Significant Accounting Policies

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Management considers many factors in selecting appropriate financial accounting policies and controls, and in developing the estimates and assumptions that are used in the preparation of these financial statements. Management must apply significant judgment in this process. In addition, other factors may affect estimates, including: expected business and operational changes, sensitivity and volatility associated with the assumptions used in developing estimates, and whether historical trends are expected to be representative of future trends. The estimation process often may yield a range of potentially reasonable estimates of the ultimate future outcomes and management must select an amount that falls within that range of reasonable estimates. This process may result in actual results differing materially from those estimated amounts used in the preparation of the financial statements. Estimates are used in the following areas, among others: stock-based compensation expense, fair value of warrants to purchase common stock, fair value of embedded derivatives on the Company’s long-term debt, revenue recognition and accrued expenses. Actual results could differ from those estimates.

Revenue Recognition

To date, the Company’s revenue has been primarily from the collaboration and license agreement with ThromboGenics (See Note 3) and, to a lesser extent, from a license agreement.

The Company recognizes revenue in accordance with Accounting Standards Codification (“ASC”) 605, Revenue Recognition (“ASC 605”). Accordingly, revenue is recognized for each unit of accounting when all of the following criteria are met:


•	Persuasive evidence of an arrangement exists;


•	Delivery has occurred or services have been rendered;


•	The seller’s price to the buyer is fixed or determinable; and


•	Collectability is reasonably assured.

Amounts received prior to satisfying the revenue recognition criteria are recorded as deferred revenue. Amounts expected to be recognized as revenue within the twelve months following the balance sheet date are classified in current liabilities. Amounts not expected to be recognized as revenue within the twelve months following the balance sheet date are classified as deferred revenue, net of current portion.

The Company evaluates multiple-element arrangements based on the guidance in ASC Topic 605-25, Revenue Recognition-Multiple-Element Arrangements (“ASC 605-25”). Pursuant to the guidance in ASC 605-25, the Company evaluates multiple-element arrangements to determine (1) the deliverables included in the arrangement and (2) whether the individual deliverables represent separate units of accounting or whether they must be accounted for as a combined unit of accounting. This evaluation involves subjective determinations and requires the Company to make judgments about the individual deliverables and whether such deliverables are separable from the other aspects of the contractual relationship. Deliverables are considered separate units of accounting provided that the delivered item has value to the customer on a standalone basis and, if the arrangement includes a general right of return relative to the delivered item, delivery or performance of the undelivered item is considered probable and substantially in the Company’s control. In assessing whether an item has standalone value, the Company considers factors such as the research, development, manufacturing and commercialization capabilities of the collaboration partner and the availability of the associated expertise in the general marketplace. In addition, the Company considers whether the collaboration partner can use a deliverable for its intended purpose without the receipt of the remaining deliverable, whether the value of the deliverable is dependent on the undelivered item and whether there are other vendors that can provide the undelivered items. The consideration received under the arrangement that is fixed or determinable is then allocated among the separate units of accounting using the relative selling price method. The Company determines the estimated selling price for units of accounting within each arrangement using vendor-specific objective evidence (“VSOE”) of selling price, if available, third-party evidence (“TPE”) of selling price if VSOE is not available, or best estimate of selling price (“BESP”) if neither VSOE nor TPE is available. Determining the BESP for a unit of accounting requires significant judgment. In developing the BESP for a unit of accounting, the Company considers applicable market conditions and relevant entity-specific factors, including factors that were contemplated in negotiating the agreement with the customer and estimated costs. The Company validates the BESP for units of accounting by evaluating whether changes in the key assumptions used to determine the BESP will have a significant effect on the allocation of arrangement consideration between multiple units of accounting.

The Company recognizes arrangement consideration allocated to each unit of accounting when all of the revenue recognition criteria in ASC 605 are satisfied for that particular unit of accounting. In the event that a deliverable does not represent a separate unit of accounting, the Company recognizes revenue from the combined unit of accounting over the Company’s contractual or estimated performance period for the undelivered elements, which is typically the term of the Company’s research and development obligations. If there is no discernible pattern of performance or objectively measurable performance measures do not exist, then the Company recognizes revenue under the arrangement on a straight-line basis over the period the Company is expected to complete its performance obligations. Conversely, if the pattern of performance in which the service is provided to the customer can be determined and objectively measurable performance measures exist, then the Company recognizes revenue under the arrangement using the proportional performance method. Revenue recognized is limited to the lesser of the cumulative amount of payments received or the cumulative amount of revenue earned, as determined using the straight-line method or proportional performance method, as applicable, as of the period ending date.

At the inception of an arrangement that includes milestone payments, the Company evaluates whether each milestone is substantive and at risk to both parties on the basis of the contingent nature of the milestone. This evaluation includes an assessment of whether: (1) the consideration is commensurate with either the Company’s performance to achieve the milestone or the enhancement of the value of the delivered item(s) as a result of a specific outcome resulting from its performance to achieve the milestone, (2) the consideration relates solely to past performance and (3) the consideration is reasonable relative to all of the deliverables and payment terms within the arrangement. The Company evaluates factors such as the scientific, clinical, regulatory, commercial and other risks that must be overcome to achieve the particular milestone and the level of effort and investment required to achieve the particular milestone in making this assessment. There is considerable judgment involved in determining whether a milestone satisfies all of the criteria required to conclude that a milestone is substantive. Milestones that are not considered substantive are recognized as earned if there are no remaining performance obligations or over the remaining period of performance, assuming all other revenue recognition criteria are met.

Research and Development Costs

Expenditures relating to research and development are expensed in the period incurred. Research and development expenses consist of both internal and external costs associated with the development of the Company’s proprietary protein engineering platform called AMP-Rx and its protein-based therapeutics, including isunakinra and EBI-031. The research and development costs include personnel-related costs, stock-based compensation, facilities, research-related overhead, clinical trial costs, manufacturing costs and other contracted services, license fees, and other external costs.

In certain circumstances, the Company is required to make advance payments to vendors for goods or services that will be received in the future for use in research and development activities. In such circumstances, the advance payments are deferred and are expensed when the activity has been performed or when the goods have been received.

Stock-Based Compensation

The Company accounts for its stock-based compensation awards in accordance with ASC Topic 718, Compensation—Stock Compensation (“ASC 718”). ASC 718 requires all stock-based payments to employees and directors, including grants of employee stock options, to be recognized as expense in the statements of operations based on their grant date fair values. For stock options granted to employees and to members of the Board of Directors for their services on the Board of Directors, the Company estimates the grant date fair value of each option award using the Black-Scholes option-pricing model. The use of the Black-Scholes option-pricing model requires management to make assumptions with respect to the expected term of the option, the expected volatility of the common stock consistent with the expected life of the option, risk-free interest rates and expected dividend yields of the common stock. For awards subject to service-based vesting conditions, the Company recognizes stock-based compensation expense, net of estimated forfeitures, equal to the grant date fair value of stock options on a straight-line basis over the requisite service period. For awards subject to both performance and service-based vesting conditions, the Company recognizes stock-based compensation expense using an accelerated recognition method.

The Company expenses restricted stock awards and restricted stock units to employees and directors based on the fair value of the award on a straight-line basis over the associated service period of the award. Awards of restricted stock to non-employees are adjusted through stock-based compensation expense at each reporting period end to reflect the current fair value of such awards and expensed on a straight-line basis.

The Company records the expense for stock option grants subject to performance-based milestone vesting using the accelerated attribution method over the remaining service period when management determines that achievement of the milestone is probable. Management evaluates when the achievement of a performance-based milestone is probable based on the relative satisfaction of the performance conditions as of the reporting date.

Share-based payments issued to non-employees are recorded at their fair values, and are periodically revalued as the equity instruments vest and are recognized as expense over the related service period in accordance with the provisions of ASC 718 and ASC Topic 505, Equity. For equity instruments granted to non-employees, the Company recognizes stock-based compensation expense on a straight-line basis.

During the years ended December 31, 2015, 2014 and 2013, the Company recorded stock-based compensation expense, which was allocated as follows in the statements of operations (in thousands):



	Year Ended December 31,
	2015		2014		2013
Research and development expense	$	1,032	$	1,069	$	1,150
General and administrative expense	1,497		1,363		110
	$	2,529	$	2,432	$	1,260

No related tax benefits were recognized for the years ended December 31, 2015, 2014 and 2013.

Income Taxes

The Company provides for income taxes using the liability method. Under this method, deferred tax assets and liabilities are determined based on differences between the financial statement carrying amounts and the tax bases of the assets and liabilities using the enacted tax rates in effect in the years in which the differences are expected to reverse. A valuation allowance against deferred tax assets is recorded if, based on the weight of the available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized.

The Company accounts for uncertain tax positions in accordance with the provisions of ASC 740. When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than not be realized. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. As of December 31, 2015 and 2014, the Company did not have any significant uncertain tax positions.

Comprehensive Loss

Comprehensive loss is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources. For the years ended December 31, 2015, 2014 and 2013, comprehensive loss was equal to net loss.

Cash and Cash Equivalents

The Company considers highly liquid investments with a maturity of 3 months or less when purchased to be cash equivalents.

Concentrations of Credit Risk and Off-Balance-Sheet Risk

The Company has no significant off-balance-sheet risk, such as foreign exchange contracts, option contracts, or other foreign hedging arrangements. Financial instruments that potentially expose the Company to concentrations of credit risk primarily consist of cash and cash equivalents. The Company places its cash and cash equivalents in a custodian account in accredited financial institutions.

Fair Value of Financial Instruments

The fair value hierarchy prioritizes the inputs to valuation techniques used to measure fair value into three broad levels as follows: Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities; Level 2 inputs are inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly; and Level 3 inputs are unobservable inputs that reflect the Company’s own assumptions about the assumptions market participants would use in pricing the asset or liability. Financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement.

The following table presents information about the Company’s financial assets and liabilities that have been measured at fair value, and indicates the fair value hierarchy of the valuation inputs utilized to determine such fair value. The Company determines the fair value of the common stock warrants (See Note 9) using Level 3 inputs.

The following table summarizes the assets and liabilities measured at fair value on a recurring basis at December 31, 2015 (in thousands):



Description	December 31, 2015		Active Markets (Level 1)		Observable Inputs (Level 2)		Unobservable Inputs (Level 3)
Assets:
Cash and cash equivalents	$	36,079	$	36,079
Restricted cash	94		94
Total assets	$	36,173	$	36,173	$	—	$	—
Liabilities:
Warrant liability	$	115	$	—	$	—	$	115
Total liabilities	$	115	$	—	$	—	$	115

The following table summarizes the assets and liabilities measured at fair value on a recurring basis at December 31, 2014 (in thousands):



Description	December 31, 2014		Active Markets (Level 1)		Observable Inputs (Level 2)		Unobservable Inputs (Level 3)
Assets:
Cash and cash equivalents	$	54,059	$	54,059	$	—	$	—
Restricted cash	94		94		—		—
Total assets	$	54,153	$	54,153	$	—	$	—
Liabilities:
Warrant liability	$	3,219	$	—	$	—	$	3,219
Total liabilities	$	3,219	$	—	$	—	$	3,219

The carrying amounts reflected in the balance sheets for prepaid expenses and other current assets, other assets, accounts payable and accrued expenses approximate their fair values at December 31, 2015 and 2014, due to their short-term nature. At December 31, 2015, the carrying value of the notes payable approximates fair value.

There have been no changes to the valuation methods during the years ended December 31, 2015 and 2014. The Company evaluates transfers between levels at the end of each reporting period. There were no transfers of assets or liabilities between levels during the years ended December 31, 2015 and 2014.

Property and Equipment

Property and equipment consists of lab equipment, furniture and fixtures, computer equipment, software, and leasehold improvements. Expenditures for maintenance and repairs are recorded to expense as incurred. Major betterments are capitalized as additions to property and equipment. Depreciation is calculated over the estimated useful lives of the assets using the straight-line method.

Impairment of Long-Lived Assets

The Company periodically evaluates its long-lived assets for potential impairment in accordance with ASC Topic 360, Property, Plant and Equipment. Potential impairment is assessed when there is evidence that events or changes in circumstances indicate that the carrying amount of an asset may not be recovered. Recoverability of these assets is assessed based on undiscounted expected future cash flows from the assets, considering a number of factors, including past operating results, budgets and economic projections, market trends and product development cycles. If impairments are identified, assets are written down to their estimated fair value. The Company has not recognized any impairment charges through December 31, 2015.

Warrant Liability

The Company accounts for warrant instruments that either conditionally or unconditionally obligate the issuer to transfer assets as liabilities regardless of the timing of the redemption feature or price, even though the underlying shares may be classified as permanent or temporary equity. These warrants are subject to revaluation at each balance sheet date, and any changes in fair value are recorded as a component of other expense, until the earlier of their exercise or expiration or upon the completion of a liquidation event. The following table sets forth a summary of changes in the fair value of the Company’s common stock warrant liability, which represented a recurring measurement classified within Level 3 of the fair value hierarchy, wherein fair value was estimated using significant unobservable inputs (in thousands):



Beginning balance, January 1, 2015	$	3,219
Change in fair value of common stock warrants	(3,104		)
Ending balance, December 31, 2015	$	115

Segment Information

Operating segments are identified as components of an enterprise for which separate discrete financial information is available for evaluation by the chief operating decision maker, or decision making group, in making decisions on how to allocate resources and assess performance. The Company views its operations and manages its business in one operating segment. The Company operates in one geographic segment.

Subsequent Events (See Note 14)

The Company considers events or transactions that occur after the balance sheet date, but prior to the issuance of the financial statements, to provide additional evidence relative to certain estimates or to identify matters that require additional disclosure. Subsequent events have been evaluated through the date these financial statements were issued.

Net Loss Per Share

Basic net loss per share applicable to common stockholders is calculated by dividing net loss applicable to common stockholders by the weighted average shares outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share is calculated by adjusting weighted average shares outstanding for the dilutive effect of common stock equivalents outstanding for the period, determined using the treasury-stock method and the if-converted method. For purposes of the diluted net loss per share calculation, convertible preferred stock, stock options, unvested restricted stock, restricted stock units and common and preferred stock warrants are considered to be common stock equivalents but have been excluded from the calculation of diluted net loss per share, as their effect would be anti-dilutive for all periods presented. Therefore, basic and diluted net loss per share was the same for all periods presented.

The following common stock equivalents were excluded from the calculation of diluted net loss per share applicable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect or the exercise prices were greater than the average market price of the common shares.



	As of December 31,
	2015	2014	2013
Convertible preferred stock	—	—	8,260,444
Stock options	1,803,574	1,438,528	1,346,238
Unvested restricted stock	41,657	125,027	163,353
Restricted stock units	150,932	—	—
Common stock warrants	926,840	899,340	333,799
Preferred stock warrants	—	—	30,708
	2,923,003	2,462,895	10,134,542

Recent Accounting Pronouncements

In the second quarter of 2014, the Financial Accounting Standards Board (FASB) issued guidance applicable to revenue recognition that will be effective for the Company for the year ending December 31, 2018. The new guidance must be adopted using either a full retrospective approach for all periods presented or a modified retrospective approach. Earlier application is permitted only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting period. The new guidance applies a more principles-based approach to recognizing revenue. The Company is evaluating the new guidance and the expected effect on the Company’s financial statements.

In August 2014, the FASB issued Accounting Standards Update No. 2014-15, Going Concern (Subtopic 205-40) (“ASU 2014-15”). ASU 2014-15 requires management of all entities to evaluate whether there are conditions and events that raise substantial doubt about the entity’s ability to continue as a going concern within one year after the financial statements are issued (or available to be issued when applicable). The guidance is effective for fiscal years beginning after December 15, 2016 and for interim periods within that fiscal year. The Company does not expect the adoption of this guidance to have a material effect on the Company’s financial statements, but may require further disclosure in its financial statements once adopted.

In April 2015, the FASB issued Accounting Standard Update No. 2015-3, “Interest – Imputation of Interest (Subtopic 835-30)

(“ASU 2015-3”).” ASU 2015-3 requires debt issuance costs related to a recognized debt liability to be presented in the balance

sheet as a direct deduction from the carrying amount of the debt liability, consistent with debt discounts. The recognition and

measurement guidance for debt issuance costs are not affected by the new amendment. The new guidance will be applied on a

retrospective basis to each prior reporting period presented. Upon transition, the Company is required to comply with

applicable disclosures for a change in accounting principle. The amendment is effective for financial statements issued for

fiscal years beginning after December 15, 2015, and interim periods within those fiscal years. Early adoption is permitted. The

Company does not expect the adoption of this guidance to have a material effect on the Company’s financial statements.

In November 2015, the FASB issued Accounting Standard Update No. 2015-17, Balance Sheet Classification of Deferred Taxes(“ASU 2015-17”). ASU 2015-17 requires companies to classify all deferred tax assets and liabilities as noncurrent on the balance sheet instead of separating deferred taxes into current and noncurrent amounts. The guidance is effective for financial statements issued for annual periods beginning after December 15, 2016, and interim periods within those annual periods. Early adoption is permitted. The guidance may be adopted on either a prospective or retrospective basis. The Company does not expect the adoption of this guidance to have a material effect on the Company’s financial statements.

In January 2016, the FASB issued Accounting Standard Update No. 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities ("ASU 2016-01"). ASU 2016-01 requires entities to measure equity investments that do not result in consolidation and are not accounted for under the equity method at fair value, and recognize any changes in fair value in net income unless the investments qualify for the new measurement alternative. For financial liabilities measured using the fair value option in Accounting Standards Codification 825, Financial Instruments, entities will need to present any change in fair value caused by a change in instrument-specific credit risk (own credit risk) separately in other comprehensive income. ASU 2016-01 also changes certain disclosure requirements and other aspects of current GAAP. It does not change the guidance for classifying and measuring investments in debt securities and loans. The guidance is effective for annual periods, beginning after December 15, 2017, including interim periods within those annual periods. Early adoption is not permitted. The Company does not expect the adoption of this guidance to have a material effect on the Company’s financial statements.

In February 2016, the FASB issued Accounting Standard Update No. 2016-02, Leases (Topic 842) ("ASU 2016-02"). ASU 2016-02 addresses the financial reporting of leasing transactions. Under current guidance for lessees, leases are only included on the balance sheet if certain criteria, classifying the agreement as a capital lease, are met. This update will require the recognition of a right-of-use asset and a corresponding lease liability, discounted to the present value, for all leases that extend beyond 12 months. For operating leases, the asset and liability will be expensed over the lease term on a straight-line basis, with all cash flows included in the operating section of the statement of cash flows. For finance leases, interest on the lease liability will be recognized separately from the amortization of the right-of-use asset in the statement of operations and the repayment of the principal portion of the lease liability will be classified as a financing activity while the interest component will be included in the operating section of the statement of cash flows. This guidance is effective for annual and interim reporting periods beginning after December 15, 2018. Early adoption is permitted. The Company has not yet completed the analysis of how adopting this guidance will affect our financial statements.