ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)

12 Months Ended

Dec. 31, 2017

Basic net income (loss) per share is calculated by dividing net income (loss) by the weighted‑average number of shares of common stock outstanding during the periods presented, without consideration for potential common shares. Diluted net income per share is calculated by adjusting the weighted‑average number of shares of common stock outstanding for the dilutive effect of potential common shares outstanding for the periods presented, as determined using the treasury‑stock method. Potential dilutive securities primarily consist of outstanding stock options, restricted stock awards and warrants to purchase our common stock. For periods in which we have incurred a net loss, potential common shares outstanding for the periods presented, as determined using the treasury‑stock method, are excluded, as their effect would be anti‑dilutive, resulting in the same number of shares being used for the calculation of basic and diluted net loss per share. For all periods presented in the accompanying statements of operations, the net income (loss) applicable to common stockholders is equal to the reported net income (loss).

	Year Ended December 31,
(In thousands, except share and per share data)	2017			2016			2015
Net (loss) income	$	(27,916	)	$	(29,537	)	$	46
Weighted-average shares:
Basic		159,224,986			159,045,644			158,036,162
Effect of dilutive securities:
Stock options and restricted stock awards		—			—			4,627,732
Diluted		159,224,986			159,045,644			162,663,894
Net (loss) income per share:
Basic	$	(0.18	)	$	(0.19	)	$	0.00
Diluted	$	(0.18	)	$	(0.19	)	$	0.00

Because we were in a net loss position for 2017 and 2016, 2,389,310 and 3,023,520 potential common shares, respectively, related to outstanding stock options and restricted stock awards (as determined using the treasury‑stock method at the estimated average market value) were excluded from the diluted net loss per share calculation as their effect would have been anti‑dilutive. In addition for 2017, 2016 and 2015, 14,475,616, 11,352,766 and 9,375,851 potentially dilutive securities, respectively, were excluded from the treasury‑stock method and calculation of diluted net income (loss) per share as their effect would have been anti‑dilutive.

Use of Estimates

1. ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Continued)

Use of Estimates

The accompanying financial statements have been prepared in accordance with U.S. generally accepted accounting principles, or GAAP. The preparation of financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, we evaluate our estimates, including those related to accrued liabilities, revenue recognition, fair value of marketable securities, income taxes, and stock-based compensation. We base our estimates on historical experience and on various other market specific and relevant assumptions that we believe to be reasonable under the circumstances. Actual results could differ from those estimates.

Fair Value of Financial Instruments

Cash Equivalents and Marketable Securities

We consider all highly liquid investments with an original maturity of three months or less to be cash equivalents. We are subject to credit risk related to our cash equivalents and marketable securities. We place our cash and cash equivalents in money market funds, commercial paper, corporate notes and cash operating accounts. Our marketable securities include U.S. government‑sponsored enterprise securities, commercial paper and corporate notes.

We classify our marketable securities as available‑for‑sale. We record available‑for‑sale securities at fair value with unrealized gains and losses reported in accumulated other comprehensive income (loss) in stockholders’ equity. Realized gains and losses are included in interest and other income and are derived using the specific identification method for determining the cost of securities sold and have been insignificant to date. Dividend and interest income are recognized when earned and included in interest and other income in our statements of operations. We recognize a charge when the declines in the fair values below the amortized cost basis of our available‑for‑sale securities are judged to be other‑than‑temporary. We consider various factors in determining whether to recognize an other‑than‑temporary charge, including whether we intend to sell the security or whether it is more likely than not that we would be required to sell the security before recovery of the amortized cost basis. Declines in market value judged as other‑than‑temporary result in a charge to interest and other income. We have not recorded any other‑than‑temporary impairment charges on our available‑for‑sale securities for the years ended December 31, 2017, 2016 and 2015. See Note 2 on Fair Value Measurements.

Cost Method Investments

We use the cost method of accounting for non-marketable equity securities where our ownership represents less than 20% of such entity, and we cannot exert significant influence over its operations. These securities are carried at cost and adjusted for impairments.

Fair Value of Derivatives

Non‑employee options classified as derivative liabilities are marked to fair value at each financial reporting date with any resulting changes in fair value being recorded in the statements of operations as unrealized gain (loss) on derivatives. The non‑employee options continue to be reported as a derivative liability until such time as the instruments are exercised or expire, at which time these instruments are marked to fair value and reclassified from liabilities to stockholders’ equity. As of March 31, 2015, all non‑employee options classified as derivative liabilities expired unexercised.

Revenue Recognition

We recognize revenue for each unit of accounting when all of the following criteria have been met: (a) persuasive evidence of an arrangement exists, (b) delivery has occurred or services have been rendered, (c) the seller’s price to the buyer is fixed or determinable, and (d) collectability is reasonably assured. Amounts received prior to satisfying these revenue recognition criteria are recorded as deferred revenue. Amounts expected to be recognized as revenue within the 12 months following the balance sheet date are classified as current deferred revenue. Amounts not expected to be recognized as revenue within the 12 months following the balance sheet date are classified as noncurrent deferred revenue.

License and/or Collaboration Agreements

In addition to the Collaboration Agreement (which is more fully described in Note 4 on License Agreements), we have entered into several license or collaboration agreements with various oncology, diagnostics, research tools and biologics production companies. Economic terms in these agreements may include non‑refundable upfront license payments in cash or equity securities, option payments in cash or equity securities, cost reimbursements, cost‑sharing arrangements, milestone payments, royalties on future sales of products, or any combination of these items. In applying the appropriate revenue recognition guidance related to these agreements, we first assess whether the arrangement contains multiple elements. In this evaluation, we consider: (i) the deliverables included in the arrangement and (ii) whether the individual deliverables represent separate units of accounting or whether they must be accounted for as a combined unit of accounting. This evaluation involves subjective determinations and requires us to make judgments about the individual deliverables and whether such deliverables are separable from the other aspects of the contractual relationship. Deliverables are considered separate units of accounting provided that: (i) the delivered item(s) has value to the customer on a standalone basis, and (ii) if the arrangement includes a general right of return relative to the delivered item(s), delivery or performance of the undelivered item(s) is considered probable and substantially in our control. In assessing whether an item has standalone value, we consider factors such as the research, manufacturing and commercialization capabilities of the collaboration partner or licensee and the availability of the associated expertise in the general marketplace. In addition, we consider whether the collaboration partner or licensee can use the other deliverable(s) for their intended purpose without the receipt of the remaining element(s), whether the value of the deliverable is dependent on the undelivered item(s) and whether there are other vendors that can provide the undelivered element(s).

Arrangement consideration that is fixed or determinable is allocated among the separate units of accounting using the relative selling price method. We then apply the applicable revenue recognition criteria noted above to each of the separate units of accounting in determining the appropriate period and pattern of recognition. We determine how to allocate arrangement consideration to identified units of accounting based on the selling price hierarchy provided under relevant accounting guidance. The estimated fair value of deliverables under the arrangement may be derived using a best estimate of selling price if vendor‑specific‑objective evidence and third‑party evidence are not available.

Upfront non‑refundable signing, license or non‑exclusive option fees are recognized as revenue: (i) when rights to use the intellectual property have been delivered, if the license has standalone value from the other deliverables to be provided under the agreement, or (ii) over the term of the agreement if we have continuing performance obligations, as the arrangement would be accounted for as a single unit of accounting. When payments are received in equity securities, we do not recognize any revenue unless such securities are determined to be realizable in cash.

1. ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Continued)

At the inception of an arrangement that includes milestone payments, we assess whether each milestone is substantive and at risk on the basis of the contingent nature of the milestone. This evaluation includes an assessment of whether: (i) the consideration is commensurate with either (1) our performance to achieve the milestone or (2) the enhancement of the value of the delivered item(s) as a result of a specific outcome resulting from our performance to achieve the milestone, (ii) the consideration relates solely to past performance and (iii) the consideration is reasonable relative to all of the deliverables and payment terms (including other potential milestone consideration) within the arrangement. We consider various factors, such as the scientific, clinical, regulatory, commercial and other risks that must be overcome to achieve the respective milestone and the level of effort and investment required to achieve the respective milestone, in making this assessment. There is considerable judgment involved in determining whether a milestone satisfies all of the criteria required to conclude that a milestone is substantive. Milestone payments for milestones that are considered substantive would be recognized as revenue in their entirety upon successful accomplishment of the milestone, assuming all other revenue recognition criteria are met. Milestone payments for milestones that are not considered substantive would be recognized as revenue over the remaining period of performance, assuming all other revenue recognition criteria are met.

Our license and collaboration agreements with certain partners also provide for contingent payments to us based solely upon the performance of the respective partner. For such contingent amounts, we recognize the payments as revenue when earned under the applicable contract, which is generally upon completion of performance by the respective partner, provided that collection is reasonably assured.

Royalties are recognized as earned in accordance with contract terms when royalties from licensees can be reasonably estimated and collection is reasonably assured. If royalties cannot be reasonably estimated or collection of a royalty amount is not reasonably assured, royalties are recognized as revenue when the cash is received. Revenue from commercial milestone payments is accounted for as royalties and recorded as revenue upon achievement of the milestone, assuming all other revenue recognition criteria are met and we have no performance obligations related to the milestone.

Cost‑sharing expenses are recorded as earned or owed based on the performance requirements by both parties under the respective contracts. For arrangements in which we and our collaboration partner in the agreement are exposed to significant risks and rewards that depend on the commercial success of the activity, we recognize payments between the parties on a net basis and record such amounts as a reduction or addition to research and development expense. For arrangements in which we have agreed to perform certain research and development services for our collaboration partner and are not exposed to significant risks and rewards that depend on the commercial success of the activity, we recognize the respective cost reimbursements as revenue under the collaborative agreement as the related research and development services are rendered.

Restricted Cash

Restricted cash consists of funds maintained in a separate certificate of deposit account for credit card purchases.

Research and Development Expenses

Research and development expenses consist of expenses incurred in identifying, developing and testing product candidates resulting from our independent efforts as well as efforts associated with collaborations. These expenses include, but are not limited to, in‑process research and development acquired in an asset acquisition and deemed to have no alternative future use, payroll and personnel expense, lab supplies, preclinical studies, clinical trials, including support for investigator‑sponsored clinical trials, raw materials to manufacture clinical trial drugs, manufacturing costs for research and clinical trial materials, sponsored research at other labs, consulting, costs to maintain technology licenses, our proportionate share of research and development costs under cost‑sharing arrangements with collaboration partners and research‑related overhead. Research and development costs are expensed as incurred, including costs incurred under our collaboration and/or license agreements.

1. ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Continued)

For the clinical development activities being conducted by Janssen under the Collaboration Agreement, we monitor patient enrollment levels and related activities to the extent possible through discussions with Janssen personnel and base our estimates on the best information available at the time. However, additional information may become available to us which would allow us to make a more accurate estimate in future periods. In this event, we may be required to record adjustments to research and development expenses in future periods when the actual level of activity becomes more certain.

Depreciation and Amortization

We record property and equipment at cost and calculate depreciation using the straight‑line method over the estimated useful lives of the assets, generally four years. Leasehold improvements are amortized over the shorter of the estimated useful life or remaining term of the lease.

Stock-Based Compensation

Stock‑Based Compensation

We maintain various stock incentive plans under which stock options and restricted stock awards are granted to employees, directors and consultants. We also have an employee stock purchase plan for all eligible employees. We recognize stock‑based compensation expense based on the grant-date fair values of these instruments on a straight‑line basis over the requisite service period, which is generally the vesting period. The determination of grant-date fair values for our stock options and employee stock purchases using the Black Scholes option‑pricing model is affected by our stock price as well as assumptions regarding a number of complex and subjective variables. The grant-date fair value for service-based restricted stock awards is determined using the fair value of our common stock on the date of grant.

For our non‑employee stock‑based awards, the measurement date on which the fair value of the stock‑based award is calculated is equal to the earlier of: (i) the date at which a commitment for performance by the counterparty to earn the equity instrument is reached or (ii) the date at which the counterparty’s performance is complete. We recognize stock‑based compensation expense for the fair value of the vested portion of non‑employee stock‑based awards in our statements of operations. For additional information, see Note 8 on Stockholders’ Equity.

Accumulated Other Comprehensive Loss

Accumulated other comprehensive loss includes certain changes in stockholders’ equity which are excluded from net income (loss). Accumulated other comprehensive loss on our balance sheets as of December 31, 2017 and 2016 is solely comprised of net unrealized losses on marketable securities.

Income Taxes

We maintain deferred tax assets and liabilities that 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 tax purposes and are subject to tests of recoverability. Our deferred tax assets include net operating loss carryforwards, research credits and capitalized research and development. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. Our net deferred tax asset has been fully offset by a valuation allowance because of our history of losses. Any potential accrued interest and penalties related to unrecognized tax benefits would be recorded as income tax expense.

Concentrations of Customers and Suppliers

1. ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Continued)

Concentrations of Customers and Suppliers

The majority of our revenues was earned in the United States. Two customers accounted for approximately 39% of our 2017 revenues. Approximately 81% of our 2016 revenues represented an upfront payment from Janssen Pharmaceuticals, Inc., or Janssen Pharmaceuticals, in connection with a license agreement signed in September 2016, or the License Agreement. Approximately 96% of our 2015 revenues represented an upfront payment from Janssen under the imetelstat Collaboration Agreement.

In accordance with the Collaboration Agreement, Janssen is now responsible for the manufacture and management of the supply of imetelstat on a global basis for clinical trials and, after any regulatory approval, all commercial activities. Janssen contracts third‑party manufacturers to produce GMP‑grade drugs for preclinical and clinical studies. Janssen also contracts for starting materials to supply those manufacturers and for its own use. Certain development and clinical activities may be delayed if Janssen is unable to obtain sufficient quantities of starting materials or GMP‑grade drugs from current third‑party suppliers or other third‑party sources.

Segment Information

Our executive management team represents our chief decision maker. We view our operations as a single segment, the development of therapeutic products for oncology. As a result, the financial information disclosed herein materially represents all of the financial information related to our principal operating segment.

Recent Accounting Pronouncements Not Yet Effective

In May 2014, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update No. 2014-09, or ASU 2014-09, which created Accounting Standards Codification Topic 606, Revenue from Contracts with Customers, or Topic 606, and superseded the revenue recognition requirements in Accounting Standards Codification Topic 605, Revenue Recognition, including most industry-specific revenue recognition guidance throughout the Industry Topics of the Codification. In summary, the core principle of Topic 606 is to recognize revenue when promised goods or services are transferred to customers in an amount that reflects the consideration that is expected to be received for those goods or services. Companies are allowed to select between two transition methods: (1) a full retrospective transition method with the application of the new guidance to each prior reporting period presented, or (2) a modified retrospective transition method that recognizes the cumulative effect on prior periods at the date of adoption together with additional footnote disclosures. The amendments in ASU 2014-09 are effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. In March, April, May and December 2016, the FASB issued Accounting Standards Update No. 2016-08 (Topic 606), Revenue From Contracts With Customers: Principal vs. Agent Considerations, or ASU 2016-08, Accounting Standards Update No. 2016-10 (Topic 606), Revenue From Contracts with Customers: Identifying Performance Obligations and Licensing, or ASU 2016-10, Accounting Standards Update No. 2016-12 (Topic 606), Revenue From Contracts with Customers: Narrow-Scope Improvements and Practical Expedients, or ASU 2016-12, and Accounting Standards Update No. 2016-20 (Topic 606), Revenue from Contracts with Customers: Technical Corrections and Improvements to Topic 606, or ASU 2016-20, respectively, to provide supplemental adoption guidance and clarification to ASU 2014-09. We will adopt ASU 2014-09 and its related supplemental guidance on January 1, 2018 using the modified retrospective transition method.

The new revenue standard is principles-based and the interpretation of those principles may vary from company to company based on their unique circumstances. It is possible that interpretations, industry practice, and guidance may evolve as companies and the accounting profession work to implement this new standard. We have assessed the differences in accounting for our existing contracts under the new guidance compared to current revenue accounting standards. We have not identified any material differences in the accounting treatment under ASU 2014-09 compared to the current accounting treatment for the Collaboration Agreement with Janssen and the License Agreement with Janssen Pharmaceuticals, which are our most significant license agreements. With the adoption of ASU 2014-09, we expect royalty revenues from product sales by licensees of our human telomerase reverse transcriptase, or hTERT, technology and cell-based research products to be recognized earlier than under our current accounting policy for revenue recognition. Accordingly, we expect to record a one-time cumulative catch-up adjustment in 2018 to reflect

1. ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Continued)

estimated royalty revenues on product sales earned in 2017 for which payments have not yet been received. We do not expect that the adoption of ASU 2014-09 will have a material impact on our financial statements and related disclosures.

In January 2016, the FASB issued Accounting Standards Update No. 2016-01, Financial Instruments - Overall: Recognition and Measurement of Financial Assets and Financial Liabilities, or ASU 2016-01, which requires equity investments to be measured at fair value with changes in fair value recognized in net income. However, equity investments without readily determinable fair values can either be measured at fair value or use a measurement alternative which adjusts cost for changes in observable prices minus impairment. ASU 2016-01 requires separate presentation of financial assets and liabilities by category and form. ASU 2016-01 is effective for annual periods beginning after December 15, 2017, and interim periods within those annual periods. To further clarify ASU 2016-01, the FASB issued Accounting Standards Update No. 2018-03, Technical Corrections and Improvements to Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, or ASU 2018-03, in February 2018. ASU 2018-03 requires application of a prospective transition approach only for those equity investments for which the new measurement alternative is being applied. Additionally, if an entity voluntarily discontinues using the measurement alternative, the investment and all identical or similar investments of the same issuer must be measured at fair value. ASU 2018-03 is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years beginning after June 15, 2018. Early adoption is permitted. We currently hold equity investments without readily determinable fair values that are accounted for under the cost method and are evaluating the method and timing of adoption of ASU 2016-01 and ASU 2018-03. The adoption of ASU 2016-01 and ASU 2018-03 may have a material impact on our financial statements and related disclosures.

In February 2016, the FASB issued Accounting Standards Update No. 2016-02, Leases (Topic 842), or ASU 2016-02. ASU 2016-02 requires an entity to recognize a right-of-use asset and lease liability for all leases with terms of more than 12 months. Recognition, measurement and presentation of expenses will depend on classification as a finance or operating lease. Certain quantitative and qualitative disclosures about leasing arrangements also are required. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. The updated guidance requires a modified retrospective adoption. We are currently evaluating the impact that the adoption of ASU 2016-02 will have on our financial statements and related disclosures and have not made any decision regarding the timing of adoption.

In August 2016, the FASB issued Accounting Standards Update No. 2016-15, Classification of Certain Cash Receipts and Cash Payments, or ASU 2016-15, to clarify how certain cash receipts and cash payments are presented and classified in the statement of cash flows. ASU 2016-15 is effective for annual periods beginning after December 15, 2017, and interim periods within those annual periods. ASU 2016-15 must be applied retrospectively to each period presented. We will adopt ASU 2016-15 on January 1, 2018. We do not expect that the adoption of ASU 2016-15 will have a material impact on our financial statements and related disclosures.

In November 2016, the FASB issued Accounting Standards Update No. 2016-18, Statement of Cash Flows (Topic 230) Restricted Cash, or ASU 2016-18, to address the diversity in practice in the classification and presentation of changes in restricted cash on the statement of cash flows. ASU 2016-18 is effective for annual periods beginning after December 15, 2017, and interim periods within those annual periods. ASU 2016-18 must be applied using a retrospective transition method to each period presented. We will adopt ASU 2016-18 on January 1, 2018. We do not expect that the adoption of ASU 2016-18 will have a material impact on our financial statements and related disclosures.

In May 2017, the FASB issued Accounting Standards Update No. 2017-09, Compensation — Stock Compensation: Scope of Modification Accounting, or ASU 2017-09. ASU 2017-09 clarifies when to account for a change to the terms or conditions of a share-based payment award as a modification. Under the new guidance, modification accounting is required only if the fair value, the vesting conditions, or the classification of the award (as equity or liability) changes as a result of the change in terms or conditions. ASU 2017-09 is effective for annual periods beginning after December 15, 2017, and interim periods within those annual periods. The amendments in ASU 2017-09 should be applied prospectively to an award modified on or after the adoption date. We will adopt ASU 2017-09 on January 1, 2018. We do not expect that the adoption of ASU 2017-09 will have a material impact on our financial statements and related disclosures.