, subject to satisfaction of the other requirements, or whether recognition is required to be delayed until receipt of payment. In order to conclude that the price is fixed or determinable, we must be able to (i) calculate our gross product sales from the sales to Customers and (ii) reasonably estimate our net product sales. We calculate gross product sales based on the wholesale acquisition cost that we charge our Customers for Auryxia. We estimate our net product sales by deducting from our gross product sales (a) trade allowances, such as invoice discounts for prompt payment and distributor fees, (b) estimated government and private payor rebates, chargebacks and discounts, such as Medicaid reimbursements, (c) reserves for expected product returns, upon our ultimate transition to a sell-in revenue recognition model and (d) estimated costs of incentives offered to certain indirect customers, including patients. Trade Allowances: Rebates, Chargebacks and Discounts: Product Returns: Other Incentives: Our U.S. Auryxia product sales for the three and six months ended June 30, 2016 and 2015 were offset by provisions for allowances and accruals as set forth in the tables below. (in thousands) Three months ended Percent of gross product sales Three months ended June 30, 2015 Percent of gross product sales Gross Auryxia product sales $ 12,561 $ 3,097 Less provision for product sales allowances and accruals Trade allowances 1,555 12% 348 11% Rebates, chargebacks and discounts 2,543 20% 140 5% Product returns — — — — Other incentives (1) 184 2% 851 27% Total 4,282 34% 1,339 43% Net U.S. Auryxia product sales $ 8,279 $ 1,758 (1) Includes co-pay mitigation and voucher rebates. (in thousands) Six months ended June 30, 2016 Percent of gross product sales Six months ended June 30, 2015 Percent of gross product sales Gross Auryxia product sales $ 21,185 $ 4,061 Less provision for product sales allowances and accruals Trade allowances 2,701 13% 448 11% Rebates, chargebacks and discounts 4,221 20% 170 4% Product returns — — — — Other incentives (1) 368 1% 1,263 31% Total 7,290 34% 1,881 46% Net U.S. Auryxia product sales $ 13,895 $ 2,180 (1) Includes co-pay mitigation and voucher rebates. The following table summarizes U.S. Auryxia product sales recognized and deferred during the three and six months ended June 30, 2016 and 2015. Three months ended June 30, Six months ended June 30, (in thousands) 2016 2015 2016 2015 Net U.S. Auryxia sales recognized $ 8,279 $ 1,758 $ 13,895 $ 2,180 Change in deferred product sales (360 ) 815 (168 ) 1,529 $ 7,919 $ 2,573 $ 13,727 $ 3,709 We recognize license revenue in accordance with Accounting Standards Codification 605, Revenue Recognition For arrangements for which royalty revenue information becomes available and collectability is reasonably assured, we recognize revenue during the applicable period earned. When collectability is reasonably assured but a reasonable estimate of royalty revenue cannot be made, the royalty revenue is recognized in the quarter that the licensee provides the written report and related information to us. Cost of Goods Sold Cost of goods sold includes the cost of API for Auryxia on which product sales were recognized during the period, as well as the associated costs for tableting, packaging, shipment, insurance and quality assurance. Cost of goods sold also includes expenses due to the licensor of Auryxia related to the manufacturing of product and product sales recognized during the period. In conjunction with our recognition and deferral of U.S. Auryxia product sales, we expensed and capitalized the associated cost of goods, as follows, during the three and six months ended June 30, 2016 and 2015: Three months ended June 30, Six months ended June 30, (in thousands) 2016 2015 2016 2015 Cost of goods sold expensed $ 5,099 $ 304 $ 6,170 $ 380 Change in finished goods inventory held by others 430 27 1,003 134 $ 5,529 $ 331 $ 7,173 $ 514 Finished goods inventory held by others as of June 30, 2016 and 2015 represents the cost of goods sold that has been deferred to align with our deferral of net U.S. Auryxia product sales. License Expenses License expenses include royalty and other expenses due to the licensor of Auryxia related to our license agreement with JT and Torii. With regard to royalty expense, such expense is directly related to the royalty revenue received from JT and Torii and is recognized in the same period as the revenue is recorded. Other expenses are recognized in the period they are incurred. Research and Development Costs Research and development costs are expensed as incurred. Pre-approval inventory expenditures are recorded as research and development expense as incurred. The capitalization of inventory for our product candidate(s) commence when it is probable that the product will be approved for commercial marketing. Non-refundable advance payments for goods or services that will be used or rendered for future research and development activities are deferred and amortized over the period that the goods are delivered or the related services are performed, subject to an assessment of recoverability. We make estimates of costs incurred in relation to external clinical research organizations, or CROs, and clinical site costs. We analyze the progress of clinical trials, including levels of patient enrollment, invoices received and contracted costs when evaluating the adequacy of the amount expensed and the related prepaid asset and accrued liability. Significant judgments and estimates must be made and used in determining the accrued balance and expense in any accounting period. We review and accrue CRO expenses and clinical trial study expenses based on work performed and rely upon estimates of those costs applicable to the stage of completion of a study. Accrued CRO costs are subject to revisions as such trials progress to completion. Revisions are charged to expense in the period in which the facts that give rise to the revision become known. With respect to clinical site costs, the financial terms of these agreements are subject to negotiation and vary from contract to contract. Payments under these contracts may be uneven, and depend on factors such as the achievement of certain events, the successful recruitment of patients, the completion of portions of the clinical trial or similar conditions. The objective of our policy is to match the recording of expenses in our condensed consolidated financial statements to the actual services received and efforts expended. As such, expense accruals related to clinical site costs are recognized based on our estimate of the degree of completion of the event or events specified in the specific clinical study or trial contract. Stock-Based Compensation We recognize all share-based payments to employees and to non-employee directors for service on our Board of Directors as compensation expense in the condensed consolidated financial statements based on the grant date fair values of the awards. Stock-based compensation expense recognized each period is based on the value of the portion of awards that is ultimately expected to vest. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. For share-based payments to consultants and other third-parties, compensation expense is determined at the “measurement date.” The expense is recognized over the vesting period of the award. Until the measurement date is reached, the total amount of compensation expense remains uncertain. We record compensation expense based on the fair value of the award at the reporting date. The awards to consultants and other third-parties are then revalued, or the total compensation is recalculated based on the then current fair value, at each subsequent reporting date. Basic and Diluted Net Loss Per Common Share Basic net loss per share is computed by dividing the losses allocable to common stockholders by the weighted average number of shares of common stock outstanding for the period. Diluted net loss per share does not reflect the effect of shares of common stock to be issued upon the exercise of stock options and warrants, as their inclusion would be anti-dilutive. The options outstanding as of June 30, 2016 and 2015, which are not included in the computation of net loss per share amounts, were 8,869,094 and 5,306,869, respectively. No warrants were outstanding during each of these periods. Acquisitions We account for acquired businesses using the acquisition method of accounting, which requires that assets acquired and liabilities assumed be recognized at their estimated fair values as of the acquisition date. Acquisition-related costs are expensed as incurred. Any excess of the consideration transferred over the estimated fair values of the identifiable net assets acquired is recorded as goodwill. Impairment Long-lived assets are reviewed for an impairment loss when circumstances indicate that the carrying value of long-lived tangible and intangible assets with finite lives may not be recoverable. Management’s policy in determining whether an impairment indicator exists, a triggering event, comprises measurable operating performance criteria as well as qualitative measures. If an analysis is necessitated by the occurrence of a triggering event, we make certain assumptions in determining the impairment amount. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to future undiscounted cash flows expected to be generated by the asset or used in its disposal. If the carrying amount of an asset exceeds its estimated future undiscounted cash flows, an impairment charge is recognized. Goodwill is reviewed for impairment annually, or when events arise that could indicate that an impairment exists. We test for goodwill impairment using a two-step process. The first step compares the fair value of the reporting unit with the unit’s carrying value, including goodwill. When the carrying value of the reporting unit is greater than fair value, the unit’s goodwill may be impaired, and the second step must be completed to measure the amount of the goodwill impairment charge, if any. In the second step, the implied fair value of the reporting unit’s goodwill is compared with the carrying amount of the unit’s goodwill. If the carrying amount is greater than the implied fair value, the carrying value of the goodwill must be written down to its implied fair value. As of December 31, 2015, management concluded that there was no impairment of our goodwill. We will continue to perform impairment tests annually, and whenever events or changes in circumstances suggest that the carrying value of an asset may not be recoverable. For the period ending June 30, 2016, management determined that there were no impairment indicators that would trigger a goodwill impairment analysis. Concentrations of Credit Risk We do not have significant off-balance-sheet risk or credit risk concentrations. We maintain our cash and cash equivalents and held-to-maturity investments, when applicable, with multiple financial institutions that invest in investment-grade securities with average maturities of less than twelve months. See Note 3 – Fair Value Measurements. Our accounts receivable, net at June 30, 2016 and December 31, 2015 represent amounts due to the Company from customers. We perform ongoing credit evaluations of our customers and generally do not require collateral. The following table sets forth customers who represented 10% or more of our total accounts receivable, net as of June 30, 2016 and December 31, 2015: June 30, 2016 December 31, 2015 Fresenius Medical Care Rx 27 % 15 % Davita Rx 20 % 19 % McKesson Corporation 19 % 23 % AmerisourceBergen Drug Corporation 16 % 17 % Cardinal Health, Inc. 16 % 24 % We currently depend on a single supply source for Auryxia drug product. On August 1, 2016, we announced that an interruption in the supply of Auryxia tablets is imminent due to a production-related issue at this supplier of Auryxia. We expect to make Auryxia available to patients when supply of Auryxia is back to adequate levels, which we anticipate will be during the fourth quarter of 2016. As a result of this supply interruption, we expect revenues to decline significantly for at least the remainder of 2016. In addition, if any of our other suppliers were to limit or terminate production, or otherwise fail to meet the quality or delivery requirements needed to supply Auryxia at adequate levels, we could experience additional losses of revenue, which could materially and adversely impact our results of operations. Leases In April 2015, we signed a lease agreement for approximately 27,300 square feet in Boston, Massachusetts, for a 94-month term that commenced on May 1, 2015. In order to make the space usable for our operations, substantial improvements were made. Our landlord agreed to pay for up to approximately $1.9 million of the improvements, and we bore all additional costs that were incurred. As such, we have determined that we are the owner of the improvements and account for tenant improvements paid by our landlord as a lease incentive. On May 1, 2015, in accordance with ASC 840-20, Operating Leases The lease for our New York City office will expire on September 30, 2016 and we have notified our landlord that we will not renew our lease. Recently Issued and Proposed Accounting Pronouncements In May 2014, the Financial Accounting Standards Board, or the FASB, issued Accounting Standards Update, or ASU, No. 2014-09, Revenue from Contracts with Customers (Topic 606) Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients In February 2016, the FASB issued ASU No. 2016-02, Leases In March 2016, the FASB issued ASU No. 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting |