2.	Summary of Significant Accounting Policies

Use of Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States (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 from these estimates.

Concentration of Credit Risk

The Company invests in a variety of financial instruments and, by its policy, limits the amount of credit exposure with any one issuer, industry or geographic area.

Accounts receivable are typically unsecured and are concentrated in the pharmaceutical industry and government sector. Accordingly, the Company may be exposed to credit risk generally associated with pharmaceutical companies and government funded entities. The Company has not historically experienced any significant losses due to concentration of credit risk.

Accounts receivable consists of the following (in thousands):


	March 31, 2018		December 31, 2017
Vifor ⁽¹⁾	$	1,698	$	51,090

(1)

Accounts receivable at March 31, 2018 and December 31, 2017 included $1.6 million and $1.1 million, respectively, of unbilled receivables related to development costs to be reimbursed by Vifor (International) Ltd., and/or its affiliates (collectively, Vifor) under the agreement relating to CCX140, which we refer to as the CCX140 Agreement. As of December 31, 2017, accounts receivable excluded the $10.0 million cash commitment received from Vifor in February 2018 in connection with the agreement that harmonized the geographic commercialization rights underlying the agreements for both avacopan and CCX140 drug candidates, which we refer to as the Avacopan Amendment. See “Note 8. Collaboration and License Agreements” for a detailed discussion.

Net Loss Per Share

Basic net loss per common share is computed by dividing net loss attributable to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration for common stock equivalents.

Diluted net loss per share is computed by dividing net loss attributable to common stockholders by the sum of the weighted-average number of common shares outstanding and dilutive common stock equivalent shares outstanding for the period. The Company’s potentially dilutive common stock equivalent shares, which include incremental common shares issuable upon (i) the exercise of outstanding stock options and warrants, (ii) vesting of restricted stock units (RSUs) and restricted stock awards (RSAs), and (iii) the purchase from contributions to the 2012 Employee Stock Purchase Plan (the ESPP), (calculated based on the treasury stock method), are only included in the calculation of diluted net loss per share when their effect is dilutive.

For the three months ended March 31, 2018 and 2017, the following potentially dilutive securities were excluded from the calculation of diluted net loss per share due to their anti-dilutive effect:


	Three Months Ended
	March 31,
	2018		2017
Options to purchase common stock, including purchases from contributions to ESPP		11,824,877		10,646,551
Restricted stock units		459,682		565,345
Restricted stock awards		85,431		31,306
Warrants to purchase common stock		150,000		150,000

		12,519,990		11,393,202

Comprehensive Loss

Comprehensive loss comprises net loss and other comprehensive loss. For the periods presented other comprehensive loss consists of unrealized losses on the Company’s available-for-sale securities. For the three months ended March 31, 2018 and 2017, there were no sales of investments, and therefore there were no reclassifications.

Revenue Recognition

Effective January 1, 2018, the Company adopted Accounting Standards Codification (ASC) Topic 606, Revenue from Contracts with Customers (ASC 606) using the modified retrospective transition method. This standard applies to all contracts with customers, except for contracts that are within the scope of other standards, such as leases, insurance, collaboration arrangements and financial instruments. Under ASC 606, the Company recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the Company expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that the Company determines are within the scope of ASC 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the Company satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that Company will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied.

The Company enters into corporate collaborations under which it may obtain upfront license fees, research and development funding and development and regulatory and commercial milestone payments and royalty payments. The Company’s performance obligations under these arrangements may include licenses of intellectual property, distribution rights, research and development services, delivery of manufactured product, and/or participation on joint steering committees.

Licenses of intellectual property: If the license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenue from upfront license fees allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgement to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring proportional performance for purposes of recognizing revenue from non-refundable, up-front fees. The Company evaluates the measure of proportional performance each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition.

Milestone payments: At the inception of each arrangement that includes development, regulatory or commercial milestone payments, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price. ASC 606 suggests two alternatives to use when estimating the amount of variable consideration: the expected value method and the most likely amount method. Under the expected value method, an entity considers the sum of probability-weighted amounts in a range of possible consideration amounts. Under the most likely amount method, an entity considers the single most likely amount in a range of possible consideration amounts. Whichever method is used, it should be consistently applied throughout the life of the contract; however, it is not necessary for the Company to use the same approach for all contracts. The Company expects to use the most likely amount method for development and regulatory milestone payments. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s or the licensee’s control, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. The transaction price is then allocated to each performance obligation on a relative stand-alone selling price basis. The Company recognizes revenue as or when the performance obligations under the contract are satisfied. At the end of each subsequent reporting period, the Company re-evaluates the probability or achievement of each such milestone and any related constraint, and if necessary, adjusts its estimates of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment.

Commercial milestones and royalties: For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and in which the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue when the related sales occur. To date, the Company has not recognized any royalty revenue resulting from its collaboration arrangements.

Up-front payments and fees are recorded as deferred revenue upon receipt or when due, and may require deferral of revenue recognition to a future period until the Company performs its obligations under these arrangements. Amounts payable to the Company are recorded as accounts receivable when the Company’s right to consideration is unconditional.

Upon adoption of ASC 606 under the modified retrospective transition method, the Company recognized the cumulative effect of initially applying the new revenue standard of $47.3 million as an adjustment to the opening balance of accumulated deficit and an increase in deferred revenue. The comparative information has not been restated and continues to be reported under the accounting standards in effect for those periods. Before the adoption of ASC 606, the Company recognized upfront fees straight-line under ASC 605 over the estimated performance period and recognized milestones when earned under the milestone method of accounting. See “Note 2. Summary of Significant Accounting Policies – Revenue Recognition” in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2017, filed with the SEC on March 12, 2018 for a detailed discussion.

The impact of adoption on the Company’s consolidated statement of operations and balance sheet was as follows (in thousands):


	For the Three Months Ended March 31, 2018
	As Reported			Balances Without Adoption of ASC606			Effect of Change
Statement of Operations
Collaboration and license revenue	$	9,546		$	4,364		$	5,182
Loss from operations		(9,856	)		(15,038	)		5,182
Net loss		(9,417	)		(14,599	)		5,182

	March 31, 2018
	As Reported			Balances Without Adoption of ASC606			Effect of Change
Balance Sheet
Liabilities:
Deferred revenue	$	68,997		$	15,023		$	53,974
Noncurrent deferred revenue		74,554			86,379			(11,825	)

Stockholders’ equity:
Accumulated deficit		(345,948	)		(303,799	)		(42,149	)

Recent Accounting Pronouncements

On December 22, 2017, the Tax Cuts and Jobs Act (“the Act”) was enacted into law. Accounting Standards Codification (ASC) 740, Income Taxes, requires companies to recognize the effect of the tax law changes in the period of enactment. Shortly after the enactment of the Act, the SEC staff issued Staff Accounting Bulletin No. 118 (SAB 118) to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Act. The Company has adjusted its deferred tax assets and liabilities based on the reduction of the U.S. federal corporate tax rate from 34% to 21% and assessed the realizability of its deferred tax assets based on its current understanding of the provisions of the new law. The Company considers its accounting for the impacts of the new law to be provisional and the Company will continue to assess the impact of the recently enacted tax law (and expected further guidance from federal and state tax authorities as well as further guidance for the associated income tax accounting) on its business and consolidated financial statements for the remainder of 2018. No adjustments were made to the provisional estimate during the three months ended March 31, 2018.

In February 2016, the Financial Accounting Standard Board issued Accounting Standards Update No. 2016-12, Leases (Topic 842). The new standard requires all lessees recognize the assets and liabilities that arise from leases on the balance sheet and disclose qualitative and quantitative information about its leasing arrangements. The new standard will be effective for the Company on January 1, 2019. The Company is currently evaluating the impact of the adoption of this standard on its financial statements. However, the Company expects the adoption of this accounting guidance to result in an increase in lease assets and a corresponding increase in lease liabilities on its balance sheets.

The Company has reviewed other recent accounting pronouncements and concluded they are either not applicable to the business or that no material effect is expected on the consolidated financial statements as a result of future adoption.