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Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Mar. 31, 2014	Apr. 30, 2014
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2014
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	Q1
Trading Symbol	ZIOP
Entity Registrant Name	ZIOPHARM ONCOLOGY INC
Entity Central Index Key	0001107421
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		100,725,976

Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 60,385	$ 68,204
Receivables	27	145
Prepaid expenses and other current assets	1,589	1,948
Total current assets	62,001	70,297
Property and equipment, net	679	801
Deposits	128	128
Other non-current assets	517	528
Total assets	63,325	71,754
Current liabilities:
Accounts payable	578	422
Accrued expenses	5,752	6,357
Deferred revenue - current portion	800	800
Deferred rent - current portion	224	212
Total current liabilities	7,354	7,791
Deferred revenue	1,733	1,933
Deferred rent	792	851
Warrant liabilities	11,694	11,776
Other long- term liabilities	20	20
Total liabilities	21,593	22,371
Commitments and contingencies (note 7)
Stockholders' equity:
Preferred stock, $0.001 par value; 30,000,000 shares authorized and no shares issued and outstanding
Common stock, $0.001 par value; 250,000,000 shares authorized; 100,600,666 and 100,159,618 shares issued and outstanding at March 31, 2014 and December 31, 2013, respectively	101	100
Additional paid-in capital - common stock	388,570	386,511
Additional paid-in capital - warrants issued	3,603	3,603
Deficit accumulated during the development stage	(350,542)	(340,831)
Total stockholders' equity	41,732	49,383
Total liabilities and stockholders' equity	$ 63,325	$ 71,754

Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2014	Dec. 31, 2013
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	30,000,000	30,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	100,600,666	100,159,618
Common stock, shares outstanding	100,600,666	100,159,618

Statements of Operations - USD ($) $ in Thousands	3 Months Ended		127 Months Ended
Statements of Operations - USD ($) $ in Thousands	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014
Research contract revenue	$ 200	$ 200	$ 2,467
Operating expenses:
Research and development, including costs of research contracts	6,542	19,112	261,739
General and administrative	3,442	4,671	107,421
Total operating expenses	9,984	23,783	369,160
Loss from operations	(9,784)	(23,583)	(366,693)
Other income (expense), net	(9)	(4)	4,113
Change in fair value of warrants	82	10,788	12,038
Net loss	$ (9,711)	$ (12,799)	$ (350,542)
Net loss per share - basic and diluted	$ (0.10)	$ (0.15)
Weighted average common shares outstanding to compute net loss per share - basic and diluted	100,229,200	82,906,080

Statement of Stockholders' Equity - 3 months ended Mar. 31, 2014 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital Common Stock	Additional Paid-in Capital Warrants	Deficit Accumulated During the Development Stage
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	$ 1,223		1,223
Exercise of employee stock options (in shares)	479,705	479,705
Exercise of employee stock options	$ 969	$ 1	968
Cancelled restricted stock (in shares)		(8,026)
Cancelled restricted stock
Repurchase of shares of restricted common stock (in shares)		(30,631)
Repurchase of shares of restricted common stock	(132)		(132)
Net loss	(9,711)				(9,711)
Ending Balance (in shares) at Mar. 31, 2014		100,600,666
Ending Balance at Mar. 31, 2014	$ 41,732	$ 101	$ 388,570	$ 3,603	$ (350,542)

Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		127 Months Ended
Statements of Cash Flows - USD ($) $ in Thousands	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014
Cash flows from operating activities:
Net loss	$ (9,711)	$ (12,799)	$ (350,542)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	124	199	3,437
Stock-based compensation	1,223	1,541	24,911
Change in fair value of warrants	(82)	(10,788)	(12,038)
Loss on disposal of fixed assets			641
Common stock issued in exchange for in-process research and development			36,151
(Increase) decrease in:
Receivables	118	(14)	(27)
Prepaid expenses and other current assets	359	2,078	(1,589)
Other noncurrent assets	11	258	(517)
Deposits			(128)
Increase (decrease) in:
Accounts payable	156	(526)	578
Accrued expenses	(605)	2,005	5,752
Deferred revenue	(200)	(200)	2,533
Deferred rent	(47)	3	1,016
Other noncurrent liabilities			20
Net cash used in operating activities	(8,654)	(18,243)	(289,802)
Cash flows from investing activities:
Purchases of property and equipment	(2)	(114)	(4,760)
Proceeds from sale of property and equipment			2
Net cash used in investing activities	(2)	(114)	(4,758)
Cash flows from financing activities:
Stockholders' capital contribution			500
Proceeds from exercise of stock options	969	851	3,298
Payments to employees for repurchase of common stock	(132)	(246)	(3,496)
Proceeds from exercise of warrants		101	13,278
Proceeds from issuance of common stock and warrants, net			324,605
Proceeds from issuance of preferred stock, net			16,760
Net cash provided by financing activities	837	706	354,945
Net increase (decrease) in cash and cash equivalents	(7,819)	(17,651)	60,385
Cash and cash equivalents, beginning of period	68,204	73,306
Cash and cash equivalents, end of period	60,385	55,655	60,385
Supplementary disclosure of cash flow information:
Cash paid for interest
Cash paid for income taxes
Supplementary disclosure of noncash investing and financing activities:
Warrants issued to placement agents and investors			47,276
Exercise of liability-classified warrants to common shares			764
Convertible Preferred Stock
Supplementary disclosure of noncash investing and financing activities:
Preferred stock conversion/exercise of equity-classified warrants to common stock			16,760
Warrants
Supplementary disclosure of noncash investing and financing activities:
Preferred stock conversion/exercise of equity-classified warrants to common stock		$ 72	$ 9,789

Business

3 Months Ended

Mar. 31, 2014

Business

1. Business

Overview

ZIOPHARM Oncology, Inc., which we refer to as “ZIOPHARM” or the “Company”, is a biopharmaceutical company that seeks to acquire, develop and commercialize, on its own or with commercial partners, a diverse portfolio of cancer therapies that can address unmet medical needs through synthetic biology.

The Company’s operations to date have consisted primarily of raising capital and conducting research and development. Accordingly, the Company is considered to be in the development stage at March 31, 2014. 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 March 31, 2014, the Company’s accumulated deficit was approximately $350.5 million. Based upon our current plans, we anticipate that our cash resources will be sufficient to fund our operations into the second quarter of 2015. 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. There can be no assurance that any such financing can be obtained by the Company, or if obtained, what the terms thereof may be, or that any amount that the Company is able to raise will be adequate to support the Company’s working capital requirements until it achieves profitable operations.

Basis of Presentation

The accompanying unaudited interim financial statements have been prepared in accordance with the instructions to Form 10-Q pursuant to the rules and regulations of the Securities and Exchange Commission. Certain information and note disclosures required by generally accepted accounting principles in the United States have been condensed or omitted pursuant to such rules and regulations.

It is management’s opinion that the accompanying unaudited interim financial statements reflect all adjustments (which are normal and recurring) that are necessary for a fair statement of the results for the interim periods. The unaudited interim financial statements should be read in conjunction with the audited financial statements and the notes thereto for the year ended December 31, 2013, included in the Company’s Form 10-K, as amended, for such fiscal year.

The year-end balance sheet data was derived from the audited financial statements but does not include all disclosures required by generally accepted accounting principles in the United States.

The results disclosed in the Statements of Operations for the three months ended March 31, 2014 are not necessarily indicative of the results to be expected for the full fiscal year.

Use of Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States 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 its financial statements are:

•

Clinical trial expenses;

•

Fair value measurements for stock based compensation and warrants; 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. During this period, the Company did not have any material recognizable or disclosable subsequent events.

Summary of Significant Accounting Policies	3 Months Ended
Summary of Significant Accounting Policies	Mar. 31, 2014
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies The Company’s significant accounting policies were identified in the Company’s Form 10-K for the fiscal year ended December 31, 2013. There have been no material changes in those policies since the filing of our Form 10-K.

Restructuring

3 Months Ended

Mar. 31, 2014

Restructuring

3. Restructuring

On April 3, 2013, the Company completed a workforce reduction plan to reduce costs as part of the Company’s decision to terminate development of palifosfamide in first-line metastatic soft tissue sarcoma and place exclusive strategic focus on its synthetic biology programs, which are being developed in partnership with Intrexon Corporation (“Intrexon”) (see Notes 6 and 7). Pursuant to the workforce reduction plan, the Company eliminated a total of 65 positions, comprised of 40 filled positions and 25 unfilled positions across various functions and locations. Employees whose positions were eliminated as part of the plan were notified beginning on April 2, 2013. Affected employees were offered separation benefits, including severance payments, and temporary healthcare coverage assistance. In connection with the elimination of filled positions as part of the workforce reduction plan, the Company incurred charges of $1.7 million during the second quarter of 2013, primarily for one-time contractual severance benefits.

On August 30, 2013, the Company entered into a sublease agreement to lease 5,249 square feet in the Company’s Boston office 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 $42 thousand during the year ended December 31, 2013, representing the remaining contractual obligation of $367 thousand, less $325 thousand in payments from the subtenant. The Company retired assets in this subleased area as a result of this sublease with a net book value of $194 thousand, and recorded a loss on disposal of fixed assets for the same amount in the year ended December 31, 2013.

On October 17, 2013, the Company entered into a sublease agreement to lease 7,259 square feet in the Company’s New York office 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 the subtenant. The Company retired assets in this subleased area 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 a $388 thousand letter of credit. The collateral for the letter of credit is recorded in other non-current assets on the balance sheet as of March 31, 2014.

Fair Value Measurements

3 Months Ended

Mar. 31, 2014

Fair Value Measurements

4. Fair Value Measurements

The Company accounts for its financial assets and liabilities using fair value measurements. The accounting standard defines fair value, establishes a framework for measuring fair value under generally accepted accounting principles and enhances disclosures about fair value measurements. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The standard describes a fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable, that may be used to measure fair value which are the following:

•

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 March 31, 2014 and December 31, 2013 are as follows:


($ in thousands)			Fair Value Measurements at Reporting Date Using
Description	Balance as of March 31, 2014		Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)

Cash equivalents	$	57,887	$	57,887	$	—	$	—


Warrant liability	$	11,694	$	—	$	11,694	$	—


($ in thousands)			Fair Value Measurements at Reporting Date Using
Description	Balance as of December 31, 2013		Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)

Cash equivalents	$	66,974	$	66,974	$	—	$	—


Warrant liability	$	11,776	$	—	$	11,776	$	—

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. The Company’s Level 2 financial liabilities consist of long-term investor and placement agent warrants issued in connection with its December 2009 public offering. The warrants were valued using Binomial/Monte Carlo valuation models. See Note 8 for additional disclosures on the valuation methodology and significant assumptions.

Net Loss per Share

3 Months Ended

Mar. 31, 2014

Net Loss per Share

5. Net Loss per Share

Basic net loss per share is computed by dividing net loss by the weighted average number of shares of common stock outstanding for the period. The Company’s potential dilutive shares, which include outstanding common stock options, unvested restricted stock and warrants, have not been included in the computation of diluted net loss per share for any of the periods presented as the result would be anti-dilutive. Such potential shares of common stock at March 31, 2014 and 2013 consist of the following:


	March 31,
	2014		2013
Stock options		6,159,828		6,743,835
Unvested restricted common stock		296,406		602,068
Warrants		10,539,767		11,148,139

		16,996,001		18,494,042

Related Party Transactions

3 Months Ended

Mar. 31, 2014

Related Party Transactions

6. Related Party Transactions

On January 6, 2011, the Company entered into an Exclusive Channel Partner Agreement, or Channel Agreement, with Intrexon (see Note 7 to the financial statements, Commitments and Contingencies, for additional disclosure relating to the Channel Agreement). Our director, Randall J. Kirk, is the CEO, a director, and the largest stockholder of Intrexon. During the year ended December 31, 2012, the Company paid Intrexon approximately $11.4 million, of which $6.6 million was for services already incurred and the remaining $4.8 million was for services expected to be incurred within a year. This amount was included as part of prepaid expenses and other current assets on the balance sheet as of December 31, 2012. During the year ended December 31, 2013, the Company expensed $7.8 million for services performed by Intrexon, of which $4.8 million was applied to the prepaid balance in other current assets, $2.4 million was paid to Intrexon and $0.6 million was recorded in accrued expenses. As of December 31, 2013, the prepaid balance in other current assets on the accompanying balance sheet has been reduced to $0. For the three months ended March 31, 2014, the Company expensed $1.7 million for services performed by Intrexon, of which $0.5 million is included in accrued expenses at March 31, 2014.

On January 25, 2012, Intrexon purchased 1,923,075 shares of common stock in the Company’s public offering.

On November 7, 2012, the Company issued 3,636,926 shares of common stock to Intrexon under the terms of its Stock Purchase Agreement with Intrexon dated January 6, 2011.

On October 13, 2013, Intrexon purchased 2,857,143 shares of common stock in the Company’s public offering.

- Definition

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

+ References + Details

Commitments and Contingencies

3 Months Ended

Mar. 31, 2014

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, consisting of 6,251 square feet of 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 1,008 square feet of office space. As of December 31, 2012, the Company occupied 7,259 square feet of space in New York, NY, and maintained a $388 thousand letter of credit. The collateral for the letter of credit is recorded in other non-current assets on the balance sheet as of December 31, 2012. The lease for office space in New York, NY expires in October 2018.

Prior to December 31, 2012, the Company entered into separate operating lease agreements for various spaces in a building in Boston, MA. That space consisted of 5,249 square feet on the first floor, 8,538 square feet on the second floor, and 6,959 square feet on the third floor. In June 2012, the Company re-negotiated a master lease for the entire Boston office space, added 9,800 square feet of office space on the fourth floor, surrendered 4,113 square feet from the second floor, and incorporated all floors’ lease agreements under the same master agreement expiring in August 2016. The Company provided an additional $41 thousand security deposit for the additional space on the fourth floor. As of December 31, 2012, a total security deposit of $127 thousand was paid to its landlord for security deposits for these agreements.

On August 30, 2013, the Company entered into a sublease agreement to lease 5,249 square feet in the Company’s Boston office 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 $42 thousand for the year ended December 31, 2013, representing the remaining contractual obligation of $367 thousand, less $325 thousand in payments from the subtenant. The Company retired assets in this subleased area as a result of this sublease with a net book value of $194 thousand, and recorded a loss on disposal of fixed assets. In accordance with the sublease agreement, the subtenant provided the Company with a security deposit of $20 thousand, which is recorded in other non-current assets and other liabilities on the balance sheet on March 31, 2014. The sublease expires in August 2016.

As of March 31, 2014, the Company occupies 21,184 square feet of space in its Boston, MA office and has paid a total of $127 thousand for security deposits, which are recorded in other non-current assets on the balance sheet.

Total rent expense was approximately $167 thousand, $289 thousand, and $5.4 million for the three months ended March 31, 2014, 2013, and from September 9, 2003 (date of inception) to March 31, 2014, respectively.

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 March 31, 2014 and 2013 of $1 million ($224 thousand current and $792 long-term) and $442 thousand ($58 thousand current and $384 thousand long-term), respectively, which is recorded in deferred rent on the balance sheet.

License Agreements Patent and Technology License Agreement—The University of Texas M. D. 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 The Board of Regents of the University of Texas System, acting on behalf of The University of Texas M. D. Anderson Cancer Center 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) for the manufacture and commercialization of two classes of organic arsenicals (water- and lipid-based) for human and animal use. The class of water-based organic arsenicals includes darinaparsin.

As partial consideration for the license rights obtained, the Company made an upfront payment in 2004 of $125 thousand and granted the Licensors 250,487 shares of the Company’s common stock. In addition, the Company issued options to purchase an additional 50,222 shares outside the 2003 Stock Option Plan for $0.002 per share following the successful completion of certain clinical milestones, which vested with respect to 12,555 shares upon the filing of an Investigation New Drug application, or IND, for darinaparsin in 2005 and vested with respect to another 25,111 shares upon the completion of dosing of the last patient for both Phase 1 clinical trials in 2007. The Company recorded $120 thousand of stock based compensation expense related to the vesting in 2007. The remaining 12,556 shares will vest 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. In addition, the Licensors are entitled to receive certain milestone payments, including $100 thousand that was paid in 2005 upon the commencement of Phase 1 clinical trial and $250 thousand that was paid in 2006 upon the dosing of the first patient in the Registrant-sponsored Phase 2 clinical trial for darinaparsin. 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. In addition, the Company also paid the Licensors $100 thousand in 2006 and 2007 to conduct scientific research with the Company obtaining exclusive right to all resulting intellectual property rights. The sponsored research agreements governing this research and any related extensions expired in February 2008 with no payments being made subsequent to that date.

The license agreement also contains other provisions customary and common in similar agreements within the industry, such as the right to sublicense the Company rights under the agreement. However, if the Company sublicenses its rights prior to the commencement of a pivotal study i.e. a human clinical trial intended to provide the substantial evidence of efficacy necessary to support the filing of an approvable NDA, the Licensors will be entitled to receive a share of the payments received by the Company in exchange for the sublicense (subject to certain exceptions). The term of the license agreement extends until the expiration of all claims under patents and patent applications associated with the licensed technology, subject to earlier termination in the event of defaults by the Company or the Licensors under the license agreement, or if the Company becomes bankrupt or insolvent. No milestones under the license agreement were reached or expensed during the three months ended March 31, 2014 or during the years ended December 31, 2013, 2012 or 2011.

License Agreement with DEKK-Tec, Inc.

On October 15, 2004, the Company entered into a license agreement with DEKK-Tec, Inc., pursuant to which it was granted an exclusive, worldwide license for palifosfamide. As part of the signing of license agreement with DEKK-Tec, the Company expensed an upfront $50 thousand payment to DEKK-Tec in 2004.

In consideration for the license rights, DEKK-Tec is entitled to receive payments upon achieving certain milestones in varying amounts which on a cumulative basis may total $4.0 million. Of the aggregate milestone payments, most will be creditable against future royalty payments as referenced below. The Company expensed a $100 thousand milestone payment upon achieving Phase 2 milestones during the year ended December 31, 2006. Additionally, in 2004 the Company issued DEKK-Tec an option to purchase 27,616 shares of the Company’s common stock for $0.02 per share. Upon the execution of the license agreement, 6,904 shares vested and were subsequently exercised in 2005 and the remaining options will vest upon certain milestone events, culminating with final FDA approval of the first NDA submitted by the Company (or by its sublicensee) for palifosfamide. DEKK-Tec is entitled to receive single digit percentage royalty payments on the sales of palifosfamide should it be approved for commercial sale. On March 16, 2010, the Company expensed a $100 thousand milestone payment upon receiving a United States Patent for palifosfamide. There were no payments made during 2009. In December 2010, the Company expensed a $300 thousand milestone payment and vested 6,904 stock options upon achieving Phase 3 milestones. These options were subsequently exercised in 2011. The Company’s obligation to pay royalties will terminate on a country-by-country basis upon the expiration of all valid claims of patents in such country covering licensed product, subject to earlier termination in the event of defaults by the parties under the license agreement. No milestones under the license agreement have been reached or expensed since 2010.

Option Agreement with Southern Research Institute (“SRI”)

On December 22, 2004, the Company entered into an Option Agreement with the Southern Research Institute, or SRI, pursuant to which the Company was granted an exclusive option to obtain an exclusive license to SRI’s interest in certain intellectual property, including exclusive rights related to certain isophosphoramide mustard analogs.

Also on December 22, 2004, the Company entered into a Research Agreement with SRI pursuant to which the Company agreed to spend a sum not to exceed $200 thousand between the execution of the agreement and December 21, 2006, including a $25 thousand payment that was made simultaneously with the execution of the agreement, to fund research and development work by SRI in the field of isophosphoramide mustard analogs. The option agreement was exercised on February 13, 2007. Under the license agreement entered into upon exercise of the option, the Company is required to remit minimum annual royalty payments of $25 thousand until the first commercial sale of a licensed product. These payments were made for the years ended December 31, 2013, 2012, 2011, 2010, 2009 and 2008. Additionally, no payments have been made for the three months ended March 31, 2014. The Company may be required to make payments upon achievement of certain milestones in varying amounts which on a cumulative basis could total up to $775,000. In addition, SRI will be entitled to receive single digit percentage royalty payments on the sales of a licensed product in any country until all licensed patents rights in that country which are utilized in the product have expired. No milestones under the license agreement were reached or expensed since the agreement’s inception.

License Agreement with Baxter Healthcare Corporation

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. The terms of the Asset Purchase Agreement included an upfront cash payment of approximately $1.1 million and an additional $100 thousand payment for existing inventory, both of which were expensed in 2006. In addition to the upfront costs, the Asset Purchase Agreement includes additional diligence and milestone payments that could amount to approximately $8 million in the aggregate and royalties on net sales of products covered by a valid claim of a patent for the life of the patent on a country-by-country basis. The Company expensed a $625 thousand milestone payment upon the successful U.S. IND application for indibulin in 2007. The License Agreement requires payment of a $15 thousand annual patent and license prosecution/maintenance fee through the expiration of the last of the licensed patents which is expected to expire in 2025, and single digit royalties on net sales of licensed products covered by a valid claim of a patent for the life of the patent on a country-by-country basis. The term of the license agreement extends until the expiration of the last to expire of the patents covering the licensed products, subject to earlier termination in the event of defaults by the parties under the license agreement.

In October 2009, the Baxter License Agreement was amended to allow the Company to manufacture indibulin. No milestones under the license agreement were reached or expensed during the years ended December 31, 2011 or 2010. During each of the years ended December 31, 2013 and 2012, milestones of $250 thousand were reached and expensed. No milestones have been met during the three months ended March 31, 2014.

Exclusive Channel Partner Agreement with Intrexon Corporation

On January 6, 2011, the Company entered into an Exclusive Channel Partner Agreement, or the Channel Agreement, with Intrexon that governs a “channel partnering” arrangement in which the Company uses Intrexon’s technology directed towards in vivo expression of effectors in connection with the development of Ad-RTS-IL-12 + veledimex and DC-RTS-IL-12 + veledimex and generally to research, develop and commercialize products, in each case 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. The Channel Agreement establishes committees comprised of representatives of ZIOPHARM 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 the Company collectively refers 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. Subject to limited exceptions, the Company may not sublicense the rights described without Intrexon’s written consent.

Under the Channel Agreement, and subject to certain exceptions, the Company is responsible for, among other things, the performance of the Cancer Program, including development, commercialization and certain aspects of manufacturing of ZIOPHARM Products. Intrexon is responsible for the costs of 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.

Subject to certain expense allocations and other offsets provided in the Channel Agreement, the Company will pay Intrexon on a quarterly basis 50% of net profits derived in that quarter from the sale of ZIOPHARM Products, calculated on a ZIOPHARM Product-by- ZIOPHARM Product basis. The Company has likewise agreed to pay Intrexon on a quarterly basis 50% of revenue obtained in that quarter from a sublicensor in the event of a sublicensing arrangement. In addition, in partial consideration for each party’s execution and delivery of the Channel Agreement, the Company entered into a Stock Purchase Agreement with Intrexon.

Following the first 24 months of the agreement, Intrexon had the option to terminate the Channel Agreement, if the Company failed to use diligent efforts to develop and commercialize ZIOPHARM Products or if the Company elected not to pursue the development of a Cancer Program identified by Intrexon that is a “Superior Therapy” as defined in the Channel Agreement. Also following the first 24 months of the agreement, the Company had the option to voluntarily terminate the Channel Agreement, upon 90 days written notice to Intrexon. The 24 month termination period expired during the year ended December 31, 2013.

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 the Company’s election not to pursue development of a Superior Therapy).

The Company’s obligation to pay 50% of net profits or revenue described above with respect to these “retained” products will survive termination of the Channel Agreement.

Collaboration Agreement with Harmon Hill, LLC

On April 8, 2008, the Company signed a collaboration agreement for Harmon Hill, LLC, or Harmon Hill, to provide consulting and other services for the development and commercialization of oncology therapeutics by ZIOPHARM. Under the agreement the Company has agreed to pay Harmon Hill $20 thousand per month for the consulting services and has further agreed to pay Harmon Hill (a) $500 thousand upon the first patient dosing of the Specified Drug, as defined in the collaboration agreement, in a pivotal trial, which trial uses a dosing Regime introduced by Harmon Hill; and (b) provided that the Specified Drug receives regulatory approval from the FDA, the European Medicines Agency or another regulatory agency for the marketing of the Specified Drug, a 1% royalty of the Company’s net sales will be awarded to Harmon Hill.

If the Specified Drug is sublicensed to a third party, the agreement entitles Harmon Hill to 1% award of royalties or other payments received from a sublicense. Subject to renewal or extension by the parties, the term of the agreement was for a one year period that expired April 8, 2009. Following such expiration, the parties continued to operate under the terms of the agreement and, during 2010, the agreement was formally extended through April 8, 2011 and again through April 8, 2012. The agreement was extended through November 8, 2012 and has now expired. The Company expensed $240 thousand during the years ended December 31, 2011 and 2010 and expensed $200 thousand during the year ended December 31, 2012 for consulting services per the aforementioned agreement. No milestones under the collaboration agreement were reached or expensed during the years ended December 31, 2013, 2012, 2011 or 2010.

On June 27, 2013, the Company signed a new collaboration agreement with Harmon Hill to provide consulting and other services for the development and commercialization of oncology therapeutics by ZIOPHARM, effective April 1, 2013. Under the agreement the Company has agreed to pay Harmon Hill $15 thousand per month for the consulting services. Subject to renewal or extension by the parties, the term of the agreement is for a one year period. The Company expensed $135 thousand for the year ended December 31, 2013. The Company expensed $45 thousand for the three months ended March 31, 2014.

Collaboration Agreement with Solasia Pharma K.K.

On March 7, 2011, the Company entered into a License and Collaboration Agreement with Solasia Pharma K.K., or 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 territory comprised of Japan, China, Hong Kong, Macau, Republic of Korea, Taiwan, Singapore, Australia, New Zealand, Malaysia, Indonesia, Philippines and Thailand.

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 territory, and will be entitled to receive additional payments of up to $32.5 million in development-based milestones and up to $53.5 million in sales-based milestones. The Company will also be entitled to receive double digit royalty payments from Solasia based upon net sales of licensed products in the applicable territories, once commercialized, and a percentage of sublicense revenues generated by Solasia.

The upfront payment for research and development funding is earned over the period of effort. The Company currently estimates this period to be 75 months, which could be adjusted in the future.

Under the License and Collaboration Agreement, the Company provides Solasia with drug product to conduct clinical trials. These transfers are accounted for as a reduction of research and development costs and an increase in collaboration receivables.

The agreement provides that Solasia will be responsible for the development and commercialization of darinaparsin in the pan-Asian/Pacific territory.

CRO Services Agreement with PPD Development, L. P.

The Company is party to a Master Clinical Research Organization Services Agreement with PPD Development, L. P., or PPD, dated January 29, 2010, a related work order dated June 25, 2010 and a related work order dated April 8, 2011 under which PPD provides clinical research organization, or CRO, services in support of the Company’s clinical trials. PPD is entitled to cumulative payments of up to $20.0 million under these arrangements, which is payable by the Company in varying amounts upon PPD achieving specified milestones. During the year ended December 31, 2010, the Company expensed $1.8 million upon contract execution and $1.1 million upon a clinical study commencement of enrollment in North America. During the year ended December 31, 2011, additional milestones related to commencing enrollment in Europe, Latin America and Asia along with enrollment based milestones were met and the Company recorded an aggregate $4.0 million expense. During the year ended December 31, 2012, additional enrollment-based and contract modification milestones were met and expensed totaling $3.8 million. During the year ended December 31, 2013, patient progression and data based milestones totaling $9.2 million were met and expensed. There are no remaining milestones on this agreement.

CRO Services Agreement with Pharmaceutical Research Associates, Inc.

On December 13, 2011, the Company entered into a Master Clinical Research Organization Services Agreement with Pharmaceutical Research Associates, Inc., or PRA, under which PRA provides CRO services in support of our clinical trials. PRA is entitled to cumulative payments of up to $9.5 million under these arrangements, which is payable by the Company in varying amounts upon PRA achieving specified milestones. During the year ended December 31, 2012, the Company expensed $7.3 million upon the achievement of various letter of intent and enrollment-based milestones. During the year ended December 31, 2013, contract modification and patient enrollment based milestones totaling $2.2 million were met and expensed. There are no remaining milestones on this agreement.

CRO Services Agreement with Novella Clinical, Inc.

On December 4, 2008, the Company entered into a Master Clinical Research Organization Services Agreement with Novella Clinical, Inc., or Novella, under which PRA provides CRO services in support of our clinical trials. The work order for the newest trial being conducted by Novella was signed on November 2, 2012. Novella is entitled to cumulative payments of up to $790 thousand under these arrangements, which is payable in varying amounts upon Novella achieving specified milestones. During the year ended December 31, 2012, the Company expensed $256 thousand upon the achievement of various milestones. During the year ended December 31, 2013, two database related milestones and one site activation related milestone were met and expensed totaling $136 thousand. During the three months ended March 31, 2014, one clinical milestone was met and expensed totaling $10 thousand.

Warrants

3 Months Ended

Mar. 31, 2014

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 the binomial valuation model.

The number of warrants outstanding at March 31, 2014 and December 31, 2013 were as follows:


	March 31,		December 31,
	2014		2013

Liability-classified warrants		8,235,076		8,235,076
Equity-classified warrants		2,304,691		2,304,691


Total warrants		10,539,767		10,539,767

Liability-Classified Warrants

In May 2005, the Company issued 419,786 warrants to placement agents for services performed in connection with a 2005 private placement (the “2005 Warrants”), 11,083 of which were subsequently exercised. The remaining 408,703 warrants were originally valued at $1.6 million. Subject to certain exceptions, the 2005 Warrants provide for anti-dilution protection should common stock or common stock equivalents be subsequently issued at a price less than the exercise price of the 2005 Warrants then in effect, which was initially $4.75 per share. This provision was triggered when the Company sold stock in a 2006 private placement at $4.63 per share. Accordingly, the 2005 Warrants were re-priced at $4.69. The provision was triggered a second time upon completion of a 2009 private placement in which the Company sold stock at $1.825 per share and issued common stock purchase warrants with an exercise price of $2.04, and the 2005 Warrants were re-priced at $4.25. The provision was triggered again when the Company sold stock in a December 2009 public offering at $3.10 per share and the 2005 Warrants were re-priced at $3.93 per share. Of the total warrant tranche, 419,207 were exercised and the remaining 579 expired on May 31, 2012.

Also, in connection with its December 2009 public securities 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 for the offering) (the “2009 Warrants”). The 2009 Warrants issued to investors were exercisable immediately and the warrants issued to underwriters became exercisable six months after the date of issuance. The 2009 Warrants have an exercise price of $4.02 per share and have a five-year term. The fair value of the 2009 Warrants was estimated at $22.9 million using a Black-Scholes model with the following assumptions: expected volatility of 105%, risk free interest rate of 2.14%, expected life of five years and no dividends.

Subject to certain exceptions, these warrants provide for anti-dilution protection should common stock or common stock equivalents be subsequently issued at a price less than the exercise price of the warrants then in effect, which was initially $4.02 per share. This provision was triggered in 2013 when stock was sold at $3.50 per share in our 2013 public offering. Accordingly, the outstanding warrants were increased by 184,367 warrants to 8,235,076 warrants.

The Company assessed whether the 2005 Warrants and the 2009 Warrants require accounting as derivatives. The Company determined that these warrants were not indexed to the Company’s own stock in accordance with accounting standards codification Topic 815, Derivatives and Hedging. As such, the Company has concluded these warrants did not meet the scope exception for determining whether the instruments require accounting as derivatives and were classified as liabilities.

The Company uses the Binomial/Monte Carlo pricing model to estimate the value of the liability-classified warrants. The following assumptions were used in the Binomial/Monte Carlo valuation model at March 31, 2014 and 2013:


	March 31, 2014			March 31, 2013

Risk-free interest rate		0.11	%		0.25	%
Expected life in years		0.69			1.69
Expected volatility		80	%		70	%
Expected dividend yield		0			0
Steps per year		13			12

The change in the fair value of the warrant liability resulted in a gain of $82 thousand for the three months ended March 31, 2014, respectively. The change in the fair value of the warrant liability resulted in a gain of $10.8 million for the three months ended March 31, 2013. The change in the fair value of the warrant liability was charged to other income (expense) in the Statements of Operations.

There were no warrant exercises during the three months ended March 31, 2014.

During the three months ended March 31, 2013, warrant exercises were as follows:


(in thousands, except share data)	Equity Warrants		Liability Warrants		Common Stock Issued		Liability Reclassed Equity		Cash Received

Cash exercises		49,315		—		49,315	$	—	$	101
Cashless exercises		—		—		—		—		—

		49,315		—		49,315	$	—	$	101

Common Stock

3 Months Ended

Mar. 31, 2014

Common Stock

9. Common Stock

On October 23, 2013, 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 14,300,000 shares of our common stock. The price to the public in the offering was $3.50 per share, and the underwriters agreed to purchase the shares from the Company pursuant to the underwriting agreement at a purchase price of $3.29 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 2,145,000 shares of common stock at a purchase price of $3.29 per share, and the underwriters elected to exercise such option in full. The offering was made pursuant to the Company’s effective registration statement on Form S-3 (Registration Statement No. 333-177793) previously filed with the SEC, and a prospectus supplement thereunder. The underwriters purchased the 14,300,000 shares and the additional 2,145,000 shares on October 29, 2013. The net proceeds from the offering were approximately $53.9 million after deducting underwriting discounts and estimated offering expenses payable by the Company.

Stock-Based Compensation

3 Months Ended

Mar. 31, 2014

Stock-Based Compensation

10. Stock-Based Compensation

The Company recognized stock-based compensation expense on all employee and non-employee awards as follows:


	For the three months ended March 31,
(in thousands)	2014		2013

Research and development	$	376	$	537
General and administrative		847		1,004

Stock-based employee compensation expense	$	1,223	$	1,541

The Company granted 80,500 and 110,900 stock options during the three ended March 31, 2014 and 2013 that had a weighted-average grant date fair value of $3.34 and $3.32 per share, respectively.

At March 31, 2014, total unrecognized compensation costs related to unvested stock options outstanding amounted to $7.1 million. The cost is expected to be recognized over a weighted-average period of 1.68 years.

On May 31, 2013, the Company extended the contractual life of 66,667 fully vested stock options held by one employee from 3 to 12 months.

On June 14, 2013, the Company extended the contractual life of 71,167 fully vested stock options held by one employee from 3 to 12 months.

On March 31, 2014, the Company extended the contractual life of 71,167 fully vested stock options held by one employee by an additional 9 months.

For the three months ended March 30, 2014 and 2013, the fair value of stock options was estimated on the date of grant using a Black-Scholes option valuation model with the following assumptions:


	For the three months ended March 31,
	2014	2013

Risk-free interest rate	1.76 - 2.11%	1.0 - 1.15%
Expected life in years	6	6
Expected volatility	94.46 - 94.55%	83.40 - 83.69%
Expected dividend yield	0	0

Stock option activity under the Company’s stock option plan for the three months ended March 31, 2014 is as follows:


(in thousands, except share and per share data)	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Contractual Term (Years)		Aggregate Intrinsic Value

Outstanding, December 31, 2013		6,747,302		$	3.81

Granted		80,500			4.36
Exercised		(479,705	)		2.02
Cancelled		(188,269	)		5.10


Outstanding, March 31, 2014		6,159,828		$	3.92		7.45	$	6,459


Vested and unvested expected to vest at March 31, 2014		6,105,689		$	4.28		5.37	$	5,845


Options exercisable, March 31, 2014		2,843,928		$	4.28		5.37	$	1,810


Options exercisable, December 31, 2013		3,471,935		$	4.01		5.03	$	2,654


Options available for future grant		338,631

A summary of the status of unvested restricted stock for the three months ended March 31, 2014 is as follows:


	Number of Shares			Weighted-Average Grant Date Fair Value

Non-vested, December 31, 2013		352,865		$	4.38
Granted		—			—
Vested		(48,433	)		4.51
Cancelled		(8,026	)		4.41


Non-vested, March 31, 2014		296,406		$	4.36

At March 31, 2014, total unrecognized compensation costs related to unvested restricted stock outstanding amounted to $0.9 million. The cost is expected to be recognized over a weighted-average period of 1.10 years.

Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2014

Assets and Liabilities Measured at Fair Value on Recurring Basis

Assets and liabilities measured at fair value on a recurring basis as of March 31, 2014 and December 31, 2013 are as follows:


($ in thousands)			Fair Value Measurements at Reporting Date Using
Description	Balance as of March 31, 2014		Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)

Cash equivalents	$	57,887	$	57,887	$	—	$	—


Warrant liability	$	11,694	$	—	$	11,694	$	—


($ in thousands)			Fair Value Measurements at Reporting Date Using
Description	Balance as of December 31, 2013		Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)

Cash equivalents	$	66,974	$	66,974	$	—	$	—


Warrant liability	$	11,776	$	—	$	11,776	$	—

Net Loss per Share (Tables)

3 Months Ended

Mar. 31, 2014

Potential Dilutive Shares Excluded from Computation of Diluted Net Loss Per Share

The Company’s potential dilutive shares, which include outstanding common stock options, unvested restricted stock and warrants, have not been included in the computation of diluted net loss per share for any of the periods presented as the result would be anti-dilutive. Such potential shares of common stock at March 31, 2014 and 2013 consist of the following:


	March 31,
	2014		2013
Stock options		6,159,828		6,743,835
Unvested restricted common stock		296,406		602,068
Warrants		10,539,767		11,148,139

		16,996,001		18,494,042

Warrants (Tables)

3 Months Ended

Mar. 31, 2014

Number of Warrants Outstanding

The number of warrants outstanding at March 31, 2014 and December 31, 2013 were as follows:


	March 31,		December 31,
	2014		2013

Liability-classified warrants		8,235,076		8,235,076
Equity-classified warrants		2,304,691		2,304,691


Total warrants		10,539,767		10,539,767

Assumptions Used in Binomial and Monte Carlo Valuation Model

The following assumptions were used in the Binomial/Monte Carlo valuation model at March 31, 2014 and 2013:


	March 31, 2014			March 31, 2013

Risk-free interest rate		0.11	%		0.25	%
Expected life in years		0.69			1.69
Expected volatility		80	%		70	%
Expected dividend yield		0			0
Steps per year		13			12

Warrant Exercises

During the three months ended March 31, 2013, warrant exercises were as follows:


(in thousands, except share data)	Equity Warrants		Liability Warrants		Common Stock Issued		Liability Reclassed Equity		Cash Received

Cash exercises		49,315		—		49,315	$	—	$	101
Cashless exercises		—		—		—		—		—

		49,315		—		49,315	$	—	$	101

- Definition

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

+ References + Details

Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2014

Stock-Based Compensation Expense on All Employee and Non-Employee Awards

The Company recognized stock-based compensation expense on all employee and non-employee awards as follows:


	For the three months ended March 31,
(in thousands)	2014		2013

Research and development	$	376	$	537
General and administrative		847		1,004

Stock-based employee compensation expense	$	1,223	$	1,541

Fair Value of Stock Options Assumptions Using Black-Scholes Option Valuation Model

For the three months ended March 30, 2014 and 2013, the fair value of stock options was estimated on the date of grant using a Black-Scholes option valuation model with the following assumptions:


	For the three months ended March 31,
	2014	2013

Risk-free interest rate	1.76 - 2.11%	1.0 - 1.15%
Expected life in years	6	6
Expected volatility	94.46 - 94.55%	83.40 - 83.69%
Expected dividend yield	0	0

Stock Option Activity Under Stock Option Plan

Stock option activity under the Company’s stock option plan for the three months ended March 31, 2014 is as follows:


(in thousands, except share and per share data)	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Contractual Term (Years)		Aggregate Intrinsic Value

Outstanding, December 31, 2013		6,747,302		$	3.81

Granted		80,500			4.36
Exercised		(479,705	)		2.02
Cancelled		(188,269	)		5.10


Outstanding, March 31, 2014		6,159,828		$	3.92		7.45	$	6,459


Vested and unvested expected to vest at March 31, 2014		6,105,689		$	4.28		5.37	$	5,845


Options exercisable, March 31, 2014		2,843,928		$	4.28		5.37	$	1,810


Options exercisable, December 31, 2013		3,471,935		$	4.01		5.03	$	2,654


Options available for future grant		338,631

Summary of Unvested Restricted Stock

A summary of the status of unvested restricted stock for the three months ended March 31, 2014 is as follows:


	Number of Shares			Weighted-Average Grant Date Fair Value

Non-vested, December 31, 2013		352,865		$	4.38
Granted		—			—
Vested		(48,433	)		4.51
Cancelled		(8,026	)		4.41


Non-vested, March 31, 2014		296,406		$	4.36

Business - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2014	Dec. 31, 2013
Nature Of Operations [Line Items]
Accumulated deficit	$ 350,542	$ 340,831

Restructuring - Additional Information (Detail) $ in Thousands	1 Months Ended		3 Months Ended	12 Months Ended	127 Months Ended
	Oct. 17, 2013 ft²	Aug. 30, 2013 ft²	Jun. 30, 2013 USD ($)	Dec. 31, 2013 USD ($)	Mar. 31, 2014 USD ($)	Apr. 03, 2013 Position	Dec. 31, 2012 USD ($)	Dec. 31, 2011 USD ($)
Restructuring Cost and Reserve [Line Items]
Total charges incurred related to workforce reduction			$ 1,700
Number of positions eliminated \| Position						65
Loss on disposal of fixed assets					$ (641)
Filled positions
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated \| Position						40
Unfilled positions
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated \| Position						25
Boston, MA
Restructuring Cost and Reserve [Line Items]
Area under sublease agreement \| ft²		5,249
Loss on sublease				$ 42
Remaining contractual obligation				367
Sublease revenue from subtenant				325
Loss on disposal of fixed assets				(194)
New York, NY
Restructuring Cost and Reserve [Line Items]
Area under sublease agreement \| ft²	7,259
Loss on sublease				729
Remaining contractual obligation				2,300
Sublease revenue from subtenant				1,600
Loss on disposal of fixed assets				$ (392)
Letter of credit					$ 388		$ 388	$ 388

Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Mar. 31, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 57,887	$ 66,974
Warrant liability	11,694	11,776
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	57,887	66,974
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant liability	$ 11,694	$ 11,776

Potential Dilutive Shares Excluded from Computation of Diluted Net Loss Per Share (Detail) - shares	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	16,996,001	18,494,042
Stock Option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	6,159,828	6,743,835
Restricted Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	296,406	602,068
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	10,539,767	11,148,139

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended	12 Months Ended
	Oct. 13, 2013	Nov. 07, 2012	Jan. 25, 2012	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Related Party Transaction [Line Items]
Prepaid expenses and other current assets				$ 1,589	$ 1,948
Intrexon Corporation
Related Party Transaction [Line Items]
Payments for services				1,700	2,400	$ 11,400
Amounts paid for services incurred					7,800	6,600
Prepaid expenses and other current assets					0	$ 4,800
Accrued expense				$ 500	$ 600
Stock issued during period	2,857,143	3,636,926	1,923,075

Commitments and Contingencies - Additional Information (Detail)	1 Months Ended										3 Months Ended		12 Months Ended										24 Months Ended	127 Months Ended
	Oct. 17, 2013 ft²	Aug. 30, 2013 ft²	Jun. 27, 2013 USD ($)	Mar. 07, 2011 USD ($)	Jan. 06, 2011	Mar. 16, 2010 USD ($)	Apr. 08, 2008 USD ($)	Nov. 03, 2006 USD ($)	Oct. 15, 2004 USD ($)	Aug. 24, 2004 Patent	Mar. 31, 2014 USD ($) ft² shares	Mar. 31, 2013 USD ($) shares	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($) ft²	Dec. 31, 2011 USD ($) ft² shares	Dec. 31, 2010 USD ($) shares	Dec. 31, 2009 USD ($)	Dec. 31, 2008 USD ($)	Dec. 31, 2007 USD ($) shares	Dec. 31, 2006 USD ($)	Dec. 31, 2005 USD ($) shares	Dec. 31, 2004 USD ($) $ / shares shares	Dec. 22, 2006 USD ($)	Mar. 31, 2014 USD ($) ft² shares	Nov. 02, 2012 USD ($)	Jun. 30, 2012 USD ($) ft²	Jan. 31, 2012 ft²	Jan. 29, 2010 USD ($)
Commitments and Contingencies Disclosure [Line Items]
Loss on disposal of fixed assets																								$ (641,000)
Total rent Expense											$ 167,000	$ 289,000												5,400,000
Deferred rent - current portion											224,000	58,000	$ 212,000											224,000
Deferred rent - non-current portion											792,000	384,000	851,000											792,000
Deferred rent liability net											$ 1,000,000	$ 442,000												1,000,000
Stock options, granted \| shares											80,500	110,900
Stock based compensation											$ 1,223,000	$ 1,541,000												24,911,000
Shares exercised \| shares											479,705
Research expenses											$ 6,542,000	$ 19,112,000												261,739,000
Milestones under the license agreement expense											0		$ 250,000	$ 250,000	$ 0	$ 0
Harmon Hill LLC \| Collaboration Agreement
Commitments and Contingencies Disclosure [Line Items]
Percent of company net profit													1.00%
Other expense											45,000		$ 135,000	200,000	$ 240,000	$ 240,000
Agreement term			1 year
Harmon Hill LLC \| Collaboration Agreement \| Upon the dosing of the first patient
Commitments and Contingencies Disclosure [Line Items]
Payment for consulting services fee							$ 500,000
Harmon Hill LLC \| Monthly Payment \| Collaboration Agreement
Commitments and Contingencies Disclosure [Line Items]
Payment for consulting services fee			$ 15,000				$ 20,000
Solasia
Commitments and Contingencies Disclosure [Line Items]
Upfront payment received				$ 5,000,000
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
The University of Texas M.D. Anderson Cancer Center and The Texas A & M University System
Commitments and Contingencies Disclosure [Line Items]
Number of products \| Patent										2
Stock options, granted \| shares																						250,487
Option to purchase common stock \| shares																						50,222
Sale of stock price per share \| $ / shares																						$ 0.002
Stock based compensation																			$ 120,000
Milestone maximum payment											$ 4,500,000													$ 4,500,000
The University of Texas M.D. Anderson Cancer Center and The Texas A & M University System \| Upon the commencement of Phase 1 clinical trial
Commitments and Contingencies Disclosure [Line Items]
Milestone payment																					$ 100,000
The University of Texas M.D. Anderson Cancer Center and The Texas A & M University System \| Upon the dosing of the first patient
Commitments and Contingencies Disclosure [Line Items]
Milestone payment																				$ 250,000
The University of Texas M.D. Anderson Cancer Center and The Texas A & M University System \| Intellectual Property Rights
Commitments and Contingencies Disclosure [Line Items]
Milestone payment																			$ 100,000	100,000
The University of Texas M.D. Anderson Cancer Center and The Texas A & M University System \| Upon the filing of an Investigation New Drug application (IND) for darinaparsin
Commitments and Contingencies Disclosure [Line Items]
Shares vested \| shares																					12,555
The University of Texas M.D. Anderson Cancer Center and The Texas A & M University System \| Upon the completion of dosing of the last patient for both Phase 1 clinical trials
Commitments and Contingencies Disclosure [Line Items]
Shares vested \| shares																			25,111
The University of Texas M.D. 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 expected to vest \| shares											12,556													12,556
The University of Texas M.D. Anderson Cancer Center and The Texas A & M University System \| Up Front Payment
Commitments and Contingencies Disclosure [Line Items]
Licensing fee																						$ 125,000
DEKK Tec Inc
Commitments and Contingencies Disclosure [Line Items]
Option to purchase common stock \| shares																						27,616
Sale of stock price per share \| $ / shares																						$ 0.02
Shares vested \| shares																						6,904
Milestone maximum payment									$ 4,000,000
Shares exercised \| shares																					6,904
DEKK Tec Inc \| Upon the dosing of the first patient
Commitments and Contingencies Disclosure [Line Items]
Milestone payment																				$ 100,000
DEKK Tec Inc \| Phase 3
Commitments and Contingencies Disclosure [Line Items]
Shares vested \| shares																6,904
Milestone payment																$ 300,000
Shares exercised \| shares															6,904
DEKK Tec Inc \| Upon receiving a United States Patent for palifosfamide
Commitments and Contingencies Disclosure [Line Items]
Milestone payment						$ 100,000
DEKK Tec Inc \| Up Front Payment
Commitments and Contingencies Disclosure [Line Items]
Licensing fee									$ 50,000
Southern Research Institute
Commitments and Contingencies Disclosure [Line Items]
Milestone maximum payment											$ 775,000													$ 775,000
Royalty payment											25,000			25,000	$ 25,000	25,000	$ 25,000	$ 25,000
Southern Research Institute \| Execution Agreement
Commitments and Contingencies Disclosure [Line Items]
Research expenses																							$ 25,000
Southern Research Institute \| Maximum
Commitments and Contingencies Disclosure [Line Items]
Research expenses																							$ 200,000
Baxter Healthcare Corporation
Commitments and Contingencies Disclosure [Line Items]
Asset Purchase Agreement, upfront cash payment								$ 1,100,000
Asset Purchase Agreement, additional cash payment for existing inventory								100,000
Annual patent and license prosecution/maintenance fee								15,000
Baxter Healthcare Corporation \| Upon the successful U.S. IND application for indibulin
Commitments and Contingencies Disclosure [Line Items]
Milestone payment																			$ 625,000
Baxter Healthcare Corporation \| Royalty Payments
Commitments and Contingencies Disclosure [Line Items]
Milestone maximum payment								$ 8,000,000
PPD Development L. P.
Commitments and Contingencies Disclosure [Line Items]
Milestone maximum payment																												$ 20,000,000
PPD Development L. P. \| Upon contract execution
Commitments and Contingencies Disclosure [Line Items]
Milestone payment															4,000,000	1,800,000
PPD Development L. P. \| Upon a clinical study commencement of enrollment in North America
Commitments and Contingencies Disclosure [Line Items]
Milestone payment																$ 1,100,000
PPD Development L. P. \| Upon initial clinical study enrollment
Commitments and Contingencies Disclosure [Line Items]
Milestone payment														3,800,000
PPD Development L. P. \| Upon the achievement of various milestones
Commitments and Contingencies Disclosure [Line Items]
Milestone payment													9,200,000
Novella Clinical, Inc.
Commitments and Contingencies Disclosure [Line Items]
Milestone maximum payment																									$ 790,000
Novella Clinical, Inc. \| Upon the achievement of various milestones
Commitments and Contingencies Disclosure [Line Items]
Milestone payment														256,000
Novella Clinical, Inc. \| Upon two database related milestones
Commitments and Contingencies Disclosure [Line Items]
Milestone payment											$ 10,000		136,000
Intrexon Corporation
Commitments and Contingencies Disclosure [Line Items]
Contract termination description											The Company's obligation to pay 50% of net profits or revenue described above with respect to these "retained" products will survive termination of the Channel Agreement.
Intrexon Corporation \| Quarterly Payment
Commitments and Contingencies Disclosure [Line Items]
Percent of company net profit					50.00%
Percentage of revenue agreed to pay which is obtained from sublicensor					50.00%
Pharmaceutical Research Associates Inc
Commitments and Contingencies Disclosure [Line Items]
Milestone maximum payment															$ 9,500,000
Pharmaceutical Research Associates Inc \| Upon the achievement of various milestones
Commitments and Contingencies Disclosure [Line Items]
Milestone payment													$ 2,200,000	$ 7,300,000
New York, NY
Commitments and Contingencies Disclosure [Line Items]
Office space under operating lease \| ft²														7,259	6,251
Letter of credit											$ 388,000			$ 388,000	$ 388,000									$ 388,000
Additional office space under operating lease \| ft²																											1,008
Operating lease expiration month and year													2018-10	2018-10
Area under sublease agreement \| ft²	7,259
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]
Office space under operating lease \| ft²											21,184													21,184
Operating lease expiration month and year															2016-08
Area under sublease agreement \| ft²		5,249
Loss on sublease													42,000
Remaining contractual obligation													367,000
Sublease revenue from subtenant													325,000
Loss on disposal of fixed assets													$ (194,000)
Security deposits											$ 127,000			$ 127,000										$ 127,000
Security deposit from subtenant											$ 20,000													$ 20,000
Boston, MA \| The first floor
Commitments and Contingencies Disclosure [Line Items]
Operating lease space \| ft²															5,249
Boston, MA \| The second floor
Commitments and Contingencies Disclosure [Line Items]
Office space under operating lease \| ft²																										4,113
Operating lease space \| ft²															8,538
Boston, MA \| The third floor
Commitments and Contingencies Disclosure [Line Items]
Operating lease space \| ft²															6,959
Boston, MA \| The four floor
Commitments and Contingencies Disclosure [Line Items]
Office space under operating lease \| ft²																										9,800
Security deposits																										$ 41,000

Number of Warrants Outstanding (Detail) - shares	Mar. 31, 2014	Dec. 31, 2013
Class of Warrant or Right [Line Items]
Warrant outstanding	10,539,767	10,539,767
Liability
Class of Warrant or Right [Line Items]
Warrant outstanding	8,235,076	8,235,076
Equity
Class of Warrant or Right [Line Items]
Warrant outstanding	2,304,691	2,304,691

Warrants - Additional Information (Detail) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended		12 Months Ended	127 Months Ended
	May 31, 2012 shares	May 31, 2005 USD ($) $ / shares shares	Mar. 31, 2014 USD ($) shares	Mar. 31, 2013 USD ($)	Dec. 31, 2009 USD ($) $ / shares $ / Right shares	Mar. 31, 2014 USD ($) shares	Dec. 31, 2013 $ / shares shares	Dec. 31, 2006 $ / shares
Class of Warrant or Right [Line Items]
Warrant exercised			0
Warrant outstanding			10,539,767			10,539,767	10,539,767
Warrants to purchase an aggregate of shares of common stock					8,206,520
Warrant term					5 years
Estimated fair value of warrant \| $					$ 22,900
Expected volatility					105.00%
Risk-free interest rate					2.14%
Expected life in years					5 years
Expected dividend yield					0.00%
Change in fair value of warrants \| $			$ 82	$ 10,788		$ 12,038
Liability
Class of Warrant or Right [Line Items]
Warrant outstanding			8,235,076			8,235,076	8,235,076
Warrants to purchase an aggregate of shares of common stock			184,367
J. P. Morgan Securities LLC
Class of Warrant or Right [Line Items]
Warrants issued					464,520
Warrant exercise price \| $ / shares					$ 4.02
Warrant exercisable Period					6 months
Private Placement
Class of Warrant or Right [Line Items]
Warrant issued		419,786
Warrant exercised	419,207	11,083
Warrant outstanding		408,703
Value of warrant issued \| $		$ 1,600
Sale of stock price per share \| $ / shares		$ 4.75			$ 1.825			$ 4.63
Revised price for warrants \| $ / shares		$ 4.69			$ 4.25
Common stock warrants, exercise price \| $ / Right					2.04
Warrant expired	579
Registered direct offering
Class of Warrant or Right [Line Items]
Sale of stock price per share \| $ / shares					$ 3.10		$ 3.5
Revised price for warrants \| $ / shares					$ 3.93

Assumptions Used In Binomial Valuation Model and Black-Scholes Valuation Model (Detail)	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2009
Class of Warrant or Right [Line Items]
Risk-free interest rate			2.14%
Expected volatility			105.00%
Expected dividend yield			0.00%
Expected life in years			5 years
Black Scholes Option Pricing Model
Class of Warrant or Right [Line Items]
Risk-free interest rate	0.11%	0.25%
Expected volatility	80.00%	70.00%
Expected dividend yield	0.00%	0.00%
Expected life in years	13 years	12 years
Black Scholes Option Pricing Model \| Minimum
Class of Warrant or Right [Line Items]
Expected life in years	8 months 9 days	1 year 8 months 9 days

Warrant Exercise (Detail) - USD ($) $ in Thousands	3 Months Ended		127 Months Ended
Warrant Exercise (Detail) - USD ($) $ in Thousands	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014
Class of Warrant or Right [Line Items]
Warrant exercised	0
Liability Reclassed Equity
Cash Received		$ 101	$ 13,278
Equity Warrants
Class of Warrant or Right [Line Items]
Warrant exercised		49,315
Common Stock Issued
Class of Warrant or Right [Line Items]
Warrant exercised		49,315
Cash exercises
Class of Warrant or Right [Line Items]
Liability Reclassed Equity
Cash Received		$ 101
Cash exercises \| Equity Warrants
Class of Warrant or Right [Line Items]
Warrant exercised		49,315
Cash exercises \| Common Stock Issued
Class of Warrant or Right [Line Items]
Warrant exercised		49,315
Cashless Exercise
Class of Warrant or Right [Line Items]
Liability Reclassed Equity

Common Stock - Additional Information (Detail) - J.P. Morgan Securities Inc. - USD ($) $ / shares in Units, $ in Millions	1 Months Ended
	Oct. 29, 2013	Oct. 23, 2013
Class of Stock [Line Items]
Stock issued during period	2,145,000	14,300,000
Issuance & sale of common stock in public offering price per share		$ 3.50
Common stock, shares issued		30 days
Option to purchase common stock	2,145,000
Sale of stock price per share		$ 3.29
Net proceeds from issuance of common stock	$ 53.9

Stock-Based Compensation Expense on All Employee and Non-Employee Awards (Detail) - USD ($) $ in Thousands	3 Months Ended		127 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 1,223	$ 1,541	$ 24,911
Research and Development Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	376	537
General and Administrative Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 847	$ 1,004

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended
	Jun. 14, 2013	Mar. 31, 2014	May 31, 2013	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, granted		80,500		110,900
Weighted-average grant date fair value		$ 3.34		$ 3.32
Unrecognized compensation costs		$ 7.1
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected recognition period		1 year 8 months 5 days
Unvested Restricted Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected recognition period		1 year 1 month 6 days
Unrecognized compensation costs related to unvested restricted stock outstanding		$ 0.9
Vested options held by 1 employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Based Compensation Arrangement By Share Based Payment Award Option Fully Vested	71,167	71,167	66,667
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		9 months
Vested options held by 1 employees \| Before Extension
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 months		3 months
Vested options held by 1 employees \| After Extension
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	12 months		12 months

Fair Value of Stock Options Assumptions Using Black-Scholes Option Valuation Model (Detail)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, Minimum	1.76%	1.00%
Risk-free interest rate, Maximum	2.11%	1.15%
Expected life in years	6 years	6 years
Expected volatility, Minimum	94.46%	83.40%
Expected volatility, Maximum	94.55%	83.69%
Expected dividend yield	0.00%	0.00%

Stock Option Activity Under Stock Option Plan (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Number of Shares
Beginning Balance	6,747,302
Granted	80,500	110,900
Exercised	(479,705)
Cancelled	(188,269)
Ending Balance	6,159,828		6,747,302
Vested and unvested expected to vest at end of period	6,105,689
Options exercisable, at end of period	2,843,928		3,471,935
Options available for future grant	338,631
Weighted Average Exercise Price
Beginning Balance	$ 3.81
Granted	4.36
Exercised	2.02
Cancelled	5.10
Ending Balance	3.92		$ 3.81
Vested and unvested expected to vest at end of period	4.28
Options exercisable, at end of period	$ 4.28		$ 4.01
Weighted Average Contractual Term (Years)
Outstanding, at end of period	7 years 5 months 12 days
Vested and unvested expected to vest at end of period	5 years 4 months 13 days
Options exercisable, at end of period	5 years 4 months 13 days		5 years 11 days
Aggregate Intrinsic Value
Outstanding, at end of period	$ 6,459
Vested and unvested expected to vest at end of period	5,845
Options exercisable, at end of period	$ 1,810		$ 2,654

Summary of Unvested Restricted Stock (Detail) - Unvested Restricted Common Stock	3 Months Ended
	Mar. 31, 2014 $ / shares shares
Number of Shares
Beginning Balance \| shares	352,865
Granted \| shares
Vested \| shares	(48,433)
Cancelled \| shares	(8,026)
Ending Balance \| shares	296,406
Weighted Average Grant Date Fair Value
Beginning Balance \| $ / shares	$ 4.38
Granted \| $ / shares
Vested \| $ / shares	4.51
Cancelled \| $ / shares	4.41
Ending Balance \| $ / shares	$ 4.36