2. Summary of Significant Accounting Policies

Use of Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make certain 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 revenues and expenses during the reporting period. On an ongoing basis, the Company evaluates its estimates, including those related to the recoverability of patent costs included in intangible assets, valuation of warrants, stock-based compensation, the valuation allowance for deferred tax assets, allowance for doubtful accounts and business combinations. The Company bases its estimates on historical experience and on various other market-specific and relevant assumptions that it believes to be reasonable under the circumstances. Actual results could differ from those estimates.

Risks and Uncertainties

Concentration of Credit Risk

Financial instruments, which potentially expose the Company to concentrations of credit risk, consist principally of cash balances on deposit with a bank, which exceed insured limits.

USPTO Proceeding

In March 2009, the Company received a final rejection in one of the Company’s original patent applications pertaining to certain limited methods of use claims for NK-92 from the U.S. Patent and Trademark Office (the USPTO) (but the USPTO allowed claims on all of the other proposed claims, including other methods of use). The Company appealed this decision with the USPTO Board of Appeals and, in the fall of 2013, the Board of Appeals reversed the Examiner’s rejection of the claim to certain limited methods of use with NK-92, but affirmed the Examiner’s rejection of the remaining patent claims. In December 2013, the Company brought an action in the U.S. District Court for the Eastern District of Virginia to review the decision of the USPTO as the Company disagreed with the decision as to the certain limited non-allowed claims. On September 2, 2015, the U.S. District Court granted the USPTO’s motion for summary judgment. The Company has filed a notice of appeal and will be appealing the decision.

Cash and Cash Equivalents

The Company considers all highly liquid investments purchased with original maturities of three months or less to be cash equivalents. The Company minimizes its credit risk associated with cash and cash equivalents by periodically evaluating the credit quality of its primary financial institution. The balance at times may exceed federally insured limits. The Company has not experienced any losses on such accounts.

Intangible Assets

Intangible assets consist of costs incurred in connection with patent applications (principally legal fees), patent purchases, trademarks related to the Company’s aNK cells and technology acquired in the asset purchase of Inex Bio. The Company calculates amortization expense for its patents and acquired technology using the straight-line method over the estimated useful lives, generally 4-15 years. Other intangibles, consisting of trademarks and copyrights, are considered to have indefinite lives and are not amortized but reviewed for impairment annually, or sooner under certain circumstances.

The Company has no historical data to support a probable future economic benefit for patent applications, filing and prosecution costs other than for the Company’s aNK cells. Therefore, these patent-related costs are expensed as incurred and are included in selling, general and administrative in the statements of operations. The Company capitalizes patent application costs for those patents that are generating revenue currently. Should the Company experience a legal cost to defend a patent in the future, that cost would be capitalized only when it is part of the cost of retaining and obtaining the future economic benefit of the patent. Costs related to an unsuccessful outcome would be expensed.

Fair Value of Financial Instruments

The accounting standard for fair value measurements provides a framework for measuring fair value and requires disclosures regarding fair value measurements. Fair value is defined as the price 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, based on the Company’s principal or, in absence of a principal, most advantageous market for the specific asset or liability.

The Company uses a three-tier fair value hierarchy to classify and disclose all assets and liabilities measured at fair value on a recurring basis, as well as assets and liabilities measured at fair value on a non-recurring basis, in periods subsequent to their initial measurement. The hierarchy requires the Company to use observable inputs when available, and to minimize the use of unobservable inputs, when determining fair value.

The three tiers are defined as follows:

Level 1—Observable inputs that reflect quoted market prices (unadjusted) for identical assets or liabilities in active markets;

Level 2—Observable inputs other than quoted prices in active markets that are observable either directly or indirectly in the marketplace for identical or similar assets and liabilities; and

Level 3—Unobservable inputs that are supported by little or no market data, which require the Company to develop its own assumptions.

Deferred Rent

Rent expense is recognized on a straight-line basis over the term of the lease. The difference between rent expense and amounts paid under lease agreements is recorded as deferred rent in the liability section of the consolidated balance sheets.

Revenue Recognition and Deferred Revenue

The Company derives substantially all of its revenue from non-exclusive license agreements with numerous pharmaceutical and biotechnology companies granting them the right to use the Company’s cell lines and intellectual property for non-clinical use. These license agreements generally include upfront fees and annual research license fees for such use, as well as commercial fees for sales of the licensees’ products developed or manufactured using the Company’s intellectual property and cell lines. The Company’s license agreements also may include milestone payments, although to date, the Company has not generated any revenue from milestone payments. The Company recognizes revenue when (i) persuasive evidence of an arrangement exists; (ii) delivery of the products and/or services has occurred; (iii) the fees are fixed or determinable; and (iv) collectibility is reasonably assured.

When entering into an arrangement, the Company first determines whether the arrangement includes multiple deliverables and is subject to accounting guidance in Accounting Standards Codification (ASC) Subtopic 605-25, Multiple-Element Arrangements. If the Company determines that an arrangement includes multiple elements, it determines whether the arrangement should be divided into separate units of accounting and how the arrangement consideration should be measured and allocated among the separate units of accounting.

An element qualifies as a separate unit of accounting when the delivered element has standalone value to the customer. The Company’s agreements do not include a general right of return relative to delivered elements. Any delivered elements that do not qualify as separate units of accounting are combined with other undelivered elements within the arrangement as a single unit of accounting. If the arrangement constitutes a single combined unit of accounting, the Company determines the revenue recognition method for the combined unit of accounting and recognizes the revenue over the period from inception through the date the last deliverable within the single unit of accounting is delivered.

License rights and non-contingent deliverables, such as knowledge transfer, do not have standalone value as they are not sold separately and they cannot be resold and, consequently are considered a single unit of accounting.

Therefore, license revenue in the form of upfront payments is deferred and recognized over the applicable relationship period, which historically has been the estimated period of the Company’s substantive performance obligations or the period the rights granted are in effect.

The Company recognizes a milestone payment when earned if it is substantive and the Company has no ongoing performance obligations related to the milestone. A milestone payment is considered substantive if it 1) is commensurate with either the Company’s performance to achieve the milestone or the enhanced value of the delivered item as a result of a specific outcome resulting from the Company’s performance to achieve the milestone; 2) relates solely to past performance; and 3) is reasonable relative to all of the deliverables and payment terms, including other potential milestone consideration, within the arrangement.

The Company records any amounts received prior to satisfying the revenue recognition criteria as deferred revenue in the accompanying balance sheets.

Stock-Based Compensation

The Company measures and recognizes compensation expense for all stock-based payment awards made to employees, officers and directors based on the estimated fair values of the awards as of the grant date. The Company records the value of the portion of the award that is ultimately expected to vest as expense over the requisite service period.

The Company also accounts for equity instruments issued to non-employees using a fair value approach under ASC Subtopic 505-50, Equity-Based Payments to Non-Employees. The Company values equity instruments and stock options granted using the Black-Scholes option-pricing model. The value of non-employee stock-based compensation is subject to periodic adjustments as the underlying equity instruments vest and is recognized as an expense over the term of the related financing or the period over which services are received.

Basic and Diluted Net Loss per Share of Common Stock

Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period. Diluted loss per share is computed similarly to basic loss per share except that the denominator is increased to include the number of additional shares that would have been outstanding if the potential common shares had been issued and if the additional common shares were dilutive.

For all periods presented, potentially dilutive securities are excluded from the computation of fully diluted loss per share as their effect is anti-dilutive. The following table details those securities which have been excluded from the computation of potentially dilutive securities:

	As of September 30,
	2015		2014
Series B convertible preferred stock		—		8,888,597
Series C convertible preferred stock		—		5,789,699
Class B common shares not exercised		—		5,509,925
Outstanding options		9,811,356		3,055,469
Outstanding restricted stock units		485,150		—
Outstanding warrants		17,824,525		2,052,408
Total		28,121,031		25,296,098

Amounts in the table above reflect the common stock equivalents of the noted instruments.

Comprehensive Loss

The functional currency of our foreign subsidiary is the South Korean Won. Adjustments resulting from translating foreign functional currency financial statements into U.S. dollars are recorded as part of a separate component of the condensed consolidated statements of comprehensive loss.

Segment and Geographic Information

Operating segments are defined as components of an enterprise (business activity from which it earns revenue and incurs expenses) for which discrete financial information is available and regularly reviewed by the chief operating decision maker in deciding how to allocate resources and in assessing performance. The Company’s chief operating decision maker (CODM) is its Chief Executive Officer. The Company views its operations and manages its business as a single operating and reporting segment.

Recent Accounting Pronouncements

The Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2014-08, Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity, which amends ASC 205, Presentation of Financial Statements, and ASC 360, Property, Plant and Equipment. This ASU changes the criteria for determining which disposals can be presented as a discontinued operation and modifies existing disclosure requirements. The provisions of this update were effective as of January 1, 2015, and the Company has adopted this standard accordingly.

The FASB issued ASU 2014-15, Presentation of Financial Statements — Going Concern, which will require management to make a going concern assessment for 24 months after the financial statement date. Previously, this assessment was made by the external auditors. The provisions of this update are effective as of December 31, 2016, and are not expected to significantly impact the Company.

In May 2014, the FASB issued guidance codified in ASC Topic 606, Revenue Recognition—Revenue from Contracts with Customers, which amends the guidance in former ASC Topic 605, Revenue Recognition, and was initially to be effective beginning January 1, 2017. This guidance requires that entities recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The Company is currently evaluating the impact of the provisions of ASC Topic 606 on its financial statements and disclosures. On August 12, 2015, the FASB issued guidance which defers the effective date of ASC Topic 606 by one year to January 1, 2018.

In June 2014, the FASB issued ASU 2014-12, Compensation-Stock Compensation (Topic 718): Accounting for Share-Based Payments when the Terms of an Award Provide that a Performance Target Could Be Achieved After the Requisite Service Period, or ASU 2014-12. The ASU requires that a performance target that affects vesting and that could be achieved after the requisite service period be treated as a performance condition. ASU 2014-12 is effective for annual periods and interim periods within those annual periods beginning after December 15, 2015. Earlier adoption is permitted. The Company is currently evaluating the impact of the adoption of ASU 2014-12 on its financial statements and disclosures.

In January 2015, the FASB issued ASU No. 2015-01, Income Statement—Extraordinary and Unusual Items (Subtopic 225-20); Simplifying Income Statement Presentation by Eliminating the Concept of Extraordinary Items, which eliminates from GAAP the concept of extraordinary items, stating that the concept causes uncertainty because (1) it is unclear when an item should be considered both unusual and infrequent and (2) users do not find the classification and presentation necessary to identify those events and transactions. This standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015, with early adoption permitted provided the guidance is applied from the beginning of the fiscal year of adoption. The Company does not expect this standard to have an impact on its financial statements upon adoption.

In February 2015, the FASB issued ASU 2015-02, Consolidation (Topic 810)—Amendments to the Consolidation Analysis, or ASU 2015-02. ASU 2015-02 affects reporting entities that are required to evaluate whether they should consolidate certain legal entities. Specifically, the amendments (1) modify the evaluation of whether limited partnerships and similar legal entities are variable interest entities (VIEs) or voting interest entities, (2) eliminate the presumption that a general partner should consolidate a limited partnership, (3) affect the consolidated analysis of reporting entities that are involved with VIEs, and (4) provide a scope exception for certain entities. ASU 2015-02 is effective for interim and annual reporting periods beginning after December 15, 2015. The Company is currently evaluating the impact of the adoption of ASU 2015-02 on its financial statements and disclosures.

In April 2015, the FASB issued ASU 2015-03, Interest—Imputation of Interest (Subtopic 835-30), or ASU 2015-03, which requires the debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with the presentation of debt discounts. This guidance is effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years. The Company does not expect this standard to have a material impact on its financial statements upon adoption.