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Nature of Business and Basis of Presentation

1.	Nature of Business and Basis of Presentation

Nature of Business

Altimmune, Inc., headquartered in Gaithersburg, Maryland, United States, together with its subsidiaries (collectively, the “Company” or “Altimmune”) is a clinical stage biopharmaceutical company incorporated under the laws of the State of Delaware. The Company is focused on discovering and developing immunotherapies and vaccines to address significant unmet medical needs. Since its inception, The Company has devoted substantially all of its efforts to business planning, research and development, recruiting management and technical staff, and raising capital, and has financed its operations through the issuance of common and convertible preferred stock, long-term debt, and proceeds from research grants and government contracts. The Company has not generated any revenues from the sale of any products to date, and there is no assurance of any future revenues from product sales.

The Company’s business is a result of a merger between PharmAthene, Inc. (“PharmAthene”) and the business previously known as Altimmune, Inc. (“Private Altimmune”). In May of 2017, Private Altimmune merged with PharmAthene pursuant to an Agreement and Plan of Merger and Reorganization (the “Merger Agreement”) dated January 18, 2017 among Private Altimmune, PharmAthene, its wholly owned acquisition subsidiaries Mustang Merger Sub Corp I Inc. (“Merger Sub Corp”) and Mustang Merger Sub II LLC (“Merger Sub LLC”). Pursuant to the Merger Agreement, Merger Sub LLC agreed to acquire 100% of the outstanding capital stock of Private Altimmune in a reverse triangular merger and reorganization pursuant to section 368(a) of the Internal Revenue Code (the “Mergers”) (see Note 3). Prior to the Mergers, PharmAthene was a publicly traded biodefense company engaged in Phase 2 clinical trials in developing a next generation anthrax vaccine.

Prior to and as a condition for the Mergers, in January 2017, Private Altimmune entered into a Convertible Promissory Note Purchase Agreement (the “Note Agreement”) for the private placement of $8.6 million of 6% convertible notes (the “Notes”) (See Note 12) to be issued in two separate closings. The initial closing dated March 9, 2017 resulted in $3,150,630 of gross proceeds. The initial closing also included $196,496 of certain existing outstanding notes payable and $881,044 of certain accrued expenses that were modified and became a component of the Notes on March 9, 2017. In connection with the Notes, Private Altimmune issued warrants to purchase 49,776 shares of Private Altimmune common stock to certain noteholders, with an exercise price of $0.01 per share. These warrants are classified as permanent equity (see Note 16). The second closing under the Note Agreement was satisfied in connection with the sale of Series B redeemable convertible preferred stock (“redeemable preferred stock”) that closed on August 16, 2017 (see Note 14).

On May 4, 2017, Private Altimmune and PharmAthene closed the Mergers in accordance with the terms of the Merger Agreement. Upon the closing of the Mergers, (i) Merger Sub Corp merged with and into Private Altimmune, with Private Altimmune remaining as the surviving corporation; (ii) Private Altimmune then merged with and into Merger Sub LLC, with Merger Sub LLC (renamed as “Altimmune LLC”) remaining as the surviving entity; and (iii) PharmAthene was renamed as “Altimmune, Inc.” Upon closing of the Mergers, all equity instruments of Private Altimmune were exchanged for corresponding equity instruments of PharmAthene (see Note 3). Except where the context indicates otherwise, references to “we,” “us,” “our,” “Altimmune” or the “Company” refer, for periods prior to the completion of the Mergers, to Private Altimmune and its subsidiaries, and for periods following the completion of the Mergers to the combined company and its subsidiaries.

Basis of Presentation

The accompanying consolidated financial statements are prepared in conformity with accounting principles general accepted in the United States (“U.S. GAAP”). The consolidated financial statements have been prepared on the basis of continuity of operations, realization of assets, and the satisfaction of liabilities in the ordinary course of business. The consolidated financial statements do not include any adjustments relating to the recoverability and classification of recorded assets and liabilities that might be necessary should the Company be unable to continue as a going concern (see Note 2). As more fully described in Note 3, the comparable information included in these consolidated financial statements is that of Altimmune, Inc., the deemed accounting acquirer and in connection with the Mergers, all historical share and per share information including common stock, convertible preferred stock, redeemable preferred stock, common stock warrants, restricted stock and stock options, has been retroactively adjusted to reflect the effect of the share exchange ratio.

Guarantees and Indemnifications

As permitted under Delaware law, the Company indemnifies its officers, directors, consultants and employees for certain events or occurrences that happen by reason of the relationship with, or position held at, the Company. Through December 31, 2017, the Company had not experienced any losses related to these indemnification obligations, and no claims were outstanding. The Company does not expect significant claims related to these indemnification obligations and, consequently, concludes that the fair value of these obligations is negligible, and no related reserves are established.

Going Concern

12 Months Ended

Dec. 31, 2017

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Going Concern

2.	Going Concern

The accompanying consolidated financial statements have been prepared assuming the Company will continue as a going concern. The Company has experienced recurring losses in past years. The Company incurred a net loss of $46,425,390 and used $20,214,079 in cash to fund operations during 2017 and had an accumulated deficit of $77,684,839 as of December 31, 2017. The Company expects to incur additional losses in the future in connection with research and development activities. Since inception, the Company has financed its activities principally from the issuance of equity and debt securities. The Company’s ability to continue as a going concern is dependent upon the Company’s ability to raise additional debt and equity capital. There can be no assurance that such capital will be available in sufficient amounts or on terms acceptable to the Company. These factors raise substantial doubt about the Company’s ability to continue as a going concern. The accompanying consolidated financial statements do not include any adjustments relating to the recoverability of the recorded assets or the classification of liabilities that may be necessary should the Company be unable to continue as a going concern. As of December 31, 2017, the Company does not have sufficient capital to fund its plan of operations for a twelve-month period from the date the 2017 consolidated financial statements are expected to be issued.

In order to address its capital needs, including its planned clinical trials, the Company must continue to actively pursue additional equity or debt financing. The Company has been in ongoing discussions with institutional investors and investment banks with respect to such financing. Adequate financing opportunities might not be available to the Company, when and if needed, on acceptable terms, or at all. If the Company is unable to obtain additional financing in sufficient amounts or on acceptable terms under such circumstances the Company’s operating results and prospects will be adversely affected. As more fully described in Note 12, in January 2017, in connection with the Mergers, the Company entered into a private placement of the Notes. In addition, as more fully described in Note 14, in August 2017, the Company issued shares of redeemable preferred stock and the related common stock warrants for an aggregate net proceeds of $13,018,570. The Company expects that the combination of the net proceeds from the Notes, cash assumed from the Mergers, the anticipated receipt of tax refunds (Note 17), redeemable preferred financing, and revenue from our government sponsored contracts will be insufficient to fund our operations and research and development efforts for at least twelve months from the expected issuance date of our 2017 financial statements.

Business Combination

12 Months Ended

Dec. 31, 2017

Business Combinations [Abstract]

Business Combination

3.	Business Combination

Pursuant to the Merger Agreement, the Company closed the Mergers with PharmAthene on May 4, 2017. In accordance with the terms of the Merger Agreement, PharmAthene issued 0.749106 (the “share exchange ratio”) of a share of PharmaAthene common stock for each share of Private Altimmune’s common stock (“common stock”) outstanding as of the closing date. All historical share and per share information including common and preferred stock, restricted stock, common stock warrants, and stock options, has been retroactively adjusted to reflect the effect of the share exchange ratio. In addition, Private Altimmune’s stock options and warrants were also replaced with options and warrants to purchase PharmAthene’s common stock at the same share exchange ratio of 0.749106 share. Immediately prior to closing, 599,285 shares of Series B convertible preferred stock (“convertible preferred stock”) converted into Private Altimmune common stock on a 1-for-1 basis. Due to the convertible preferred stock having unique terms and conditions, the convertible preferred stock outstanding in periods prior to the Mergers continues to be presented separately on our balance sheet for periods prior to conversion. In addition, outstanding principal and accrued interest on the Notes converted into 316,734 shares of Private Altimmune common stock. Further, 39,758 shares of Private Altimmune common stock were issued pursuant to the accelerated vesting of restricted stock, and 660,715 shares of Private Altimmune common stock were issued as a result of warrant exercises, both in accordance with their original terms. Upon the closing of the Mergers, Private Altimmune common stock totaling 6,883,498 shares were exchanged for 6,883,498 shares of PharmAthene common stock.

Although PharmAthene was the issuer of the shares and considered the legal acquirer in the Mergers, following the closing, shareholders of Private Altimmune held 58.2% of the equity interest of the combined entity and assumed control of the combined entity. As a result, the transaction has been accounted for as a reverse merger, with Private Altimmune considered the accounting acquirer, and the assets and liabilities of PharmAthene have been recorded at their estimated fair value. The unadjusted purchase price allocated to PharmAthene’s assets and liabilities was estimated to be $44,742,737 as of the closing date and consisted of the shares of the combined company retained by PharmAthene shareholders, and the estimated fair value of vested PharmAthene stock options and warrants which remained outstanding as of the closing date. Also at the closing, 7,569 outstanding unvested options of PharmAthene with an estimated fair value of $15,173 remained subject to vesting and service requirements. These unvested options will be recorded as operating expense in future periods as the services are delivered and the options vest.

Headquartered in Annapolis, Maryland, PharmAthene was incorporated in Delaware in April 2005. PharmAthene was a biodefense company engaged in Phase 2 clinical trials in developing a next generation anthrax vaccine. The next generation vaccine is intended to have more rapid time to protection, fewer doses for protection and less stringent requirements for temperature-controlled storage and handling than the currently used vaccine. The Mergers enable the combined company to become a fully integrated, commercially-focused immunotherapeutics company with the ability to create more value than either company could achieve individually. As a publicly listed entity, the Mergers also provide us with additional capital financing alternatives to support the combined entity’s planned research and development activities.

In addition to the operating assets and liabilities of PharmAthene, Private Altimmune also acquired PharmAthene’s tax attributes, which primarily consisted of a tax refund receivable and $965,583 of net operating losses (“NOLs”) which were limited under Section 382 of the U.S. Internal Revenue Service and were fully reserved, which will expire in 2023. The Company recorded a deferred tax liability related to future tax benefits arising from an in-process research and development asset (“IPR&D”) acquired in the Mergers. Goodwill generated from the Mergers is not expected to be deductible for tax purposes.

For accounting purposes, the historical financial statements of Private Altimmune have not been adjusted to reflect the Mergers, other than adjustments to the capital structure of Private Altimmune to reflect the historical capital structure of PharmAthene. Private Altimmune incurred $2,183,671 of transaction costs, which have been expensed as incurred in the accompanying consolidated financial statements.

The following table lists the various securities of PharmAthene which were outstanding as of May 4, 2017 and whose rights and obligations were assumed by the combined entity following the Mergers:


Outstanding PharmAthene common stock		6,883,498
Outstanding PharmAthene stock options		123,003
Outstanding PharmAthene stock warrants		4,658
Per share fair value of PharmAthene common stock	$	6.50
Weighted average per share fair value of PharmAthene stock options, vested and unvested	$	0.26
Per share fair value of PharmAthene stock warrants	$	0.01
Aggregate fair value of consideration	$	44,757,910
Less fair value of unvested common stock options		(15,173	)

Total fair value of consideration	$	44,742,737

Since the acquisition date, the Company has recorded adjustments to the allocation of the purchase consideration that included a $44,700 adjustment to increase our tax refund receivable and a $4,535 adjustment to reduce our deferred tax liabilities, with a total adjustment of $49,235 resulting in an increase in goodwill. The adjustments were the result of a change in the tax rate being applied from 34% to 35%. These purchase price adjustments were reflected in the accompanying consolidated balance sheet as of December 31, 2017. The adjusted allocation of the purchase consideration to the assets acquired and liabilities assumed of PharmAthene in these financial statements is still preliminary and subject to change as management gathers information regarding these items.

The adjusted allocation of the purchase consideration was as follows:


Cash and cash equivalents	$	13,684,535
Accounts receivable		1,124,462
Prepaid expenses and other current assets		597,172
Tax refund receivable		2,047,234
Property and equipment		75,779
IPR&D		22,389,000
Goodwill		15,573,822

Total assets acquired		55,492,004

Accounts payable and accrued expenses		(2,193,785	)
Deferred tax liability		(8,555,482	)

Total liabilities assumed		(10,749,267	)

Net assets acquired	$	44,742,737

The Company relied on significant Level 3 unobservable inputs to estimate the fair value of acquired IPR&D assets using management’s estimate of future revenue and expected profitability of the products after taking into account an estimate of future expenses, net of contract revenue and other funding, necessary to bring the products to completion. These projected cash flows were then discounted to their present values using a discount rate of 23%, which was considered commensurate with the risks and stages of development of the products.

The operating activities of PharmAthene have been included in the accompanying consolidated financial statements from the date of the Mergers. For the period from May 4, 2017 to December 31, 2017, revenues and net loss of PharmAthene included in the accompanying consolidated financial statements aggregated $1,765,212 and $36,003, respectively.

The following unaudited pro forma information for the year ended December 31, 2017 and 2016 gives effect to the acquisition of PharmAthene as if the Mergers had occurred at the beginning of the respective full annual reporting period:


	Year Ended December 31,
	2017			2016
Pro forma revenue and grants and contracts	$	11,844,273		$	8,466,371
Pro forma net (loss) income attributable to common stockholders	$	(52,315,978	)	$	186,664,464
Pro forma weighted average common shares outstanding, basic		15,547,863			14,368,157
Pro forma net (loss) income per share, basic	$	(3.36	)	$	12.99
Pro forma weighted average common shares outstanding, diluted		15,547,863			15,201,819
Pro forma net (loss) income per share, diluted	$	(3.36	)	$	12.28

Significant nonrecurring pro forma adjustments included acquisition costs of $1,512,423 and $671,248, and PharmAthene stock compensation expenses incurred prior to the Mergers of $66,180 and $2,240,015 for the years ended December 31, 2017 and 2016, respectively, that would have been incurred prior to the pro forma acquisition date had the Mergers occurred at the beginning of the respective full annual reporting period.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2017

Summary of Significant Accounting Policies

4.	Summary of Significant Accounting Policies

Principles of Consolidation

The accompanying consolidated financial statements include the accounts of the Company and its subsidiaries, all of which are wholly owned. Intercompany accounts and transactions have been eliminated in consolidation.

Reclassification

Certain 2016 amounts and disclosures have been reclassified to conform to the 2017 presentation. The 2016 amounts and disclosures reclassified include the combining of all noncurrent liabilities, other than deferred income taxes, into other long-term liabilities on the consolidated balance sheets; the combining of other income and other expenses into other income, net in the consolidated statements of operations and comprehensive loss; and the disclosure of additional property and equipment components in Note 6.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenue and expenses, and the disclosure of contingent assets and liabilities as of and during the reporting period. The Company bases estimates and assumptions on historical experience when available and on various factors that it believes to be reasonable under the circumstances. Significant estimates relied upon in preparing the accompanying consolidated financial statements related to revenue recognition, the fair value of common stock and other equity instruments, accounting for stock-based compensation, income taxes, collectability of accounts receivable, useful lives of long lived assets, fair value of assets acquired and liabilities assumed, impairment of goodwill and other long-lived assets, and accounting for project development and certain accruals. The Company assesses the above estimates on an ongoing basis; however, actual results could differ materially from those estimates.

Comprehensive Loss

For the years presented, the total comprehensive loss includes net loss and other comprehensive loss which represents foreign currency translation adjustments.

Foreign Currency Translation

Assets and liabilities of Altimmune UK Limited, PharmAthene UK Limited, and Altimmune France SAS, whose functional currencies are the British pound and Euro, respectively, are translated at year end exchange rates, while revenues and expenses are translated at average exchange rates for the year. Translation adjustments are reflected as accumulated other comprehensive loss within stockholders’ equity. Translation adjustments from intercompany advances that the Company does not anticipate settling in the foreseeable future are recorded in accumulated other comprehensive loss within stockholders’ equity. Gains and losses on foreign currency transactions are included in the consolidated statements of operations and comprehensive loss as a component of operating expenses.

Segment

Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker, the Company’s Chief Executive Officer, in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating segment, the research and development of immunotherapies and vaccines.

Business Combination

The Company uses its best estimates and assumptions to assign fair value to the tangible and intangible assets acquired and liabilities assumed at the acquisition date. The Company’s estimates are inherently uncertain and subject to refinement. During the measurement period, which may be up to one year from the acquisition date, the Company may record adjustments to the fair value of these tangible and intangible assets acquired and liabilities assumed, with the corresponding offset to goodwill. In addition, uncertain tax positions and tax-related valuation allowances are initially established in connection with a business combination as of the acquisition date. The Company collects information and reevaluates these estimates and assumptions quarterly and records any adjustments to the Company’s preliminary estimates to goodwill during the measurement period. Upon the conclusion of the measurement period or final determination of the fair value of assets acquired or liabilities assumed, whichever comes first, any subsequent adjustments are recorded to the Company’s consolidated statements of operations and comprehensive loss. Amounts paid for acquisitions are allocated to the tangible assets acquired and liabilities assumed based on their estimated fair values at the date of acquisition. The Company allocates the purchase price in excess of net tangible assets acquired to identifiable intangible assets, including purchased research and development. The fair value of identifiable intangible assets is based on detailed valuations that use information and assumptions provided by management. The Company allocates any excess purchase price over the fair value of the net tangible and intangible assets acquired to goodwill.

The Company’s purchased research and development represents the estimated fair value as of the acquisition date of substantive in-process projects that have not reached technological feasibility. The primary basis for determining technological feasibility of these projects is obtaining regulatory approval. The valuation of IPR&D assets is determined using the discounted cash flow method. In determining the value of IPR&D assets, the Company considers, among other factors, the stage of completion of the projects, the technological feasibility of the projects, whether the projects have an alternative future use and the estimated residual cash flows that could be generated from the various projects and technologies over their respective projected economic lives. The discount rate used is determined at the time of acquisition and includes a rate of return which accounts for the time value of money, as well as risk factors that reflect the economic risk that the cash flows projected may not be realized.

Intangible Assets

Intangible assets acquired in a business combination consist primarily of IPR&D assets. The value attributable to IPR&D projects at the time of acquisition is capitalized as an indefinite-lived intangible asset and tested for impairment until the project is completed or abandoned. Upon completion of the project, the indefinite-lived intangible asset will be accounted for as a finite-lived intangible asset and amortized on a straight-line basis over its estimated useful life. If the project is abandoned, the indefinite-lived intangible asset will be charged to expense. Intangible assets acquired in other transactions are recorded at cost. Intangible assets with finite useful lives consist of legal costs incurred in the course of obtaining patents and license issuance fees for the use of proprietary technologies. Costs incurred for obtaining patents are amortized on a straight-line basis over the estimated useful lives of the assets from the time of approval of the patent. Prior to approval, these costs are carried on the balance sheets and not amortized. In the event approval is denied, the cost of the denied application is expensed. License issuance fees are amortized on a straight-line basis over the estimated useful lives of the underlying licensed technology. Intangible assets with finite useful lives are being amortized over 6 to 20 years and are evaluated separately from indefinite-lived intangible assets for impairment at least annually or whenever events or circumstances indicate that the carrying amount of an asset may not be recoverable.

Acquisition-related Costs

Acquisition-related costs incurred in connection with the Mergers are expensed as incurred and include direct and incremental costs associated with the acquisition. The $1,512,423 and $671,248 of acquisition-related costs incurred in 2017 and 2016, respectively, were primarily professional fees and are classified as general and administrative expenses.

Impairment of Long-lived Assets and Goodwill

The Company evaluates our long-lived tangible and intangible assets, including IPR&D assets and goodwill, for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. Impairment of long-lived assets other than goodwill and indefinite lived intangibles is assessed by comparing the undiscounted cash flows expected to be generated by the asset to its carrying value. Goodwill is tested for impairment by comparing the estimated fair value of our single reporting unit to its carrying value.

Our IPR&D assets are currently non-amortizing. Until such time as the projects are either completed or abandoned, we test those assets for impairment at least annually at year end, or more frequently at interim periods, by evaluating qualitative factors which could be indicative of impairment. Qualitative factors being considered include, but are not limited to, the current project status, forecasted changes in the timing or amounts required to complete the project, forecasted in timing or changes in the future cash flows to be generated by the completed products, and changes to other market-based assumptions, such as discount rates. If impairment indicators are present as a result of our qualitative assessment, we test those assets for impairment by comparing the fair value of the assets to their carrying value. Upon completion or abandonment, the value of the IPR&D assets will be amortized to expense over the anticipated useful life of the developed products, if completed, or charged to expense when abandoned if no alternative future use exists. As of December 31, 2017, our projects continue to progress as originally anticipated, and no significant changes to the estimated timing or amount of cash flows or any other market assumptions have occurred. We believe our assumptions to be reasonable, however development of IPR&D assets are unpredictable and inherently uncertain. Actual future progress may differ from our initial expectations. We performed qualitative assessments of our long-lived assets, including IPR&D, and have determined that our long-lived assets, including IPR&D, are not impaired as of and during the year ended December 31, 2017.

Goodwill represents the excess of the purchase price of an acquired entity over the amounts assigned to assets and liabilities assumed in a business combination. We test goodwill for impairment during the fourth quarter of each year, or more frequently if impairment indicators arise. During the year ended December 31, 2017, we early adopted the Financial Accounting Standards Board (“FASB”) Accounting Standards Update (“ASU”) No. 2017-04, Simplifying the Test for Goodwill Impairment (“ASU 2017-04”), which provides for a one-step quantitative test to simplify our goodwill impairment analysis. If the carrying value of a reporting unit exceeds its fair value, the amount of goodwill impairment is the excess of the reporting unit’s carrying amount over its fair value, not to exceed the total amount of goodwill allocated to the reporting unit. We consider multiple methods including both market and income approaches to determine fair value of our one reporting unit, and primarily rely on fair value estimated based on our market capitalization (a Level 2 input and non-recurring fair value measurement) as of or near the testing date, adjusted for an estimated control premium.

From the date of the Mergers through December 31, 2017, the Company experienced a significant decline in the trading price of our common stock which indicated potential impairment. We performed interim impairment tests on our goodwill as of September 30, 2017 and December 21, 2017, by estimating our average market capitalization using a volume weighted average price (“VWAP”) (a Level 2 input and non-recurring fair value measurement) as of the testing dates and applying a control premium of 35% (a Level 2 input). Based on the results of our impairment tests, the carrying value of our reporting unit exceeded its estimated fair value by more than the goodwill carrying value. As a result, we have concluded that our goodwill was impaired and the full amount of its carrying value of $35,919,695 was written off as an impairment charge which was classified as a component of operating expenses.

Fair Value Measurements

The Company follows the guidance in FASB Accounting Standard Codification (“ASC”) 820, Fair Value Measurements and Disclosures, which defines fair value and establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). The three levels of the fair value hierarchy are described below:

Level 1 — Quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company can access at the measurement date.

Level 2 — Inputs other than quoted prices included within Level 1 that are either directly or indirectly observable. If the asset or liability has a specified (contractual) term, a Level 2 input must be observable for substantially the full term.

Level 3 — Unobservable inputs developed using estimates of assumptions developed by the Company, which reflect those that a market participant would use.

To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.

Fair value is a market-based measure considered from the perspective of a market participant rather than an entity-specific measure. Therefore, even when market assumptions are not readily available, the Company’s own assumptions are set to reflect those that market participants would use in pricing the asset or liability at the measurement date. The Company uses prices and inputs that are current as of the measurement date, including during periods of market dislocation. In periods of market dislocation, the observability of prices and inputs may change for many instruments. This condition could cause an instrument to be reclassified within levels in the fair value hierarchy. There were no transfers within the fair value hierarchy during the years ended December 31, 2017 and 2016.

Financial Instruments

The Company’s financial instruments consist of cash, cash equivalents, restricted cash, accounts receivable, notes payable, accounts payable, accrued expenses, BPI France notes, common stock warrants classified as a liability, common stock warrant classified as equity, convertible preferred stock, redeemable convertible preferred stock, and an embedded derivative. The carrying amounts of cash, cash equivalents, restricted cash, accounts receivable, accounts payable, and accrued expenses approximate their fair value due to the short-term nature of those financial instruments. The carrying amounts of notes payable approximate their fair value because their stated interest rates approximate the market rates and due to the short-term nature of the notes. BPI France notes are recorded at their repayment value which approximates fair value. Redeemable convertible preferred stock is classified as temporary equity and its carrying amount is accreted over the term of the instrument up to its liquidation and redemption value. Common stock warrant classified as equity and convertible preferred stock classified as permanent equity are initially recorded at their grant date fair value but are not subsequently remeasured. Common stock warrants classified as a liability and the embedded derivative are recorded at fair value and are remeasured every reporting period with the changes in fair value recorded as a component of other income (expenses), net.

License Revenue

License revenue is recognized when (i) persuasive evidence of an arrangement exists, (ii) delivery has occurred or services have been rendered, (iii) the fee is fixed or determinable, and (iv) collectability is reasonably assured. When one or more of the revenue recognition criteria are not met, the Company defers the recognition of revenue until such time that all criteria are met. The Company has granted a license to one of its investors providing for an exclusive right to use, market, sell, and import the Company’s potential vaccine products in the territory provided by the license. The terms of the agreement included nonrefundable upfront fees, annual license maintenance fees, and potential royalties from the licensee’s sale of the licensed products. The non-refundable upfront fees are deferred and recognized over the license term, which represents the service period, is considered to extend to the expiration of all licensed patents included in the license. Annual license maintenance fees are recognized when due and payable if collection is reasonably assured. Royalty revenue, if any, will be recognized based upon actual and estimated net sales by the licensee in the period sales occur.

Research Grants and Contracts

Research grants and contracts are derived from government and foundation grants and contracts that support the Company’s efforts on specific research projects. We have determined that the government agencies and foundations providing grants and contracts to the Company are not our customers. These grants and contracts generally provide for reimbursement of approved costs as those costs are incurred by the Company. Research grants and contracts and the related accounts receivable are recognized as earned when reimbursable expenses are incurred and the earnings process is complete. Payments received in advance of services being provided are recorded as deferred revenue.

Research and Development

Research and development costs are expensed as incurred. Research and development costs include payroll and personnel expense; consulting costs; external contract research and development expenses; raw materials; drug product manufacturing costs; and allocated overhead, including depreciation and amortization, rent and utilities. Research and development costs that are paid in advance of performance are capitalized as a prepaid expense and amortized over the service period as the services are provided.

Clinical Trial Costs

Clinical trial costs are a component of research and development expenses. The Company accrues and expenses clinical trial activities performed by third parties based on an evaluation of the progress to completion of specific tasks using data such as patient enrollment, clinical site activation, and other information provided to the Company by our vendors.

Cash Equivalents

The Company considers all highly liquid investments purchased with remaining maturities of 90 days or less on the purchase date to be cash equivalents, and include amounts held in money market funds which are actively traded (a Level 1 input).

Restricted Cash

The Company had restricted cash of $34,174 at December 31, 2017 held in a money market savings account as collateral for the Company’s facility lease obligation. In addition, until all the redeemable preferred stock shares have been converted, redeemed, or otherwise satisfied in accordance with their terms, the Company is required to maintain cash on deposit in an unrestricted account with an aggregate amount not less than the lower of $3,500,000 or the redeemable preferred stock outstanding conversion amount. The Company has elected to record this amount within restricted cash. Restricted cash is classified as a component of cash, cash equivalents, and restricted cash in the accompanying consolidated balance sheets and consolidated statements of cash flows.

Accounts Receivable

Accounts receivable includes both billed and unbilled amounts. The Company makes judgments as to its ability to collect outstanding receivables and provides an allowance for receivables when collection becomes doubtful. Provisions are made based upon a specific review of all significant outstanding invoices and the overall quality and age of those invoices not specifically reviewed. The Company’s receivables represent amounts reimbursed under its government grants and contracts. The Company believes that credit risks associated with these government grants and contracts is not significant. To date, the Company has not experienced any losses associated with accounts receivable and do not maintain an allowance for doubtful accounts.

Concentrations of Credit Risk

Financial instruments that potentially subject the Company to significant concentration of credit risk consist primarily of cash, cash equivalents, restricted cash, and accounts receivable. Periodically, the Company maintains deposits in financial institutions in excess of government insured limits. Management believes that the Company is not exposed to significant credit risk as the Company’s deposits are held at financial institutions that management believes to be of high credit quality. The Company has not experienced any losses in these deposits. The Company recognizes research grants and contracts earned in connection with the services provided on research and development projects. The Company provides credit in the normal course of providing such services based on evaluations of the grantors’ financial condition and generally does not require collateral. To manage accounts receivable credit risk, the Company monitors the creditworthiness of its grantors. Grantors that represented 10% or more of research grants and contracts for the years ended December 31, 2017 and 2016 and grantors that accounted for 10% or more of accounts receivable at December 31, 2017 and 2016, are presented below:


	Year Ended December 31,
	2017			2016
Research Grants and Contracts
BARDA		83	%		81	%
NIAID		17			—
Texas A&M University System		—			19


	December 31,
	2017			2016
Accounts Receivable
BARDA		73	%		100	%
NIAID		27			—

Property and Equipment, Net

Property and equipment are stated at cost. Expenditures for maintenance and repairs are charged to operations as incurred, whereas major improvements are capitalized as additions to property and equipment. Costs of assets under construction are capitalized but are not depreciated until the construction is substantially complete and the assets being constructed are ready for their intended use. Depreciation and amortization are recorded using the straight-line method over the estimated useful lives of the assets, as follows:


Asset Category		Estimated Useful Life
Computer and telecommunications		3 – 5 years
Software		3 years
Furniture, fixtures and equipment		5 years
Laboratory equipment		7 years
Leasehold improvements		Lesser of lease term or estimated useful lives

Patent and licensing costs

Patent and licensing costs that are incurred on behalf of, or reimbursable under, research grant arrangements are capitalized as intangible assets and amortized over the estimated useful lives of the assets. All other patents and licensing costs are expensed as incurred because their realization is uncertain. These costs are classified as research and development expenses in the accompanying statements of operations and comprehensive loss.

Preferred Stock

The Company issued convertible preferred stock under a stock purchase agreement entered into in connection with a 2015 acquisition. Upon a deemed liquidation event, the convertible preferred stock terms permitted holders to vote as a single class to either liquidate or redeem their shares. Upon such an election, all of the Company’s stockholders, including the common stock holders, would always be entitled to receive the same form of consideration. As a result, the Company’s convertible preferred stock met the limited exception allowed for shares containing such liquidation rights to be classified as permanent equity with net issuance price in excess of par value recorded as additional paid-in capital. In connection with the Mergers, all outstanding shares of convertible preferred stock converted into Private Altimmune common stock on a 1-for-1 basis (see Note 3).

Shares of redeemable preferred stock issued in August 2017 represented the second closing under the Note Agreement (see Notes 1 and 12). Redeemable preferred stock was classified as temporary equity and was initially recorded at its original issuance price, net of issuance costs and discounts. Such discounts included common stock warrants issued as part of the financing which were required to be classified as a liability and recorded at fair value (Note 16), an embedded derivative related to certain redemption features which was classified as a liability and recorded at fair value (Note 14), and the intrinsic value of a beneficial conversion feature present in the instrument at issuance (Note 14). The carrying value of the redeemable preferred stock will be accreted over the term of the redeemable preferred stock up to its redemption value, using the straight-line method which approximates the interest method due to the short-term nature of the redeemable preferred stock terms with the amount of the accretion recorded as a reduction of additional paid-in capital.

Warrants

Common stock warrants issued in connection with the convertible preferred stock and the Notes were classified as a component of permanent equity because they were freestanding financial instruments that were legally detachable and separately exercisable from other debt and equity instruments, were contingently exercisable, did not embody an obligation for the Company to repurchase our own shares, and permitted the holders to receive a fixed number of common shares upon exercise. In addition, such warrants required physical settlement and did not provide any guarantee of value or return. These warrants were initially recorded at their issuance date allocated fair value and were not subsequently remeasured. These warrants were valued using the Black Scholes option pricing model (“Black-Scholes”) and were converted into Private Altimmune common stock according to their original terms upon the Mergers.

Common stock warrants issued in connection with redeemable preferred stock are classified as a liability because these warrants contain terms which could, in certain circumstances, require the Company to settle the instruments for cash and such circumstances are outside the Company’s control. Common stock warrants classified as a liability are initially recorded at their issuance date fair value and are remeasured on each subsequent balance sheet date with changes in fair value recorded as a component of other income (expenses), net. These common stock warrants were valued using the Monte Carlo simulation valuation model.

Stock-based Compensation

The Company accounts for all stock-based compensation granted to employees and non-employees using a fair value method. Stock-based compensation awarded to employees is measured at the grant date fair value of stock option grants and is recognized over the requisite service period of the awards, usually the vesting period, on a straight-line basis, net of estimated forfeitures. Stock-based compensation awarded to non-employees are subject to revaluation over their vesting terms. For performance-based awards where the vesting of the options may be accelerated upon the achievement of certain milestones, vesting and the related stock-based compensation is recognized as an expense when it is probable the milestone will be met. For awards containing a market condition, the effect of the market condition is reflected in measuring the grant date fair value of the award and is recognized over the requisite service period, which is usually the vesting period, on a straight-line basis, net of estimated forfeitures.

When awards are modified, the Company compares the fair value of the affected award measured immediately prior to modification to its value after modification. To the extent that the fair value of the modified award exceeds the original award, the incremental fair value of the modified award is recognized as compensation on the date of modification for vested awards, and over the remaining vesting period for unvested awards.

The Company adopted FASB’s ASU No. 2016-09, Compensation – Stock Compensation (“ASU 2016-09”) on January 1, 2017. The adoption of ASU 2016-09 did not have a material impact on the Company’s financial statements. The Company elected to adopt the cash flow presentation of the excess tax benefits prospectively, commencing with our statement of cash flows for the three months ended March 31, 2017. We have elected to continue to estimate the number of stock-based awards expected to vest, rather than electing to account for forfeitures as they occur to determine the amount of compensation cost to be recognized in each period. There was no impact to our computation of dilutive EPS as all securities were considered anti-dilutive.

Income Taxes

We account for income taxes using the asset and liability approach, which requires the recognition of future tax benefits or liabilities on the temporary differences between the financial reporting and tax bases of our assets and liabilities. Deferred tax assets and liabilities represent future tax consequences of temporary differences between the financial statement carrying amounts and the tax basis of assets and liabilities and for loss carryforwards using enacted tax rates expected to be in effect in the years in which the differences reverse. A valuation allowance is established when necessary to reduce deferred tax assets to the amounts expected to be realized. We also recognize a tax benefit from uncertain tax positions only if it is “more likely than not” that the position is sustainable based on its technical merits. The Company accounts for interest and penalties related to uncertain tax positions as part of its provision for income taxes. To date, the Company has not incurred interest and penalties related to uncertain tax positions. Should such costs be incurred, they would be classified as a component of provision for income taxes.

Net Loss per Share

Basic net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common shares outstanding for the period without consideration for potentially dilutive securities. Net loss attributable to common stockholders and participating preferred stock is allocated to each share on an as-converted basis as if all of the net loss for the period had been distributed. During periods in which the Company incurred a net loss, the Company does not allocate net loss to participating securities because they do not have a contractual obligation to share in the net loss of the Company.

The Company computes diluted net loss per common share after giving consideration to all potentially dilutive common equivalents, including convertible preferred stock, redeemable preferred stock, common stock options, restricted stock awards, and common stock warrants outstanding during the period except where the effect of such non-participating securities would be antidilutive.

Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common shares and dilutive common stock equivalents outstanding for the period determined using the treasury-stock and if-converted methods.

Lease Incentive Obligations

Lease incentives and allowance provided by our landlord for the construction of leasehold improvements are recorded as lease incentive obligations as the related construction costs are incurred, up to the maximum allowance. Lease incentive obligations are classified as a component of deferred rent and are amortized on a straight-line basis over the lease term as a reduction of rent expense.

Deferred Rent

Rent expense from operating leases is recognized on a straight-line basis over the lease term. The difference between rent expense recognized and rental payments is recorded as deferred rent in the consolidated balance sheets.

Recently Issued Accounting Pronouncements

In February 2016, FASB issued ASU No. 2016-02, Leases (“ASU 2016-02”). ASU 2016-02 requires a lessee to separate the lease components from the non-lease components in a contract and recognize in the statement of financial position a liability to make lease payments (the lease liability) and a right-of-use asset representing its right to use the underlying asset for the lease term. It also aligns lease accounting for lessors with the revenue recognition guidance in ASU 2014-09. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, and is to be applied at the beginning of the earliest period presented using a modified retrospective approach. We expect the adoption of ASU 2016-02 will not have a material impact on our financial statements.

Net Loss Per Share

12 Months Ended

Dec. 31, 2017

Earnings Per Share [Abstract]

Net Loss Per Share

5.	Net Loss Per Share

Because we have reported net loss attributable to common stockholders for both years presented, basic and diluted net loss per share attributable to common stockholders are the same for both years. All convertible preferred stock, redeemable preferred stock, unvested restricted stock, common stock warrants, and stock options have been excluded from the computation of diluted weighted-average shares outstanding because such securities would have an antidilutive impact. As more fully described in Note 3, in connection with the Mergers, all historical share and per share information including common stock, convertible preferred stock, redeemable preferred stock, common stock warrants, unvested restricted stock, and stock options, has been retroactively adjusted to reflect the effect of the share exchange ratio.

The following table sets forth the computation of basic and diluted net loss per share:


	Year Ended December 31,
	2017			2016
Numerator
Net loss	$	(46,425,390	)	$	(11,086,812	)
Less: preferred stock accretion and dividends		(4,930,010	)		(368,548	)

Net loss attributable to common stockholders	$	(51,355,400	)	$	(11,455,360	)

Denominator
Weighted-average common shares outstanding, basic and diluted		12,805,095			6,911,534

Net loss per share attributable to common stockholders, basic and diluted		(4.01	)		(1.66	)

Potential common shares issuable upon conversion, vesting or exercise of convertible preferred stock, redeemable preferred stock, unvested restricted stock, common stock warrants, and stock options that are excluded from the computation of diluted weighted-average shares outstanding are as follows:


	Year Ended December 31,
	2017		2016
Convertible preferred stock		—		599,285
Redeemable preferred stock		4,560,550		—
Common stock warrants		2,350,085		612,112
Common stock options		1,819,316		1,205,920
Unvested restricted stock		23,428		74,546

Property and Equipment, Net

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Property and Equipment, Net

6.	Property and Equipment, Net

Property and equipment, net consisted of the following:


	December 31,
	2017			2016
Furniture, fixtures and equipment	$	61,121		$	60,320
Laboratory equipment		1,001,810			932,065
Computers and telecommunications		81,342			45,837
Software		16,244			595
Leasehold improvements		44,352			44,352
Construction in progress		350,075			—

Property and equipment, at cost		1,554,944			1,083,169
Less accumulated depreciation and amortization		(951,798	)		(905,310	)

Property and equipment, net	$	603,146		$	177,859

The presentation of property and equipment at December 31, 2016 has been reclassified to conform to the 2017 presentation. Depreciation expense for the years ended December 31, 2017 and 2016 was $83,834 and $63,109, respectively.

Intangible Assets, Net

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible Assets, Net

7.	Intangible Assets, Net

The Company’s intangible assets consisted of the following:


	December 31, 2017
	Estimated Useful Lives		Gross Carrying Value		Accumulated Amortization			Net Book Value
Internally developed patents		6 – 10 years	$	678,340	$	(249,601	)	$	428,739
Acquired licenses		16 – 20 years		285,000		(237,340	)		47,660

Total intangible assets subject to amortization				963,340		(486,941	)		476,399
IPR&D assets		Indefinite		38,245,871		—			38,245,871

Total			$	39,209,211	$	(486,941	)	$	38,722,270


	December 31, 2016
	Estimated Useful Lives		Gross Carrying Value		Accumulated Amortization			Net Book Value
Internally developed patents		6 – 10 years	$	624,454	$	(211,956	)	$	412,498
Acquired licenses		16 – 20 years		285,000		(219,800	)		65,200

Total intangible assets subject to amortization				909,454		(431,756	)		477,698
IPR&D assets		Indefinite		14,477,019		—			14,477,019

Total			$	15,386,473	$	(431,756	)	$	14,954,717

Amortization expense of intangible assets subject to amortization totaled $55,185 and $72,236 for the years ended December 31, 2017 and 2016, respectively, and was classified as research and development expenses in the accompanying consolidated statements of operations and comprehensive loss.

As of December 31, 2017, future estimated amortization expense is as follows:


Year ending December 31,
2018	$	53,113
2019		48,314
2020		34,868
2021		14,308
2022		14,308
2023 and thereafter		311,488

Total	$	476,399

The above future estimated amortization expense does not include potential amortization charges related to the IPR&D assets. Those assets, which represent incomplete technologies, will be amortized to expense once the underlying technologies are substantially complete over their estimated useful lives, expected to be 15 to 18 years. In the event that the Company ceases the development of these assets, the carrying value would be written off at that time. IPR&D assets are periodically assessed for impairment by considering the state of completion of the projects, the remaining activities required to complete development, the anticipated market for the completed products, and anticipated future cash required to complete development.

IPR&D and Goodwill

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

IPR&D and Goodwill

8.	IPR&D and Goodwill

Changes in the carrying amounts of IPR&D assets and goodwill for the years ended December 31, 2017 and 2016 were:


	IPR&D			Goodwill
Balance, January 1, 2016	$	17,366,791		$	22,494,691
Foreign currency translation adjustments		(2,889,772	)		(3,736,270	)

Balance, December 31, 2016		14,477,019			18,758,421
Additions from the Mergers		22,389,000			15,573,822
Foreign currency translation adjustments		1,379,852			1,587,452
Impairment charges		—			(35,919,695	)

Balance, December 31, 2017	$	38,245,871		$	—

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

Accrued Expenses

12 Months Ended

Dec. 31, 2017

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Accrued Expenses

9.	Accrued Expenses

Accrued expenses consist of the following:


	December 31,
	2017		2016
Accrued professional services	$	835,326	$	689,135
Accrued board of director compensation		—		606,199
Accrued payroll and employee benefits		909,455		957,719
Accrued interest		536		169,790
Accrued construction costs		328,384		—
Accrued research and development		1,551,556		549.902

Accrued expenses	$	3,625,257	$	2,972,745

As a condition for the Mergers as described in Note 3, the Company entered into the Note Agreement on January 18, 2017. On February 28, 2017, $881,044 of the Notes were issued upon the conversion of certain accrued expenses that were outstanding as of that date.

Licenses

12 Months Ended

Dec. 31, 2017

Licenses

10.

Licenses

University of Alabama at Birmingham Research Foundation

The Company has an agreement with the University of Alabama at Birmingham Research Foundation (“UABRF”) for the exclusive worldwide license to develop, manufacture, and commercialize certain proprietary technology developed at UABRF. The UABRF agreement expires on the last of the related patent expiration date which may be extended upon patent renewal. The latest of the patent expiration date is currently on August 7, 2033. Under the terms of the amended and restated agreement, the Company is obligated to pay an annual license fee of $20,000 and royalty fees upon the commencement of product sales. Fees incurred under the UABRF agreement totaled $20,000 in each of the years ended December 31, 2017 and 2016, respectively, and are classified as a component of research and development expenses in the accompanying consolidated statements of operations and comprehensive loss.

Janssen Vaccines & Prevention B.V. (Formerly Crucell Holland, B.V.)

The Company has a royalty-bearing, worldwide non-exclusive license agreement with Janssen Vaccines & Prevention B.V. (“Janssen”) for use of its vaccine technology. The Janssen agreement expires on the last of the related patent expiration date which may be extended upon patent renewal. The latest of the patent expiration date is currently on March 21, 2020. Under the agreement, the Company is required to pay an annual license fee and annual royalty fees upon reaching certain milestones in an amount that equals the greater of a percentage of net sales or $100,000. Fees incurred under the Janssen agreement totaled $200,000 and $100,000 for the years ended December 31, 2017 and 2016, respectively, and are included in research and development expenses in the accompanying consolidated statements of operations and comprehensive loss.

Auburn University

The Company has an exclusive, world-wide license agreement to develop, manufacture, and commercialize certain vaccine technology developed at Auburn University. The Auburn University agreement expires on the last of the related patent expiration date which may be extended upon patent renewal. The last of the patent expiration date is currently on August 15, 2025. Under the agreement, the Company is required to pay an upfront fee of $1,000 upon signing of the agreement, an annual license fee of $5,000, and royalty fees from net product sales or sublicenses of the technology. Fees incurred under the Auburn University agreement totaled $5,000 in each of the years ended December 31, 2017 and 2016 and are included in research and development expenses in the accompanying consolidated statements of operations and comprehensive loss.

Notes Payable

12 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

Notes Payable

11.

Notes Payable

The Company’s outstanding notes payable are summarized as follows:


	December 31,
	2017		2016
Line of credit	$	49,702	$	49,702
Economic Development Partnership of Alabama (“EDPA”) promissory note		—		96,496
Hammond promissory note		—		100,000
Alex Choi promissory note		—		100,000
Frommer, Lawrence and Haug LLP (“FLH”) promissory note		—		112,431

Total notes payable	$	49,702	$	458,629

Line of Credit

The Company has a secured line of credit agreement with a financial institution that provides for borrowings up to $250,000 and matures in April 2018. The borrowings are secured by all of the Company’s accounts receivable from BARDA. Interest is payable monthly at the financial institution’s prime rate (5.00% at December 31, 2017) plus 2.0% per annum with a floor of 5.0%. Accrued interest was $536 and $33 as of December 31, 2017 and 2016, respectively. Interest expense for the years ended December 31, 2017 and 2016 totaled $3,321 and $2,956, respectively.

EDPA Promissory Note

The EDPA promissory note was in default as of December 31, 2016 and was classified as a current liability. The promissory note continued accruing interest at the stated interest rate of 6% per annum, compounded annually, through February 28, 2017 when the outstanding principal and accrued interest were converted into the Notes according to the Note Agreement. Accrued interest was $34,121 at December 31, 2016. Interest expense on the promissory note was $1,079 and $5,621 in 2017 and 2016, respectively.

Hammond Promissory Note

The Hammond promissory note was in default as of December 31, 2016 and was classified as a current liability. The promissory note continued accruing interest at the stated default interest rate of 15% per annum through February 28, 2017 when accrued interest was converted into the Notes according to the Note Agreement and the principal was repaid with proceeds from the Notes. Accrued interest was $94,685 at December 31, 2016. Interest expense on the promissory note was $4,663 and $15,000 in 2017 and 2016, respectively.

Alex Choi Promissory Note

Alex Choi is one of the Company’s stockholders. The Alex Choi promissory note was in default as of December 31, 2016 and was classified as a current liability. The promissory note continued accruing interest at the stated interest rate of 6% per annum through February 28, 2017 when the outstanding principal and accrued interest were converted into the Notes according to the Note Agreement. Accrued interest was $40,951 at December 31, 2016. Interest expense on the promissory note was $1,575 and $8,149 in 2017 and 2016, respectively.

FLH Promissory Note

The FLH promissory note was in default as of December 31, 2016 and was classified as a current liability. The promissory note was noninterest bearing and was repaid with proceeds from the Notes.

Other Long-Term Liabilities

12 Months Ended

Dec. 31, 2017

Other Long-Term Liabilities

12.

Other Long-Term Liabilities

The Company’s other long-term liabilities are summarized as follows:


	December 31,
	2017		2016
Unvested restricted stock (see Note 15)	$	315	$	1,001
BPI France notes		599,927		525,950
Deferred revenue, long-term portion (see Note 4)		159,671		179,424
Deferred rent, long-term portion		386,489		15,914
Common stock warrant liability (see Note 16)		3,400,869		—
Embedded derivative (see Note 14)		27,236		—

Total other long-term liabilities	$	4,574,507	$	722,289

Note Agreement

As a condition for the Mergers as described in Note 3, the Company entered into the Note Agreement on January 18, 2017. The Notes bore interest at a rate of 6% per annum, compounded annually. On February 28, 2017, $196,496 of the Notes were issued upon the conversion of outstanding principal of the EDPA and the Alex Choi promissory notes (see Note 11), and $174,594 of the Notes were issued upon the conversion of accrued interest on the EDPA, Alex Choi, and Hammond promissory notes. The conversion of these promissory notes and accrued interest into the Notes was accounted for as an extinguishment with no resulting gains or losses being recognized. On March 9, 2017, the remainder of the initial closing of the Notes was issued for an aggregate of $3,150,630 in gross proceeds. In connection with the issuance of the Notes, we granted a warrant for the purchase of up to 49,776 shares of our common stock to one noteholder. The allocated fair value of the warrant on the issuance date of $566,793 was accounted for as a debt issuance discount and was accreted over the term of the Notes using the interest method. On May 4, 2017, upon the close of the Mergers, outstanding principal and accrued interest of the Notes, net of unamortized discount and deferred financing costs, totaling $3,645,424 were converted into 316,734 shares of our common stock. Interest expense incurred on the Notes during 2017 totaled $136,629.

Deferred Rent, Long-Term Portion

Deferred rent, long-term portion, includes the difference between rent expense recognized and rental payments made, and lease incentive obligations. Lease incentive obligations represent lease incentives and allowances provided by our landlord for the construction of leasehold improvements located at our new office and laboratory facilities. We record lease incentive obligations as construction costs are incurred and billable, up to the maximum allowance amount. Lease incentive obligations are amortized on a straight-line basis over the lease term as a reduction of rent expense. Through December 31, 2017, $350,076 of construction costs have been incurred and recorded as lease incentive obligation with $29,854 of amortization recorded as a reduction of rent expense during the year ended December 31, 2017.

BPI France Notes

Altimmune France has two non-interest-bearing research and development funding arrangements with BPI France that were entered into in December 2013 to provide Altimmune France up to €750,000 ($899,890 at December 31, 2017) in research funding in the first arrangement and up to €250,000 ($299,963 at December 31, 2017) in the second arrangement. Altimmune France is permitted to draw 50% of the funds upon the signing of the arrangements, an additional 30% contingent upon a financial audit and technical progress report, and the remaining amounts at the completion of the research and development project being funded by the arrangements. In October 2016, the Company and BPI agreed to extend the term on the arrangement by two years. Each of the two obligations is repayable in sixteen quarterly installments from June 2019 through March 2023. The total amount advanced under the arrangements was €500,000 as of December 31, 2017 and 2016 ($599,927 and $525,950 as of December 31, 2017 and 2016, respectively).

Common Stock

12 Months Ended

Dec. 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Common Stock

13.

Common Stock

As more fully described in Note 3, in connection with the Mergers, all historical share and per share information including common stock, convertible preferred stock, redeemable preferred stock, common stock warrants, restricted stock, and stock options, has been retroactively adjusted to reflect the effect of the share exchange ratio. The Company had 100,000,000 authorized shares of our $0.0001 par value common stock with 18,103,691 shares and 6,917,204 shares issued and outstanding at December 31, 2017 and 2016, respectively.

The voting, dividend and liquidation rights of the common stockholders are subject to and qualified by the rights, powers and preferences of the preferred stock. Common stockholders are entitled to one vote for each share of common stock held at all meetings of stockholders. Common stockholders are entitled to receive dividends declared out of funds legally available, subject to the payment in full of all preferential dividends to which the holders of preferred stock, if any, are entitled. In the event of any voluntary or involuntary liquidation, dissolution, or winding up of the Company, after the payment of all preferential amounts that the holders of preferred stock are entitled, if any, the common stockholders and preferred holders (on an as-converted basis) share ratably in the remaining assets of the Company available for distribution.

As of December 31, 2017, the Company’s common stock available for future issuance is summarized as follows:


Common stock authorized			100,000,000

Common stock issued and reserved for future issuance:
Common stock issued and outstanding			18,103,691
Common stock reserved for the exercises of common stock warrants			3,522,799
Common stock reserved for the conversion of redeemable preferred stock			6,840,818
Common stock reserved for the exercise of options			1,819,316
Common stock reserved for the vesting of unvested restricted stock			23,428
Common stock reserved for future option awards			708,073

Total common stock issued and reserved for future issuance			31,018,125

Unreserved common stock available for future issuance			68,981,875

Preferred Stock

12 Months Ended

Dec. 31, 2017

Equity [Abstract]

Preferred Stock

14.

Preferred Stock

The Company had 599,285 shares of its $0.01 par value convertible preferred stock issued and outstanding at December 31, 2016, all of which converted into common stock on a 1-to-1 basis in connection with the Mergers. As more fully described in Note 3, in connection with the Mergers, all historical preferred stock information has been retroactively adjusted to reflect the effect of the share exchange ratio.

On August 16, 2017, we issued 15,656 shares of our $0.0001 par value, redeemable preferred stock and warrants to purchase up to 2,345,427 shares of our common stock (see Note 16), satisfying the second closing requirement under the Note Agreement for total gross proceeds of $14,716,370, and incurred issuance costs totaling $1,697,800. The redeemable preferred stock matures on August 16, 2018. The maturity date may be extended at the option of the holders to ten trading days after the curing of a triggering event (as defined), or ten business days after the consummation of a change of control. In addition, the redeemable preferred stock agreements require that we reserve a sufficient number of common shares to cover at least 150% of the common shares expected to be issued upon the conversion of the redeemable preferred stock at the then current conversion price, and the exercises of common stock warrants issued in connection with the redeemable preferred stock.

The rights, preferences, and privileges of redeemable preferred stock are summarized below:

Voting — Holders of redeemable preferred stock have no voting rights, except as required by law.

Dividends — Holders of redeemable preferred stock are entitled to participate in dividends, when and if declared by our board of directors, on an as converted basis at the initial conversion price of $2.67 per share, not to exceed the maximum ownership percentages (as defined).

Optional conversion — Holders of redeemable preferred stock have the option to convert redeemable preferred stock into shares of common stock, rounded up to the nearest whole shares, at any time, not to exceed the maximum ownership percentages (as defined), at the conversion rate calculated as (1) whole shares of redeemable preferred shares to be converted at $1,000 per share, plus any accrued but unpaid dividends, and any accrued but unpaid late charges, divided by (2) the conversion price which is $2.67 per share initially, or as adjusted for any dilutive events and down rounds.

Mandatory conversion — If for any ten consecutive trading days after the redeemable preferred stock issuance date, the weighted average price of our common stock equals or exceeds 200% of the then current conversion price (initially $2.67 per share, subject to adjustment for stock dividends, stock splits, or a stock combination), we have the option to require all holders of redeemable preferred stock to convert all or a pro rata portion of their outstanding unconverted redeemable preferred stock (plus accrued and unpaid dividends and accrued and unpaid late charges) into common stock at the then current conversion rate (initially $2.67 per share), up to the maximum ownership percentage (as defined).

Triggering event conversion — Upon a triggering event, holders of redeemable preferred stock may elect to convert all, or a portion of, the outstanding conversion amount at the triggering event conversion price determined based on the lowest of (1) the conversion price then in effect (initially $2.67 per share), (2) 75% of the lowest VWAP during the 20-day period prior to the triggering event conversion date, and (3) 75% of the VWAP on the triggering event conversion date, adjusted for any share dividend, share split, or share combination.

Installment — On each of the nine specified installment dates beginning in December 2017 through maturity, we are required to convert, redeem, or a combination, one-ninth of the originally issued number of redeemable preferred shares at their stated value of $1,000 per share, for an aggregate value of $1,739,524 at each installment. If we elect to convert the installment shares, the conversion price is determined based on the lowest of (i) the then applicable conversion price (initially $2.67 per share), (ii) 85% of the average of the three lowest weighted-average prices of the common stock during the ten trading days up to the installment date, and (iii) 85% of the weighted average price of common stock on the trading day immediately before the installment date. If we elect cash redemption, the redemption amount is $1,000 per share, plus any accrued but unpaid dividends and any accrued but unpaid late charges.

Liquidation preference — In the event of a voluntary or involuntary liquidation, dissolution, or winding up of business involving substantially all of our assets, holders of redeemable preferred stock are entitled to receive cash payments in priority to holders of common stock in the amount that equals the sum of any outstanding shares at $1,000 per share, plus any accrued and unpaid dividends, and any accrued and unpaid late charges. If assets available for distribution are insufficient to satisfy the liquidation payment in full, funds available for distribution shall be allocated pari passu among holders of redeemable preferred stock, and other equity classes equal in preference, based on their relative shareholdings. When the holders of redeemable preferred stock are satisfied in full, any excess assets available for distribution will be allocated ratably among holders of common stock and holders of redeemable preferred stock based on the number of common shares held by each holders of redeemable preferred stock on an as-converted basis.

Mandatory redemption — Upon maturity, we are required to redeem remaining outstanding redeemable preferred stock, if any, in cash at $1,000 per share, plus any accrued and unpaid dividends, and any accrued and unpaid late charges.

Change of control redemption or triggering event redemption — In the event of a change of control or upon a triggering event, holders of redeemable preferred stock may redeem for cash all or a portion of their outstanding redeemable preferred stock at the greater of (i) 125% of the amount to be redeemed, or (ii) the amount to be redeemed multiplied by the quotient of the highest closing sale price during the period from the earlier of consummation or public announcement of the change of control to the date of the redemption notice, divided by the lowest conversion price in effect during such period. If we are unable to redeem all redeemable preferred stock submitted for redemption, we may be required to pay a penalty until the redemption amount is paid in full.

Stock purchasing rights — Holders of redeemable preferred stock are entitled to the same stock purchasing rights granted to holders of common stock.

Late charges — We may be required to pay a late charge for any amounts due to the holders of redeemable preferred stock that are not paid timely, at 12% per annum on the unpaid amount, until it is paid in full.

Affirmative covenants — Until all the redeemable preferred stock shares have been converted, redeemed, or otherwise satisfied in accordance with their terms, the Company is required to meet certain affirmative covenants that include maintaining its existence as a Delaware corporation, and maintaining cash on deposit in an unrestricted account with an aggregate amount not less than the lower of $3,500,000 or the redeemable preferred stock outstanding conversion amount.

Because the securities contain contingencies which could require the Company to redeem the shares for cash, and such contingencies are outside the control of the Company, the redeemable preferred stock is classified outside of permanent equity. Because a substantive conversion feature is present at issuance, the redeemable preferred stock is only contingently redeemable and therefore is classified as temporary equity and carried on the balance sheet in between liabilities and equity at its accreted redemption value.

In addition, certain features present in the redeemable preferred stock require separate recognition. For purposes of this evaluation, we have determined that the redeemable preferred instrument is more akin to a debt host because the installment conversion feature, as the primary settlement mechanism, is indexed to an underlying other than interest rates or credit risk and settles in variable shares. Because the potential contingent redemption price contains a significant premium over the issuance price, the redemption feature is considered to be not clearly and closely related to the debt-like host instrument. All redemption features (including the change of control redemption, triggering event redemption, mandatory redemption, and installment redemption) have been determined to be a single, compound embedded derivative financial instrument to be bifurcated and separately accounted for as a liability. The embedded derivative financial instrument was initially recorded at its fair value on the redeemable preferred stock issuance date and is being remeasured on each subsequent balance date with changes in fair value classified as a component of other income (expenses), net. The embedded derivative is classified as a component of other long-term liabilities.

The redeemable preferred stock also contains a beneficial conversion feature at issuance. The conversion feature was “in-the-money” as of the commitment date as the fair value of the underlying common share was greater than the effective conversion price. The beneficial conversion feature, measured as the intrinsic value of the feature, totaled $1,506,196 on the redeemable preferred stock issuance date, and is classified as a component of additional paid-in capital. The beneficial conversion feature will not be remeasured in subsequent periods but will be released in nine equal amounts corresponding to each of the redeemable preferred stock installments. Through December 31, 2017, $167,356 of the beneficial conversion feature has been released within components of additional paid-in capital with a balance of $1,338,840 remaining at December 31, 2017.

Through December 31, 2017, the Company converted 3,480 shares of redeemable preferred stock which included a scheduled installment due on December 15, 2017 and a pre-installment on December 13, 2017 for the January 2018 scheduled installment.

The net proceeds from the redeemable preferred stock financing were allocated as follows:


Common stock warrant liability (see Note 16)	$	3,498,632
Embedded derivative		19,857
Beneficial conversion feature		1,506,196
Initial carrying value of redeemable preferred stock		7,993,885

Net proceeds from redeemable preferred stock issuance	$	13,018,570

The periodic changes in the fair value of the embedded redemption derivative financial instrument is as follows:


Balance, January 1, 2017	$	—
Issuance		19,857
Changes in fair value		7,379

Balance, December 31, 2017	$	27,236

The fair value used to determine the initial carrying value of the embedded redemption derivative financial instrument was measured using Level 3 inputs and was estimated using the Monte Carlo simulation valuation model. The assumptions used to estimate the fair value of the embedded redemption derivative financial instrument at December 31, 2017 and as of the redeemable preferred stock issuance date were as follows:


	December 31, 2017			August 16, 2017
Expected volatility		59.60	%		56.40	%
Incremental borrowing rate		12.00	%		12.00	%
Risk-free interest rate		1.59	%		1.24	%

Stock-Based Compensation

12 Months Ended

Dec. 31, 2017

Stock-Based Compensation

15.

Stock-Based Compensation

Stock Options

The Company established the 2001 Employee Stock Option Plan to provide incentive stock options and non-qualified stock options to employees, and the 2001 Non-employee Stock Option Plan to provide non-qualified stock options to the members of the board of directors and advisory board, and non-employees. The 2001 Employee Stock Option Plan and the 2001 Non-employee Stock Option Plan are collectively referred to as the “2001 Plans.” In connection with the Mergers, the Company issued options from its 2001 Plans to replace options previously granted under PharmAthene’s option plans. At the close of the Mergers, the Company de-designated common stock available for issuance under the 2001 Plans and the PharmAthene plans. No additional options or restricted stock will be granted under these plans. Options outstanding and unvested restricted stock granted under these plans through the close of the Mergers will continue to vest over the remaining vesting period through the earlier of exercise, expiration, or forfeiture no additional options, restricted stock or other awards will be granted under these plans. The replacement options issued after the Merger will continue to vest over the remaining vesting period through the earlier of exercise, expiration, or forfeiture. Also, in connection with the Mergers, the 2001 Plans were assumed by the Company.

In addition, PharmAthene had previously established the PharmAthene, Inc. Amended and Restated 2007 Long-Term Incentive Compensation Plan, or the 2007 Plan. Awards outstanding under the 2007 Plan remained outstanding following the Mergers in accordance with their applicable terms and conditions. No additional awards will be made under the 2007 Plan.

Also in connection with the Mergers, the Company established the 2017 Omnibus Incentive Plan (the “Omnibus Plan”) to provide incentive stock options, non-qualified stock options, restricted stock, and other stock-based awards denominated in shares of the Company’s common stock, and performance-based cash awards to eligible employees, consultants, and directors. Up to 1,500,000 shares of the Company’s common stock have initially been reserved and may be issued under the Omnibus Plan. The aggregate share reserve will be increased on January 1 of each year commencing in 2018 and ending on and including January 1, 2027 up to an amount equal to the lowest of (i) 1,000,000 shares of common stock, (ii) 4% of the total number of shares of common stock outstanding on a fully diluted basis as of December 31 of the immediately preceding calendar year, and (iii) such number of shares of common stock, if any, determined by the Company’s board of directors. The maximum shares of common stock that may be granted to each employee or consultant in any fiscal year under the Omnibus Plan is the lesser of 800,000 shares per type of award or a maximum compensation amount of $5,000,000. The maximum common stock that may be granted to directors under the Omnibus Plan during any fiscal year is 500,000 shares.

The 2001 Plans, the 2007 Plan, and the Omnibus Plan are collectively referred to as the “Plans.” Under the Plans, a total of 4,500,869 shares of common stock were authorized for issuance. As of December 31, 2017, options to purchase 872,348 shares of common stock have been exercised to date with 708,073 shares of common stock available for future grants.

The fair value of stock option issued to employees was estimated at the date of grant using Black-Scholes with the following weighted-average assumptions:


	Year Ended December 31,
	2017			2016
Expected volatility		89.17	%		76.50	%
Expected term (years)		5.84			6.25
Risk-free interest rate		1.95	%		2.18	%
Expected dividend yield		0.00	%		0.00	%

Expected volatility: As there is not sufficient historical volatility for the expected term of the stock options, the Company uses an average historical share price volatility based on an analysis of reported data for a peer group of comparable companies which were selected based upon industry similarities.

Expected term (years): Expected term represents the number of years that the Company’s option grants are expected to be outstanding. There is not sufficient historical share exercise data to calculate the expected term of the stock options, therefore, the Company elected to utilize the simplified method to value option grants. Under this approach, the weighted average expected life is presumed to be the average of the vesting term and the contractual term of the option.

Risk-free interest rate: The Company determined the risk-free interest rate by using a weighted-average equivalent to the expected term based on the daily U.S. Treasury yield curve rate in effect as of the date of grant.

Expected dividend yield: The Company does not anticipate paying any dividends in the foreseeable future.

Forfeitures: Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from estimates.

The fair value of each non-employee stock option is estimated at the date of grant using Black-Scholes with assumptions generally consistent with those used for employee stock options, with the exception of expected term, which is over the contractual life.

A summary of stock option activities under the Plans is presented below:


	Number of Stock Options			Weighted- Average Exercise Price		Weighted-Average Remaining Contractual Term (Year)		Weighted- Average Intrinsic Value
Outstanding, January 1, 2017		1,206,104		$	3.91		5.79	$	8,475,032
Granted		801,927			3.03
Replacement options issued in connection with the Mergers		123,003			38.76
Exercised		(200,857	)		0.08			$	413,623
Forfeited or expired		(110,861	)		37.11

Outstanding, December 31, 2017		1,819,316		$	4.27		4.45	$	882,103

Exercisable, December 31, 2017		984,666		$	3.98		4.47	$	863,426

Expected to vest, December 31, 2017		834,650		$	4.62		4.42	$	18,678

The per share weighted-average grant date fair value of stock options granted during the years ended December 31, 2017 and 2016 were $2.16 and $8.92, respectively. The aggregate intrinsic value for stock options exercised during the year ended December 31, 2016 was $10,273. At December 31, 2017, there was $2,001,250 of unrecognized compensation cost related to stock options, which is expected to be recognized over a weighted-average period of 2.15 years. As more fully described in Note 3, in connection with the Mergers, all historical option information has been retroactively adjusted to reflect the effect of the share exchange ratio.

Restricted Stock

In October 2016, the Company authorized and granted a restricted stock award of 79,516 shares at an aggregate purchase price of $1,067. The weighted average grant date fair value of the restricted stock award was $10.36 per share. The restricted stock vests ratably at the end of each quarter over four years starting on December 31, 2016 with 50% of the original issued shared subject to accelerated vesting upon a deemed liquidation event. Fair value of restricted shares that vested during the year ended December 31, 2017 totaled $331,076. Under certain conditions, the Company has the right to repurchase any unvested shares at a price of $0.01 per share. Accordingly, the aggregate repurchase price is recorded as a long-term liability to be amortized over the vesting period with the amortization classified as a component of additional paid-in capital. As more fully described in Note 3, in connection with the Mergers, all historical restricted stock information has been retroactively adjusted to reflect the effect of the share exchange ratio (Note 3).

A summary of restricted stock activities is presented below:


	Shares			Weighted- average Grant Date Fair Value		Restricted Stock Repurchase Liability
Unvested, January 1, 2017		74,546		$	10.36	$	1,001
Vested		(51,118	)		10.36		(686	)

Unvested, December 31, 2017		23,428			10.36	$	315

As of December 31, 2017, total unrecognized compensation expense related to restricted stock awards was $23,177, which the Company expects to recognize over a weighted average period of approximately 2.75 years.

Stock-based Compensation Expense

Stock-based compensation expense is classified in the accompanying consolidated statements of operations and comprehensive loss for the years ended December 31, 2017 and 2016 as follows:


	Year Ended December 31,
	2017		2016
Research and development	$	327,610	$	299,398
General and administrative		1,115,882		665,967

Total	$	1,443,492	$	965,365

Warrants

12 Months Ended

Dec. 31, 2017

Equity [Abstract]

Warrants

16. Warrants

The following common stock warrants were outstanding at December 31, 2017:

Number of
Common
Stock
Warrants

Per Share
Exercise
Price

Issuance Date

Expiration Date

Replacement warrants issued in connection with the Mergers

4,658

16.10

March 3, 2012

March 3, 2022

Issued with redeemable preferred stock

2,345,427

2.67

August 16, 2017

August 16, 2022

Total

2,350,085

The following common stock warrants were outstanding at December 31, 2016:

Number of
Common
Stock
Warrants

Per Share
Exercise
Price

Issuance Date

Expiration Date

Issued in connection with loan guarantees

74,115

0.08

October 10, 2011

October 10, 2021

Issued with convertible preferred stock

134,499

0.01

November 6, 2015

November 6, 2020

Issued with convertible preferred stock

134,500

0.01

January 12, 2016

November 6, 2020

Issued with convertible preferred stock

134,499

0.01

April 8, 2016

November 6, 2020

Issued with convertible preferred stock

134,499

0.01

August 16, 2016

November 6, 2020

Total

612,112

As is more fully described in Note 3, in connection with the Mergers, all historical warrant information has been retroactively adjusted to reflect the effect of the share exchange ratio.

In March 2017, we issued warrants to purchase up to 49,776 shares of common stock in connection with the Notes (see Note 1). Those warrants were classified as permanent equity and were recorded at the issuance date using a relative fair value allocation method which were not subsequently remeasured. In connection with the Mergers, 660,652 shares of common stock were issued upon the cashless exercises of 661,888 warrants. In May 2017, we issued 4,658 common stock warrants to replace outstanding PharmAthene common stock warrants in connection with the Mergers.

In August 2017, in connection with the redeemable preferred stock issuance (Note 14), we granted warrants to holders of redeemable preferred stock to purchase up to 2,345,427 shares of our common stock. Warrants issued with the redeemable preferred stock are classified as a liability and are initially recorded at their grant date fair value, to be remeasured on each subsequent balance sheet date. The warrant liability is classified as component of other long-term liabilities.

A summary of warrant activity during the years ended December 31, 2017 and 2016 is as follows:


	Year Ended December 31,
	2017			2016
Warrants outstanding, January 1		612,112			208,614
Issuances		2,395,203			403,498
Replacement warrants issued in connection with the Mergers		4,658			—
Exercises and conversions		(661,888	)		—

Warrants outstanding, December 31		2,350,085			612,112

Warrants outstanding at December 31, 2017 have an aggregate grant date fair value of $3,498,720 with a weighted average exercise price of $2.70.

The fair value used to determine the initial carrying value of warrants classified as permanent equity was measured using Level 3 inputs and was estimated using the Black-Scholes option pricing model. The following assumptions were used to estimate the fair value of warrants issued during the years ended December 31, 2017 and 2016 that were classified as permanent equity:


	March 9, 2017 Issuance			August 19, 2016 Issuance			April 8, 2016 Issuance			January 12, 2016 Issuance
Expected volatility		84.40	%		71.00	%		77.00	%		76.00	%
Expected term (years)		5.00			4.22			4.58			4.82
Risk-free interest rate		2.13	%		1.08	%		1.15	%		1.65	%
Expected dividend yield		0.00	%		0.00	%		0.00	%		0.00	%

The periodic changes in the fair value of the warrant liability is as follows:


Balance, January 1, 2017	$	—
Issuance		3,498,632
Changes in fair value		(97,763	)

Balance, December 31, 2017	$	3,400,869

The following assumptions were used to estimate the fair value of warrants classified as a liability using the Monte Carlo simulation valuation model with Level 3 inputs at December 31, 2017 and as of the redeemable preferred stock issuance date were as follows:


	December 31, 2017			August 16, 2017
Expected volatility		91.30	%		86.90	%
Expected term (years)		4.60			5.00
Risk-free interest rate		2.16	%		1.76	%
Expected dividend yield		0.00	%		0.00	%

Income Taxes

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Income Taxes

17.

Income Taxes

Pursuant to federal and state tax regulations with respect to carryback periods of certain NOLs, as a result of the Mergers, we anticipate that we will be able to carryback 2017 NOLs to 2016 which we expect will allow us to recover federal and state income taxes previously paid by PharmAthene and other tax credits of $6,361,657. These anticipated refunds are classified as a component of current assets at December 31, 2017.

The components of net loss before income tax benefit are as follows:


	Year Ended December 31,
	2017		2016
U.S. operations	$	27,814,653	$	8,175,119
Non-U.S. operations		24,249,112		2,911,693

Net loss before income tax benefit	$	52,063,765	$	11,086,812

The components of the income tax benefits are as follows:


	Year Ended December 31,
	2017		2016
U.S. federal
Current	$	2,432,088	$	—
Deferred		2,608,256		—
US state and local
Current		587,711		—
Deferred		10,320		—

Income tax benefit	$	5,638,375	$	—

Reconciliation between the effect of applying the federal statutory rate and the effective income tax rate used to calculate the Company’s income tax benefit is as follows:


	Year Ended December 31,
	2017			2016
Federal statutory rate		34.00	%		34.00	%
State income taxes, net of federal benefit		1.20			3.51
Foreign income tax rate differential		(0.05	)		(3.50	)
Effect of the Tax Cuts and Jobs Act (“TCJA”) on tax rates		(2.16	)		—
Stock compensation		(2.49	)		(0.18	)
Research and development tax credit		(2.33	)		—
Acquisition costs		(0.77	)		(2.05	)
Goodwill impairment		(22.69	)		—
Permanent differences and other		(0.78	)		(6.34	)
Change in valuation allowance		6.90			(25.44	)

Effective tax rate		10.83	%		0.00	%

On December 22, 2017, the President of the United States signed into law the TCJA. The TCJA makes significant changes in the U.S. tax code including the following:

•

reduction of the corporate federal income tax rate from 35% to 21%;

•

repeal of the domestic manufacturing deduction;

•

repeal of the corporate alternative minimum tax;

•

a one-time transition tax on accumulated foreign earnings (if any);

•

a move to a territorial tax system; and

•

acceleration of business asset expensing.

In December 2017, 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 income tax effects of the TCJA. The Company has recognized the provisional tax impacts in 2017, including $1,125,708 in incremental income tax provision in the fourth quarter of 2017 to re-measure our deferred tax assets to the 21% enacted rate. The final amounts may differ from these provisional amounts, possibly materially, due to, among other things, additional analysis, changes in interpretations and assumptions the Company has made, additional regulatory guidance that may be issued, and actions the Company may take as a result of the TCJA.

The TCJA provided for a one-time deemed mandatory repatriation of post-1986 undistributed foreign subsidiary earnings and profits through December 31, 2017. Based on the Company’s provisional analysis performed to date, we do not expect to be subject to the one-time transition tax due to our foreign subsidiaries being in a net accumulated deficit position.

While the TCJA provides for a territorial tax system, beginning in 2018, it includes the following new anti-abuse provisions:

•

The global intangible low-taxed income (“GILTI”) provisions require the Company to include in our U.S. income tax base foreign subsidiary earnings in excess of an allowable return on the foreign subsidiary’s tangible assets. The Company expects that we will be subject to incremental U.S. tax resulting from GILTI inclusions beginning in 2018. However, our analysis and accounting for the effects of the GILTI provision is incomplete and an accounting policy on whether we will account for impact of GILTI inclusions in the period in which it is incurred or record deferred taxes for anticipated GILTI inclusions has not been made.

•

The base-erosion and anti-abuse tax (“BEAT”) provisions in the TCJA impose an alternative minimum tax on taxpayers with substantial base-erosion payments. Our preliminary assessment is that the Company will not be subject to the BEAT; however, our analysis is incomplete and we will continue to analyze the impact of the BEAT provisions to determine if these would be material to the company’s effective tax rate.

Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income and for tax carryforwards. Significant components of the Company’s deferred tax assets and liabilities are as follows:


	December 31,
	2017			2016
Deferred tax assets:
Domestic NOLs	$	6,320,893		$	6,761,452
Foreign NOLs		8,323,454			4,094,141
Accrued expenses		19,597			793,148
Amortization		1,187,512			254,990
Deferred revenue		49,373			78,565
Stock compensation		589,986			561,749
Deferred rent		110,731			11,954
Depreciation		6,955			(6,081	)

Total deferred tax assets		16,608,501			12,549,918

Deferred tax liabilities:
IPR&D assets		(8,856,561	)		(2,607,364	)
Prepaid expenses		—			(54,549	)
IRC §481(a) adjustment		(20,118	)		(32,194	)

Total deferred tax liabilities		(8,876,679	)		(2,694,107	)

Deferred tax assets, net		7,731,822			9,855,811
Valuation allowance		(13,670,224	)		(9,855,811	)

Total deferred tax liabilities, net	$	(5,938,402	)	$	—

The Company assesses the need for a valuation allowance against our deferred tax assets and considers both positive and negative evidence related to the likelihood of realization of the deferred tax assets to determine, based on the weight of available evidence, whether it is more-likely-than-not that some or all of the deferred tax assets will not be realized. This determination requires significant judgment, including assumptions about future taxable income that are based on historical and projected information. The $3,814,411 net change in the valuation allowance during the year ended December 31, 2017 primarily relates to the Mergers, goodwill impairment, and the re-measurement of our deferred income taxes to the new U.S. statutory tax rate. The Company has recorded a valuation allowance against the majority of its gross U.S. net deferred tax assets it believes are not more likely than not realizable and the net non-U.S. deferred tax assets. Deferred tax liabilities, consist primarily of indefinite life IPR&D assets located in the U.S. and the U.K., will be applied in the future to offset against NOLs generated after 2017 which will have an unlimited life.

At December 31, 2017, the Company had U.S. federal NOLs totaling approximately $24,499,476, that will begin to expire in 2020, and U.S. state NOLs of approximately $18,043,782 that will begin to expire in 2023. Also at December 31, 2017, NOLs for the Company’s U.K. subsidiaries and France subsidiary totaled $18,819,106 and $845,651, respectively, which do not expire as long as the U.K. and France subsidiaries continue to engage in the same trade or business. Under Section 382 of the Internal Revenue Code of 1986, as amended, substantial changes in the Company’s ownership may limit the amount of NOLs that can be utilized annually in the future to offset its U.S. federal and state taxable income. Specifically, this limitation may arise in the event of a cumulative change in ownership of the Company of more than 50% within any three-year period. The amount of the annual limitation is determined based on the value of the Company immediately before the ownership change. Subsequent ownership changes may further affect the limitation in future years. The Company believes that as of December 31, 2017, there was no material limitation on our ability to utilize NOLs and other tax attributes in the future.

As of December 31, 2017 and 2016, we do not have any material unrecognized tax benefits. We file income tax returns in the United States, various U.S. states, U.K., and France. The Company is still open to examination by the applicable taxing authorities from 2009 forward, although tax attributes that were generated prior to 2009 may still be adjusted upon examination by federal, state, foreign, or local tax authorities if they either have been or will be used in a future period. In March 2017, the Internal Revenue Service notified the Company regarding its plans to examine PharmAthene’s tax return for the year ended December 31, 2016.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

18.

Commitments and Contingencies

See Note 10 for the Company’s commitments under license agreements.

Operating Leases

The Company rents office and laboratory space in the United States under non-cancelable operating leases, which expire at various dates through October 2018. The leases require a security deposit of $22,248. The Company also leases office equipment under a non-cancellable equipment lease through June 2019. In addition, the Company rents office and laboratory space in the United Kingdom under a month-to-month arrangement that may be terminated by either the Company or the lessor at any time.

In June 2017, the Company entered into a new lease agreement for our new U.S. headquarters that includes 14,141 square foot of office and laboratory facilities under a noncancelable operating lease commencing on November 1, 2017 for an initial lease term of 90 months. The lease requires a security deposit of $34,174 which is recorded as a component of other assets. The lease provides for six months of free rent with the first base rent payment of $17,087 due on May 1, 2018. The base rent is subject to an annual 3% escalation effective on May 1 of each year during lease term. The Company is also required to pay our share of operating expenses billable by the landlord. Aggregate rent over the lease term plus free rent and rent escalation are recognized on a straight-line basis over the lease term with the difference between rent expense and rent payment recorded as deferred rent.

In addition, the lease agreement provides the Company tenant improvement incentives and allowances that include an upfront payment to the Company of $282,820, and up to $1,060,575 of additional tenant improvement allowances to be reimbursed by the landlord for construction costs incurred by the Company. Additional tenant improvement allowances, up to the maximum amount of $1,060,575, will be amortized and added to monthly rent payment beginning on May 1, 2018 and over the remaining lease term, regardless of whether the construction is complete, plus interest at 8.5% per annum. Additional monthly rent payment resulting from additional tenant improvement allowance is not subject to the annual 3% rent escalation applicable to the base rent.

Construction costs incurred are recorded as construction in progress with a corresponding lease incentive obligation which is classified as a component of deferred rent. The amounts to be reimbursed by the landlord are recorded as a component of prepaid expenses and other current assets when billed. Through December 31, 2017, the Company has incurred $350,076 in construction costs and recorded $29,854 of amortization of lease incentive obligation as a reduction of rent expense.

Rent expense under all of the Company’s operating leases was $562,840 and $352,559 for the years ended December 31, 2017 and 2016, respectively. Deferred rent resulting from rent escalation totaled $82,180 and $30,302 at December 31, 2017 and 2016, respectively.

Future minimum lease payments for non-cancelable operating leases at December 31, 2017 are as follows:


Year ending December 31,
2018	$	438,409
2019		416,394
2020		422,668
2021		429,131
2022		435,788
2023 and thereafter		1,029,744

Total	$	3,172,134

Other Contingencies

We are a party in various contractual disputes, litigation, and potential claims arising in the ordinary course of business. We do not believe that the resolution of these matters will have a material adverse effect on our financial position or results of operations.

Fair Value Measurement

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Fair Value Measurement

19.

Fair Value Measurement

The Company records cash equivalents, warrant liability, and an embedded derivative at fair value on a recurring basis. Fair value is an exit price, representing the amount that would be received from the sale of an asset or paid to transfer a liability in an orderly transaction between market participants based on assumptions that market participants would use in pricing an asset or liability. As a basis for classifying the fair value measurements, a three-tier fair value hierarchy, which classifies the fair value measurements based on the inputs used in measuring fair value, was established. This hierarchy requires the Company to use observable market data, when available, and to minimize the use of unobservable inputs when determining fair value.

The Company’s cash equivalents are composed of money market funds which are classified as Level 1 in the fair value hierarchy. The Company’s warrant liability and an embedded derivative classified within Level 3 of the fair value hierarchy are valued using the Monte Carlo simulation valuation model. For certain other financial instruments, including accounts receivable, accounts payable, accrued expenses, and notes payable the carrying value approximate their fair value due to the short-term nature of these items. If applicable, the Company will recognize transfers into and out of levels within the fair value hierarchy at the end of the reporting period in which the actual event or change in circumstance occurs. There were no transfers into and out of any of the levels of the fair value hierarchy during 2017. The Company did not have assets or liabilities recorded at fair value on a recurring basis during the year ended December 31, 2016.

Assets recorded at fair value on a nonrecurring basis, such as property and equipment, intangible assets, and goodwill are recognized at fair value when they are impaired. During 2017, the Company recognized goodwill impairments measured at fair value on a nonrecurring basis. The Company did not have assets or liabilities recorded at fair value on a nonrecurring basis during the year ended December 31, 2016.

The Company’s assets and liabilities measured at fair value on a recurring and nonrecurrent basis at December 31, 2017 consisted of the following:


	Fair Value Measurement at December 31, 2017
	Total			Level 1		Level 2		Level 3			Total Loss
Recurring fair value measurements
Cash equivalents — money market fund	$	259,551		$	259,551	$	—	$	—		$	—
Restricted cash — money market fund		3,500,000			3,500,000
Warrant liability		(3,400,869	)						(3,400,869	)
Embedded derivative		(27,236	)		—		—		(27,236	)
Nonrecurring fair value measurement
Goodwill		—			—		—		—			35,919,695

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

Employee Benefit Plans

12 Months Ended

Dec. 31, 2017

Retirement Benefits [Abstract]

Employee Benefit Plans

20.

Employee Benefit Plans

We have a 401(k) retirement plan in which substantially all of our employees in the United States are eligible to participate. Eligible employees may elect to contribute up to the maximum limits, as set by the Internal Revenue Service, of their eligible compensation. During 2017 and 2016, we made discretionary plan contributions of $196,373 and $73,024, respectively.

Subsequent Events

12 Months Ended

Dec. 31, 2017

Subsequent Events [Abstract]

Subsequent Events

21.

Subsequent Events

None.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2017

Principles of Consolidation

Principles of Consolidation

Reclassification

Reclassification

Use of Estimates

Use of Estimates

Comprehensive Loss

Comprehensive Loss

For the years presented, the total comprehensive loss includes net loss and other comprehensive loss which represents foreign currency translation adjustments.

Foreign Currency Translation

Foreign Currency Translation

Segment

Segment

Business Combination

Business Combination

Intangible Assets

Intangible Assets

Acquisition-related Costs

Acquisition-related Costs

Impairment of Long-lived Assets and Goodwill

Impairment of Long-lived Assets and Goodwill

Fair Value Measurements

Fair Value Measurements

Level 1 — Quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company can access at the measurement date.

Level 3 — Unobservable inputs developed using estimates of assumptions developed by the Company, which reflect those that a market participant would use.

Financial Instruments

Financial Instruments

License Revenue

License Revenue

Research Grants and Contracts

Research Grants and Contracts

Research and Development

Research and Development

Clinical Trial Costs

Clinical Trial Costs

Cash Equivalents

Cash Equivalents

Restricted Cash

Restricted Cash

Accounts Receivable

Accounts Receivable

Concentrations of Credit Risk

Concentrations of Credit Risk


	Year Ended December 31,
	2017			2016
Research Grants and Contracts
BARDA		83	%		81	%
NIAID		17			—
Texas A&M University System		—			19


	December 31,
	2017			2016
Accounts Receivable
BARDA		73	%		100	%
NIAID		27			—

Property and Equipment, Net

Property and Equipment, Net


Asset Category		Estimated Useful Life
Computer and telecommunications		3 – 5 years
Software		3 years
Furniture, fixtures and equipment		5 years
Laboratory equipment		7 years
Leasehold improvements		Lesser of lease term or estimated useful lives

Patent and licensing costs

Patent and licensing costs

Preferred Stock

Preferred Stock

Warrants

Warrants

Stock-based Compensation

Stock-based Compensation

Income Taxes

Income Taxes

We account for income taxes using the asset and liability approach, which requires the recognition of future tax benefits or liabilities on the temporary differences between the financial reporting and tax bases of our assets and liabilities. Deferred tax assets and liabilities represent future tax consequences of temporary differences between the financial statementcarrying amounts and the tax basis of assets and liabilities and for loss carryforwards using enacted tax rates expected to be in effect in the years in which the differences reverse. A valuation allowance is established when necessary to reduce deferred tax assets to the amounts expected to be realized. We also recognize a tax benefit from uncertain tax positions only if it is “more likely than not” that the position is sustainable based on its technical merits. The Company accounts for interest and penalties related to uncertain tax positions as part of its provision for income taxes. To date, the Company has not incurred interest and penalties related to uncertain tax positions. Should such costs be incurred, they would be classified as a component of provision for income taxes.

Net Loss per Share

Net Loss per Share

Lease Incentive Obligations

Lease Incentive Obligations

Deferred Rent

Deferred Rent

Recently Issued Accounting Pronouncements

Recently Issued Accounting Pronouncements

Business Combination (Tables)

12 Months Ended

Dec. 31, 2017

Business Combinations [Abstract]

Schedule of Lists of Various Securities

The following table lists the various securities of PharmAthene which were outstanding as of May 4, 2017 and whose rights and obligations were assumed by the combined entity following the Mergers:


Outstanding PharmAthene common stock		6,883,498
Outstanding PharmAthene stock options		123,003
Outstanding PharmAthene stock warrants		4,658
Per share fair value of PharmAthene common stock	$	6.50
Weighted average per share fair value of PharmAthene stock options, vested and unvested	$	0.26
Per share fair value of PharmAthene stock warrants	$	0.01
Aggregate fair value of consideration	$	44,757,910
Less fair value of unvested common stock options		(15,173	)

Total fair value of consideration	$	44,742,737

Schedule of Purchase Price Allocation

The adjusted allocation of the purchase consideration was as follows:


Cash and cash equivalents	$	13,684,535
Accounts receivable		1,124,462
Prepaid expenses and other current assets		597,172
Tax refund receivable		2,047,234
Property and equipment		75,779
IPR&D		22,389,000
Goodwill		15,573,822

Total assets acquired		55,492,004

Accounts payable and accrued expenses		(2,193,785	)
Deferred tax liability		(8,555,482	)

Total liabilities assumed		(10,749,267	)

Net assets acquired	$	44,742,737

Summary of Unaudited Pro Forma Information


	Year Ended December 31,
	2017			2016
Pro forma revenue and grants and contracts	$	11,844,273		$	8,466,371
Pro forma net (loss) income attributable to common stockholders	$	(52,315,978	)	$	186,664,464
Pro forma weighted average common shares outstanding, basic		15,547,863			14,368,157
Pro forma net (loss) income per share, basic	$	(3.36	)	$	12.99
Pro forma weighted average common shares outstanding, diluted		15,547,863			15,201,819
Pro forma net (loss) income per share, diluted	$	(3.36	)	$	12.28

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2017

Summary of Concentration Risk by Percentage

Grantors that represented 10% or more of research grants and contracts for the years ended December 31, 2017 and 2016 and grantors that accounted for 10% or more of accounts receivable at December 31, 2017 and 2016, are presented below:


	Year Ended December 31,
	2017			2016
Research Grants and Contracts
BARDA		83	%		81	%
NIAID		17			—
Texas A&M University System		—			19


	December 31,
	2017			2016
Accounts Receivable
BARDA		73	%		100	%
NIAID		27			—

Summary of Depreciation and Amortization Recorded using Straight-line Method over Estimated Useful Lives

Depreciation and amortization are recorded using the straight-line method over the estimated useful lives of the assets, as follows:


Asset Category		Estimated Useful Life
Computer and telecommunications		3 – 5 years
Software		3 years
Furniture, fixtures and equipment		5 years
Laboratory equipment		7 years
Leasehold improvements		Lesser of lease term or estimated useful lives

Net Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2017

Earnings Per Share [Abstract]

Schedule of Computation of Basic and Diluted Net Loss Per Share

The following table sets forth the computation of basic and diluted net loss per share:


	Year Ended December 31,
	2017			2016
Numerator
Net loss	$	(46,425,390	)	$	(11,086,812	)
Less: preferred stock accretion and dividends		(4,930,010	)		(368,548	)

Net loss attributable to common stockholders	$	(51,355,400	)	$	(11,455,360	)

Denominator
Weighted-average common shares outstanding, basic and diluted		12,805,095			6,911,534

Net loss per share attributable to common stockholders, basic and diluted		(4.01	)		(1.66	)

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share


	Year Ended December 31,
	2017		2016
Convertible preferred stock		—		599,285
Redeemable preferred stock		4,560,550		—
Common stock warrants		2,350,085		612,112
Common stock options		1,819,316		1,205,920
Unvested restricted stock		23,428		74,546

Property and Equipment, Net (Tables)

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Summary of Property and Equipment, Net

Property and equipment, net consisted of the following:


	December 31,
	2017			2016
Furniture, fixtures and equipment	$	61,121		$	60,320
Laboratory equipment		1,001,810			932,065
Computers and telecommunications		81,342			45,837
Software		16,244			595
Leasehold improvements		44,352			44,352
Construction in progress		350,075			—

Property and equipment, at cost		1,554,944			1,083,169
Less accumulated depreciation and amortization		(951,798	)		(905,310	)

Property and equipment, net	$	603,146		$	177,859

Intangible Assets, Net (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Intangible Assets

The Company’s intangible assets consisted of the following:


	December 31, 2017
	Estimated Useful Lives		Gross Carrying Value		Accumulated Amortization			Net Book Value
Internally developed patents		6 – 10 years	$	678,340	$	(249,601	)	$	428,739
Acquired licenses		16 – 20 years		285,000		(237,340	)		47,660

Total intangible assets subject to amortization				963,340		(486,941	)		476,399
IPR&D assets		Indefinite		38,245,871		—			38,245,871

Total			$	39,209,211	$	(486,941	)	$	38,722,270


	December 31, 2016
	Estimated Useful Lives		Gross Carrying Value		Accumulated Amortization			Net Book Value
Internally developed patents		6 – 10 years	$	624,454	$	(211,956	)	$	412,498
Acquired licenses		16 – 20 years		285,000		(219,800	)		65,200

Total intangible assets subject to amortization				909,454		(431,756	)		477,698
IPR&D assets		Indefinite		14,477,019		—			14,477,019

Total			$	15,386,473	$	(431,756	)	$	14,954,717

Schedule of Future Estimated Amortization Expense

As of December 31, 2017, future estimated amortization expense is as follows:


Year ending December 31,
2018	$	53,113
2019		48,314
2020		34,868
2021		14,308
2022		14,308
2023 and thereafter		311,488

Total	$	476,399

IPR&D and Goodwill (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Changes in Carrying Amounts of IPR&D Assets and Goodwill

Changes in the carrying amounts of IPR&D assets and goodwill for the years ended December 31, 2017 and 2016 were:


	IPR&D			Goodwill
Balance, January 1, 2016	$	17,366,791		$	22,494,691
Foreign currency translation adjustments		(2,889,772	)		(3,736,270	)

Balance, December 31, 2016		14,477,019			18,758,421
Additions from the Mergers		22,389,000			15,573,822
Foreign currency translation adjustments		1,379,852			1,587,452
Impairment charges		—			(35,919,695	)

Balance, December 31, 2017	$	38,245,871		$	—

Accrued Expenses (Tables)

12 Months Ended

Dec. 31, 2017

Schedule of Accrued Expenses

Accrued expenses consist of the following:


	December 31,
	2017		2016
Accrued professional services	$	835,326	$	689,135
Accrued board of director compensation		—		606,199
Accrued payroll and employee benefits		909,455		957,719
Accrued interest		536		169,790
Accrued construction costs		328,384		—
Accrued research and development		1,551,556		549.902

Accrued expenses	$	3,625,257	$	2,972,745

Notes Payable (Tables)

12 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

Summary of Outstanding Notes Payable

The Company’s outstanding notes payable are summarized as follows:


	December 31,
	2017		2016
Line of credit	$	49,702	$	49,702
Economic Development Partnership of Alabama (“EDPA”) promissory note		—		96,496
Hammond promissory note		—		100,000
Alex Choi promissory note		—		100,000
Frommer, Lawrence and Haug LLP (“FLH”) promissory note		—		112,431

Total notes payable	$	49,702	$	458,629

Other Long-Term Liabilities (Tables)

12 Months Ended

Dec. 31, 2017

Summary of Other Long-Term Liabilities

The Company’s other long-term liabilities are summarized as follows:


	December 31,
	2017		2016
Unvested restricted stock (see Note 15)	$	315	$	1,001
BPI France notes		599,927		525,950
Deferred revenue, long-term portion (see Note 4)		159,671		179,424
Deferred rent, long-term portion		386,489		15,914
Common stock warrant liability (see Note 16)		3,400,869		—
Embedded derivative (see Note 14)		27,236		—

Total other long-term liabilities	$	4,574,507	$	722,289

Common Stock (Tables)

12 Months Ended

Dec. 31, 2017

Summary of Common Stock Reserved and Unreserved for Future Issuance

As of December 31, 2017, the Company’s common stock available for future issuance is summarized as follows:


Common stock authorized			100,000,000

Common stock issued and reserved for future issuance:
Common stock issued and outstanding			18,103,691
Common stock reserved for the exercises of common stock warrants			3,522,799
Common stock reserved for the conversion of redeemable preferred stock			6,840,818
Common stock reserved for the exercise of options			1,819,316
Common stock reserved for the vesting of unvested restricted stock			23,428
Common stock reserved for future option awards			708,073

Total common stock issued and reserved for future issuance			31,018,125

Unreserved common stock available for future issuance			68,981,875

Allocation of Net Proceeds from Redeemable Preferred Stock Financing

Tabular disclosure of an entity's stock, including par or stated value per share, number and dollar amount of share subscriptions, shares authorized, shares issued, shares outstanding, number and dollar amount of shares held in an employee trust, dividend per share, total dividends, share conversion features, par value plus additional paid in capital, the value of treasury stock and other information necessary to a fair presentation, and EPS information. Stock by class includes common, convertible, and preferred stocks which are not redeemable or redeemable solely at the option of the issuer. Includes preferred stock with redemption features that are solely within the control of the issuer and mandatorily redeemable stock if redemption is required to occur only upon liquidation or termination of the reporting entity. If more than one issue is outstanding, state the title of each issue and the corresponding dollar amount; dollar amount of any shares subscribed but unissued and the deduction of subscriptions receivable there from; number of shares authorized, issued, and outstanding.

+ References

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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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+ Details

Preferred Stock (Tables)

12 Months Ended

Dec. 31, 2017

The net proceeds from the redeemable preferred stock financing were allocated as follows:


Common stock warrant liability (see Note 16)	$	3,498,632
Embedded derivative		19,857
Beneficial conversion feature		1,506,196
Initial carrying value of redeemable preferred stock		7,993,885

Net proceeds from redeemable preferred stock issuance	$	13,018,570

Summary of Periodic Changes Fair Value of Embedded Redemption Derivative Financial Instrument

The periodic changes in the fair value of the embedded redemption derivative financial instrument is as follows:


Balance, January 1, 2017	$	—
Issuance		19,857
Changes in fair value		7,379

Balance, December 31, 2017	$	27,236

Assumptions Used to Estimate Fair Value of Embedded Redemption Derivative Financial Instrument


	December 31, 2017			August 16, 2017
Expected volatility		59.60	%		56.40	%
Incremental borrowing rate		12.00	%		12.00	%
Risk-free interest rate		1.59	%		1.24	%

Monte Carlo Simulation Model [Member]

Assumptions Used to Estimate Fair Value of Embedded Redemption Derivative Financial Instrument


	December 31, 2017			August 16, 2017
Expected volatility		91.30	%		86.90	%
Expected term (years)		4.60			5.00
Risk-free interest rate		2.16	%		1.76	%
Expected dividend yield		0.00	%		0.00	%

Black Scholes Option Pricing Model [Member]

Assumptions Used to Estimate Fair Value of Embedded Redemption Derivative Financial Instrument


	March 9, 2017 Issuance			August 19, 2016 Issuance			April 8, 2016 Issuance			January 12, 2016 Issuance
Expected volatility		84.40	%		71.00	%		77.00	%		76.00	%
Expected term (years)		5.00			4.22			4.58			4.82
Risk-free interest rate		2.13	%		1.08	%		1.15	%		1.65	%
Expected dividend yield		0.00	%		0.00	%		0.00	%		0.00	%

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary of Fair Value of Stock Options Issued to Employees

The fair value of stock option issued to employees was estimated at the date of grant using Black-Scholes with the following weighted-average assumptions:


	Year Ended December 31,
	2017			2016
Expected volatility		89.17	%		76.50	%
Expected term (years)		5.84			6.25
Risk-free interest rate		1.95	%		2.18	%
Expected dividend yield		0.00	%		0.00	%

Schedule of Information Related to Stock Options Outstanding

A summary of stock option activities under the Plans is presented below:


	Number of Stock Options			Weighted- Average Exercise Price		Weighted-Average Remaining Contractual Term (Year)		Weighted- Average Intrinsic Value
Outstanding, January 1, 2017		1,206,104		$	3.91		5.79	$	8,475,032
Granted		801,927			3.03
Replacement options issued in connection with the Mergers		123,003			38.76
Exercised		(200,857	)		0.08			$	413,623
Forfeited or expired		(110,861	)		37.11

Outstanding, December 31, 2017		1,819,316		$	4.27		4.45	$	882,103

Exercisable, December 31, 2017		984,666		$	3.98		4.47	$	863,426

Expected to vest, December 31, 2017		834,650		$	4.62		4.42	$	18,678

Summary of Restricted Stock Activity

A summary of restricted stock activities is presented below:


	Shares			Weighted- average Grant Date Fair Value		Restricted Stock Repurchase Liability
Unvested, January 1, 2017		74,546		$	10.36	$	1,001
Vested		(51,118	)		10.36		(686	)

Unvested, December 31, 2017		23,428			10.36	$	315

Schedule of Stock-based Compensation Expense

Stock-based compensation expense is classified in the accompanying consolidated statements of operations and comprehensive loss for the years ended December 31, 2017 and 2016 as follows:


	Year Ended December 31,
	2017		2016
Research and development	$	327,610	$	299,398
General and administrative		1,115,882		665,967

Total	$	1,443,492	$	965,365

Warrants (Tables)

12 Months Ended

Dec. 31, 2017

Equity [Abstract]

Summary of Common Stock Warrants Outstanding

The following common stock warrants were outstanding at December 31, 2017:

Number of
Common
Stock
Warrants

Per Share
Exercise
Price

Issuance Date

Expiration Date

Replacement warrants issued in connection with the Mergers

4,658

16.10

March 3, 2012

March 3, 2022

Issued with redeemable preferred stock

2,345,427

2.67

August 16, 2017

August 16, 2022

Total

2,350,085

The following common stock warrants were outstanding at December 31, 2016:

Number of
Common
Stock
Warrants

Per Share
Exercise
Price

Issuance Date

Expiration Date

Issued in connection with loan guarantees

74,115

0.08

October 10, 2011

October 10, 2021

Issued with convertible preferred stock

134,499

0.01

November 6, 2015

November 6, 2020

Issued with convertible preferred stock

134,500

0.01

January 12, 2016

November 6, 2020

Issued with convertible preferred stock

134,499

0.01

April 8, 2016

November 6, 2020

Issued with convertible preferred stock

134,499

0.01

August 16, 2016

November 6, 2020

Total

612,112

Summary of Warrant Activity

A summary of warrant activity during the years ended December 31, 2017 and 2016 is as follows:


	Year Ended December 31,
	2017			2016
Warrants outstanding, January 1		612,112			208,614
Issuances		2,395,203			403,498
Replacement warrants issued in connection with the Mergers		4,658			—
Exercises and conversions		(661,888	)		—

Warrants outstanding, December 31		2,350,085			612,112

Summary of Periodic Changes in Fair Value of Warrant Liability

The periodic changes in the fair value of the warrant liability is as follows:


Balance, January 1, 2017	$	—
Issuance		3,498,632
Changes in fair value		(97,763	)

Balance, December 31, 2017	$	3,400,869

Tabular disclosure of warrants or rights issued. Warrants and rights outstanding are derivative securities that give the holder the right to purchase securities (usually equity) from the issuer at a specific price within a certain time frame. Warrants are often included in a new debt issue to entice investors by a higher return potential. The main difference between warrants and call options is that warrants are issued and guaranteed by the company, whereas options are exchange instruments and are not issued by the company. Also, the lifetime of a warrant is often measured in years, while the lifetime of a typical option is measured in months. Disclose the title of issue of securities called for by warrants and rights outstanding, the aggregate amount of securities called for by warrants and rights outstanding, the date from which the warrants or rights are exercisable, and the price at which the warrant or right is exercisable.

Components of Net Loss Before Income Tax Benefit

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

The components of net loss before income tax benefit are as follows:


	Year Ended December 31,
	2017		2016
U.S. operations	$	27,814,653	$	8,175,119
Non-U.S. operations		24,249,112		2,911,693

Net loss before income tax benefit	$	52,063,765	$	11,086,812

Components of Income Tax Benefits

The components of the income tax benefits are as follows:


	Year Ended December 31,
	2017		2016
U.S. federal
Current	$	2,432,088	$	—
Deferred		2,608,256		—
US state and local
Current		587,711		—
Deferred		10,320		—

Income tax benefit	$	5,638,375	$	—

Reconciliation Between Effect of Applying Federal Statutory Rate and Effective Income Tax Rate Used to Calculate Income Tax Benefit

Reconciliation between the effect of applying the federal statutory rate and the effective income tax rate used to calculate the Company’s income tax benefit is as follows:


	Year Ended December 31,
	2017			2016
Federal statutory rate		34.00	%		34.00	%
State income taxes, net of federal benefit		1.20			3.51
Foreign income tax rate differential		(0.05	)		(3.50	)
Effect of the Tax Cuts and Jobs Act (“TCJA”) on tax rates		(2.16	)		—
Stock compensation		(2.49	)		(0.18	)
Research and development tax credit		(2.33	)		—
Acquisition costs		(0.77	)		(2.05	)
Goodwill impairment		(22.69	)		—
Permanent differences and other		(0.78	)		(6.34	)
Change in valuation allowance		6.90			(25.44	)

Effective tax rate		10.83	%		0.00	%

Components of Deferred Tax Assets and Liabilities

Significant components of the Company’s deferred tax assets and liabilities are as follows:


	December 31,
	2017			2016
Deferred tax assets:
Domestic NOLs	$	6,320,893		$	6,761,452
Foreign NOLs		8,323,454			4,094,141
Accrued expenses		19,597			793,148
Amortization		1,187,512			254,990
Deferred revenue		49,373			78,565
Stock compensation		589,986			561,749
Deferred rent		110,731			11,954
Depreciation		6,955			(6,081	)

Total deferred tax assets		16,608,501			12,549,918

Deferred tax liabilities:
IPR&D assets		(8,856,561	)		(2,607,364	)
Prepaid expenses		—			(54,549	)
IRC §481(a) adjustment		(20,118	)		(32,194	)

Total deferred tax liabilities		(8,876,679	)		(2,694,107	)

Deferred tax assets, net		7,731,822			9,855,811
Valuation allowance		(13,670,224	)		(9,855,811	)

Total deferred tax liabilities, net	$	(5,938,402	)	$	—

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Summary of Future Minimum Lease Payments

Future minimum lease payments for non-cancelable operating leases at December 31, 2017 are as follows:


Year ending December 31,
2018	$	438,409
2019		416,394
2020		422,668
2021		429,131
2022		435,788
2023 and thereafter		1,029,744

Total	$	3,172,134

Fair Value Measurement (Tables)

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis and Nonrecurrent Basis

The Company’s assets and liabilities measured at fair value on a recurring and nonrecurrent basis at December 31, 2017 consisted of the following:


	Fair Value Measurement at December 31, 2017
	Total			Level 1		Level 2		Level 3			Total Loss
Recurring fair value measurements
Cash equivalents — money market fund	$	259,551		$	259,551	$	—	$	—		$	—
Restricted cash — money market fund		3,500,000			3,500,000
Warrant liability		(3,400,869	)						(3,400,869	)
Embedded derivative		(27,236	)		—		—		(27,236	)
Nonrecurring fair value measurement
Goodwill		—			—		—		—			35,919,695

Tabular disclosure of financial instruments measured at fair value, including those classified in shareholders' equity measured on a recurring or nonrecurring basis. Disclosures include, but are not limited to, fair value measurements recorded and the reasons for the measurements, level within the fair value hierarchy in which the fair value measurements are categorized and transfers between levels 1 and 2. Nonrecurring fair value measurements are those that are required or permitted in the statement of financial position in particular circumstances.

Nature of Business and Basis of Presentation - Additional Information (Detail) - USD ($)			12 Months Ended
	Mar. 09, 2017	Feb. 28, 2017	Dec. 31, 2017	Jan. 31, 2017
Business And Basis Of Presentation [Line Items]
Shares of common stock called by warrants	49,776
Warrants exercise price per share	$ 0.01		$ 2.70
Indemnification Obligations [Member]
Business And Basis Of Presentation [Line Items]
Reserve for indemnification obligations			$ 0
Merger Agreement [Member]
Business And Basis Of Presentation [Line Items]
Agreement of reorganization and merger date			Jan. 18, 2017
Merger Agreement [Member] \| Merger Sub Corp I Inc and Mustang Merger Sub II LLC [Member]
Business And Basis Of Presentation [Line Items]
Business acquisition, percentage of voting interest acquired			100.00%
Convertible Promissory Note Purchase Agreement [Member]
Business And Basis Of Presentation [Line Items]
Accrued expenses modified and replaced with convertible notes		$ 881,044
Convertible Promissory Note Purchase Agreement [Member] \| 6% Convertible Notes [Member]
Business And Basis Of Presentation [Line Items]
Notes payable				$ 8,600,000
Notes payable, interest rate				6.00%
Description of second closing			The second closing under the Note Agreement was satisfied in connection with the sale of Series B redeemable convertible preferred stock ("redeemable preferred stock") that closed on August 16, 2017 (see Note 14).
Convertible Promissory Note Purchase Agreement [Member] \| 6% Convertible Notes [Member] \| Convertible Promissory Note Purchase Agreement Initial Closing [Member]
Business And Basis Of Presentation [Line Items]
Gross proceeds from notes payable	$ 3,150,630
Notes payable modified and replaced with convertible notes	196,496
Accrued expenses modified and replaced with convertible notes	$ 881,044

Going Concern - Additional Information (Detail) - USD ($)		12 Months Ended
	Aug. 16, 2017	Dec. 31, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Net loss		$ (46,425,390)	$ (11,086,812)
Cash used to fund operations		(20,214,079)	(6,353,008)
Accumulated deficit		$ (77,684,839)	$ (31,259,449)
Proceeds from issuance of preferred stock and related common stock warrants, net of issuance costs	$ 13,018,570

Business Combination - Additional Information (Detail)		8 Months Ended	12 Months Ended
Business Combination - Additional Information (Detail)	May 04, 2017 USD ($) shares	Dec. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Business Acquisition [Line Items]
Share exchange ratio			1-for-1 basis
Debt converted in to equity	316,734
Conversion of stock \| shares	6,883,498
Transaction costs	$ 2,183,671
Change in tax rate			34.00%	34.00%
Discount rate	23.00%
Revenue			$ 10,738,322	$ 3,236,175
Net loss			(46,425,390)	(11,086,812)
Restricted Stock Units (RSUs) [Member]
Business Acquisition [Line Items]
Conversion of stock \| shares	39,758
Series B Preferred Stock [Member]
Business Acquisition [Line Items]
Conversion of preferred stock	$ 599,285
Common Stock Class A [Member]
Business Acquisition [Line Items]
Common stock issued \| shares	6,883,498
United States [Member]
Business Acquisition [Line Items]
Operating loss carryforwards		$ 965,583	$ 965,583
Operating loss carryforwards, expiration date			Jan. 01, 2023
Acquisition-related Costs [Member]
Business Acquisition [Line Items]
Nonrecurring pro forma adjustments			$ 1,512,423	$ 671,248
Common Stock Warrants [Member]
Business Acquisition [Line Items]
Conversion of stock \| shares	660,715
PharmAthene [Member]
Business Acquisition [Line Items]
Reverse stock split of common stock	0.749106
Equity interests acquired	58.20%
Total fair value of consideration	$ 44,742,737
Outstanding unvested options \| shares	7,569
Stock options estimated fair value	$ 15,173
Increase tax refund receivable due to adjustments to the allocation of the purchase consideration		44,700
Reduce deferred tax liability due to adjustments to the allocation of the purchase consideration		4,535
Increase in goodwill due to adjustments to the allocation of the purchase consideration		49,235
Change in tax rate			35.00%	34.00%
Revenue		1,765,212
Net loss		$ 36,003
Nonrecurring pro forma adjustments			$ (52,315,978)	$ 186,664,464
PharmAthene [Member] \| Stock Compensation Expense [Member]
Business Acquisition [Line Items]
Nonrecurring pro forma adjustments			$ 66,180	$ 2,240,015

Business Combination - Schedule of Lists of Various Securities (Detail) - USD ($)	May 04, 2017	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Outstanding PharmAthene common stock		18,103,691	6,917,204
Outstanding PharmAthene stock options		1,819,316	1,206,104
Weighted average per share fair value of PharmAthene stock options, vested and unvested		$ 4.27	$ 3.91
PharmAthene [Member]
Business Acquisition [Line Items]
Outstanding PharmAthene common stock	6,883,498
Outstanding PharmAthene stock options	123,003
Outstanding PharmAthene stock warrants	4,658
Per share fair value of PharmAthene common stock	$ 6.50
Weighted average per share fair value of PharmAthene stock options, vested and unvested	0.26
Per share fair value of PharmAthene stock warrants	$ 0.01
Aggregate fair value of consideration	$ 44,757,910
Less fair value of unvested common stock options	(15,173)
Total fair value of consideration	$ 44,742,737

Business Combination - Schedule of Purchase Price Allocation (Detail) - USD ($)	May 04, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Goodwill		$ 18,758,421	$ 22,494,691
PharmAthene [Member]
Business Acquisition [Line Items]
Cash and cash equivalents	$ 13,684,535
Accounts receivable	1,124,462
Prepaid expenses and other current assets	597,172
Tax refund receivable	2,047,234
Property and equipment	75,779
IPR&D	22,389,000
Goodwill	15,573,822
Total assets acquired	55,492,004
Accounts payable and accrued expenses	(2,193,785)
Deferred tax liability	(8,555,482)
Total liabilities assumed	(10,749,267)
Net assets acquired	$ 44,742,737

Business Combination - Summary of Unaudited Pro Forma Information (Detail) - PharmAthene [Member] - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Pro forma revenue and grants and contracts	$ 11,844,273	$ 8,466,371
Pro forma net (loss) income attributable to common stockholders	$ (52,315,978)	$ 186,664,464
Pro forma weighted average common shares outstanding, basic	15,547,863	14,368,157
Pro forma net (loss) income per share, basic	$ (3.36)	$ 12.99
Pro forma weighted average common shares outstanding, diluted	15,547,863	15,201,819
Pro forma net (loss) income per share, diluted	$ (3.36)	$ 12.28

Summary of Significant Accounting Policies - Additional Information (Detail)			9 Months Ended	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2017	Dec. 31, 2017 USD ($) Reporting_Unit Segment	Dec. 31, 2016 USD ($)
Significant Accounting Policies [Line Items]
Number of operating segments \| Segment				1
Acquisition-related costs				$ 1,512,423	$ 671,248
Number of reporting units \| Reporting_Unit				1
Control premium percentage			35.00%	35.00%
Goodwill impairment charges				$ 35,919,695
Fair value transfers, Level 1 to Level 2 assets	$ 0	$ 0		0	0
Fair value transfers, Level 2 to Level 1 assets	0	0		0	0
Fair value transfers, Level 1 to Level 2 liabilities	0	0		0	0
Fair value transfers, Level 2 to Level 1 liabilities	0	$ 0		0	$ 0
Restricted cash	3,534,174			$ 3,534,174
Minimum [Member]
Significant Accounting Policies [Line Items]
Intangible assets amortization period				6 years
Maximum [Member]
Significant Accounting Policies [Line Items]
Intangible assets amortization period				20 years
Money Market Funds [Member]
Significant Accounting Policies [Line Items]
Restricted cash	34,174			$ 34,174
Cash on deposit in an unrestricted account [Member] \| Minimum [Member]
Significant Accounting Policies [Line Items]
Restricted cash	$ 3,500,000			$ 3,500,000
Research Grants and Contracts [Member] \| Revenue from Rights Concentration Risk [Member] \| Minimum [Member]
Significant Accounting Policies [Line Items]
Percentage of concentration of credit risk				10.00%	10.00%
Accounts Receivable [Member] \| Revenue from Rights Concentration Risk [Member] \| Minimum [Member]
Significant Accounting Policies [Line Items]
Percentage of concentration of credit risk	10.00%	10.00%

Summary of Significant Accounting Policies - Summary of Concentration Risk by Percentage (Detail) - Revenue from Rights Concentration Risk [Member]			12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Research Grants and Contracts [Member] \| Biomedical Advanced Research and Development Authority [Member]
Concentration Risk [Line Items]
Concentration risk, percentage			83.00%	81.00%
Research Grants and Contracts [Member] \| National Institute of Allergy and Infectious Diseases [Member]
Concentration Risk [Line Items]
Concentration risk, percentage			17.00%
Research Grants and Contracts [Member] \| Texas A&M University System [Member]
Concentration Risk [Line Items]
Concentration risk, percentage				19.00%
Accounts Receivable [Member] \| Biomedical Advanced Research and Development Authority [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	73.00%	100.00%
Accounts Receivable [Member] \| National Institute of Allergy and Infectious Diseases [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	27.00%

Summary of Significant Accounting Policies - Summary of Depreciation and Amortization Recorded using Straight-line Method over Estimated Useful Lives (Detail)	12 Months Ended
	Dec. 31, 2017
Software [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	3 years
Furniture, Fixtures and Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	5 years
Laboratory Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	7 years
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	Lesser of lease term or estimated useful lives
Minimum [Member] \| Computers and Telecommunications [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	3 years
Maximum [Member] \| Computers and Telecommunications [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	5 years

Net Loss Per Share - Schedule of Computation of Basic and Diluted Net Loss Per Share (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Numerator
Net loss	$ (46,425,390)	$ (11,086,812)
Less: preferred stock accretion and dividends	(4,930,010)	(368,548)
Net loss attributable to common stockholders	$ (51,355,400)	$ (11,455,360)
Denominator
Weighted-average common shares outstanding, basic and diluted	12,805,095	6,911,534
Net loss per share attributable to common stockholders, basic and diluted	$ (4.01)	$ (1.66)

Net Loss Per Share - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Detail) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share		599,285
Series B Redeemable Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	4,560,550
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	1,819,316	1,205,920
Common Stock Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	2,350,085	612,112
Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	23,428	74,546

Property and Equipment, Net - Summary of Property and Equipment, Net (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	$ 1,554,944	$ 1,083,169
Less accumulated depreciation and amortization	(951,798)	(905,310)
Property and equipment, net	603,146	177,859
Furniture, Fixtures and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	61,121	60,320
Laboratory Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	1,001,810	932,065
Computers and Telecommunications [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	81,342	45,837
Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	16,244	595
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	44,352	$ 44,352
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	$ 350,075

Property and Equipment, Net - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Depreciation, Total	$ 83,834	$ 63,109

Intangible Assets, Net - Schedule of Intangible Assets (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule Of Intangible Assets [Line Items]
Total intangible assets, Gross Carrying Value	$ 39,209,211	$ 15,386,473
Intangible assets subject to amortization, Gross Carrying Value	963,340	909,454
Intangible assets subject to amortization, Accumulated Amortization	(486,941)	(431,756)
Intangible assets subject to amortization, Net Book Value	476,399	477,698
Total intangible assets, Net Book Value	38,722,270	14,954,717
IPR&D [Member]
Schedule Of Intangible Assets [Line Items]
Intangible assets, Net Book Value	$ 38,245,871	14,477,019	$ 17,366,791
IPR&D [Member] \| Minimum [Member]
Schedule Of Intangible Assets [Line Items]
Estimated Useful Lives	15 years
IPR&D [Member] \| Maximum [Member]
Schedule Of Intangible Assets [Line Items]
Estimated Useful Lives	18 years
Internally Developed Patents [Member]
Schedule Of Intangible Assets [Line Items]
Intangible assets subject to amortization, Gross Carrying Value	$ 678,340	624,454
Intangible assets subject to amortization, Accumulated Amortization	(249,601)	(211,956)
Intangible assets subject to amortization, Net Book Value	$ 428,739	$ 412,498
Internally Developed Patents [Member] \| Minimum [Member]
Schedule Of Intangible Assets [Line Items]
Estimated Useful Lives	6 years	6 years
Internally Developed Patents [Member] \| Maximum [Member]
Schedule Of Intangible Assets [Line Items]
Estimated Useful Lives	10 years	10 years
Acquired Licenses [Member]
Schedule Of Intangible Assets [Line Items]
Intangible assets subject to amortization, Gross Carrying Value	$ 285,000	$ 285,000
Intangible assets subject to amortization, Accumulated Amortization	(237,340)	(219,800)
Intangible assets subject to amortization, Net Book Value	$ 47,660	$ 65,200
Acquired Licenses [Member] \| Minimum [Member]
Schedule Of Intangible Assets [Line Items]
Estimated Useful Lives	16 years	16 years
Acquired Licenses [Member] \| Maximum [Member]
Schedule Of Intangible Assets [Line Items]
Estimated Useful Lives	20 years	20 years

Intangible Assets, Net - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Research and Development [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense of intangible assets	$ 55,185	$ 72,236
Minimum [Member] \| IPR&D [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Lives	15 years
Maximum [Member] \| IPR&D [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Lives	18 years

Intangible Assets, Net - Schedule of Future Estimated Amortization Expense (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
2018	$ 53,113
2019	48,314
2020	34,868
2021	14,308
2022	14,308
2023 and thereafter	311,488
Intangible assets subject to amortization, Net Book Value	$ 476,399	$ 477,698

IPR&D and Goodwill - Schedule of Changes in Carrying Amounts of IPR&D Assets and Goodwill (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Indefinite-lived Intangible Assets [Line Items]
Goodwill, Additions from the Mergers	$ 15,573,822
Goodwill Balance, beginning of period	18,758,421	$ 22,494,691
Goodwill, Foreign currency translation adjustments	1,587,452	(3,736,270)
Goodwill, Impairment charges	(35,919,695)
Goodwill Balance, end of period		18,758,421
IPR&D [Member]
Indefinite-lived Intangible Assets [Line Items]
IPR&D Balance, beginning of period	14,477,019	17,366,791
IPR&D, Additions from the Mergers	22,389,000
IPR&D, Foreign currency translation adjustments	1,379,852	(2,889,772)
IPR&D Balance, end of period	$ 38,245,871	$ 14,477,019

Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Accrued Liabilities and Other Liabilities [Abstract]
Accrued professional services	$ 835,326	$ 689,135
Accrued board of director compensation		606,199
Accrued payroll and employee benefits	909,455	957,719
Accrued interest	536	169,790
Accrued construction costs	328,384
Accrued research and development	1,551,556	549,902
Accrued expenses	$ 3,625,257	$ 2,972,745

Accrued Expenses - Additional Information (Detail)	Feb. 28, 2017 USD ($)
Convertible Promissory Note Purchase Agreement [Member]
Accrued Expenses [Line Items]
Accrued expenses modified and replaced with convertible notes	$ 881,044

Licenses - Additional Information (Detail) - USD ($)	12 Months Ended
Licenses - Additional Information (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
University of Alabama at Birmingham Research Foundation [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Annual license fee	$ 20,000
License fee costs	$ 20,000	$ 20,000
Patent expiration date	Aug. 07, 2033
Janssen Vaccines and Prevention BV [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Annual license fee	$ 100,000
License fee costs	$ 200,000	100,000
Patent expiration date	Mar. 21, 2020
Auburn University [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Annual license fee	$ 5,000
License fee costs	$ 5,000	$ 5,000
Patent expiration date	Aug. 15, 2025
Upfront fee	$ 1,000

Notes Payable - Summary of Outstanding Notes Payable (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Total notes payable	$ 49,702	$ 458,629
Line of Credit [Member]
Debt Instrument [Line Items]
Total notes payable	$ 49,702	49,702
Economic Development Partnership of Alabama ("EDPA") Promissory Note [Member]
Debt Instrument [Line Items]
Total notes payable		96,496
Hammond Promissory Note [Member]
Debt Instrument [Line Items]
Total notes payable		100,000
Alex Choi Promissory Note [Member]
Debt Instrument [Line Items]
Total notes payable		100,000
Frommer, Lawrence and Haug LLP ("FLH") Promissory Note [Member]
Debt Instrument [Line Items]
Total notes payable		$ 112,431

Notes Payable - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Accrued interest	$ 536	$ 169,790
Economic Development Partnership of Alabama ("EDPA") Promissory Note [Member]
Debt Instrument [Line Items]
Borrowings interest rate		6.00%
Accrued interest		$ 34,121
Interest expense, debt	1,079	$ 5,621
Hammond Promissory Note [Member]
Debt Instrument [Line Items]
Borrowings interest rate		15.00%
Accrued interest		$ 94,685
Interest expense, debt	4,663	$ 15,000
Alex Choi Promissory Note [Member]
Debt Instrument [Line Items]
Borrowings interest rate		6.00%
Accrued interest		$ 40,951
Interest expense, debt	1,575	8,149
Line of Credit [Member]
Debt Instrument [Line Items]
Maximum borrowings capacity	$ 250,000
Borrowings maturity date	2018-04
Interest payable	Monthly
Borrowings prime rate	5.00%
Accrued interest	$ 536	33
Interest expense, debt	$ 3,321	$ 2,956
Line of Credit [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Borrowings interest rate	5.00%
Line of Credit [Member] \| Prime Rate [Member]
Debt Instrument [Line Items]
Borrowings variable rate	2.00%

Other Long-Term Liabilities - Summary of Other Long-Term Liabilities (Detail)	Dec. 31, 2017 USD ($)	Dec. 31, 2017 EUR (€)	Dec. 31, 2016 USD ($)	Dec. 31, 2016 EUR (€)
Debt Instrument [Line Items]
Unvested restricted stock (see Note 15)	$ 315		$ 1,001
Deferred revenue, long-term portion (see Note 4)	159,671		179,424
Deferred rent, long-term portion	386,489		15,914
Common stock warrant liability (see Note 16)	3,400,869
Embedded derivative (see Note 14)	27,236
Total other long-term liabilities	4,574,507		722,289
BPI France Notes [Member]
Debt Instrument [Line Items]
BPI France notes	$ 599,927	€ 500,000	$ 525,950	€ 500,000

The noncurrent portion of deferred revenue amount as of balance sheet date. Deferred revenue is a liability related to a revenue producing activity for which revenue has not yet been recognized, and is not expected to be recognized in the next twelve months. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP.