Significant Accounting Policies (Policies) |
12 Months Ended | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Dec. 31, 2018 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Accounting Policies [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Basis of Accounting, Policy [Policy Text Block] |
Basis of Presentation The Company’s financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). The Company has no subsidiaries. The financial statements may not be indicative of future performance and may not reflect what the Company’s results of operations, financial position, and cash flows would have been had Mustang operated as an independent entity. Certain estimates have been made to provide financial statements for stand-alone reporting purposes. All inter-company transactions between Fortress and Mustang are classified as due to related party in the financial statements. The Company believes that the assumptions underlying the financial statements are reasonable. |
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| Segment Reporting, Policy [Policy Text Block] |
Segments Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company views its operations and manages its business in one operating and reporting segment. |
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| Use of Estimates, Policy [Policy Text Block] |
Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates. |
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| Cash and Cash Equivalents, Policy [Policy Text Block] |
Cash and Cash Equivalents The Company considers all short-term investments with an original maturity of three months or less when purchased to be cash equivalents. Cash and cash equivalents at December 31, 2018 and at December 31, 2017 consisted of cash, money market funds and certificates of deposit in institutions in the United States. Balances at certain institutions have exceeded Federal Deposit Insurance Corporation (“FDIC”) insured limits. |
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| Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] |
Restricted Cash The Company records cash held in an escrow account as a security deposit for the manufacturing facility in Worcester, Massachusetts as restricted cash. The Facility initiated cell processing operations for personalized CAR T and gene therapies in late 2018.
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| Investment, Policy [Policy Text Block] |
Short-term Investments The Company classifies its certificates of deposit as cash and cash equivalents or held to maturity in accordance with the Financial Accounting Standards Board ("FASB") Accounting Standards Codification (“ASC”) 320,
Investments - Debt and Equity Securities . The Company considers all investments with an original maturity in excess of three months when purchased to be short-term investments. Investments consist of short-term FDIC insured certificates of deposit carried at amortized cost using the effective interest method. The cost of the Company’s certificates of deposit approximated fair value. The Company reassesses the appropriateness of the classification of its investments at the end of each reporting period.
At December 31, 2018, the Company had approximately $27.6 million in certificates of deposit. The Company classified $10.0 million as cash and cash equivalents and classified $17.6 million of its certificates of deposits as short-term investments as of December 31, 2018. At December 31, 2017, the Company had approximately $40.0 million in certificates of deposit. The Company classified $14.0 million as cash and cash equivalents and classified $26.0 million of its certificates of deposits as short-term investments as of December 31, 2017. The classification was based upon management’s determination that it has the positive intent and ability to hold the securities until their maturity dates, as its investments mature within one year and the underlying cash invested in these securities is not required for current operations.
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| Property, Plant and Equipment, Policy [Policy Text Block] |
Property, plant and equipment, net Property and equipment, net, which consists mainly of laboratory equipment, are carried at cost less accumulated depreciation. Depreciation is computed over the estimated useful lives of the respective assets, generally five years, using the straight-line method. Property and equipment - Construction in Process In connection with the Company’s cell processing facility, the Company incurred $0.4 million related to the design and construction of the facility and the purchase of equipment which are recorded in fixed assets on the balance sheet at December 31, 2018. Upon completion of the facility’s construction all costs associated with the buildout will be recorded as leasehold improvements and amortized over the shorter of the estimated useful lives or the term of the respective leases, upon the improvement being placed in service. |
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| Research and Development Expense, Policy [Policy Text Block] |
Research and Development Costs Research and development costs are expensed as incurred. Advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received rather than when the payment is made. Upfront and milestone payments due to third parties that perform research and development services on the Company’s behalf will be expensed as services are rendered or when the milestone is achieved. Research and development costs primarily consist of personnel related expenses, including salaries, benefits, travel, and other related expenses, stock-based compensation, payments made to third parties for license and milestone costs related to in-licensed products and technology, payments made to third party contract research organizations for preclinical and clinical studies, investigative sites for clinical trials, consultants, the cost of acquiring and manufacturing clinical trial materials, costs associated with regulatory filings, laboratory costs and other supplies. Costs incurred in obtaining technology licenses are charged to research and development expense if the technology licensed has not reached commercial feasibility and has no alternative future use. The licenses purchased by the Company require substantial completion of research and development, regulatory and marketing approval efforts to reach commercial feasibility and has no alternative future use. Accordingly, the total purchase price for the licenses acquired is reflected as research and development - licenses acquired on the Company’s Statements of Operations. |
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| Annual Stock Dividend [Policy Text Block] |
Annual Stock Dividend In July 2016, in connection with the Amended and Restated Articles of Incorporation, the Company issued 250,000 Class A preferred shares to Fortress. The Class A preferred shares entitle the holder to a stock dividend equal to 2.5% of the fully diluted outstanding equity of the Company (“The Annual Stock Dividend”). The Annual Stock Dividend was part of the consideration payable for formation of the Company and the identification of certain assets, including the license contributed to Mustang by Fortress (see Note 4). In 2017, the Company recorded the Annual Stock Dividend due to Fortress as contingent consideration. Contingent consideration is recorded when probable and reasonably estimable. The Company’s future share prices cannot be estimated due to the nature of its assets and the Company’s stage of development. Due to these uncertainties, the Company concluded that it could not reasonably estimate the contingent consideration until shares were actually issued on March 13, 2018. Because the issuance of shares on March 13, 2018 occurred prior to the issuance of the December 31, 2017 financial statements, the Company recorded approximately $9.6 million in research and development - licenses acquired for the year ended December 31, 2017. In June 2018, in connection with the Amended and Restated Articles of Incorporation, the Company amended the annual stock dividend due date from March 13th to January 1st. Pursuant to the Amended and Restated Articles of Incorporation, the Company issued 709,314 shares of common stock to Fortress for the Annual Stock Dividend, representing 2.0%, on a pro rata basis, of the fully-diluted outstanding equity of Mustang on January 1, 2019. |
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| Fair Value Measurement, Policy [Policy Text Block] |
Fair Value Measurement The Company follows accounting guidance on fair value measurements for financial assets and liabilities measured at fair value on a recurring basis. Under the accounting guidance, fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. The accounting guidance requires fair value measurements be classified and disclosed in one of the following three categories:
The fair value hierarchy also requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability. |
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| Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] |
Stock-Based Compensation Expenses The Company expenses stock-based compensation to employees over the requisite service period based on the estimated grant-date fair value of the awards and forfeiture rates. For stock-based compensation awards to non-employees, the Company re-measures the fair value of the non-employee awards at each reporting period prior to vesting and finally at the vesting date of the award. Changes in the estimated fair value of these non-employee awards are recognized as stock-based compensation expense in the period of change. The assumptions used in calculating the fair value of stock-based awards represent management’s best estimates and involve inherent uncertainties and the application of management’s judgment. |
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| Income Tax, Policy [Policy Text Block] |
Income Taxes The Company records income taxes using the asset and liability method. Deferred income tax assets and liabilities are recognized for the future tax effects attributable to temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective income tax bases, and operating loss and tax credit carryforwards. The Company establishes a valuation allowance if management believes it is more likely than not that the deferred tax assets will not be recovered based on an evaluation of objective verifiable evidence. For tax positions that are more likely than not of being sustained upon audit, the Company recognizes the largest amount of the benefit that is greater than 50% likely of being realized. For tax positions that are not more likely than not of being sustained upon audit, the Company does not recognize any portion of the benefit.
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| Earnings Per Share, Policy [Policy Text Block] |
Net Loss per Share Net loss per share is computed by dividing net loss by the weighted average number of common shares outstanding during the period less unvested restricted stock. Since dividends are declared, paid and set aside among the holders of shares of common stock and Class A common shares pro-rata on an as-if-converted basis, the two-class method of computing net loss per share is not required. Diluted net loss per share does not reflect the effect of shares of common stock to be issued upon the exercise of warrants or outstanding Class A preferred shares, as their inclusion would be anti-dilutive. The table below summarizes potentially dilutive securities that were not considered in the computation of diluted net loss per share because they would be anti-dilutive.
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| Comprehensive Income, Policy [Policy Text Block] |
Comprehensive Loss The Company has no components of other comprehensive loss, and therefore, comprehensive loss equals net loss. |
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| New Accounting Pronouncements, Policy [Policy Text Block] |
Recently Adopted Accounting Pronouncements In May 2017, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2017-09,
Compensation-Stock Compensation (Topic 718): Scope of Modification Accounting . ASU 2017-09 provides clarity and reduces both (1) diversity in practice and (2) cost and complexity when applying the guidance in Topic 718, to a change to the terms or conditions of a share-based payment award. The amendments in ASU 2017-09 should be applied prospectively to an award modified on or after the adoption date. This ASU is effective for fiscal years, and interim periods within those years, beginning after December 15, 2017. The Company adopted ASU No. 2017-09 as of January 1, 2018. The adoption of this update did not impact the Company’s financial statements and related disclosures.
In January 2017, the FASB issued an ASU 2017-01, “
Business Combinations (Topic 805) Clarifying the Definition of a Business ”. The amendments in this ASU clarify the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The definition of a business affects many areas of accounting including acquisitions, disposals, goodwill, and consolidation. The guidance is effective for annual periods beginning after December 15, 2017, including interim periods within those periods. The Company adopted ASU 2017-01 on January 1, 2018. The adoption of this update did not impact the Company’s financial statements.In June 2018, the FASB issued ASU 2018-07, “Improvements to Nonemployee Share-Based Payment Accounting , which simplifies the accounting for share-based payments granted to nonemployees for goods and services. Under the ASU, most of the guidance on such payments to nonemployees would be aligned with the requirements for share-based payments granted to employees. The changes take effect for public companies for fiscal years starting after December 15, 2018, including interim periods within that fiscal year. For all other entities, the amendments are effective for fiscal years beginning after December 15, 2019, and interim periods within fiscal years beginning after December 15, 2020. Early adoption is permitted, but no earlier than an entity’s adoption date of Topic 606. The Company adopted ASU No. 2018-07 as of January 1, 2019. The adoption of this update did not have a material impact on the Company’s financial statements.
Recent Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) in order to increase transparency and comparability among organizations by, among other provisions, recognizing lease assets and lease liabilities on the balance sheet for those leases classified as operating leases under previous GAAP. For public companies, ASU 2016-02 is effective for fiscal years beginning after December 15, 2018 (including interim periods within those periods) using a modified retrospective approach and early adoption is permitted. In transition, entities may also elect a package of practical expedients that must be applied in its entirety to all leases commencing before the adoption date, unless the lease is modified, and permits entities to not reassess (a) the existence of a lease, (b) lease classification or (c) determination of initial direct costs, as of the adoption date, which effectively allows entities to carryforward accounting conclusions under previous U.S. GAAP. In July 2018, the FASB issued ASU 2018-11, Leases (Topic 842): Targeted Improvements, which provides entities an optional transition method to apply the guidance under Topic 842 as of the adoption date, rather than as of the earliest period presented. The Company adopted Topic 842 on January 1, 2019, using the optional transition method to apply the new guidance as of January 1, 2019 rather than as of the earliest period presented, and elected the package of practical expedients described above. The Company is still finalizing its analysis, but expects to recognize additional operating liabilities of $1.9 million, with corresponding ROU assets of approximately the same amount as of January 1, 2019 based on the present value of the remaining lease payments. In August 2018, the FASB issued ASU 2018-13,
Fair Value Measurement (Topic 820), - Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement , which makes a number of changes meant to add, modify or remove certain disclosure requirements associated with the movement amongst or hierarchy associated with Level 1, Level 2 and Level 3 fair value measurements. This guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. Early adoption is permitted upon issuance of the update. The Company does not expect the adoption of this guidance to have a material impact on its financial statements.In August 2018, the SEC adopted the final rule under SEC Release No. 33-10532, “Disclosure Update and Simplification”, amending certain disclosure requirements that were redundant, duplicative, overlapping, outdated or superseded. In addition, the amendments expanded the disclosure requirements on the analysis of stockholders' equity for interim financial statements. Under the amendments, an analysis of changes in each caption of stockholders' equity presented in the balance sheet must be provided in a note or separate statement. The analysis should present a reconciliation of the beginning balance to the ending balance of each period for which a statement of comprehensive income is required to be filed. This final rule is effective on November 5, 2018. The Company does not expect the adoption of this guidance to have a material impact on its financial statements and anticipates its first presentation of changes in stockholders’ equity will be included in its Form 10-Q for the quarter ended March 31, 2019.
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