Alaunos Therapeutics (TCRT) 10-K 16 Feb 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Feb. 06, 2017	Jun. 30, 2016
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Trading Symbol	ZIOP
Entity Registrant Name	ZIOPHARM ONCOLOGY INC
Entity Central Index Key	1,107,421
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		132,376,670
Entity Public Float			$ 659,304,778

BALANCE SHEETS

BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 81,053	$ 140,717
Receivables	21	446
Prepaid expenses and other current assets	23,810	11,358
Total current assets	104,884	152,521
Property and equipment, net	843	581
Deposits	128	128
Other non current assets	493	494
Total assets	106,348	153,724
Current liabilities:
Accounts payable	156	2,008
Accrued expenses	9,109	8,906
Deferred revenue - current portion	6,389	6,861
Deferred rent - current portion	155	348
Total current liabilities	15,809	18,123
Deferred revenue, net of current portion	41,528	47,917
Deferred rent, net of current portion	126	313
Derivative liabilities	862
Total liabilities	58,325	66,353
Commitments and contingencies (note 7)
Stockholders' equity (deficit):
Common stock, $0.001 par value; 250,000,000 shares authorized; 132,376,670 and 131,718,579 shares issued and outstanding at December 31, 2016 and 2015, respectively	132	132
Additional paid-in capital - common stock	580,567	579,939
Accumulated Deficit	(657,997)	(492,700)
Total stockholders' equity (deficit)	(77,298)	87,371
Total liabilities and stockholders' equity (deficit)	106,348	$ 153,724
Series 1 Preferred Stock
Current liabilities:
Series 1 preferred stock, $1,200 stated value; 250,000 designated; 106,184 and 0 shares issued and outstanding at December 31, 2016, respectively; liquidation preference of $127.4 million and $0 at December 31, 2016 and December 31, 2015, respectively	$ 125,321

BALANCE SHEETS (Parenthetical)

BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	132,376,670	131,718,579
Common stock, shares outstanding	132,376,670	131,718,579
Series 1 Preferred Stock
Preferred stock, stated value	$ 1,200	$ 1,200
Preferred stock, shares authorized	250,000	250,000
Preferred stock, shares issued	106,184	0
Preferred stock, shares outstanding	106,184	0
Preferred stock, liquidation preference	$ 127.4	$ 0

STATEMENTS OF OPERATIONS

STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Collaboration Revenue	$ 6,861	$ 4,332	$ 1,373
Operating expenses:
Research and development	157,791	106,785	32,706
General and administrative	14,377	17,647	12,166
Total operating expenses	172,168	124,432	44,872
Loss from operations	(165,307)	(120,100)	(43,499)
Other income (expense), net	134	12	(5)
Change in fair value of warrants			11,723
Change in fair value of derivative liabilities	(124)
Net loss	(165,297)	(120,088)	(31,781)
Preferred stock dividends	(7,123)
Net loss applicable to common stockholders	$ (172,420)	$ (120,088)	$ (31,781)
Basic and diluted net loss per share	$ (1.32)	$ (0.96)	$ (0.31)
Weighted average common shares outstanding used to compute basic and diluted net loss per share	130,391,463	125,416,084	101,130,710

STATEMENTS OF CHANGES IN STOCKH

STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital Common Stock	Additional Paid-in Capital Warrants	Accumulated Deficit	Series 1 Preferred Stock - Mezzanine
Beginning Balance (in shares) at Dec. 31, 2013		100,159,618
Beginning Balance at Dec. 31, 2013	$ 49,383	$ 100	$ 386,511	$ 3,603	$ (340,831)
Stock-based compensation	$ 4,743		4,743
Exercise of warrants to purchase common stock (in shares)	3,725,277	3,747,254
Exercise of warrants to purchase common stock	$ 10,654	$ 4	13,963	(3,313)
Exercise of employee stock options (in shares)	613,138	613,138
Exercise of employee stock options	$ 1,386		1,386
Issuance of restricted common stock		66,828
Repurchase of shares of restricted common stock (in shares)		(112,333)
Repurchase of shares of restricted common stock	(544)		(544)
Cancelled of restricted stock		(22,400)
Expired warrants			290	(290)
Net loss	(31,781)				(31,781)
Ending Balance (in shares) at Dec. 31, 2014		104,452,105
Ending Balance at Dec. 31, 2014	33,841	$ 104	406,349	$ 0	(372,612)
Stock-based compensation	$ 7,997		7,997
Exercise of employee stock options (in shares)	3,249,160	2,519,267
Exercise of employee stock options	$ 4,568	$ 3	4,566
Issuance of restricted common stock		1,590,574
Issuance of restricted common stock		$ 2	(2)
Issuance of common stock in licensing agreement (in shares)		11,722,163
Issuance of common stock in licensing agreement	67,285	$ 12	67,273
Repurchase of shares of restricted common stock (in shares)		(61,819)
Repurchase of shares of restricted common stock	(518)		(518)
Repurchase of common stock (Shares)		(3,711)
Repurchase of common stock	(34)		(34)
Issuance of common stock, net of commissions and expenses of $6,305 (in shares)		11,500,000
Issuance of common stock, net of commissions and expenses of $6,305	94,320	$ 12	94,309
Net loss	(120,088)				(120,088)
Ending Balance (in shares) at Dec. 31, 2015		131,718,579
Ending Balance at Dec. 31, 2015	87,371	$ 132	579,939		(492,700)
Stock-based compensation	$ 8,452		8,452
Exercise of employee stock options (in shares)	234,833	189,696
Exercise of employee stock options	$ 714	$ 2	712
Issuance of restricted common stock		711,770
Issuance of restricted common stock		$ 712	(712)
Issuance of common stock in licensing agreement (in shares)						100,000
Issuance of common stock in licensing agreement	87		87			$ 118,242
Repurchase of shares of restricted common stock (in shares)		(243,207)
Repurchase of shares of restricted common stock	(1,500)	$ (2)	(1,498)
Repurchase of common stock (Shares)		(168)
Repurchase of common stock	(2)		(2)
Issuance of preferred stock dividends (in shares)						6,184
Issuance of preferred stock dividends	(7,123)		(7,123)			$ 7,079
Net loss	(165,297)				(165,297)
Ending Balance (in shares) at Dec. 31, 2016		132,376,670				106,184
Ending Balance at Dec. 31, 2016	$ (77,298)	$ 132	$ 580,567		$ (657,997)	$ 125,321

STATEMENTS OF CHANGES IN STOCK6

STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (DEFICIT) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Issuance of common stock, commissions and expenses	$ 109	$ 6,305

STATEMENTS OF CASH FLOWS

STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net loss	$ (165,297)	$ (120,088)	$ (31,781)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	290	357	462
Stock-based compensation	8,452	7,997	4,743
Change in fair value of warrants			(11,723)
Common stock issued in exchange for license agreement		67,285
Preferred stock issued in exchange for 2016 ECP amendment	118,936
Change in fair value of derivative liabilities	124
Issuance of common stock in a license agreement	87
(Increase) decrease in:
Receivables	425	(301)
Prepaid expenses and other current assets	(12,452)	(10,214)	809
Other noncurrent assets		(3)	37
Increase (decrease) in:
Accounts payable	(1,852)	4	1,582
Accrued expenses	203	1,724	827
Deferred revenue	(6,861)	53,418	(1,373)
Deferred rent	(380)	(189)	(213)
Other noncurrent liabilities			(20)
Net cash used in operating activities	(58,325)	(10)	(36,650)
Cash flows from investing activities:
Purchases of property and equipment	(551)	(412)	(193)
Net cash used in investing activities	(551)	(412)	(193)
Cash flows from financing activities:
Proceeds from exercise of stock options	714	4,568	1,386
Payments to employees for repurchase of restricted common stock	(1,500)	(518)	(544)
Proceeds from exercise of warrants			10,600
Repurchase of common stock	(2)	(34)
Proceeds from issuance of common stock, net		94,320
Net cash provided by (used in) financing activities	(788)	98,336	11,442
Net decrease in cash and cash equivalents	(59,664)	97,914	(25,401)
Cash and cash equivalents, beginning of period	140,717	42,803	68,204
Cash and cash equivalents, end of period	81,053	140,717	42,803
Supplementary disclosure of cash flow information:
Cash paid for interest	0	0	0
Cash paid for income taxes	0	0	0
Supplementary disclosure of noncash investing and financing activities:
Exercise of equity-classified warrants to common shares			692
Exercise of liability-classified warrants to common shares			$ 54
Common Stock
Supplementary disclosure of noncash investing and financing activities:
Issuance of stock		$ 67,285
Series 1 Preferred Stock
Supplementary disclosure of noncash investing and financing activities:
Issuance of stock	119,045
Payment of dividends in preferred stock	$ 7,123

Organization and Going Concern

Organization and Going Concern	12 Months Ended
	Dec. 31, 2016
Organization and Going Concern	1. Organization and Going Concern ZIOPHARM Oncology, Inc., which is referred to herein as “ZIOPHARM” or the “Company,” is a biopharmaceutical company seeking to develop, acquire, and commercialize, on its own or with partners, a diverse portfolio of cancer therapies that address unmet medical needs. The Company’s operations to date have consisted primarily of raising capital and conducting research and development. The Company’s fiscal year ends on December 31. The Company has operated at a loss since its inception in 2003 and has minimal revenues. The Company anticipates that losses will continue for the foreseeable future. At December 31, 2016, the Company’s accumulated deficit was approximately $658.0 million. Given its current development plans, the Company anticipates cash resources will be sufficient to fund operations into the fourth quarter of 2017. The Company’s ability to continue operations after its current cash resources are exhausted depends on its ability to obtain additional financing or to achieve profitable operations, as to which no assurances can be given. Cash requirements may vary materially from those now planned because of changes in the Company’s focus and direction of its research and development programs, competitive and technical advances, patent developments, regulatory changes or other developments. Additional financing will be required to continue operations after the Company exhausts its current cash resources and to continue its long-term plans for clinical trials and new product development (Note 3). As of December 31, 2016, we have approximately $81.1 million of cash and cash equivalents. Given our development plans, we anticipate cash resources will be sufficient to fund our operations into the fourth quarter of 2017 and the Company has no committed sources of additional capital. The forecast of cash resources is forward-looking information that involves risks and uncertainties, and the actual amount of our expenses could vary materially and adversely as a result of a number of factors. We have based our estimates on assumptions that may prove to be wrong, and our expenses could prove to be significantly higher than we currently anticipate. Management does not know whether additional financing will be on terms favorable or acceptable to the Company when needed, if at all. If adequate additional funds are not available when required, or if the Company is unsuccessful in entering into partnership agreements for further development of its products, management may need to curtail development efforts. Based on the forecast, management determined that there is substantial doubt regarding our ability to continue as a going concern.

Financings

Financings	12 Months Ended
	Dec. 31, 2016
Financings	2. Financings On February 3, 2015, the Company entered into an underwriting agreement with J.P. Morgan Securities LLC, as representative of the several underwriters named therein, relating to the issuance and sale of 10,000,000 shares of its common stock. The price to the public in the offering was $8.75 per share, and the underwriters agreed to purchase the shares from the Company pursuant to the underwriting agreement at a purchase price of $8.225 per share. Under the terms of the underwriting agreement, the Company also granted the underwriters an option, exercisable for 30 days, to purchase up to an additional 1,500,000 shares of common stock at a purchase price of $8.225 per share. The offering was made pursuant to the Company’s effective registration statement on Form S-3 No. 333-201826)

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Summary of Significant Accounting Policies	3. Summary of Significant Accounting Policies Basis of Presentation The accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America or U.S. GAAP. 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 estimates and assumptions that affect the reported amounts of assets and liabilities and the 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. Although the Company regularly assesses these estimates, actual results could differ from those estimates. Changes in estimates are recorded in the period in which they become known. The Company’s most significant estimates and judgments used in the preparation of our financial statements are: • Clinical trial expenses; • Collaboration agreements; • Fair value measurements of stock based compensation, warrants and Series 1 preferred stock; and • Income taxes. Subsequent Events The Company evaluated all events and transactions that occurred after the balance sheet date through the date of this filing. Except as discussed below, the Company did not have any other material subsequent events that impacted its financial statements or disclosures. On January 9, 2017, the Company signed a Cooperative Research and Development Agreement, or CRADA, with the National Cancer Institute for the development of adoptive cell transfer-based immunotherapies genetically modified using the Sleeping Beauty T-cell Cash and Cash Equivalents Cash equivalents consist primarily of demand deposit accounts and deposits in short-term U.S. treasury money market mutual funds. Cash equivalents are stated at cost, which approximates fair market value. Concentrations of Credit Risk Financial instruments which potentially subject the Company to concentrations of credit risk consist principally of cash and cash equivalents. The Company maintains cash accounts in commercial banks, which may, at times, exceed federally insured limits. The Company has not experienced any losses in such accounts. The Company believes it is not exposed to any significant credit risk on cash and cash equivalents. Property and Equipment Property and equipment are recorded at cost. Expenditures for maintenance and repairs are charged to expense while the costs of significant improvements are capitalized. Depreciation is provided using the straight-line method over the following estimated useful lives of the related assets, which is between three and five years. Upon retirement or sale, the cost of the assets disposed of and the related accumulated depreciation are eliminated from the balance sheets and related gains or losses are reflected in the statements of operations. Restricted Cash Restricted cash consists of $388 thousand, which is restricted as collateral for the Company’s facility leases, and $104 thousand, which is restricted as collateral for a line of credit is included in other assets. Long-Lived Assets The Company reviews the carrying values of its long-lived assets for possible impairment whenever events or changes in circumstances indicate that the carrying amounts of the assets may not be recoverable. Any long-lived assets held for disposal are reported at the lower of their carrying amounts or fair values less costs to sell. Operating Segments 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 and does not track expenses on a program-by-program basis. Warrants The Company applied the accounting standard which provided guidance in assessing whether an equity-based financial instrument is indexed to an entity’s own stock for purposes of determining whether a financial instrument should be treated as a derivative. In applying the methodology, the Company concluded that certain warrants issued by the Company had terms that did not meet the criteria to be considered indexed to the Company’s own stock and therefore were classified as liabilities in the Company’s balance sheet. The liability classified warrants were subject to re-measurement Fair Value Measurements The Company has certain financial assets and liabilities recorded at fair value which have been classified as Level 1, 2 or 3 within the fair value hierarchy as described in the accounting standards for fair value measurements. • Level 1—Quoted prices in active markets for identical assets or liabilities. • Level 2—Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. • Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Assets and liabilities measured at fair value on a recurring basis as of December 31, 2016 and 2015 are as follows: ($ in thousands) Fair Value Measurements at Reporting Date Using Description Balance as of Quoted Prices in Significant Significant Cash equivalents $ 77,120 $ 77,120 $ — $ — Derivative liabilities $ 862 $ — $ — $ 862 ($ in thousands) Fair Value Measurements at Reporting Date Using Description Balance as of Quoted Prices in Significant Other Significant Cash equivalents $ 137,405 $ 137,405 $— $— The cash equivalents represent deposits in a short term United States treasury money market mutual fund quoted in an active market and classified as a Level 1 asset. As discussed further in Notes 7 and 10, the Company issued Intrexon 100,000 shares of the Company’s Series 1 preferred stock, a new class of preferred stock authorized by the Company’s board of directors, in consideration of the parties entering into a Third Amendment to Exclusive Channel Partner Agreement, or the 2016 ECP Amendment, amending their existing Exclusive Channel Partner Agreement, effective January 6, 2011 and as amended to date, which the Company refers to as the Channel Agreement, and an Amendment to Exclusive Channel Collaboration Agreement, or the 2016 GvHD Amendment, amending their existing Exclusive Channel Collaboration Agreement, effective September 28, 2015, which the Company refers to as the GvHD Agreement. At June 30, 2016, the Company’s Series 1 preferred stock was valued using a probability-weighted approach and a Monte Carlo simulation model. Additionally, the monthly dividends issued on the outstanding Series 1 preferred stock are valued using the same probability-weighted approach and a Monte Carlo simulation model. However, there is no adjustment or further revaluation after the initial valuation on the Series 1 preferred stock. The Company’s Level 3 financial liabilities consist of a conversion option and a redemption feature associated with the Company’s Series 1 preferred stock issued to Intrexon that has been bifurcated from the Series 1 preferred stock and are accounted for as derivative liabilities at fair value. The preferred stock derivative liabilities were valued using a probability-weighted approach and a Monte Carlo simulation model. The fair value of the embedded derivatives was estimated using the “with” and “without” method where the preferred stock was first valued with all of its features (“with” scenario) and then without derivatives subject to the valuation analysis (“without” scenario). The fair value of the derivatives was then estimated as the difference between the fair value of the preferred stock in the “with” scenario and the preferred stock in the “without” scenario. See Note 7 for additional disclosures on the 2016 ECP Amendment and 2016 GvHD Amendments and Note 10 for additional disclosure on the rights and preferences of the Series 1 preferred stock and valuation methodology. Revenue Recognition from Collaboration Agreements The Company has primarily generated revenue through collaboration arrangements with strategic partners for the development and commercialization of product candidates. The Company recognizes revenue for each unit of accounting when evidence of an arrangement exists, delivery has occurred or services have been rendered, the seller’s price to the buyer is fixed or determinable and collectability is reasonably assured. The Company’s collaboration agreements may provide for various types of payments, including upfront payments, funding of research and development, milestone payments, licensing fees and product royalties. The specifics of the Company’s significant agreements are detailed in Note 7. The Company considers a variety of factors in determining the appropriate method of accounting for its collaboration agreements, including whether multiple deliverables can be separated and accounted for individually as separate units of accounting. Pursuant to the guidance in FASB Accounting Standards Codification (ASC) 605-25, Multiple-Element Arrangements 605-25), Where there are multiple deliverables within a collaboration agreement that cannot be separated and therefore are combined into a single unit of accounting, revenues are deferred and recognized over the estimated period of performance, which is typically the development term. If the deliverables can be separated, the Company applies the relevant revenue recognition guidance to each individual unit of accounting. The specific methodology for the recognition of the underlying revenue is determined on a case-by-case At the inception of an arrangement that includes milestone payments, the Company evaluates whether each milestone is substantive and at risk to both parties on the basis of the contingent nature of the milestone. This evaluation includes an assessment of whether: (i) the consideration is commensurate with either the Company’s performance to achieve the milestone or the enhancement of the value of the delivered item(s) as a result of a specific outcome resulting from the Company’s 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 within the arrangement. The Company evaluates 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 judgement involved in determining whether a milestone satisfies all of the criteria required to conclude that a milestone is substantive. In accordance with FASB ASC 605-28, Milestone Method 605-28), Research and Development Costs Research and development expenditures are charged to the statement of operations as incurred. Such costs include proprietary research and development activities, purchased research and development, and expenses associated with research and development contracts, whether performed by the Company or contracted with independent third parties. Income Taxes Income taxes are accounted for under the liability method. Deferred tax assets and liabilities are recognized for the estimated future tax consequences of temporary differences between the financial statement carrying amounts and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the year in which the temporary differences are expected to be recovered or settled. The Company evaluates the realizability of its deferred tax assets and establishes a valuation allowance when it is more likely than not that all or a portion of deferred tax assets will not be realized. The Company accounts for uncertain tax positions using a “more-likely-than-not” Accounting for Stock-Based Compensation Stock-based compensation cost is measured at the grant date, based on the estimated fair value of the award, and is recognized as expense over the employee’s requisite service period. Stock-based compensation expense is based on the number of awards ultimately expected to vest and is therefore reduced for an estimate of the awards that are expected to be forfeited prior to vesting. Consistent with prior years, the Company uses the Black-Scholes option pricing model which requires estimates of the expected term option holders will retain their options before exercising them and the estimated volatility of the Company’s common stock price over the expected term. The Company recognizes the full impact of its share-based employee payment plans in the statements of operations for each of the years ended December 31, 2016, 2015, and 2014 and did not capitalize any such costs on the balance sheets. The Company recognized $3.0 million, $5.3 million, and $3.7 million of compensation expense related to vesting of stock options during the years ended December 31, 2016, 2015, and 2014, respectively. In the years ended December 31, 2016, 2015, and 2014, the Company recognized $5.5 million, $2.7 million, and $1.0 million of compensation expense, respectively, related to vesting of restricted stock (see Note 12). In the years ended December 31, 2016, 2015, and 2014, the Company recognized $8.5 million, $8.0 million, and $4.7 million of compensation expense, respectively, related to vesting of all employee and director awards. The following table presents share-based compensation expense included in the Company’s Statements of Operations: Year ended December 31, (in thousands) 2016 2015 2014 Research and development $ 2,077 $ 1,403 $ 1,416 General and administrative 6,375 6,594 3,327 Share based employee compensation expense before tax 8,452 7,997 4,743 Income tax benefit — — — Net share based employee compensation expense $ 8,452 $ 7,997 $ 4,743 The fair value of each stock option is estimated at the date of grant using the Black-Scholes option pricing model. The estimated weighted-average fair value of stock options granted to employees in 2016, 2015, and 2014 was approximately $4.43, $10.47, and $3.58 per share, respectively. Assumptions regarding volatility, expected term, dividend yield and risk-free interest rate are required for the Black-Scholes model. The volatility assumption is based on the Company’s historical experience. The risk-free interest rate is based on a U.S. treasury note with a maturity similar to the option award’s expected life. The expected life represents the average period of time that options granted are expected to be outstanding. The Company calculated expected term using the simplified method described in SEC Staff Accounting Bulletin, or SAB, No. 107 and No. 110 as it continues to meet the requirements promulgated in SAB No. 110. The assumptions for volatility, expected life, dividend yield and risk-free interest rate are presented in the table below: 2016 2015 2014 Weighted average risk-free interest rate 1.27 - 2.09% 1.46 - 1.93% 1.74 - 2.11% Expected life in years 6 6 6 Expected volatility 79.15 - 82.95% 79.13 - 86.81% 85.22 - 94.55% Expected dividend yield 0 0 0 Net Loss Per Share Basic net loss per share is computed by dividing net loss by the weighted average number of common shares outstanding for the period. The Company’s potentially dilutive shares, which include outstanding common stock options, unvested restricted stock and preferred stock, have not been included in the computation of diluted net loss per share for any of the periods presented as the result would be antidilutive. Such potential common shares at December 31, 2016, 2015, and 2014 consist of the following: December 31, 2016 2015 2014 Stock options 3,465,335 3,481,468 6,505,664 Unvested restricted stock 1,680,492 1,586,388 144,508 Preferred stock 20,465,067 — — 25,610,894 5,067,856 6,650,172 The Series 1 preferred stock automatically converts into shares of common stock upon the date the first approval in the United States of (i) a ZIOPHARM Product, as defined in and developed under the Exclusive Channel Partner Agreement dated as of January 6, 2011 and as amended from time to time, by and between the Company and Intrexon, or (ii) a Product, as defined in and developed under the Exclusive Channel Collaboration Agreement dated September 28, 2015 and as amended from time to time, by and between the Company and Intrexon, or (iii) a Product as defined in and developed under the License and Collaboration Agreement dated March 27, 2015 and as amended from time to time, by and among Intrexon, ARES TRADING, S.A. and the Company, is publicly announced. Assuming a conversion event date of December 31, 2016, the Series 1 preferred stock would convert into 20,465,067 shares of common stock using the greater of (i) the volume weighted average closing price of the Company’s Common Stock as reported by the Nasdaq Stock Market, LLC over previous the 20 trading days ending on the conversion event date or (ii) $1.00 per share. See Note 7 and Note 10 for additional disclosure regarding the 2016 ECP Amendment and 2016 GvHD Amendment, valuation methodology and significant assumptions. New Accounting Pronouncements In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers In August 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements—Going Concern 205-40) In November 2015, the FASB issued ASU 2015-17, Income Taxes (Topic 740), Balance Sheet Classification of Deferred Taxes In March 2016, the FASB issued ASU No. 2016-09, Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting In August 2016, the FASB issued ASU No. 2016-15, Classification of Certain Cash Receipts and Cash Payments In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash Payments In February 2016, the FASB issued ASU 2016-02, Leases (“ ”) Leases

Property and Equipment, net

Property and Equipment, net	12 Months Ended
	Dec. 31, 2016
Property and Equipment, net	4. Property and Equipment, net Property and equipment, net, consists of the following: December 31, (in thousands) 2016 2015 Office and computer equipment $ 1,162 $ 1,105 Software 907 886 Leasehold improvements 1,158 990 Manufacturing equipment 878 572 4,105 3,553 Less: accumulated depreciation (3,262 ) (2,972 ) Property and equipment, net $ 843 $ 581 Depreciation and amortization charged to the Statement of Operations for the years ended December 31, 2016, 2015, and 2014 was $290 thousand, $358 thousand and $462 thousand, respectively.

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2016
Accrued Expenses	5. Accrued Expenses Accrued expenses consist of the following: December 31, (in thousands) 2016 2015 Clinical consulting services $ 2,342 $ 2,331 Preclinical services 2,693 3,976 Employee compensation 1,446 1,453 Professional services 488 317 Payroll taxes and benefits 646 289 Manufacturing services 1,116 253 Accrued vacation 294 221 Other consulting services 28 66 Accrued rent 56 — Total $ 9,109 $ 8,906

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2016
Related Party Transactions	6. Related Party Transactions On January 6, 2011, the Company entered into the Channel Agreement, with Intrexon (see Note 7). A director of the Company, Randall J. Kirk, is the CEO, a director, and the largest stockholder of Intrexon. On February 3, 2015, Intrexon purchased 1,440,000 shares of common stock in the Company’s public offering (see Note 2) upon the same terms as others that participated in the offering. On March 27, 2015, the Company and Intrexon entered into a Second Amendment to the Exclusive Channel Partner Agreement amending the Channel Agreement, which is referred to as the ECP Amendment. The ECP Amendment modified the scope of the parties’ collaboration under the Channel Agreement in connection with the worldwide License and Collaboration Agreement, or the Ares Trading Agreement, which the Company and Intrexon entered into with Ares Trading S.A., or Ares Trading, on March 27, 2015. The ECP Amendment provided that Intrexon will pay to the Company fifty percent of all payments that Intrexon receives for upfronts, milestones and royalties under the Ares Trading Agreement (see Note 10). The Amendment also reduces Intrexon’s aggregate commitment under a Stock Purchase Agreement that the parties executed in connection with the initial Channel Agreement to purchase the Company’s common stock from $50.0 million to $43.5 million, which has been satisfied. On January 13, 2015, the Company, together with Intrexon, entered into a license agreement with MD Anderson, which is referred to as the MD Anderson License. Pursuant to the MD Anderson License, the Company and Intrexon hold an exclusive, worldwide license to certain technologies owned and licensed by MD Anderson including technologies relating to novel CAR+ T cell therapies arising from the laboratory of Laurence Cooper, M.D., Ph.D., the Chief Executive Officer of the Company, formerly a professor of pediatrics at MD Anderson and now currently a visiting scientist under that institution’s policies, as well as either co-exclusive non-exclusive in-process On June 29, 2015, the Company re-purchased 3,711 shares of common stock from Intrexon, at a discount of 5% to the closing price of the Company’s common stock on the date of purchase, which represented fractional shares that resulted from Intrexon’s special stock dividend of the Company’s shares to Intrexon’s shareholders, for $34 thousand. On January 8, 2016, the Company re-purchased an additional 168 shares of common stock from Intrexon for $2 thousand at the same terms as the previous share repurchase. On September 28, 2015, the Company, entered into the GvHD Agreement with Intrexon, whereby the Company will use Intrexon’s technology directed towards in vivo On June 29, 2016, the Company entered into the 2016 ECP Amendment and the 2016 GvHD Amendment. The 2016 ECP Amendment reduced the royalty percentage that the Company will pay to Intrexon under the Channel Agreement on a quarterly basis from 50% to 20% of net profits derived in that quarter from the sale of ZIOPHARM Products (as defined in the Channel Agreement), calculated on a ZIOPHARM Product-by-ZIOPHARM In consideration for the execution and delivery of the 2016 ECP Amendment and the 2016 GvHD Amendment, the Company issued Intrexon 100,000 shares of its Series 1 preferred stock. Each share of the Company’s Series 1 preferred stock has a stated value of $1,200, subject to appropriate adjustment in the event of any stock dividend, stock split, combination or other recapitalization, and certain other rights, preferences, privileges and obligations (Note 10). The holders of the shares of Series 1 preferred stock are entitled to receive a monthly dividend, payable in additional shares of Series 1 preferred stock, equal to $12.00 per preferred share held by such holder per month divided by the stated value of the preferred shares, rounded down to the nearest whole share. During the year ended December 31, 2016, the Company issued an aggregate of 6,184 shares of Series 1 preferred stock to Intrexon, the holder of all of the outstanding shares of the Company’s Series 1 preferred stock, as monthly dividend payments. The Company recorded $44 thousand for the fair value of the derivatives as a liability and $7.1 million for the fair value of the Series 1 preferred stock as a component of temporary equity. See Notes 3, 8 and 9 for additional discussion regarding the accounting for and valuation of these derivative financial instruments. During the years ended December 31, 2016, 2015 and 2014, the Company expensed $22.2 million, $16.3 million, and $12.0 million, respectively, for services performed by Intrexon. As of December 31, 2016 and 2015. The Company has recorded $3.4 million and $4.6 million in current liabilities, respectively, for amounts due to Intrexon.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies	7. Commitments and Contingencies Operating Leases Prior to December 31, 2012, the Company entered into an operating lease in New York, NY for office space. In accordance with this agreement, the Company entered into a letter of credit in the amount of $388 thousand, naming the Company’s landlord as beneficiary. In January 2012, the Company amended the lease agreement, adding additional office space. The collateral for the letter of credit is restricted cash and recorded in other non-current On October 17, 2013, the Company entered into a sublease agreement to lease all of its New York office space to a subtenant. The Company remains primarily liable to pay rent on the original lease. The Company recorded a loss on the sublease in the amount of $729 thousand for the year ended December 31, 2013, representing the remaining contractual obligation of $2.3 million, less $1.6 million in payments from its subtenant. The Company retired assets as a result of this sublease with a net book value of $392 thousand, and recorded a loss on disposal of fixed assets for the same amount for the year ended December 31, 2013. The Company continues to maintain the $388 thousand letter of credit in respect of the New York office space. Prior to December 31, 2012, the Company entered into separate operating lease agreements for various spaces in a building in Boston, MA. In June 2012, the Company re-negotiated On August 30, 2013, the Company entered into a sublease agreement to lease a portion of its Boston office to a subtenant. The Company remains liable to pay rent on the original lease. The Company recorded a loss on the sublease in the amount of $42 thousand for the year ended December 31, 2013, representing the remaining contractual obligation of $367 thousand, less $325 thousand in payments from its subtenant. This sublease tenant vacated the leased premises in October 2014. At December 31, 2014, the Company applied the $20 thousand deposit received from the sublease tenant against its outstanding rent obligation. On March 31, 2015, the Company recorded a loss of $167 thousand on the first floor sublease. On May 22, 2015, the Company subleased the vacant office space for approximately $105 thousand for the period of June 2015 through August 2016, and the tenant provided a security deposit of $17 thousand. Since the prior lease obligation has been fully expensed, rent received from the tenant reduced current rent expense. Future net minimum lease payments under operating leases as of December 31, 2016 are as follows (in thousands): 2017 $ 1,183 2018 1,113 2019 706 2020 719 2021 and beyond 484 4,205 Less: contractual sublease income (612 ) Future minimum lease payments, net $ 3,593 Total rent expense was approximately $0.3 million, $1.0 million, and $1.2 million for the years ended December 31, 2016, 2015, and 2014. The Company records rent expense on a straight-line basis over the term of the lease. Accordingly, the Company has recorded a liability for deferred rent at December 31, 2016 and 2015 of $281 thousand ($155 thousand current and $126 thousand long-term) and $661 thousand ($348 thousand current and $313 long-term) respectively, which is recorded in deferred rent on the balance sheet. License Agreements Exclusive Channel Partner Agreement with Intrexon Corporation for the Cancer Programs On January 6, 2011, the Company entered into the Channel Agreement with Intrexon that governs a “channel partnering” arrangement in which the Company uses Intrexon’s technology to research, develop and commercialize products in which DNA is administered to humans for expression of anti-cancer effectors for the purpose of treatment or prophylaxis of cancer, which the Company collectively refers to as the Cancer Program. This Channel Agreement establishes committees comprised of representatives of the Company and Intrexon that govern activities related to the Cancer Program in the areas of project establishment, chemistry, manufacturing and controls, clinical and regulatory matters, commercialization efforts and intellectual property. The Channel Agreement grants the Company a worldwide license to use patents and other intellectual property of Intrexon in connection with the research, development, use, importing, manufacture, sale, and offer for sale of products involving DNA administered to humans for expression of anti-cancer effectors for the purpose of treatment or prophylaxis of cancer, which is collectively referred to as the ZIOPHARM Products. Such license is exclusive with respect to any clinical development, selling, offering for sale or other commercialization of ZIOPHARM Products, and otherwise is non-exclusive. Under the Channel Agreement, and subject to certain exceptions, the Company is responsible for, among other things, the performance of the Cancer Program, including the development, commercialization and certain aspects of manufacturing of ZIOPHARM Products. Intrexon is responsible for establishing manufacturing capabilities and facilities for the bulk manufacture of products developed under the Cancer Program, certain other aspects of manufacturing and costs of discovery-stage research with respect to platform improvements and costs of filing, prosecution and maintenance of Intrexon’s patents. Subsequent to the Third Amendment to the Exclusive Channel Partner Agreement, or the 2016 ECP Amendment, discussed below, and subject to certain expense allocations and other offsets provided in the Channel Agreement, the Company is obligated to pay Intrexon on a quarterly basis 20% of net profits derived in that quarter from the sale of ZIOPHARM Products, calculated on a ZIOPHARM Product-by- Upon termination of the Channel Agreement, the Company may continue to develop and commercialize any ZIOPHARM Product that, at the time of termination: • Is being commercialized by the Company; • Has received regulatory approval; • Is a subject of an application for regulatory approval that is pending before the applicable regulatory authority; or • Is the subject of at least an ongoing Phase 2 clinical trial (in the case of a termination by Intrexon due to an uncured breach or a voluntary termination by the Company), or an ongoing Phase 1 clinical trial in the field (in the case of a termination by the Company due to an uncured breach or a termination by Intrexon following an unconsented assignment by the Company or its election not to pursue development of a Superior Therapy (as defined in the Channel Agreement)). The Company’s obligation to pay 20% of net profits or revenue described above with respect to these “retained” products will survive termination of the Channel Agreement. Exclusive Channel Collaboration Agreement with Intrexon Corporation for Graft-Versus-Host Disease (GvHD) On September 28, 2015, the Company entered into the GvHD Agreement with Intrexon, whereby the Company will use Intrexon’s technology directed towards in vivo The exclusive collaboration, or the GvHD Program, will focus on the pursuit of the following engineered cell therapy strategies, used either separately or in combination, for the targeted treatment of GvHD: (i) the infusion of regulatory T cells expressing membrane-bound and/or soluble interleukin-2 L. lactis interleukin-2 The GvHD Agreement grants the Company a worldwide license to use specified patents and other intellectual property of Intrexon in connection with the research, development, use, importing, manufacture, sale, and offer for sale of products developed under the GvHD Program, or the Products. Such license is exclusive with respect to any clinical development, selling, offering for sale or other commercialization of the Products, and otherwise is non-exclusive. Under the GvHD Agreement, and subject to certain exceptions, the Company is responsible for, among other things, the performance of the GvHD Program including development, commercialization and certain aspects of manufacturing of the Products. Among other things, Intrexon is responsible for the costs of establishing manufacturing capabilities and facilities for the bulk manufacture of the Products, certain other aspects of manufacturing, costs of discovery-stage research with respect to platform improvements and costs of filing, prosecution and maintenance of Intrexon’s patents. The Company paid Intrexon a technology access fee of $10.0 million in cash in October 2015 and will reimburse Intrexon for all research and development costs. Subject to certain expense allocations and other offsets provided in the GvHD Agreement, the GvHD Agreement also provides for equal sharing of the profits derived from the sale of the Products. The Company has determined that the rights acquired in the GvHD Agreement represent in-process During the first 24 months after September 28, 2015, the GvHD Agreement may be terminated by (i) either party in the event of a material breach by the other, except for the failure of the other party to use diligent efforts or to comply with any diligence obligations set forth in the GvHD Agreement and (ii) Intrexon under certain circumstances if the Company assigns its rights under the GvHD Agreement without Intrexon’s consent. Following such twenty-four-month period, Intrexon may also terminate the GvHD Agreement if the Company elects not to pursue the development of the GvHD Program identified by Intrexon that is a “Superior Therapy,” as such term is defined in the GvHD Agreement. Also following such period, the Company may voluntarily terminate the GvHD Agreement upon 90 days’ written notice to Intrexon. Upon termination of the GvHD Agreement, the Company may continue to develop and commercialize any Product that, at the time of termination: • is being commercialized by the Company, • has received regulatory approval, • is a subject of an application for regulatory approval that is pending before the applicable regulatory authority, or • is the subject of at least an ongoing Phase 2 clinical trial (in the case of a termination by Intrexon due to a Company uncured breach or a voluntary termination by the Company), or an ongoing Phase 1 clinical trial (in the case of a termination by the Company due to an Intrexon uncured breach or a termination by Intrexon following an unconsented assignment by the Company or the Company’s election not to pursue development of a Superior Therapy). The Company’s obligation to pay 20% of net profits or revenue with respect to these “retained” products will survive termination of the GvHD Agreement. Amendment of Collaborations with Intrexon On March 27, 2015, the Company and Intrexon entered into an Exclusive Channel Partner Amendment, or ECP Amendment, amending the Channel Agreement. The ECP Amendment modifies the scope of the parties’ collaboration under the Channel Agreement in connection with the Ares Trading Agreement discussed below. Pursuant to the ECP Amendment, the chimeric antigen receptor T cell products to be developed and commercialized pursuant to the Ares Trading Agreement shall be included within the Intrexon/ZIOPHARM collaboration under the Channel Agreement. The ECP Amendment provides that Intrexon will pay to the Company fifty percent of all payments Intrexon receives for upfronts, milestones and royalties under the Ares Trading Agreement. On June 29, 2016, the Company entered into (1) the 2016 ECP Amendment with Intrexon amending the Channel Agreement, and (2) the 2016 GvHD Amendment, amending the GvHD Agreement. The 2016 ECP Amendment reduced the royalty percentage that the Company will pay to Intrexon under the Channel Agreement on a quarterly basis from 50% to 20% of net profits derived in that quarter from the sale of ZIOPHARM Products, calculated on a ZIOPHARM Product-by-ZIOPHARM In consideration for the execution and delivery of the 2016 ECP Amendment and the 2016 GvHD Amendment, the Company agreed to issue to Intrexon 100,000 shares of its Series 1 preferred stock. Each share of the Company’s Series 1 preferred stock has a stated value of $1,200, subject to appropriate adjustment in the event of any stock dividend, stock split, combination or other recapitalization, and certain other rights, preferences, privileges and obligations. (see Note 10). License Agreement—The University of Texas MD Anderson Cancer Center On January 13, 2015, the Company, together with Intrexon, entered into a License Agreement, or the MD Anderson License, with MD Anderson. Pursuant to the MD Anderson License, the Company and Intrexon hold an exclusive, worldwide license to certain technologies owned and licensed by MD Anderson including technologies relating to novel chimeric antigen receptor (CAR) T cell therapies, non-viral T-cell co-exclusive non-exclusive Pursuant to the terms of the MD Anderson License, MD Anderson received consideration consisting of $50.0 million in shares of the Company’s common stock (or 10,124,561 shares), and $50.0 million in shares of Intrexon’s common stock, in each case based on a trailing 20 day volume weighted average of the closing price of the Company’s and Intrexon’s common stock ending on the date prior to the announcement of the entry into the MD Anderson License, collectively referred to as the License Shares, pursuant to the terms of the License Shares Securities Issuance Agreement described below. The License Shares were issued to MD Anderson on March 11, 2015 pursuant to the terms of the MD Anderson License. On January 9, 2015, in order to induce MD Anderson to enter into the MD Anderson License on an accelerated schedule, the Company and Intrexon entered into a letter agreement, or the Letter Agreement, pursuant to which MD Anderson received consideration of $7.5 million in shares of the Company’s common stock (or 1,597,602 shares), and $7.5 million in shares of Intrexon’s common stock, in each case based on a trailing 20 day volume weighted average of the closing price of the Company’s and Intrexon’s common stock ending on the date prior to the execution of the Letter Agreement, collectively referred to as the Incentive Shares, in the event that the MD Anderson License was entered into on or prior to 8:00 am Pacific Time on January 14, 2015. The Incentive Shares were issued to MD Anderson on March 11, 2015 pursuant to the terms of the Incentive Shares Securities Issuance Agreement described below. On August 17, 2015, the Company, Intrexon and MD Anderson entered into a research and development agreement, or the Research and Development Agreement, to formalize the scope and process for the transfer by MD Anderson, pursuant to the terms of the MD Anderson License, of certain existing research programs and related technology rights, as well as the terms and conditions for future collaborative research and development of new and ongoing research programs. Pursuant to the Research and Development Agreement, the Company, Intrexon and MD Anderson have agreed to form a joint steering committee that will oversee and manage the new and ongoing research programs. As provided under the MD Anderson License, the Company will provide funding for research and development activities in support of the research programs under the Research and Development Agreement for a period of three years and in an amount of no less than $15.0 million and no greater than $20.0 million per year. During the years ended December 31, 2016 and 2015, the Company made payments of $15.0 million and $11.3 million, respectively. As of December 31, 2016, MD Anderson has used $3.4 million to offset costs incurred pursuant to the MD Anderson License and the Research and Development Agreement. The net balance of $22.9 million is included in other current assets at December 31, 2016. The term of the MD Anderson License expires on the last to occur of (a) the expiration of all patents licensed thereunder, or (b) the twentieth anniversary of the date of the License; provided, however, that following the expiration of the term of the MD Anderson License, the Company and Intrexon shall then have a fully-paid up, royalty free, perpetual, irrevocable and sublicensable license to use the licensed intellectual property thereunder. After ten years from the date of the MD Anderson License and subject to a 90-day non-exclusive case-by-case 180-day In connection with the License and the issuance of the License Shares and the Incentive Shares, on January 13, 2015, the Company and MD Anderson entered into a Registration Rights Agreement, or the Registration Rights Agreement, pursuant to which the Company agreed to file a “resale” registration statement, or the Registration Statement, registering the resale of the License Shares, the Incentive Shares and any other shares of the Company’s common stock held by MD Anderson on the date that the Registration Statement is filed Under the Registration Rights Agreement, the Company is obligated to maintain the effectiveness of the Registration Statement until all securities therein are sold or are otherwise can be sold pursuant to Rule 144, without any restrictions. A prospectus supplement under the Company’s already effective registration statement on Form S-3 No. 333-201826) The Company has determined that the rights acquired in the MD Anderson License represent in process research and development with no alternative future use. Accordingly, the Company recorded a charge of $67.3 million to research and development expense in 2015, representing the fair value of the 11,722,163 shares of its common stock on the date the MD Anderson License was executed. Ares Trading License and Collaboration Agreement On March 27, 2015, the Company and Intrexon signed a worldwide License and Collaboration Agreement, or the Ares Trading Agreement, with Ares Trading S.A., or Ares Trading, a subsidiary of the biopharmaceutical business of Merck KGaA, Darmstadt, Germany, through which the parties established a collaboration for the research and development and commercialization of certain products for the prophylactic, therapeutic, palliative or diagnostic use for cancer in humans. Under the collaboration, Ares Trading has elected two CAR + + opt-in Intrexon is entitled to receive $5.0 million payable in equal quarterly installments over two years for each identified product candidate, which will be used to fund discovery work. The Company will be responsible for costs exceeding the quarterly installments and all other costs of the preclinical research and development. Ares Trading paid a non-refundable The Ares Trading Agreement provides for up to $60.0 million in development milestone payments, up to $148.0 million in regulatory milestone payments and up to $205.0 million in commercial milestone payments for each product candidate. Development milestone payments are triggered upon initiation of a defined phase of clinical research for a product candidate. Regulatory milestone payments are triggered upon approval to market a product candidate by the U.S. Food and Drug Administration (FDA) or other global regulatory authorities. Commercial milestone payments are triggered when an approved pharmaceutical product reaches certain defined levels of net sales by the licensee. The Ares Trading Agreement also provides for up to $50.0 million of one-time low-teens The term of the Ares Trading Agreement commenced in May 2015 and may be terminated by either party in the event of a material breach as defined in the agreement and may be terminated voluntarily by Ares Trading upon 90 days written notice to the Company. The Company considered FASB Accounting Standards Codification 605-25, Multiple-Element Arrangements Patent and Technology License Agreement—The University of Texas MD Anderson Cancer Center and the Texas A&M University System. On August 24, 2004, the Company entered into a patent and technology license agreement with MD Anderson and the Texas A&M University System, which the Company refers to, collectively, as the Licensors. Under this agreement, the Company was granted an exclusive, worldwide license to rights (including rights to U.S. and foreign patent and patent applications and related improvements and know-how) The Company issued options to purchase 50,222 shares outside of the Company’s stock option plans following the successful completion of certain clinical milestones, of which 37,666 have vested. The remaining 12,556 shares vested upon enrollment of the first patient in a multi-center pivotal clinical trial i.e. a human clinical trial intended to provide the substantial evidence of efficacy necessary to support the filing of an approvable New Drug Application, or NDA. An expense of $87 thousand was charged to research and development expense for the vesting event which occurred in March 2016. This trial was initiated by Solasia Pharma K.K., or Solasia, on March 28, 2016 and triggered a $1.0 million milestone payment to the Company from Solasia which was received in May 2016. An equivalent milestone payment of $1.0 million was made to MD Anderson, and reported net. In addition, the Licensors are entitled to receive certain milestone payments. The Company may be required to make additional payments upon achievement of certain other milestones in varying amounts which on a cumulative basis could total up to an additional $4.5 million. In addition, the Licensors are entitled to receive single digit percentage royalty payments on sales from a licensed product and will also be entitled to receive a portion of any fees that the Company may receive from a possible sublicense under certain circumstances. Collaboration Agreement with Solasia Pharma K.K. On March 7, 2011, the Company entered into a License and Collaboration Agreement with Solasia. Pursuant to the License and Collaboration Agreement, the Company granted Solasia an exclusive license to develop and commercialize darinaparsin in both IV and oral forms and related organic arsenic molecules, in all indications for human use in a pan-Asian/Pacific As consideration for the license, the Company received an upfront payment of $5.0 million to be used exclusively for further clinical development of darinaparsin outside of the pan-Asian/Pacific On July 31, 2014, the Company entered into an amendment and restatement of the License and Collaboration Agreement granting Solasia an exclusive worldwide license to develop and commercialize darinaparsin, and related organoarsenic molecules, in both intravenous and oral forms in all indications for human use. In exchange, the Company will be eligible to receive from Solasia development-and Solasia will be responsible for all costs related to the development, manufacturing and commercialization of darinaparsin. The Company’s Licensors, as defined in the agreement, will receive a portion of all milestone and royalty payments made by Solasia to the Company in accordance with the terms of the Company’s license agreement with the Licensors. On March 28, 2016, Solasia initiated a multi-center pivotal clinical trial intended to provide substantial evidence of efficacy necessary to support the filing of an application for an NDA for darinaparsin in certain of the territories assigned to Solasia. The initiation of the trial on March 28, 2016 triggered a $1.0 million milestone payment from Solasia to the Company which was received in May 2016. The Company subsequently made an equivalent payment to MD Anderson as the ultimate licensor of darinaparsin (see above). License Agreement with Baxter Healthcare S.A. On November 3, 2006, the Company entered into a definitive Asset Purchase Agreement for indibulin and a License Agreement to proprietary nanosuspension technology with affiliates of Baxter Healthcare S.A. The purchase included the entire indibulin intellectual property portfolio as well as existing drug substance and capsule inventories. One additional payment of $250 thousand is due in November 2017. The terms of the Asset Purchase Agreement included an upfront cash payment and an additional payment for existing inventory. During each of the years ending December 31, 2016, 2015 and 2014, the Company made payments of $250 thousand.

Warrants

Warrants	12 Months Ended
	Dec. 31, 2016
Warrants	8. Warrants The Company has issued both warrants that are accounted for as liabilities and warrants that are accounted for as equity instruments. The Company follows accounting standards that provide guidance in assessing whether an equity-issued financial instrument is indexed to an entity’s own stock for purposes of determining whether a financial instrument should be treated as a derivative and classified as a liability. Accounting standards require that liability classified warrants be recorded at their fair value at each financial reporting period and the resulting gain or loss be recorded as other income (expense) in the Statements of Operations. Fair value is measured using a binomial valuation model. Liability-Classified Warrants In connection with a December 2009 public offering, the Company issued warrants to purchase an aggregate of 8,206,520 shares of common stock, including the investor warrants and 464,520 warrants issued to the Underwriters. The warrants had a 5-year The Company assessed whether the Warrants required accounting as derivatives. The Company determined that the warrants were not indexed to the Company’s own stock in accordance with FASB Accounting Standards Codification, Derivatives and Hedging In December 2014, the Company recognized a gain of $195 thousand on the expiration of these liability-classified warrants. In connection with its 2009 private placement, the Company issued warrants to purchase an aggregate of 2,910,954 shares of common stock (including 138,617 warrants issued to the placement agents) which were exercisable immediately. The warrants had an exercise price of $2.04 per share and a 5-year During 2014, 4,004,907 warrants were exercised for 3,725,277 shares of common stock. Of these warrants, 2,249,062 were equity-classified warrants and 1,755,845 were liability-classified warrants. Additionally, 12,329 equity-classified warrants and 6,479,231 liability-classified warrants expired without being exercised. All remaining warrants expired during the year ended December 31, 2014.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
Income Taxes	9. Income Taxes There is no provision for income taxes because the Company has incurred operating losses since inception. The reported amount of income tax expense for the years differs from the amount that would result from applying domestic federal statutory tax rates to pretax losses primarily because of the changes in the valuation allowance. Significant components of the Company’s deferred tax assets at December 31, 2016 and 2015 are as follows: December 31, (in thousands) 2016 2015 Net operating loss carryforwards $ 100,790 $ 96,215 Start-up 59,360 64,942 Research and development credit carryforwards 34,845 29,564 Stock compensation 2,014 1,997 Capitalized acquisition costs 9,389 10,429 Deferred revenue 18,636 2,695 Depreciation 227 251 Other 1,537 1,673 226,798 207,766 Less valuation allowance (226,798 ) (207,766 ) Effective tax rate $ — $ — Deferred income taxes reflect the net tax effects of temporary differences between the carrying amount of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. At December 31, 2016, the Company has aggregate net operating loss carryforwards for federal tax purposes of approximately $264 million and $224 million for Federal and state purposes, respectively, available to offset future federal and state taxable income to the extent permitted under the Internal Revenue Code, or IRC, expiring in varying amounts through 2036. Additionally, the Company has approximately $34 million of research and development credits at December 31, 2016, expiring in varying amounts through 2036, which may be available to reduce future taxes. Under the IRC Section 382, certain substantial changes in the Company’s ownership may limit the amount of net operating loss carryforwards that can be utilized in any one year to offset future taxable income. The net operating loss carryforwards for the year ended December 31, 2016 includes approximately $10.2 million resulting from excess tax deductions from stock options. Pursuant to ASC 740, the deferred tax asset relating to excess tax benefits generated from exercises of stock options was fully offset by the valuation allowance and not recognized for financial statement purposes. Section 382 of the IRC provides limits to which a corporation that has undergone a change in ownership (as defined) can utilize any net operating loss, or NOL, and general business tax credit carryforwards it may have. The Company commissioned an analysis to determine whether Section 382 could limit the use of its carryforwards in this manner. After completing the analysis, it was determined an ownership change had occurred in February 2007. As a result of this change, the Company’s NOL’s and general business tax credits from February 23, 2007 and prior would be completely limited under IRC Section 382. The deferred tax assets related to NOL’s and general business credits have been reduced by $11.2 million and $636 thousand, respectively, as a result of the change. The Company updated the IRC Section 382 analysis through December 31, 2014. It was determined a change of ownership occurred on February 28, 2011. The Company’s NOL’s were not further limited as a result of the change. The Company updated the IRC Section 382 analysis through December 31, 2016 and its was determined that there was no further change in ownership. The Company has provided a valuation allowance for the full amount of these net deferred tax assets, since it is more likely than not that these future benefits will not be realized. However, these deferred tax assets may be available to offset future income tax liabilities and expenses. The valuation allowance increased by $19.0 million in 2016 primarily due to net operating loss carryforwards, deferred revenue and the increase in research and development credits. Income taxes using the federal statutory income tax rate differ from the Company’s effective tax rate primarily due to non-deductible A reconciliation of income tax expense (benefit) at the statutory federal income tax rate and income taxes as reflected in the financial statements is as follows: Year Ended December 31, (in thousands) 2016 2015 2014 Federal income tax at statutory rates 34 % 34 % 34 % State income tax, net of federal tax benefit 1 % 5 % 2 % Research and development credits 3 % 3 % 3 % Stock compensation -1 % -1 % -4 % Channel rights -25 % 0 % 0 % Other 0 % 0 % -4 % Increase in valuation allowance -12 % -41 % -31 % Effective tax rate 0 % 0 % 0 % The Company adopted ASC740, “Accounting for Uncertain Tax Positions” on January 1, 2007. ASC740 clarifies the accounting for uncertainty in income taxes recognized in an enterprise’s financial statements in accordance with FASB Statement No. 109, “Accounting for Income Taxes.” ASC 740 prescribes a recognition threshold and measurement of a tax position taken or expected to be taken in a tax return. The Company did not establish any additional reserves for uncertain tax liabilities upon adoption of ASC 740. A summary of the company’s adjustments to its uncertain tax positions in the years ended December 31, 2016, 2015, and 2014 are as follows: (in thousands) Balance at December 31, 2013 $ 238 Increase/Decrease for tax positions related to the current year — Increase/Decrease for tax positions related to prior years — Decrease for settlements with applicable taxing authorities — Decrease for lapses of statute of limitations — Balance at December 31, 2014 $ 238 Increase/Decrease for tax positions related to the current year — Increase/Decrease for tax positions related to prior years — Decreases for settlements with applicable taxing authorities — Decrease for previous year’s lapses of statute of limitations (20 ) Decrease for impact of §382 limitations (218 ) Decrease for lapses of statute of limitations — Balance at December 31, 2015 $ — Increase/Decrease for tax positions related to the current year — Increase/Decrease for tax positions related to prior years — Decrease for settlements with applicable taxing authorities — Decrease for lapses of statute of limitations — Balance at December 31, 2016 $ — The Company has not recognized any interest and penalties in the statement of operations because of the Company’s net operating losses and tax credits that are available to be carried forward. When necessary, the Company will account for interest and penalties related to uncertain tax positions as part of its provision for federal and state income taxes. The Company does not expect the amounts of unrecognized benefits will change significantly within the next twelve months. The Company is currently open to audit under the statute of limitations by the Internal Revenue Service and state jurisdictions for the years ended December 31, 1999 through 2016. See Note 3 for additional information on ASU 2015-17, Income Taxes (Topic 740), Balance Sheet Classification of Deferred Taxes , Compensation – Stock Compensation (Topic 718) , Improvements to Employee Share-Based Payment Accounting ,

Preferred Stock and Stockholder

Preferred Stock and Stockholders' Equity	12 Months Ended
	Dec. 31, 2016
Preferred Stock and Stockholders' Equity	10. Preferred Stock and Stockholders’ Equity On April 26, 2006, the date of the Company’s annual stockholders meeting that year, the shareholders approved the adoption of an Amended and Restated Certificate of Incorporation pursuant to which the Company has 280,000,000 shares of authorized capital stock, of which 250,000,000 shares are designated as common stock (par value $.001 per share), and 30,000,000 shares are designated as preferred stock (par value $.001 per share). Common Stock On February 3, 2015, the Company entered into an underwriting agreement with J.P. Morgan Securities LLC, as representative of the several underwriters named therein, relating to the issuance and sale of 10,000,000 shares of our common stock. The price to the public in the offering was $8.75 per share, and the underwriters agreed to purchase the shares from the Company pursuant to the underwriting agreement at a purchase price of $8.225 per share. Under the terms of the underwriting agreement, the Company also granted the underwriters an option, exercisable for 30 days, to purchase up to an additional 1,500,000 shares of common stock at a purchase price of $8.225 per share. The offering was made pursuant to the Company’s effective registration statement on Form S-3 No. 333-201826) On January 13, 2015, the Company, together with Intrexon, entered into the MD Anderson License. Pursuant to the terms of the MD Anderson License, MD Anderson received consideration of 11,722,163 shares of the Company’s common stock (see Note 7). Preferred Stock The Company’s Board of Directors are authorized to designate any series of Preferred Stock, to fix and determine the variations in relative rights, preferences, privileges and restrictions as between and among such series. On June 29, 2016, the Company entered into the 2016 ECP Amendment and 2016 GvHD Amendment with Intrexon (see Note 7). In consideration for the execution and delivery of the 2016 ECP Amendment and the 2016 GvHD Amendment, the Company issued to Intrexon 100,000 shares of its newly designated Series 1 preferred stock. Each share of the Company’s Series 1 preferred stock has a stated value of $1,200, subject to appropriate adjustment in the event of any stock dividend, stock split, combination or other recapitalization. The Series 1 preferred stock has the following rights and preferences and certain other rights, preferences, privileges and obligations. Conversion All shares of Series 1 preferred stock shall automatically convert into shares of common stock upon the public announcement of the first approval in the United States of (i) a ZIOPHARM Product under the Channel Agreement, (ii) a Product under the GvHD Agreement or (iii) a Product under the Ares Trading Agreement, which the Company refers to as the Conversion Event Date. On the second business day following the Conversion Event Date, each of Series 1 preferred stock shall convert into a number of shares of common stock equal to the stated value of such Series 1 preferred stock, divided by the greater of (i) the volume weighted average closing price of common stock as reported by The Nasdaq Stock Market, LLC over the 20 trading days ending on the Conversion Event Date or (ii) $1.00 per share; however, without shareholder approval in accordance with the NASDAQ listing rules, the Company will not affect any conversion of the Series 1 preferred stock into shares of common stock in excess of 19.9% of the lesser of (i) the pre-transaction Dividends The Series 1 preferred stock provides for a monthly dividend, payable in additional shares of Series 1 preferred stock, equal to $12.00 per share, per month divided by the stated value per share, or the PIK Dividend; provided, that if any shares of Series 1 preferred stock are not converted on the Conversion Event Date (discussed below), then the rate of the PIK Dividend on all remaining unconverted shares of Series 1 preferred stock shall automatically increase from $12.00 to $24.00 per share, per month. Liquidation Preference In the event of any voluntary or involuntary liquidation, dissolution or winding up of the Company or a change of control or sale, lease transfer or exclusive license of all or substantially all of the Company’s assets prior to the conversion of the Series 1 preferred stock into shares of common stock, then the Series 1 preferred stock will participate in the proceeds of the transaction on a pro rata basis along with common stock, treating the Series 1 preferred stock as if it had been converted into a number of shares of common stock equal to the aggregate stated value of the Series 1 preferred stock, divided by the volume weighted average closing price of common stock over the 20 trading days ending on the public announcement of such voluntary or involuntary liquidation, dissolution or winding up of the Company or change of control or sale, lease transfer or exclusive license of all or substantially all of the Company’s assets. Alternatively, the Company may redeem the Series 1 preferred stock at a redemption price equal to the pro rata amount that the Series 1 preferred stock would have received if it had been converted using the same formula. Voting Rights The Series 1 preferred stock does not have any voting rights except that the Company may not, without the consent of the holders of a majority of the outstanding shares of the Series 1 preferred stock, voting as a separate class, (i) amend, alter or repeal any provision of its Certificate of Incorporation in a manner that adversely affects the powers, preferences or rights of the Series 1 preferred stock in a manner that is more adverse than the effect on any other class or series of the Company’s capital stock; (ii) (A) create, or authorize the creation of, or issue or obligate itself to issue shares of, any additional class or series of the Company’s capital stock unless the same ranks junior or pari passu to the Series 1 preferred stock with respect to the distribution of assets on the liquidation, dissolution or winding up of the Company, the payment of dividends and rights of redemption, or (B) reclassify, alter or amend any existing security that is junior or pari passu to the Series 1 preferred stock with respect to the distribution of assets on the liquidation, dissolution or winding up of the Company, the payment of dividends or rights of redemption, if such reclassification, alteration or amendment would render such other security senior to the Series 1 preferred in respect of any such right, preference or privilege; or (iii) enter into any transaction (or series of related transactions) the effect of which would adversely affect the holders of the Series 1 preferred stock in a manner that is more adverse than the effect on any other class or series of capital stock. Analysis The Company analyzed the features of the Series 1 preferred stock and determined that the conversion option and the Company’s right to redeem the shares at liquidation are embedded derivatives that required bifurcation from the Series 1 preferred stock in accordance with FASB ASC 815, Derivatives and Hedging The fair value of the Series 1 preferred stock was estimated using a probability-weighted approach and a Monte Carlo simulation model. The fair value of the embedded derivatives was estimated using the “with” and “without” method where the preferred stock was first valued with all of its features (“with” scenario) and then without derivatives subject to the valuation analysis (“without” scenario). The fair value of the derivatives was then estimated as the difference between the fair value of the preferred stock in the “with” scenario and the preferred stock in the “without” scenario. The model also takes into account, management estimates of clinical success/failure based upon market studies and probability of potential conversion and liquidation events. If these estimates were different, the valuations would change and that change could be material. Inputs to the models included the following: Risk-free interest rate 1.04 % Expected dividend rate 0 Expected volatility 70.50 % Preferred stock conversion limit—percentage of outstanding common stock 19.90 % Preferred conversion floor price $ 1.00 During the year ended December 31, 2016, the Company issued an aggregate of 6,184 shares of Series 1 preferred stock to Intrexon, the holder of all of the outstanding shares of its Series 1 preferred stock, as monthly dividend payments. The Company recorded such shares of Series 1 preferred stock at a fair value of $7.1 million, which is a component of temporary equity and recorded a gain on the change of the derivative liabilities in the amount of $124 thousand (Note 11).

Derivative Financial Instrument

Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2016
Derivative Financial Instruments	11. Derivative Financial Instruments The Company determined that certain embedded features related to the Series 1 preferred stock are derivative financial instruments. Fair values of derivative instruments to be classified as derivative liabilities on the balance sheet consist of the following: ($ in thousands) Liability derivates: Balance Sheet Location Fair Value December 31, 2016: Derivative liabilities Liabilities $ 862 The change in the derivative liability for the year ended December 31, 2016 consists of the following: ($ in thousands) Fair Value Balance, June 30, 2016 $ 694 Dividends 44 Mark-to-market 124 Balance, December 31, 2016 $ 862 The fair value of the Series 1 preferred stock dividends were estimated using a probability-weighted approach and a Monte Carlo simulation model. The fair value of the embedded derivatives was estimated using the “with” and “without” method where the preferred stock was first valued with all of its features (“with” scenario) and then without derivatives subject to the valuation analysis (“without” scenario). The fair value of the derivatives was then estimated as the difference between the fair value of the preferred stock in the “with” scenario and the preferred stock in the “without” scenario. The model also takes into account, management estimates of clinical success/failure based upon market studies and probability of potential conversion and liquidation events. If these estimates were different, the valuations would change and that change could be material. Inputs to the models included the following: Risk-free interest rate 1.04% - 1.69% Expected dividend rate 0 Expected volatility 70.5% - 72.70% Preferred stock conversion limit—percentage of outstanding common stock 19.90% Preferred conversion floor price $1.00 See Notes 3 and 7 for additional discussion regarding the accounting for and valuation of these derivative financial instruments.

Stock Option Plan

Stock Option Plan	12 Months Ended
	Dec. 31, 2016
Stock Option Plan	12. Stock Option Plan The Company adopted the 2003 Stock Option Plan, or the 2003 Plan, in 2003, and it was approved by the Company’s stockholders on December 21, 2004. Upon approval of the 2012 Equity Incentive Plan, no additional stock awards may be granted under the 2003 Plan. The Company adopted the 2012 Equity Incentive Plan, or the 2012 Plan, in May 2012, under which the Company initially reserved for the issuance of 4,000,000 shares of its common stock. The 2012 Plan was approved by the Company’s stockholders on June 20, 2012. On June 18, 2014, the date of the Company’s annual stockholders meeting, the Company’s stockholders approved an amendment to the 2012 Plan increasing the total shares reserved by 5,000,000 shares, for a total of 9,000,000 shares. As of December 31, 2016, the Company had outstanding options issued to its employees to purchase up to 2,652,835 shares of the Company’s common stock, to its directors to purchase up to 802,500 shares of the Company’s common stock, as well as options to consultants in connection with services rendered to purchase up to 10,000 shares of the Company’s common stock. Stock options to employees generally vest ratably over three years and have contractual terms of ten years. Stock options to directors generally vest ratably over one or three years and have contractual terms of ten years. Stock options are valued using the Black-Scholes option pricing model and compensation is recognized based on such fair value over the period of vesting on a straight-line basis. The Company has also reserved an aggregate of 26,364 additional shares for issuance under options granted outside of the 2003 Plan. Proceeds from the option exercises during the years ended December 31, 2016, 2015, and 2014 amounted to $0.7 million, $4.6 million and $1.4 million respectively. The intrinsic value of these options amounted to $1.5 million, $23.8 million and $2.6 million for years ended December 31, 2016, 2015 and 2014, respectively. Transactions under the 2012 Plan for the years ending December 31, 2016, 2015, and 2014 were as follows: (in thousands, except share and per share data) Number of Weighted- Weighted- Aggregate Outstanding, December 31, 2013 6,747,302 $ 3.81 Granted 1,099,300 4.95 Exercised (613,138 ) 2.26 Cancelled (727,801 ) 4.54 Outstanding, December 31, 2014 6,505,663 4.07 Granted 427,800 10.47 Exercised (3,249,160 ) 3.95 Cancelled (202,835 ) 4.36 Outstanding, December 31, 2015 3,481,468 4.96 Granted 362,800 6.40 Exercised (234,833 ) 4.57 Cancelled (144,100 ) 6.43 Outstanding, December 31, 2016 3,465,335 $ 5.07 6.58 $ 3,407 Vested and unvested expected to vest at December 31, 2016 3,441,247 $ 4.40 5.88 $ 3,316 Options exercisable, December 31, 2016 2,671,835 $ 4.40 5.88 $ 3,383 Options exercisable, December 31, 2015 2,120,834 $ 4.24 5.84 $ 8,622 Options available for future grant 1,777,760 At December 31, 2016, total unrecognized compensation costs related to non-vested Restricted Stock In December 2016, the Company issued 625,750 shares of restricted stock to its employees, which vest ratably in annual installments over three years, commencing on the first anniversary of the grant date. In December 2016, the Company issued 86,020 shares of restricted stock to its non-employee one-year non-employee one-year non-employee one-year In May, June and December 2016, the Company repurchased 116,667, 6,667 and 119,873 shares at average prices of $6.86, $7.74 and $5.35, respectively to cover payroll taxes. In September and December 2015, the Company repurchased 7,669 and 16,709 shares at average prices of $11.57 and $8.31, respectively to cover payroll taxes. In January, February and December 2014, the Company repurchased 16,031, 14,600 and 81,702 shares at average prices of $4.37, $4.40 and $5.04 per share, respectively, to cover payroll taxes. A summary of the status of non-vested Number of Shares Weighted-Average Non-vested, 352,865 $ 4.38 Granted 66,828 5.07 Vested (253,835 ) 4.38 Cancelled (21,350 ) 4.41 Non-vested, 144,508 4.70 Granted 1,590,574 9.01 Vested (148,694 ) 4.88 Cancelled — — Non-vested, 1,586,388 9.00 Granted 711,770 5.35 Vested (617,666 ) 8.90 Cancelled — — Non-vested, 1,680,492 $ 5.54 As of December 31, 2016, there was $10.5 million of total unrecognized stock-based compensation expense related to non-vested

Employee Benefit Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2016
Employee Benefit Plan	13. Employee Benefit Plan The Company sponsors a qualified 401(k) retirement plan under which employees are allowed to contribute certain percentages of their pay, up to the maximum allowed under Section 401(k) of the IIRC. The Company may make contributions to this plan at its discretion. The Company contributed approximately $75 thousand, $47 thousand, and $79 thousand to this plan during the years ended December 31, 2016, 2015, and 2014, respectively.

Selected Quarterly Information

Selected Quarterly Information (Unaudited)	12 Months Ended
	Dec. 31, 2016
Selected Quarterly Information (Unaudited)	14. Selected Quarterly Information (Unaudited) (in thousands, except per share amount) Year Ended December 31, 2016 First Second Third Fourth Revenue $ 1,969 $ 1,697 $ 1,598 $ 1,597 Total operating expenses 14,009 132,939 12,512 12,708 Loss from operations (12,040 ) (131,242 ) (10,914 ) (11,111 ) Change in derivative liabilities — — (3,591 ) (3,532 ) Net (loss) applicable to common shareholders (12,019 ) (131,200 ) (14,445 ) (14,756 ) Loss per share, basic and diluted $ (0.09 ) $ (1.01 ) $ (0.11 ) $ (0.11 ) Year Ended December 31, 2015 First Second Third Fourth Revenue $ 272 $ 272 $ 1,869 $ 1,919 Total operating expenses 78,499 14,497 20,035 11,401 Loss from operations (78,227 ) (14,225 ) (18,166 ) (9,482 ) Change in derivative liabilities — — — — Net (loss) applicable to common shareholders (78,231 ) (14,211 ) (18,170 ) (9,476 ) Loss per share, basic and diluted $ (0.69 ) $ (0.11 ) $ (0.14 ) $ (0.07 )

Summary of Significant Accoun22

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Basis of Presentation	Basis of Presentation The accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America or U.S. GAAP.
Use of Estimates	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 estimates and assumptions that affect the reported amounts of assets and liabilities and the 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. Although the Company regularly assesses these estimates, actual results could differ from those estimates. Changes in estimates are recorded in the period in which they become known. The Company’s most significant estimates and judgments used in the preparation of our financial statements are: • Clinical trial expenses; • Collaboration agreements; • Fair value measurements of stock based compensation, warrants and Series 1 preferred stock; and • Income taxes.
Subsequent Events	Subsequent Events The Company evaluated all events and transactions that occurred after the balance sheet date through the date of this filing. Except as discussed below, the Company did not have any other material subsequent events that impacted its financial statements or disclosures. On January 9, 2017, the Company signed a Cooperative Research and Development Agreement, or CRADA, with the National Cancer Institute for the development of adoptive cell transfer-based immunotherapies genetically modified using the Sleeping Beauty T-cell
Operating Segments	Operating Segments 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 and does not track expenses on a program-by-program basis.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash equivalents consist primarily of demand deposit accounts and deposits in short-term U.S. treasury money market mutual funds. Cash equivalents are stated at cost, which approximates fair market value.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments which potentially subject the Company to concentrations of credit risk consist principally of cash and cash equivalents. The Company maintains cash accounts in commercial banks, which may, at times, exceed federally insured limits. The Company has not experienced any losses in such accounts. The Company believes it is not exposed to any significant credit risk on cash and cash equivalents.
Property and Equipment	Property and Equipment Property and equipment are recorded at cost. Expenditures for maintenance and repairs are charged to expense while the costs of significant improvements are capitalized. Depreciation is provided using the straight-line method over the following estimated useful lives of the related assets, which is between three and five years. Upon retirement or sale, the cost of the assets disposed of and the related accumulated depreciation are eliminated from the balance sheets and related gains or losses are reflected in the statements of operations.
Restricted Cash	Restricted Cash Restricted cash consists of $388 thousand, which is restricted as collateral for the Company’s facility leases, and $104 thousand, which is restricted as collateral for a line of credit is included in other assets.
Long-Lived Assets	Long-Lived Assets The Company reviews the carrying values of its long-lived assets for possible impairment whenever events or changes in circumstances indicate that the carrying amounts of the assets may not be recoverable. Any long-lived assets held for disposal are reported at the lower of their carrying amounts or fair values less costs to sell.
Warrants	Warrants The Company applied the accounting standard which provided guidance in assessing whether an equity-based financial instrument is indexed to an entity’s own stock for purposes of determining whether a financial instrument should be treated as a derivative. In applying the methodology, the Company concluded that certain warrants issued by the Company had terms that did not meet the criteria to be considered indexed to the Company’s own stock and therefore were classified as liabilities in the Company’s balance sheet. The liability classified warrants were subject to re-measurement
Fair Value Measurements	Fair Value Measurements The Company has certain financial assets and liabilities recorded at fair value which have been classified as Level 1, 2 or 3 within the fair value hierarchy as described in the accounting standards for fair value measurements. • Level 1—Quoted prices in active markets for identical assets or liabilities. • Level 2—Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. • Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Assets and liabilities measured at fair value on a recurring basis as of December 31, 2016 and 2015 are as follows: ($ in thousands) Fair Value Measurements at Reporting Date Using Description Balance as of Quoted Prices in Significant Significant Cash equivalents $ 77,120 $ 77,120 $ — $ — Derivative liabilities $ 862 $ — $ — $ 862 ($ in thousands) Fair Value Measurements at Reporting Date Using Description Balance as of Quoted Prices in Significant Other Significant Cash equivalents $ 137,405 $ 137,405 $— $— The cash equivalents represent deposits in a short term United States treasury money market mutual fund quoted in an active market and classified as a Level 1 asset. As discussed further in Notes 7 and 10, the Company issued Intrexon 100,000 shares of the Company’s Series 1 preferred stock, a new class of preferred stock authorized by the Company’s board of directors, in consideration of the parties entering into a Third Amendment to Exclusive Channel Partner Agreement, or the 2016 ECP Amendment, amending their existing Exclusive Channel Partner Agreement, effective January 6, 2011 and as amended to date, which the Company refers to as the Channel Agreement, and an Amendment to Exclusive Channel Collaboration Agreement, or the 2016 GvHD Amendment, amending their existing Exclusive Channel Collaboration Agreement, effective September 28, 2015, which the Company refers to as the GvHD Agreement. At June 30, 2016, the Company’s Series 1 preferred stock was valued using a probability-weighted approach and a Monte Carlo simulation model. Additionally, the monthly dividends issued on the outstanding Series 1 preferred stock are valued using the same probability-weighted approach and a Monte Carlo simulation model. However, there is no adjustment or further revaluation after the initial valuation on the Series 1 preferred stock. The Company’s Level 3 financial liabilities consist of a conversion option and a redemption feature associated with the Company’s Series 1 preferred stock issued to Intrexon that has been bifurcated from the Series 1 preferred stock and are accounted for as derivative liabilities at fair value. The preferred stock derivative liabilities were valued using a probability-weighted approach and a Monte Carlo simulation model. The fair value of the embedded derivatives was estimated using the “with” and “without” method where the preferred stock was first valued with all of its features (“with” scenario) and then without derivatives subject to the valuation analysis (“without” scenario). The fair value of the derivatives was then estimated as the difference between the fair value of the preferred stock in the “with” scenario and the preferred stock in the “without” scenario. See Note 7 for additional disclosures on the 2016 ECP Amendment and 2016 GvHD Amendments and Note 10 for additional disclosure on the rights and preferences of the Series 1 preferred stock and valuation methodology.
Revenue Recognition	Revenue Recognition from Collaboration Agreements The Company has primarily generated revenue through collaboration arrangements with strategic partners for the development and commercialization of product candidates. The Company recognizes revenue for each unit of accounting when evidence of an arrangement exists, delivery has occurred or services have been rendered, the seller’s price to the buyer is fixed or determinable and collectability is reasonably assured. The Company’s collaboration agreements may provide for various types of payments, including upfront payments, funding of research and development, milestone payments, licensing fees and product royalties. The specifics of the Company’s significant agreements are detailed in Note 7. The Company considers a variety of factors in determining the appropriate method of accounting for its collaboration agreements, including whether multiple deliverables can be separated and accounted for individually as separate units of accounting. Pursuant to the guidance in FASB Accounting Standards Codification (ASC) 605-25, Multiple-Element Arrangements 605-25), Where there are multiple deliverables within a collaboration agreement that cannot be separated and therefore are combined into a single unit of accounting, revenues are deferred and recognized over the estimated period of performance, which is typically the development term. If the deliverables can be separated, the Company applies the relevant revenue recognition guidance to each individual unit of accounting. The specific methodology for the recognition of the underlying revenue is determined on a case-by-case At the inception of an arrangement that includes milestone payments, the Company evaluates whether each milestone is substantive and at risk to both parties on the basis of the contingent nature of the milestone. This evaluation includes an assessment of whether: (i) the consideration is commensurate with either the Company’s performance to achieve the milestone or the enhancement of the value of the delivered item(s) as a result of a specific outcome resulting from the Company’s 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 within the arrangement. The Company evaluates 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 judgement involved in determining whether a milestone satisfies all of the criteria required to conclude that a milestone is substantive. In accordance with FASB ASC 605-28, Milestone Method 605-28),
Research and Development Costs	Research and Development Costs Research and development expenditures are charged to the statement of operations as incurred. Such costs include proprietary research and development activities, purchased research and development, and expenses associated with research and development contracts, whether performed by the Company or contracted with independent third parties.
Income Taxes	Income Taxes Income taxes are accounted for under the liability method. Deferred tax assets and liabilities are recognized for the estimated future tax consequences of temporary differences between the financial statement carrying amounts and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the year in which the temporary differences are expected to be recovered or settled. The Company evaluates the realizability of its deferred tax assets and establishes a valuation allowance when it is more likely than not that all or a portion of deferred tax assets will not be realized. The Company accounts for uncertain tax positions using a “more-likely-than-not”
Accounting for Stock-Based Compensation	Accounting for Stock-Based Compensation Stock-based compensation cost is measured at the grant date, based on the estimated fair value of the award, and is recognized as expense over the employee’s requisite service period. Stock-based compensation expense is based on the number of awards ultimately expected to vest and is therefore reduced for an estimate of the awards that are expected to be forfeited prior to vesting. Consistent with prior years, the Company uses the Black-Scholes option pricing model which requires estimates of the expected term option holders will retain their options before exercising them and the estimated volatility of the Company’s common stock price over the expected term. The Company recognizes the full impact of its share-based employee payment plans in the statements of operations for each of the years ended December 31, 2016, 2015, and 2014 and did not capitalize any such costs on the balance sheets. The Company recognized $3.0 million, $5.3 million, and $3.7 million of compensation expense related to vesting of stock options during the years ended December 31, 2016, 2015, and 2014, respectively. In the years ended December 31, 2016, 2015, and 2014, the Company recognized $5.5 million, $2.7 million, and $1.0 million of compensation expense, respectively, related to vesting of restricted stock (see Note 12). In the years ended December 31, 2016, 2015, and 2014, the Company recognized $8.5 million, $8.0 million, and $4.7 million of compensation expense, respectively, related to vesting of all employee and director awards. The following table presents share-based compensation expense included in the Company’s Statements of Operations: Year ended December 31, (in thousands) 2016 2015 2014 Research and development $ 2,077 $ 1,403 $ 1,416 General and administrative 6,375 6,594 3,327 Share based employee compensation expense before tax 8,452 7,997 4,743 Income tax benefit — — — Net share based employee compensation expense $ 8,452 $ 7,997 $ 4,743 The fair value of each stock option is estimated at the date of grant using the Black-Scholes option pricing model. The estimated weighted-average fair value of stock options granted to employees in 2016, 2015, and 2014 was approximately $4.43, $10.47, and $3.58 per share, respectively. Assumptions regarding volatility, expected term, dividend yield and risk-free interest rate are required for the Black-Scholes model. The volatility assumption is based on the Company’s historical experience. The risk-free interest rate is based on a U.S. treasury note with a maturity similar to the option award’s expected life. The expected life represents the average period of time that options granted are expected to be outstanding. The Company calculated expected term using the simplified method described in SEC Staff Accounting Bulletin, or SAB, No. 107 and No. 110 as it continues to meet the requirements promulgated in SAB No. 110. The assumptions for volatility, expected life, dividend yield and risk-free interest rate are presented in the table below: 2016 2015 2014 Weighted average risk-free interest rate 1.27 - 2.09% 1.46 - 1.93% 1.74 - 2.11% Expected life in years 6 6 6 Expected volatility 79.15 - 82.95% 79.13 - 86.81% 85.22 - 94.55% Expected dividend yield 0 0 0
Net Loss Per Share	Net Loss Per Share Basic net loss per share is computed by dividing net loss by the weighted average number of common shares outstanding for the period. The Company’s potentially dilutive shares, which include outstanding common stock options, unvested restricted stock and preferred stock, have not been included in the computation of diluted net loss per share for any of the periods presented as the result would be antidilutive. Such potential common shares at December 31, 2016, 2015, and 2014 consist of the following: December 31, 2016 2015 2014 Stock options 3,465,335 3,481,468 6,505,664 Unvested restricted stock 1,680,492 1,586,388 144,508 Preferred stock 20,465,067 — — 25,610,894 5,067,856 6,650,172 The Series 1 preferred stock automatically converts into shares of common stock upon the date the first approval in the United States of (i) a ZIOPHARM Product, as defined in and developed under the Exclusive Channel Partner Agreement dated as of January 6, 2011 and as amended from time to time, by and between the Company and Intrexon, or (ii) a Product, as defined in and developed under the Exclusive Channel Collaboration Agreement dated September 28, 2015 and as amended from time to time, by and between the Company and Intrexon, or (iii) a Product as defined in and developed under the License and Collaboration Agreement dated March 27, 2015 and as amended from time to time, by and among Intrexon, ARES TRADING, S.A. and the Company, is publicly announced. Assuming a conversion event date of December 31, 2016, the Series 1 preferred stock would convert into 20,465,067 shares of common stock using the greater of (i) the volume weighted average closing price of the Company’s Common Stock as reported by the Nasdaq Stock Market, LLC over previous the 20 trading days ending on the conversion event date or (ii) $1.00 per share. See Note 7 and Note 10 for additional disclosure regarding the 2016 ECP Amendment and 2016 GvHD Amendment, valuation methodology and significant assumptions.
New Accounting Pronouncements	New Accounting Pronouncements In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers In August 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements—Going Concern 205-40) In November 2015, the FASB issued ASU 2015-17, Income Taxes (Topic 740), Balance Sheet Classification of Deferred Taxes In March 2016, the FASB issued ASU No. 2016-09, Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting In August 2016, the FASB issued ASU No. 2016-15, Classification of Certain Cash Receipts and Cash Payments In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash Payments In February 2016, the FASB issued ASU 2016-02, Leases (“ ”) Leases

Summary of Significant Accoun23

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2016
Assets and Liabilities Measured at Fair Value on Recurring Basis	Assets and liabilities measured at fair value on a recurring basis as of December 31, 2016 and 2015 are as follows: ($ in thousands) Fair Value Measurements at Reporting Date Using Description Balance as of Quoted Prices in Significant Significant Cash equivalents $ 77,120 $ 77,120 $ — $ — Derivative liabilities $ 862 $ — $ — $ 862 ($ in thousands) Fair Value Measurements at Reporting Date Using Description Balance as of Quoted Prices in Significant Other Significant Cash equivalents $ 137,405 $ 137,405 $— $—
Share-Based Compensation Expense Included in Statements of Operations	The following table presents share-based compensation expense included in the Company’s Statements of Operations: Year ended December 31, (in thousands) 2016 2015 2014 Research and development $ 2,077 $ 1,403 $ 1,416 General and administrative 6,375 6,594 3,327 Share based employee compensation expense before tax 8,452 7,997 4,743 Income tax benefit — — — Net share based employee compensation expense $ 8,452 $ 7,997 $ 4,743
Assumptions for Volatility, Expected life, Dividend Yield and Risk-free Interest Rate	The assumptions for volatility, expected life, dividend yield and risk-free interest rate are presented in the table below: 2016 2015 2014 Weighted average risk-free interest rate 1.27 - 2.09% 1.46 - 1.93% 1.74 - 2.11% Expected life in years 6 6 6 Expected volatility 79.15 - 82.95% 79.13 - 86.81% 85.22 - 94.55% Expected dividend yield 0 0 0
Potentially Dilutive Shares Excluded from Computation of Diluted Net Loss Per Share	The Company’s potentially dilutive shares, which include outstanding common stock options, unvested restricted stock and preferred stock, have not been included in the computation of diluted net loss per share for any of the periods presented as the result would be antidilutive. Such potential common shares at December 31, 2016, 2015, and 2014 consist of the following: December 31, 2016 2015 2014 Stock options 3,465,335 3,481,468 6,505,664 Unvested restricted stock 1,680,492 1,586,388 144,508 Preferred stock 20,465,067 — — 25,610,894 5,067,856 6,650,172

Property and Equipment, net (Ta

Property and Equipment, net (Tables)	12 Months Ended
	Dec. 31, 2016
Component of Property and Equipment, Net	Property and equipment, net, consists of the following: December 31, (in thousands) 2016 2015 Office and computer equipment $ 1,162 $ 1,105 Software 907 886 Leasehold improvements 1,158 990 Manufacturing equipment 878 572 4,105 3,553 Less: accumulated depreciation (3,262 ) (2,972 ) Property and equipment, net $ 843 $ 581

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2016
Component of Accrued Expenses	Accrued expenses consist of the following: December 31, (in thousands) 2016 2015 Clinical consulting services $ 2,342 $ 2,331 Preclinical services 2,693 3,976 Employee compensation 1,446 1,453 Professional services 488 317 Payroll taxes and benefits 646 289 Manufacturing services 1,116 253 Accrued vacation 294 221 Other consulting services 28 66 Accrued rent 56 — Total $ 9,109 $ 8,906

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2016
Future Net Minimum Lease Payments under Operating Leases	Future net minimum lease payments under operating leases as of December 31, 2016 are as follows (in thousands): 2017 $ 1,183 2018 1,113 2019 706 2020 719 2021 and beyond 484 4,205 Less: contractual sublease income (612 ) Future minimum lease payments, net $ 3,593

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Significant Component of Deferred Tax Assets	Significant components of the Company’s deferred tax assets at December 31, 2016 and 2015 are as follows: December 31, (in thousands) 2016 2015 Net operating loss carryforwards $ 100,790 $ 96,215 Start-up 59,360 64,942 Research and development credit carryforwards 34,845 29,564 Stock compensation 2,014 1,997 Capitalized acquisition costs 9,389 10,429 Deferred revenue 18,636 2,695 Depreciation 227 251 Other 1,537 1,673 226,798 207,766 Less valuation allowance (226,798 ) (207,766 ) Effective tax rate $ — $ —
Reconciliation of Income Tax Expense (Benefit)	A reconciliation of income tax expense (benefit) at the statutory federal income tax rate and income taxes as reflected in the financial statements is as follows: Year Ended December 31, (in thousands) 2016 2015 2014 Federal income tax at statutory rates 34 % 34 % 34 % State income tax, net of federal tax benefit 1 % 5 % 2 % Research and development credits 3 % 3 % 3 % Stock compensation -1 % -1 % -4 % Channel rights -25 % 0 % 0 % Other 0 % 0 % -4 % Increase in valuation allowance -12 % -41 % -31 % Effective tax rate 0 % 0 % 0 %
Summary of Adjustments to Uncertain Tax Position	A summary of the company’s adjustments to its uncertain tax positions in the years ended December 31, 2016, 2015, and 2014 are as follows: (in thousands) Balance at December 31, 2013 $ 238 Increase/Decrease for tax positions related to the current year — Increase/Decrease for tax positions related to prior years — Decrease for settlements with applicable taxing authorities — Decrease for lapses of statute of limitations — Balance at December 31, 2014 $ 238 Increase/Decrease for tax positions related to the current year — Increase/Decrease for tax positions related to prior years — Decreases for settlements with applicable taxing authorities — Decrease for previous year’s lapses of statute of limitations (20 ) Decrease for impact of §382 limitations (218 ) Decrease for lapses of statute of limitations — Balance at December 31, 2015 $ — Increase/Decrease for tax positions related to the current year — Increase/Decrease for tax positions related to prior years — Decrease for settlements with applicable taxing authorities — Decrease for lapses of statute of limitations — Balance at December 31, 2016 $ —

Preferred Stock and Stockhold28

Preferred Stock and Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value Assumptions Used in Probability Weighted Approach and Monte Carlo Simulation Model	The fair value of the Series 1 preferred stock was estimated using a probability-weighted approach and a Monte Carlo simulation model. The fair value of the embedded derivatives was estimated using the “with” and “without” method where the preferred stock was first valued with all of its features (“with” scenario) and then without derivatives subject to the valuation analysis (“without” scenario). The fair value of the derivatives was then estimated as the difference between the fair value of the preferred stock in the “with” scenario and the preferred stock in the “without” scenario. The model also takes into account, management estimates of clinical success/failure based upon market studies and probability of potential conversion and liquidation events. If these estimates were different, the valuations would change and that change could be material. Risk-free interest rate 1.04 % Expected dividend rate 0 Expected volatility 70.50 % Preferred stock conversion limit—percentage of outstanding common stock 19.90 % Preferred conversion floor price $ 1.00
Series 1 Preferred Stock
Fair Value Assumptions Used in Probability Weighted Approach and Monte Carlo Simulation Model	The fair value of the Series 1 preferred stock dividends were estimated using a probability-weighted approach and a Monte Carlo simulation model. The fair value of the embedded derivatives was estimated using the “with” and “without” method where the preferred stock was first valued with all of its features (“with” scenario) and then without derivatives subject to the valuation analysis (“without” scenario). The fair value of the derivatives was then estimated as the difference between the fair value of the preferred stock in the “with” scenario and the preferred stock in the “without” scenario. The model also takes into account, management estimates of clinical success/failure based upon market studies and probability of potential conversion and liquidation events. If these estimates were different, the valuations would change and that change could be material. Inputs to the models included the following: Risk-free interest rate 1.04% - 1.69% Expected dividend rate 0 Expected volatility 70.5% - 72.70% Preferred stock conversion limit—percentage of outstanding common stock 19.90% Preferred conversion floor price $1.00

Derivative Financial Instrume29

Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Values of Derivative Instruments to be classified as Derivative Liabilities on Balance Sheet	Fair values of derivative instruments to be classified as derivative liabilities on the balance sheet consist of the following: ($ in thousands) Liability derivates: Balance Sheet Location Fair Value December 31, 2016: Derivative liabilities Liabilities $ 862
Change in Derivative Liability	The change in the derivative liability for the year ended December 31, 2016 consists of the following: ($ in thousands) Fair Value Balance, June 30, 2016 $ 694 Dividends 44 Mark-to-market 124 Balance, December 31, 2016 $ 862

Stock Option Plan (Tables)

Stock Option Plan (Tables)	12 Months Ended
	Dec. 31, 2016
Transaction under Stock Option Plan	Transactions under the 2012 Plan for the years ending December 31, 2016, 2015, and 2014 were as follows: (in thousands, except share and per share data) Number of Weighted- Weighted- Aggregate Outstanding, December 31, 2013 6,747,302 $ 3.81 Granted 1,099,300 4.95 Exercised (613,138 ) 2.26 Cancelled (727,801 ) 4.54 Outstanding, December 31, 2014 6,505,663 4.07 Granted 427,800 10.47 Exercised (3,249,160 ) 3.95 Cancelled (202,835 ) 4.36 Outstanding, December 31, 2015 3,481,468 4.96 Granted 362,800 6.40 Exercised (234,833 ) 4.57 Cancelled (144,100 ) 6.43 Outstanding, December 31, 2016 3,465,335 $ 5.07 6.58 $ 3,407 Vested and unvested expected to vest at December 31, 2016 3,441,247 $ 4.40 5.88 $ 3,316 Options exercisable, December 31, 2016 2,671,835 $ 4.40 5.88 $ 3,383 Options exercisable, December 31, 2015 2,120,834 $ 4.24 5.84 $ 8,622 Options available for future grant 1,777,760
Summary of Non-Vested Restricted Stock	A summary of the status of non-vested Number of Shares Weighted-Average Non-vested, 352,865 $ 4.38 Granted 66,828 5.07 Vested (253,835 ) 4.38 Cancelled (21,350 ) 4.41 Non-vested, 144,508 4.70 Granted 1,590,574 9.01 Vested (148,694 ) 4.88 Cancelled — — Non-vested, 1,586,388 9.00 Granted 711,770 5.35 Vested (617,666 ) 8.90 Cancelled — — Non-vested, 1,680,492 $ 5.54

Selected Quarterly Informatio31

Selected Quarterly Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2016
Selected Quarterly Information	Year Ended December 31, 2016 First Second Third Fourth Revenue $ 1,969 $ 1,697 $ 1,598 $ 1,597 Total operating expenses 14,009 132,939 12,512 12,708 Loss from operations (12,040 ) (131,242 ) (10,914 ) (11,111 ) Change in derivative liabilities — — (3,591 ) (3,532 ) Net (loss) applicable to common shareholders (12,019 ) (131,200 ) (14,445 ) (14,756 ) Loss per share, basic and diluted $ (0.09 ) $ (1.01 ) $ (0.11 ) $ (0.11 ) Year Ended December 31, 2015 First Second Third Fourth Revenue $ 272 $ 272 $ 1,869 $ 1,919 Total operating expenses 78,499 14,497 20,035 11,401 Loss from operations (78,227 ) (14,225 ) (18,166 ) (9,482 ) Change in derivative liabilities — — — — Net (loss) applicable to common shareholders (78,231 ) (14,211 ) (18,170 ) (9,476 ) Loss per share, basic and diluted $ (0.69 ) $ (0.11 ) $ (0.14 ) $ (0.07 )

Organization and Going Concern

Organization and Going Concern - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Nature Of Operations [Line Items]
Accumulated Deficit	$ (657,997)	$ (492,700)
Cash and cash equivalents	$ 81,053	$ 140,717	$ 42,803	$ 68,204

Financings - Additional Informa

Financings - Additional Information (Detail) - J.P. Morgan Securities Inc. - USD ($) $ / shares in Units, $ in Millions	Feb. 17, 2015	Feb. 09, 2015	Feb. 03, 2015
Class of Stock [Line Items]
Stock issued during period	1,500,000	10,000,000	10,000,000
Issuance & sale of common stock in public offering price per share			$ 8.75
Option granted, exercisable period			30 days
Sale of stock price per share			$ 8.225
Net proceeds from issuance of common stock	$ 94.3

Summary of Significant Accoun34

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Jan. 09, 2017	Jun. 29, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Summary Of Significant Accounting Policies [Line Items]
Stock based compensation expenses			$ 8,452	$ 7,997	$ 4,743
Weighted average fair value of stock option granted			$ 4.43	$ 10.47	$ 3.58
Subsequent Event | Cooperative Research and Development Agreement
Summary Of Significant Accounting Policies [Line Items]
Contractual obligations over the next three years	$ 7,500
Stock Options
Summary Of Significant Accounting Policies [Line Items]
Stock based compensation expenses			$ 3,000	$ 5,300	$ 3,700
Restricted Stock
Summary Of Significant Accounting Policies [Line Items]
Stock based compensation expenses			5,500	2,700	1,000
Employee and Director Awards
Summary Of Significant Accounting Policies [Line Items]
Stock based compensation expenses			8,500	$ 8,000	$ 4,700
Other Noncurrent Assets | Lease Obligations
Summary Of Significant Accounting Policies [Line Items]
Restricted cash			388
Other Noncurrent Assets | Line of Credit
Summary Of Significant Accounting Policies [Line Items]
Restricted cash			$ 104
Minimum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment useful life			3 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment useful life			5 years
Intrexon Corporation | Series 1 Preferred Stock
Summary Of Significant Accounting Policies [Line Items]
Issuance of stock in a license agreement (in shares)		100,000	6,184
Number of shares converted into common stock			20,465,067
Preferred stock, conversion rate			$ 1

Assets and Liabilities Measured

Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 77,120	$ 137,405
Derivative liabilities	862
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	77,120	$ 137,405
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	$ 862

Stock-Based Compensation Expens

Stock-Based Compensation Expense Included in Statement of Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 8,452	$ 7,997	$ 4,743
Income tax benefit	0	0	0
Net share based employee compensation expense	8,452	7,997	4,743
Research and Development Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	2,077	1,403	1,416
General and Administrative Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 6,375	$ 6,594	$ 3,327

Fair Value of Stock Options Ass

Fair Value of Stock Options Assumptions Using Black-Scholes Option Valuation Model (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, Minimum	1.27%	1.46%	1.74%
Risk-free interest rate, Maximum	2.09%	1.93%	2.11%
Expected life in years	6 years	6 years	6 years
Expected volatility, Minimum	79.15%	79.13%	85.22%
Expected volatility, Maximum	82.95%	86.81%	94.55%
Expected dividend yield	0.00%	0.00%	0.00%

Potential Dilutive Shares Exclu

Potential Dilutive Shares Excluded from Computation of Diluted Net Loss Per Share (Detail) - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	25,610,894	5,067,856	6,650,172
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	3,465,335	3,481,468	6,505,664
Restricted Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	1,680,492	1,586,388	144,508
Series 1 Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	20,465,067

Component of Property and Equip

Component of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 4,105	$ 3,553
Less: accumulated depreciation	(3,262)	(2,972)
Property and equipment, net	843	581
Office and computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	1,162	1,105
Software
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	907	886
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	1,158	990
Manufacturing equipment
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 878	$ 572

Property and Equipment, net - A

Property and Equipment, net - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Depreciation and amortization	$ 290	$ 357	$ 462

Component of Accrued Expenses (

Component of Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Accrued Liabilities [Line Items]
Clinical consulting services	$ 2,342	$ 2,331
Preclinical services	2,693	3,976
Employee compensation	1,446	1,453
Professional services	488	317
Payroll taxes and benefits	646	289
Manufacturing services	1,116	253
Accrued vacation	294	221
Other consulting services	28	66
Accrued rent	56
Total	$ 9,109	$ 8,906

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($)	Jun. 29, 2016	Jan. 08, 2016	Sep. 28, 2015	Jun. 29, 2015	Mar. 27, 2015	Feb. 03, 2015	Jan. 13, 2015	Jan. 06, 2011	Sep. 30, 2015	Jul. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Commitment to purchase common stock											$ 2,000	$ 34,000
Research and Development Expense											157,791,000	106,785,000	$ 32,706,000
Research and Development Service Agreement Aggregate Quarterly Payments											15,000,000	11,300,000
Stock buy back											2,000	34,000
Company re-purchased additional shares Value											1,500,000	$ 518,000	544,000
Change in fair value of derivative liability											$ 124,000
Minimum
Related Party Transaction [Line Items]
Research and Development Expense							$ 15,000,000
M.D. Anderson Cancer Center | Minimum
Related Party Transaction [Line Items]
Ownership percentage											5.00%
Series 1 Preferred Stock
Related Party Transaction [Line Items]
Preferred stock, stated value											$ 1,200	$ 1,200
Temporary equity, fair value											$ 7,100,000
License Agreement
Related Party Transaction [Line Items]
Research and Development Expense											$ 67,300,000	$ 67,300,000
Issuance of common stock in licensing agreement (in shares)							11,722,163				11,722,163	11,722,163
Preferred stock, shares issued							11,722,163				11,722,163	11,722,163
Intrexon Corporation
Related Party Transaction [Line Items]
Stock issued during period						1,440,000
Commitment to purchase common stock					$ 43,500,000			$ 50,000,000
Percentage of commitment for payments from receipts of upfronts, milestones and royalties					50.00%
Stock buy back (Shares)				3,711
Stock buy back				$ 34,000
Share buy back discount on closing price				5.00%
Company re-purchased additional shares		168
Company re-purchased additional shares Value		$ 2,000
Licensing fee			$ 10,000,000							$ 115,000,000
Amounts expensed for services incurred											$ 22,200,000	$ 16,300,000	$ 12,000,000
Amount due to related party, current											$ 3,400,000	$ 4,600,000
Intrexon Corporation | Series 1 Preferred Stock
Related Party Transaction [Line Items]
Issuance of common stock in licensing agreement (in shares)	100,000										6,184
Preferred stock, shares issued	100,000										6,184
Preferred stock, stated value	$ 1,200
Dividends, preferred stock	$ 12
Intrexon Corporation | 2016 GvHD Amendment
Related Party Transaction [Line Items]
Research and Development Expense									$ 10,000,000
Licensing fee			$ 10,000,000
Royalty percentage of net profit											20.00%
Intrexon Corporation | Quarterly Payment
Related Party Transaction [Line Items]
Royalty percentage of net profit								20.00%
Intrexon Corporation | Quarterly Payment | ECP Channel Agreement | After Amendment
Related Party Transaction [Line Items]
Royalty percentage of net profit	20.00%
Intrexon Corporation | Quarterly Payment | ECP Channel Agreement | Before Amendment
Related Party Transaction [Line Items]
Royalty percentage of net profit	50.00%
Intrexon Corporation | Quarterly Payment | 2016 GvHD Amendment | After Amendment
Related Party Transaction [Line Items]
Royalty percentage of net profit	20.00%
Intrexon Corporation | Quarterly Payment | 2016 GvHD Amendment | Before Amendment
Related Party Transaction [Line Items]
Royalty percentage of net profit	50.00%

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)

Jun. 29, 2016$ / sharesshares

Sep. 28, 2015USD ($)

Jan. 13, 2015USD ($)shares

Jan. 09, 2015USD ($)shares

Mar. 07, 2011USD ($)

Jan. 06, 2011

Aug. 24, 2004Patent

Nov. 30, 2017USD ($)

Sep. 30, 2015USD ($)

Jul. 31, 2015USD ($)

Dec. 31, 2016USD ($)$ / sharesshares

Dec. 31, 2015USD ($)$ / sharesshares

May 22, 2015USD ($)

Dec. 31, 2014USD ($)shares

Dec. 31, 2013USD ($)

Dec. 31, 2012

Dec. 31, 2011USD ($)

Mar. 31, 2016USD ($)

May 31, 2015USD ($)

Commitments and Contingencies Disclosure [Line Items]

Total rent Expense

$ 300,000

$ 1,000,000

$ 1,200,000

Deferred rent - current portion

155,000

348,000

Deferred rent-non-current portion

126,000

313,000

Deferred rent liability net

281,000

661,000

Research and Development Expense

$ 157,791,000

106,785,000

32,706,000

Research and development arrangement Terms

Pursuant to the Research and Development Agreement, the Company, Intrexon and MD Anderson have agreed to form a joint steering committee that will oversee and manage the new and ongoing research programs. As provided under the MD Anderson License, the Company will provide funding for research and development activities in support of the research programs under the Research and Development Agreement for a period of three years and in an amount of no less than $15.0 million and no greater than $20.0 million per year.

Research and Development Service Agreement Aggregate Quarterly Payments

$ 15,000,000

11,300,000

Offset costs in research and development expense

3,400,000

Deferred revenue - current portion

6,389,000

6,861,000

Deferred Revenue, long term

$ 41,528,000

47,917,000

Issuance of common stock in a license agreement

67,285,000

The University of Texas MD Anderson Cancer Center and The Texas A & M University System

Commitments and Contingencies Disclosure [Line Items]

Milestone maximum payment

$ 4,500,000

Number of products | Patent

2

Options to purchase common stock | shares

50,222

Shares vested | shares

37,666

The University of Texas MD Anderson Cancer Center and The Texas A & M University System | Research and Development Expense

Commitments and Contingencies Disclosure [Line Items]

Issuance of common stock in a license agreement

$ 87,000

The University of Texas MD Anderson Cancer Center and The Texas A & M University System | Upon enrollment of the first patient in a multi-center pivotal clinical trial

Commitments and Contingencies Disclosure [Line Items]

Shares vested | shares

12,556

Solasia

Commitments and Contingencies Disclosure [Line Items]

Upfront payment received

$ 5,000,000

Milestone payment received

$ 1,000,000

Milestone Payments Payable

$ 1,000,000

Solasia | Development-based milestones

Commitments and Contingencies Disclosure [Line Items]

Expected Additional milestone payments to be received

32,500,000

Solasia | Sales-based milestones

Commitments and Contingencies Disclosure [Line Items]

Expected Additional milestone payments to be received

53,500,000

Baxter Healthcare Corporation | Upon the successful U.S. IND application for indibulin

Commitments and Contingencies Disclosure [Line Items]

Installment payments

250,000

250,000

$ 250,000

Baxter Healthcare Corporation | Upon the successful U.S. IND application for indibulin | Scenario, Forecast

Commitments and Contingencies Disclosure [Line Items]

Additional payment payable amount

$ 250,000

License Agreement

Commitments and Contingencies Disclosure [Line Items]

Research and Development Expense

$ 67,300,000

$ 67,300,000

Issuance of common stock in licensing agreement, shares | shares

11,722,163

11,722,163

11,722,163

ARES Trading License

Commitments and Contingencies Disclosure [Line Items]

Agreement termination, notice period

90 days

Milestone payments, percentage

50.00%

Agreement commencement date

2015-05

Deferred revenue, revenue recognized

$ 6,400,000

$ 3,200,000

Deferred revenue, upfront payment

$ 47,900,000

$ 54,300,000

$ 57,500,000

Minimum

Commitments and Contingencies Disclosure [Line Items]

Research and Development Expense

$ 15,000,000

Maximum

Commitments and Contingencies Disclosure [Line Items]

Research and Development Expense

20,000,000

Series 1 Preferred Stock

Commitments and Contingencies Disclosure [Line Items]

Preferred stock, stated value | $ / shares

$ 1,200

$ 1,200

Prepaid Expenses and Other Current Assets

Commitments and Contingencies Disclosure [Line Items]

Pre paid research and development expenses

$ 22,900,000

Development Milestone Payments | ARES Trading License

Commitments and Contingencies Disclosure [Line Items]

Payments for development, regulatory and commercial milestones per Product

60,000,000

Regulatory Milestone Payments | ARES Trading License

Commitments and Contingencies Disclosure [Line Items]

Payments for development, regulatory and commercial milestones per Product

148,000,000

Commercial Milestone Payments | ARES Trading License

Commitments and Contingencies Disclosure [Line Items]

Payments for development, regulatory and commercial milestones per Product

205,000,000

Substantive Milestones

Commitments and Contingencies Disclosure [Line Items]

Potential milestone payment

$ 15,000,000

Intrexon Corporation

Commitments and Contingencies Disclosure [Line Items]

Contract termination description

The Company's obligation to pay 20% of net profits or revenue described above with respect to these "retained" products will survive termination of the Channel Agreement.

Licensing fee

$ 10,000,000

$ 115,000,000

Milestone payment receivable

$ 5,000,000

Milestone payment receivable period

2 years

Upfront payment received

$ 57,500,000

Percentage of upfront fee Payable

50.00%

Milestone maximum payment

$ 50,000,000

Intrexon Corporation | 2016 GvHD Amendment

Commitments and Contingencies Disclosure [Line Items]

Royalty percentage of net profit

20.00%

Contract termination description

The Company's obligation to pay 20% of net profits or revenue with respect to these "retained" products will survive termination of the GvHD Agreement.

Licensing fee

$ 10,000,000

Research and Development Expense

$ 10,000,000

Agreement termination period

24 months

Agreement termination, notice period

90 days

Intrexon Corporation | License Agreement

Commitments and Contingencies Disclosure [Line Items]

Cash consideration for license agreement

$ 50,000,000

Intrexon Corporation | Letter Agreement

Commitments and Contingencies Disclosure [Line Items]

Cash consideration for license agreement

$ 7,500,000

Intrexon Corporation | Quarterly Payment

Commitments and Contingencies Disclosure [Line Items]

Royalty percentage of net profit

20.00%

Percentage of revenue agreed to pay which is obtained from sublicensor

50.00%

Intrexon Corporation | Quarterly Payment | 2016 GvHD Amendment | After Amendment

Commitments and Contingencies Disclosure [Line Items]

Royalty percentage of net profit

20.00%

Intrexon Corporation | Quarterly Payment | 2016 GvHD Amendment | Before Amendment

Commitments and Contingencies Disclosure [Line Items]

Royalty percentage of net profit

50.00%

Intrexon Corporation | Quarterly Payment | ECP Channel Agreement | After Amendment

Commitments and Contingencies Disclosure [Line Items]

Royalty percentage of net profit

20.00%

Intrexon Corporation | Quarterly Payment | ECP Channel Agreement | Before Amendment

Commitments and Contingencies Disclosure [Line Items]

Royalty percentage of net profit

50.00%

Intrexon Corporation | Series 1 Preferred Stock

Commitments and Contingencies Disclosure [Line Items]

Issuance of common stock in licensing agreement, shares | shares

100,000

6,184

Preferred stock, stated value | $ / shares

$ 1,200

ZIOPHARM | License Agreement

Commitments and Contingencies Disclosure [Line Items]

Common stock issued for cash | shares

10,124,561

Cash consideration for license agreement

$ 50,000,000

ZIOPHARM | Letter Agreement

Commitments and Contingencies Disclosure [Line Items]

Common stock issued for cash | shares

1,597,602

Cash consideration for license agreement

$ 7,500,000

New York, NY

Commitments and Contingencies Disclosure [Line Items]

Letter of credit

$ 388,000

$ 388,000

Operating lease expiration month and year

2018-10

Loss on sublease

$ 729,000

Remaining contractual obligation

2,300,000

Sublease revenue from subtenant

1,600,000

Loss on disposal of fixed assets

(392,000)

Boston, MA

Commitments and Contingencies Disclosure [Line Items]

Operating lease expiration month and year

2016-08

2016-08

Loss on sublease

42,000

Remaining contractual obligation

367,000

Sublease revenue from subtenant

$ 105,000

$ 325,000

Security deposits

$ 128,000

$ 128,000

$ 17,000

Sublease term amendment

Aug. 31, 2021

Security deposit from subtenant

$ 20,000

The first floor | Boston, MA

Commitments and Contingencies Disclosure [Line Items]

Loss on sublease

$ 167,000

Future Minimum Lease Payments u

Future Minimum Lease Payments under Operating Leases (Detail) $ in Thousands	Dec. 31, 2016USD ($)
Operating Leased Assets [Line Items]
2,017	$ 1,183
2,018	1,113
2,019	706
2,020	719
2021 and beyond	484
Operating Leases, Future Minimum Payments Due, Total	4,205
Less: contractual sublease income	(612)
Future minimum lease payments, net	$ 3,593

Warrants - Additional Informati

Warrants - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2014	Dec. 31, 2009
Class of Warrant or Right [Line Items]
Warrants to purchase an aggregate of shares of common stock			8,206,520
Warrant term			5 years
Warrants expiration date	2014-12
Gain on expiration of liability-classified warrants		$ 195
Warrants exercised		4,004,907
Conversion of Warrants to Common Stock		3,725,277
Liability
Class of Warrant or Right [Line Items]
Warrants outstanding		1,755,845
Warrants expired		6,479,231
Equity
Class of Warrant or Right [Line Items]
Warrants outstanding		2,249,062
Warrants expired		12,329
Private Placement
Class of Warrant or Right [Line Items]
Warrants to purchase an aggregate of shares of common stock			2,910,954
Warrant exercise price			$ 2.04
Warrant exercisable Period			5 years
Estimated fair value of warrant			$ 4,200
Private Placement | Warrants
Class of Warrant or Right [Line Items]
Expected volatility			105.00%
Risk-free interest rate			2.41%
Expected life in years			5 years
Expected dividend yield			0.00%
J. P. Morgan Securities LLC
Class of Warrant or Right [Line Items]
Warrants issued			464,520
Placement Agents | Private Placement
Class of Warrant or Right [Line Items]
Warrants to purchase an aggregate of shares of common stock			138,617

Significant Component of Deferr

Significant Component of Deferred Tax Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred Tax Assets [Line Items]
Net operating loss carryforwards	$ 100,790	$ 96,215
Start-up and organizational costs	59,360	64,942
Research and development credit carryforwards	34,845	29,564
Stock compensation	2,014	1,997
Capitalized acquisition costs	9,389	10,429
Deferred revenue	18,636	2,695
Depreciation	227	251
Other	1,537	1,673
Deferred Tax Assets Gross	226,798	207,766
Less valuation allowance	(226,798)	(207,766)
Effective tax rate	$ 0	$ 0

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2014	Dec. 31, 2015
Income Taxes [Line Items]
Net operating loss carryforwards	$ 100,790		$ 96,215
Research and development credit carryforwards	$ 34,845		$ 29,564
Net operating loss carryforwards, expiration date	2,036
Net Operating loss Carryforwards resulting from excess tax deduction	$ 10,200
Increase (decrease) in deferred tax assets	19,000
Net Operating Loss Carryforwards
Income Taxes [Line Items]
Increase (decrease) in deferred tax assets		$ (11,200)
General Business Credits
Income Taxes [Line Items]
Increase (decrease) in deferred tax assets		$ (636)
Domestic Tax Authority
Income Taxes [Line Items]
Net operating loss carryforwards	$ 264,000
Net operating loss carryforwards, expiration date	2,036
Federal and State
Income Taxes [Line Items]
Net operating loss carryforwards	$ 224,000

Reconciliation of Income Tax Ex

Reconciliation of Income Tax Expense (Benefit) (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Effective Tax Rate [Line Items]
Federal income tax at statutory rates	34.00%	34.00%	34.00%
State income tax, net of federal tax benefit	1.00%	5.00%	2.00%
Research and development credits	3.00%	3.00%	3.00%
Stock compensation	(1.00%)	(1.00%)	(4.00%)
Channel rights	(25.00%)	0.00%	0.00%
Other	0.00%	0.00%	(4.00%)
Increase in valuation allowance	(12.00%)	(41.00%)	(31.00%)
Effective tax rate	0.00%	0.00%	0.00%

Summary of Adjustments to Uncer

Summary of Adjustments to Uncertain Tax Position (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Contingency [Line Items]
Beginning Balance		$ 238	$ 238
Increase/Decrease for tax positions related to the current year	$ 0	0	0
Increase/Decrease for tax positions related to prior years	0	0	0
Decrease for settlements with applicable taxing authorities	0	0	0
Decrease for previous year's lapses of statute of limitations		(20)
Decrease for impact of §382 limitations		(218)
Decrease for lapses of statute of limitations	$ 0	$ 0	0
Ending Balance			$ 238

Preferred Stock and Stockhold50

Preferred Stock and Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Jun. 29, 2016	Feb. 17, 2015	Feb. 09, 2015	Feb. 03, 2015	Jan. 13, 2015	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Jul. 01, 2016	Apr. 26, 2006
Equity [Line Items]
Shares of authorized capital stock										280,000,000
Common stock, shares authorized							250,000,000	250,000,000		250,000,000
Common stock par value per share							$ 0.001	$ 0.001		$ 0.001
Preferred stock, shares authorized										30,000,000
Preferred stock par value										$ 0.001
Change in fair value of derivative liability							$ 124
Series 1 Preferred Stock
Equity [Line Items]
Preferred stock, stated value							$ 1,200	$ 1,200
Maximum percentage of common stock issuable upon conversion of preferred stock							19.90%
Fair value of Series 1 preferred stock as a component of temporary equity							$ 125,321
Temporary equity, fair value							7,100
Intrexon Corporation
Equity [Line Items]
Stock issued during period				1,440,000
Embedded conversion liability							$ 900
Fair value of Series 1 preferred stock as a component of temporary equity									$ 118,200
Intrexon Corporation | Series 1 Preferred Stock
Equity [Line Items]
Issuance of common stock in licensing agreement (in shares)	100,000						6,184
Preferred stock, stated value	$ 1,200
Preferred stock, conversion rate							$ 1
Maximum percentage of common stock issuable upon conversion of preferred stock							19.90%
Preferred stock monthly dividend payable (per share)	$ 12
Intrexon Corporation | Series 1 Preferred Stock | Before Conversion Event Date
Equity [Line Items]
Preferred stock monthly dividend payable (per share)						$ 12
Intrexon Corporation | Series 1 Preferred Stock | Remaining Unconverted Shares
Equity [Line Items]
Preferred stock monthly dividend payable (per share)						$ 24
License Agreement
Equity [Line Items]
Issuance of common stock in licensing agreement (in shares)					11,722,163		11,722,163	11,722,163
J.P. Morgan Securities Inc.
Equity [Line Items]
Stock issued during period		1,500,000	10,000,000	10,000,000
Issuance & sale of common stock in public offering price per share				$ 8.75
Sale of stock price per share				$ 8.225
Option granted, exercisable period				30 days
Option to purchase common stock				1,500,000
Expected net proceeds from issuance of common stock		$ 94,300

Fair Value Assumptions Used in

Fair Value Assumptions Used in Probability Weighted Approach and Monte Carlo Simulation Model (Detail) - Series 1 Preferred Stock	12 Months Ended
	Dec. 31, 2016$ / shares
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Risk-free interest rate	1.04%
Expected dividend rate	0.00%
Expected volatility	70.50%
Preferred stock conversion limit - percentage of outstanding common stock	19.90%
Preferred conversion floor price	$ 1

Fair Values of Derivative Instr

Fair Values of Derivative Instruments to be classified as Derivative Liabilities on Balance Sheet (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Derivative liabilities	$ 862	$ 694
Liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	$ 862

Change in Derivative Liability

Change in Derivative Liability (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)
Derivatives, Fair Value [Line Items]
Balance, June 30, 2016	$ 694
Dividends	44
Mark-to-market	124
Balance, December 31, 2016	$ 862

Fair Value Assumptions Used i54

Fair Value Assumptions Used in Probability Weighted Approach and Monte Carlo Simulation Model for Derivatives (Detail) - Series 1 Preferred Stock	12 Months Ended
	Dec. 31, 2016$ / shares
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Risk-free interest rate	1.04%
Expected dividend rate	0.00%
Expected volatility	70.50%
Preferred stock conversion limit - percentage of outstanding common stock	19.90%
Preferred conversion floor price	$ 1
Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Risk-free interest rate	1.04%
Expected volatility	70.50%
Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Risk-free interest rate	1.69%
Expected volatility	72.70%

Stock Option Plan - Additional

Stock Option Plan - Additional information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended										12 Months Ended
	Dec. 31, 2016	Jun. 30, 2016	May 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	May 31, 2015	Dec. 31, 2014	Feb. 28, 2014	Jan. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2012	Jun. 18, 2014	Dec. 31, 2013	May 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	26,364										26,364
Outstanding options issued	3,465,335			3,481,468				6,505,663			3,465,335	3,481,468	6,505,663			6,747,302
Proceeds from stock options exercised											$ 714	$ 4,568	$ 1,386
Total intrinsic value of options											1,500	$ 23,800	$ 2,600
Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period														3 years
Contractual terms														10 years
Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual terms														10 years
Director | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period														3 years
Director | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period														1 year
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Repurchase of shares of restricted common stock	119,873	6,667	116,667	16,709	7,669			81,702	14,600	16,031
Repurchase of shares of restricted common stock, price per share	$ 5.35	$ 7.74	$ 6.86	$ 8.31	$ 11.57			$ 5.04	$ 4.40	$ 4.37
Restricted Stock | Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years			3 years		3 years	3 years
Share-based payment award granted	625,750			403,083		50,000	1,000,000
Restricted Stock | Non Employee Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year							1 year
Share-based payment award granted	86,020			133,305	4,186			66,828
Unvested Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs related to non-vested restricted stock outstanding	$ 3,500										$ 3,500
Expected recognition period											1 year 5 months 16 days
Unvested Restricted Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected recognition period											1 year 6 months 15 days
Share-based payment award granted											711,770	1,590,574	66,828
Unrecognized stock-based compensation expense related to non-vested restricted stock arrangements	$ 10,500										$ 10,500
the "2012 Plan"
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	9,000,000										9,000,000				5,000,000		4,000,000
the "2012 Plan" | Employees | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding options issued	2,652,835										2,652,835
the "2012 Plan" | Director | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding options issued	802,500										802,500
the "2012 Plan" | Consultants | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding options issued	10,000										10,000

Stock Option Activity Under Sto

Stock Option Activity Under Stock Option Plan (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Number of Shares
Beginning Balance	3,481,468	6,505,663	6,747,302
Granted	362,800	427,800	1,099,300
Exercised	(234,833)	(3,249,160)	(613,138)
Cancelled	(144,100)	(202,835)	(727,801)
Ending Balance	3,465,335	3,481,468	6,505,663
Vested and unvested expected to vest at end of period	3,441,247
Weighted Average Exercise Price
Beginning Balance	$ 4.96	$ 4.07	$ 3.81
Granted	6.40	10.47	4.95
Exercised	4.57	3.95	2.26
Cancelled	6.43	4.36	4.54
Ending Balance	5.07	4.96	$ 4.07
Vested and unvested expected to vest at end of period	4.40
Options exercisable, at end of period	$ 4.40	$ 4.24
Options exercisable, at end of period	2,671,835	2,120,834
Options available for future grant	1,777,760
Weighted Average Contractual Term (Years)
Outstanding, at end of period	6 years 6 months 29 days
Vested and unvested expected to vest at end of period	5 years 10 months 17 days
Options exercisable, at end of period	5 years 10 months 17 days	5 years 10 months 2 days
Aggregate Intrinsic Value
Outstanding, at end of period	$ 3,407
Vested and unvested expected to vest at end of period	3,316
Options exercisable, at end of period	$ 3,383	$ 8,622

Summary of Non-Vested Restricte

Summary of Non-Vested Restricted Stock (Detail) - Unvested Restricted Common Stock - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Number of Shares
Beginning Balance	1,586,388	144,508	352,865
Granted	711,770	1,590,574	66,828
Vested	(617,666)	(148,694)	(253,835)
Cancelled			(21,350)
Ending Balance	1,680,492	1,586,388	144,508
Weighted Average Grant Date Fair Value
Beginning Balance	$ 9	$ 4.70	$ 4.38
Granted	5.35	9.01	5.07
Vested	8.90	4.88	4.38
Cancelled			4.41
Ending Balance	$ 5.54	$ 9	$ 4.70

Employee Benefit Plan - Additio

Employee Benefit Plan - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan contributions by employer	$ 75	$ 47	$ 79

Selected Quarterly Informatio59

Selected Quarterly Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information [Line Items]
Revenue	$ 1,597	$ 1,598	$ 1,697	$ 1,969	$ 1,919	$ 1,869	$ 272	$ 272	$ 6,861	$ 4,332	$ 1,373
Total operating expenses	12,708	12,512	132,939	14,009	11,401	20,035	14,497	78,499	172,168	124,432	44,872
Loss from operations	(11,111)	(10,914)	(131,242)	(12,040)	(9,482)	(18,166)	(14,225)	(78,227)	(165,307)	(120,100)	(43,499)
Change in derivative liabilities	(3,532)	(3,591)									11,723
Net (loss) applicable to common shareholders	$ (14,756)	$ (14,445)	$ (131,200)	$ (12,019)	$ (9,476)	$ (18,170)	$ (14,211)	$ (78,231)	$ (165,297)	$ (120,088)	$ (31,781)
Loss per share, basic and diluted	$ (0.11)	$ (0.11)	$ (1.01)	$ (0.09)	$ (0.07)	$ (0.14)	$ (0.11)	$ (0.69)	$ (1.32)	$ (0.96)	$ (0.31)