Aveo Pharmaceuticals (AVEO) 10-K 13 Mar 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Mar. 08, 2018	Jun. 30, 2017
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Trading Symbol	AVEO
Entity Registrant Name	AVEO PHARMACEUTICALS INC
Entity Central Index Key	1,325,879
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		118,867,471
Entity Public Float			$ 218,171,452

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 14,949	$ 15,096
Marketable securities	18,576	8,252
Accounts receivable	402	1,027
Insurance recovery (Note 15)	15,000
Clinical trial retainers	1,027	1,702
Other prepaid expenses and other current assets	229	238
Total current assets	50,183	26,315
Clinical trial retainers		940
Other assets	15	30
Total assets	50,198	27,285
Current liabilities:
Accounts payable	2,436	2,186
Accrued clinical trial costs and contract research	8,321	3,998
Other accrued liabilities	2,458	1,531
Loans payable, net of discount		2,124
Deferred revenue	395	510
Deferred research and development reimbursements	901
Estimated settlement liability (Note 15)	17,073
Other liabilities (Note 6)	540
Total current liabilities	32,124	10,349
Loans payable, net of current portion and discount	18,477	11,879
Deferred revenue	1,302	1,697
Deferred research and development reimbursements	222
PIPE warrant liability (Note 7)	37,746	4,593
Other liabilities (Note 6)	1,090	690
Total liabilities	90,961	29,208
Stockholders' deficit:
Preferred stock, $.001 par value: 5,000 shares authorized at each of December 31, 2017 and 2016; no shares issued and outstanding at each of December 31, 2017 and 2016
Common stock, $.001 par value: 250,000 shares authorized and 118,325 shares issued and outstanding at December 31, 2017; 200,000 shares authorized and 75,863 shares issued and outstanding at December 31, 2016	118	76
Additional paid-in capital	546,092	519,911
Accumulated other comprehensive income (loss)	(4)	6
Accumulated deficit	(586,969)	(521,916)
Total stockholders’ deficit	(40,763)	(1,923)
Total liabilities and stockholders’ deficit	$ 50,198	$ 27,285

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
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	200,000,000
Common stock, shares issued	118,325,396	75,863,000
Common stock, shares outstanding	118,325,396	75,863,000

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Collaboration and licensing revenue	$ 7,579	$ 2,515	$ 19,024
Operating expenses:
Research and development	25,179	23,703	12,875
General and administrative	9,138	8,205	10,217
Settlement costs (Note 15)	2,073		4,000
Restructuring and lease exit			4,358
Operating Expenses, Total	36,390	31,908	31,450
Loss from operations	(28,811)	(29,393)	(12,426)
Other income (expense), net:
Interest expense, net	(2,373)	(1,949)	(2,286)
Change in fair value of warrant liability	(33,740)	4,751
Other (expense) income		(195)	(289)
Other income (expense), net	(36,113)	2,607	(2,575)
Net loss before provision for income taxes	(64,924)	(26,786)	(15,001)
Provision for income taxes	(101)	(101)
Net loss	$ (65,025)	$ (26,887)	$ (15,001)
Basic and diluted net loss per share:
Net loss per share	$ (0.61)	$ (0.39)	$ (0.27)
Weighted average number of common shares outstanding	105,930,000	69,268,000	55,701,000

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (65,025)	$ (26,887)	$ (15,001)
Other comprehensive income (loss):
Unrealized gain (loss) on available-for-sale securities	(10)	9	(3)
Comprehensive loss	$ (65,035)	$ (26,878)	$ (15,004)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' (Deficit) Equity - USD ($) $ in Thousands	Total	Private Placement	At-The-Market Sale Agreement	Common Shares	Common SharesPrivate Placement	Common SharesAt-The-Market Sale Agreement	Additional Paid-in Capital	Additional Paid-in CapitalPrivate Placement	Additional Paid-in CapitalAt-The-Market Sale Agreement	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning Balance at Dec. 31, 2014	$ 20,606			$ 52			$ 500,582				$ (480,028)
Beginning Balance (in shares) at Dec. 31, 2014				52,289,000
Stock-based compensation expense related to equity-classified awards | Equity-classified awards	1,132						1,132
Exercise of stock options	241						241
Exercise of stock options (in shares)				166,000
Issuance of common stock to settle liability-classified share awards granted to directors | Liability Classified Awards	7						7
Issuance of common stock to settle liability-classified share awards granted to directors (in shares) | Liability Classified Awards				8,000
Issuance of common stock under employee stock purchase plan	27						27
Issuance of common stock under employee stock purchase plan (in shares)				7,000
Issuance of common stock			$ 10,218			$ 6			$ 10,212
Issuance of common stock (in shares)						5,913,000
Forfeiture of restricted stock awards (in shares)				(201,000)
Change in unrealized gain (loss) on investments	(3)									$ (3)
Net loss	(15,001)										(15,001)
Ending Balance at Dec. 31, 2015	17,227			$ 58			512,201			(3)	(495,029)
Ending Balance (in shares) at Dec. 31, 2015				58,182,000
Issuance of common stock and warrants in a private placement, excluding to related parties (net of issuance costs of $1.6 million)		$ 14,846			$ 17			$ 14,829
Issuance of common stock and warrants in a private placement, excluding to related parties, net (in shares)					17,098,000
Issuance of common stock and warrants to related parties	525			$ 1			524
Issuance of common stock and warrants to related parties (in shares)				544,000
Stock-based compensation expense related to equity-classified awards | Equity-classified awards	999						999
Issuance of warrants in connection with a private placement	(9,344)						(9,344)
Issuance of warrants in connection with loans payable	667						667
Exercise of stock options	33						33
Exercise of stock options (in shares)				39,000
Issuance of common stock under employee stock purchase plan	2						2
Change in unrealized gain (loss) on investments	9									9
Net loss	(26,887)										(26,887)
Ending Balance at Dec. 31, 2016	$ (1,923)			$ 76			519,911			6	(521,916)
Ending Balance (in shares) at Dec. 31, 2016	75,863,000			75,863,000
Net loss	$ (8,840)
Beginning Balance at Dec. 31, 2016	$ (1,923)			$ 76			519,911			6	(521,916)
Beginning Balance (in shares) at Dec. 31, 2016	75,863,000			75,863,000
Retrospective adjustment related to adoption of new stock option forfeiture standard							28				(28)
Issuance of common stock in a public offering, excluding to related parties (net of issuance costs of $1.8 million)	$ 12,219			$ 28			12,191
Issuance of common stock in a public offering, excluding to related parties, net (in shares)				28,080,000
Issuance of common stock to related parties	3,210			$ 6			3,204
Issuance of common stock to related parties (in shares)				6,420,000
Stock-based compensation expense related to equity-classified awards | Equity-classified awards	1,089						1,089
Issuance of common stock in connection with warrant exercises	259			$ 2			257
Issuance of common stock in connection with warrant exercises (in shares)				1,475,000
Reduction in PIPE warrant liability in connection with warrant exercises	587						587
Exercise of stock options	$ 15						15
Exercise of stock options (in shares)	17,576			17,000
Issuance of common stock			$ 8,816			$ 6			$ 8,810
Issuance of common stock (in shares)						6,470,000
Change in unrealized gain (loss) on investments	$ (10)									(10)
Net loss	(65,025)										(65,025)
Ending Balance at Dec. 31, 2017	$ (40,763)			$ 118			$ 546,092			$ (4)	$ (586,969)
Ending Balance (in shares) at Dec. 31, 2017	118,325,396			118,325,000
Net loss	$ (33,287)

Consolidated Statements of Sto7

Consolidated Statements of Stockholders' (Deficit) Equity (Parenthetical) - Additional Paid-in Capital - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
At-The-Market Sale Agreement
Issuance of common stock, issuance costs	$ 180		$ 157
Private Placement
Issuance of common stock, issuance costs		$ 1,600
Public Offering
Issuance of common stock, issuance costs	$ 1,800

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating activities
Net loss	$ (65,025)	$ (26,887)	$ (15,001)
Adjustments to reconcile net loss to net cash used in operating activities:
Impairment of property and equipment			232
Depreciation and amortization		30	9,567
Net loss (gain) on disposal of fixed assets			253
Stock-based compensation	1,089	999	1,132
Non-cash interest expense	514	465	655
Non-cash change in fair value of warrant liability	2,073
Amortization of premium and discount on investments	68	14	34
Changes in operating assets and liabilities:
Restricted Cash			2,997
Accounts receivable	625	3,614	(2,300)
Insurance recovery (Note 15)	(15,000)
Prepaid expenses and other current assets	684	(340)	(116)
Other noncurrent assets	955	(827)	96
Accounts payable	250	760	(1,820)
Accrued clinical trial costs and contract research	4,323	2,032	(3,562)
Other accrued liabilities	927	(609)	(1,627)
Settlement liability	15,000	(4,000)	4,000
Deferred revenue	(510)	(1,488)	2,927
Deferred research and development reimbursements	1,123
Lease exit obligation			(5,206)
Deferred rent			(10,569)
Other liabilities		(78)	78
Net cash used in operating activities	(19,164)	(31,066)	(18,230)
Investing activities
Purchases of marketable securities	(34,852)	(29,421)	(19,085)
Proceeds from maturities and sales of marketable securities	24,450	28,664	11,550
Purchases of property and equipment		(7)	(22)
Proceeds from sale of property and equipment			1,241
Net cash used in investing activities	(10,402)	(764)	(6,316)
Financing activities
Proceeds from issuance of common stock and warrants, net of issuance costs	21,294	14,846	10,218
Proceeds from issuance of common stock and warrants to related parties	3,210	525
Proceeds from issuance of loan payable and warrants	5,000	5,000
Proceeds from issuance of stock for stock-based compensation arrangements	15	36	268
Payments of debt issuance costs	(100)	(115)
Principal payments on loans payable			(11,612)
Net cash provided by (used in) financing activities	29,419	20,292	(1,126)
Net decrease in cash and cash equivalents	(147)	(11,538)	(25,672)
Cash and cash equivalents at beginning of period	15,096	26,634	52,306
Cash and cash equivalents at end of period	14,949	15,096	26,634
Supplemental cash flow information
Cash paid for interest	2,069	1,539	$ 1,983
Non-cash financing activity
Fair value of warrants issued in connection with long term debt		667
Fair value of warrants issued in connection with private placement		9,344
PIPE Warrants
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash change in fair value of warrant liability	$ 33,740	$ (4,751)

Organization

Organization	12 Months Ended
	Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization	(1) Organization AVEO Pharmaceuticals, Inc. (the “Company”) is a biopharmaceutical company dedicated to advancing a broad portfolio of targeted medicines for oncology and other areas of unmet medical need. The Company’s strategy is to retain North American rights to its oncology portfolio while securing partners in development and commercialization outside of North America. The Company is working to develop and commercialize its lead candidate tivozanib in North America as a treatment for renal cell carcinoma (“RCC”). The Company has entered into partnerships to fund the development and commercialization of its preclinical and clinical stage assets, including AV-203 and ficlatuzumab in oncology, AV-380 in cachexia, and tivozanib in oncology outside of North America. Tivozanib (FOTIVDA ® As used throughout these condensed consolidated financial statements, the terms “AVEO,” and the “Company” refer to the business of AVEO Pharmaceuticals, Inc. and its two wholly-owned subsidiaries, AVEO Pharma Limited and AVEO Securities Corporation. Liquidity and Going Concern The Company has financed its operations to date primarily through private placements and public offerings of its common stock and preferred stock, license fees, milestone payments and research and development funding from strategic partners, and loan proceeds. The Company has devoted substantially all of its resources to its drug development efforts, comprising research and development, manufacturing, conducting clinical trials for its product candidates, protecting its intellectual property and general and administrative functions relating to these operations. The future success of the Company is dependent on its ability to develop its product candidates and ultimately upon its ability to attain profitable operations. As of December 31, 2017, the Company had cash, cash equivalents and marketable securities totaling approximately $33.5 million, working capital of $18.1 million and an accumulated deficit of $587.0 million. During the year ended December, 2017, the Company raised approximately $29.5 million in net cash proceeds, including $15.4 million from an underwritten public offering of 34.5 million shares of its common stock in March 2017, $8.8 million from sales of 6.5 million shares of its common stock under an at-the-market issuance sales agreement (the “Sales Agreement”) with FBR & Co. and MLV & Co. LLC (together “FBR”) and $5.0 million in additional borrowings under its loan and security agreement (the “Loan Agreement”) with Hercules Technology II, L.P. and Hercules Technology III, L.P., affiliates of Hercules Technology Growth (collectively, “Hercules”) in June 2017, and $0.3 million in July 2017 from the issuance of 0.3 million shares of its common stock upon the exercise of 0.3 million warrants issued in connection with the May 2016 private placement (the “PIPE Warrants”). Refer to Notes 6 and 7. The Company is subject to a number of risks, including the need for substantial additional capital for clinical research and product development. As of December 31, 2017, the Company had approximately $33.5 million in existing cash, cash equivalents and marketable securities. In the first quarter of 2018 to-date, the Company has raised an additional approximate $1.9 million in net funding, including approximately $0.5 million received in January 2018 related to the exercise of 0.5 million PIPE Warrants and $1.4 million in net partnership-related funding in connection with the $2.0 million milestone payment by EUSA Pharma (UK) Limited (“EUSA”) for the February 2018 reimbursement approval by the National Institute for Health and Care Excellence (the “NICE”) for RCC in the United Kingdom that was received in March 2018, net of the corresponding 30% sub-license fee due to Kyowa Hakko Kirin Co., Ltd. (formerly Kirin Brewery Co., Ltd.) (“KHK”). Refer to Note 4. Based on these available cash resources, the Company does not have sufficient cash on hand to support current operations for at least the next twelve months from the date of filing this Annual Report on Form 10-K. This condition raises substantial doubt about the Company’s ability to continue as a going concern The Company’s plans to address this condition include pursuing one or more of the following options to secure additional funding, none of which can be guaranteed or are entirely within our control : • Earn royalty payments pursuant to the license agreement with EUSA. In August 2017, EUSA obtained marketing approval from the European Medicines Agency (the “EMA”) for tivozanib (FOTIVDA) for the treatment of RCC. • Earn milestone payments pursuant to the collaboration and license agreements described in Note 4 or restructure / monetize existing potential milestone and/or royalty payments under those collaboration and license agreements. Pursuant to the Company’s license agreement with EUSA, the Company is entitled to receive up to an additional $8.0 million in milestone payments of $2.0 million per country upon reimbursement approval for RCC, if any, in each of France, Germany, Italy and Spain, and an additional $2.0 million milestone payment for the grant of marketing approval, if any, in three of the five following countries: Argentina, Australia, Brazil, South Africa and Venezuela. The Company is also eligible to receive an additional research and development reimbursement payment from EUSA of fifty percent (50%) of the total costs for the Company’s TIVO-3 phase 3 study in third-line RCC, up to $20.0 million, if EUSA elects to opt-in to that study • Raise funding through the possible additional sales of the Company’s common stock, including public or private equity financings and / or sales of the Company’s common stock under the at-the-market-issuance sales agreement (the “Leerink Sales Agreement”) with Leerink Partners LLC (“Leerink”), as discussed in Note 7. • Partner AV-353 to secure potential additional non-dilutive funds and advance development of the AV-353 platform for the potential treatment of PAH . There can be no assurance, however, that the Company will receive cash proceeds from any of these potential resources or to the extent cash proceeds are received those proceeds would be sufficient to support its current operating plan for at least the next twelve months from the date of filing this Annual Report on Form 10-K. Pursuant to the requirements of Accounting Standards Codification (ASC) 205-40, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern Under ASC 2015-40, the future receipt of potential funding from the Company’s collaborators and other resources cannot be considered probable at this time because none of the Company’s current plans have been finalized at the time of filing this Annual Report on Form 10-K and the implementation of any such plan is not probable of being effectively implemented as none of the plans are entirely within the Company’s control. Accordingly, substantial doubt is deemed to exist about the Company’s ability to continue as a going concern within one year after the date these financial statements are issued. The Company believes that its approximate $33.5 million in cash, cash equivalents and marketable securities at December 31, 2017, along with the additional approximate $1.9 million in net funding raised in the first quarter of 2018 to-date, as described above, would allow it to fund its planned operations into the first quarter of 2019. This estimate assumes no receipt of additional milestone payments from its partners or additional related payments of potential licensing milestones to third parties, no funding from new partnership agreements, no equity financings, no debt financings, no sales of equity under its Leerink Sales Agreement and no additional sales of equity through the exercise of the PIPE Warrants. Accordingly, the timing and nature of activities contemplated for the remainder of 2018 and thereafter will be conducted subject to the availability of sufficient financial resources. If the Company is unable to obtain sufficient capital to continue to advance its programs, the Company would be forced to delay, reduce or eliminate its research and development programs and any future commercialization efforts. The accompanying financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the ordinary course of business. The financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of the uncertainties described above.

Basis of Presentation

Basis of Presentation	12 Months Ended
	Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation	(2) Basis of Presentation These consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries, AVEO Pharma Limited and AVEO Securities Corporation. The Company has eliminated all significant intercompany accounts and transactions in consolidation. Certain reclassifications have been made to prior periods to conform to current period presentation. Reclassification of prior year amounts have been made to separately present settlement costs from general and administrative expenses in the consolidated statements of operations. There was no impact on total operating expenses or net income (loss) resulting from these reclassifications.

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Significant Accounting Policies	(3) Significant Accounting Policies Revenue Recognition The Company’s revenues are generated primarily through collaborative research, development and commercialization agreements. The terms of these agreements generally contain multiple elements, or deliverables, which may include (i) licenses, or options to obtain licenses, to the Company’s technology, (ii) research and development activities to be performed on behalf of the collaborative partner, and (iii) in certain cases, services in connection with the manufacturing of pre-clinical and clinical material. Payments to the Company under these arrangements typically include one or more of the following: non-refundable, upfront license fees; option exercise fees; funding of research and/or development efforts; milestone payments; and royalties on future product sales. The Company analyzes its collaboration arrangements to assess whether they are within the scope of ASC 808 to determine whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards dependent on the commercial success of such activities. This assessment is performed throughout the life of the arrangement based on changes in the responsibilities of all parties in the arrangement. For collaboration arrangements that are deemed to be within the scope of ASC 808, the Company first determines which elements of the collaboration are deemed to be within the scope of ASC 808 and those that are more reflective of a vendor-customer relationship and therefore within the scope of ASC 605. The Company’s policy is to recognized amounts received from collaborators in connection with joint operating activities that are within the scope of ASC 808 as a reduction to research and development expense. When evaluating multiple element arrangements under ASC 605, the Company considers whether the deliverables under the arrangement represent separate units of accounting. This evaluation requires subjective determinations and requires management to make judgments about the individual deliverables and whether such deliverables are separable from the other aspects of the contractual relationship. In determining the units of accounting, management evaluates certain criteria, including whether the deliverables have standalone value, based on the relevant facts and circumstances for each arrangement. The consideration received is allocated among the separate units of accounting using the relative selling price method, and the applicable revenue recognition criteria are applied to each of the separate units. The Company determines the estimated selling price for deliverables within each agreement using vendor-specific objective evidence (“VSOE”) of selling price, if available, third-party evidence (“TPE”) of selling price if VSOE is not available, or best estimate of selling price if neither VSOE nor TPE is available. Determining the best estimate of selling price for a deliverable requires significant judgment. The Company typically uses best estimate of selling price to estimate the selling price for licenses to the Company’s proprietary technology, since the Company often does not have VSOE or TPE of selling price for these deliverables. In those circumstances where the Company utilizes best estimate of selling price to determine the estimated selling price of a license to the Company’s proprietary technology, the Company considers market conditions as well as entity-specific factors, including those factors contemplated in negotiating the agreements and internally developed models that include assumptions related to the market opportunity, estimated development costs, probability of success and the time needed to commercialize a product candidate pursuant to the license. In validating the Company’s best estimate of selling price, the Company evaluates whether changes in the key assumptions used to determine the best estimate of selling price will have a significant effect on the allocation of arrangement consideration among multiple deliverables. The Company typically receives non-refundable, upfront payments when licensing its intellectual property in conjunction with a research and development agreement. When management believes the license to its intellectual property does not have stand-alone value from the other deliverables to be provided in the arrangement, the Company generally recognizes revenue attributed to the license on a straight-line basis over the Company’s contractual or estimated performance period, which is typically the term of the Company’s research and development obligations. If management cannot reasonably estimate when the Company’s performance obligation ends, then revenue is deferred until management can reasonably estimate when the performance obligation ends. When management believes the license to its intellectual property has stand-alone value, the Company generally recognizes revenue attributed to the license upon delivery. The periods over which revenue should be recognized are subject to estimates by management and may change over the course of the research and development agreement. Such a change could have a material impact on the amount of revenue the Company records in future periods. Payments or reimbursements resulting from the Company’s research and development efforts for those arrangements where such efforts are considered as deliverables are recognized as the services are performed and are presented on a gross basis so long as there is persuasive evidence of an arrangement, the fee is fixed or determinable, and collection of the related receivable is reasonably assured. Amounts received prior to satisfying the above revenue recognition criteria are recorded as deferred revenue in the accompanying balance sheets. At the inception of each agreement 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 (a) the consideration is commensurate with either (1) the entity’s performance to achieve the milestone, or (2) the enhancement of the value of the delivered item(s) as a result of a specific outcome resulting from the entity’s performance to achieve the milestone, (b) the consideration relates solely to past performance, and (c) the consideration is reasonable relative to all of the deliverables and payment terms within the arrangement. The Company evaluates factors such as the scientific, regulatory, commercial and other risks that must be overcome to achieve the respective milestone, the level of effort and investment required to achieve the respective milestone and whether the milestone consideration is reasonable relative to all deliverables and payment terms in the arrangement in making this assessment. The Company aggregates its milestones into four categories: (i) clinical and development milestones, (ii) regulatory milestones, (iii) commercial milestones, and (iv) patent-related milestones. Clinical and development milestones are typically achieved when a product candidate advances into a defined phase of clinical research or completes such phase. For example, a milestone payment may be due to the Company upon the initiation of a phase 3 clinical trial for a new indication, which is the last phase of clinical development and could eventually contribute to marketing approval by the FDA or other global regulatory authorities. Regulatory milestones are typically achieved upon acceptance of the submission for marketing approval of a product candidate or upon approval to market the product candidate by the FDA or other global regulatory authorities. For example, a milestone payment may be due to the Company upon the FDA’s acceptance of a New Drug Application (“NDA”). Commercial milestones are typically achieved when an approved pharmaceutical product reaches certain defined levels of net sales by the licensee, such as when a product first achieves global sales or annual sales of a specified amount. Patent-related milestones are typically achieved when a patent application is filed or a patent is issued with respect to certain intellectual property related to the applicable collaboration. Revenues from clinical and development, regulatory, and patent-related milestone payments, if the milestones are deemed substantive and the milestone payments are nonrefundable, are recognized upon successful accomplishment of the milestones. The Company has concluded that the clinical and development, regulatory and patent-related milestones pursuant to its current research and development arrangements are substantive. Milestones that are not considered substantive are accounted for as license payments and recognized on a straight-line basis over the remaining period of performance. Revenues from commercial milestone payments are accounted for as royalties and are recorded as revenue upon achievement of the milestone, assuming all other revenue recognition criteria are met. Research and Development Expenses Research and development expenses are charged to expense as incurred. Research and development expenses consist of costs incurred in performing research and development activities, including internal costs for salaries, bonuses, benefits, stock-based compensation, facilities, and research-related overhead, and external costs for clinical trials, drug manufacturing and distribution, license fees, consultants and other contracted services. Warrants Issued in Connection with Private Placement In May 2016, the Company issued PIPE warrants to purchase an aggregate of 17,642,482 shares of common stock in connection with a private placement financing and recorded the warrants as a liability (the “PIPE Warrants”). The Company accounts for warrant instruments that either conditionally or unconditionally obligate the issuer to transfer assets as liabilities regardless of the timing of the redemption feature or price, even though the underlying shares may be classified as permanent or temporary equity. As of December 31, 2017, PIPE Warrants exercisable for 259,067 shares of common stock had been exercised and PIPE Warrants exercisable for 17,383,415 shares of common stock were outstanding. In January 2018, PIPE Warrants with respect to 518,134 shares of common stock underlying such PIPE Warrants were exercised, and the Company issued 518,134 shares of its common stock and received approximately $0.5 million in cash proceeds. Refer to Note 7, “Common Stock—Private Placement / PIPE Warrants” for further discussion of the private placement financing. The PIPE Warrants contain a provision giving the warrant holder the option to receive cash, equal to the fair value of the remaining unexercised portion of the warrant, as cash settlement in the event that there is a fundamental transaction (contractually defined to include various merger, acquisition or stock transfer activities). Due to this provision, ASC 480, Distinguishing Liabilities from Equity The following table rolls forward the fair value of the Company’s PIPE warrant liability, the fair value of which is determined by Level 3 inputs for the year ended December 31, 2017 (in thousands): Issuance of warrants on May 13, 2016 $ 9,344 Decrease in fair value (4,751 ) Fair value at December 31, 2016 $ 4,593 Increase in fair value 33,740 Reduction in warrant liability for PIPE Warrant exercises (587 ) Fair value at December 31, 2017 $ 37,746 The key assumptions used to value the PIPE Warrants were as follows: Original Issuance December 31, 2016 December 31, 2017 Expected price volatility 76.25% 78.18% 84.86% Expected term (in years) 5.00 4.50 3.50 Risk-free interest rates 1.22% 1.93% 2.09% Stock price $ 0.89 $ 0.54 $ 2.79 Dividend yield — — — Potential Class Action Settlement In December 2017, the Company entered into a binding memorandum of understanding (the “MOU”) with class representatives Bob Levine and William Windham (the “Plaintiffs”), regarding the settlement of a securities class action lawsuit (the “Class Action”) filed in 2013 and pending in the United States District Court for the District of Massachusetts (the “District Court”) against us and certain of our former officers (Tuan Ha-Ngoc, David Johnston, and William Slichenmyer, together, the “Individual Defendants”), In re AVEO Pharmaceuticals, Inc. Securities Litigation et al. , No. 1:13-cv-11157-DJC. As previously disclosed, the Class Action was purportedly brought on behalf of stockholders who purchased our common stock between May 16, 2012 and May 1, 2013 (the “Class”). In December 2017, upon entering into the MOU, this settlement became estimable and probable. Accordingly, the Company recorded an estimated $17.1 million contingent liability, including $15.0 million for the cash portion of the settlement with a corresponding insurance recovery for the 100% portion to be paid directly by certain of the Company’s insurance carriers, and an approximate $2.1 million estimate for the fair value on December 31, 2017 of 2.0 million warrants to purchase shares of its common stock exercisable from the date of issue until the expiration of a one-year period after the date of issue at an exercise price equal to the closing price on December 22, 2017, the trading day prior to the execution of the MOU, which was $3.00 per share (“the Settlement Warrants”) The settlement is subject to the execution of a definitive settlement agreement, notice to the Class, and final approval of the District Court and shall be effective on the date (the “Effective Date”) on which all of the following circumstances have occurred: (a) a final judgment containing the requisite release of claims has been entered by the District Court (“Final Judgment”); (b) no appeal is pending with respect to the Final Judgment; (c) the Final Judgment has not been reversed, modified, vacated or amended; (d) the time to file any appeal from the Final Judgment has expired without the filing of an appeal or an order dismissing the appeal or affirming the Final Judgment has been entered, and any time to file a further appeal (including a writ of certiorari or for reconsideration of the appeal) has expired; and (e) the MOU and any settlement agreement with respect to the claims released in the Final Judgment have not expired or been terminated. The Company as agreed to use its best efforts to issue and deliver the Settlement Warrants within ten business days following the Effective Date. In January 2018, the Company entered into a stipulation of settlement agreement (the “Stipulation”) that was preliminarily approved by the District Court in February 2018. A hearing by the District Court for final approval of the Stipulation has been scheduled for May 30, 2018. Refer to Note 15, “Legal Proceedings” for further discussion of this class action settlement. The estimated fair value of the Settlement Warrants to be issued on the Effective Date has been determined using the Black-Scholes pricing model. The estimated fair value of the Settlement Warrants to be issued on the Effective Date are subject to revaluation at each balance sheet date and any changes in fair value are recorded as a non-cash gain or (loss) in the Statement of Operations as a component of operating expenses until the Settlement Warrants are issued, at which point they will be recorded as equity or as a liability based upon the issuance terms The key assumptions used to estimate the fair value the Settlement Warrants were as follows: December 31, 2017 Expected price volatility 101.52% Expected term (in years) 1.00 Risk-free interest rates 1.76% Stock price $ 2.79 Dividend yield — Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less at the date of purchase and an investment in a U.S. government money market fund to be cash equivalents. Changes in the balance of cash and cash equivalents may be affected by changes in investment portfolio maturities, as well as actual cash disbursements to fund operations. The Company’s cash is deposited in highly-rated financial institutions in the United States. The Company invests in U.S. government money market funds, high-grade, short-term commercial paper, corporate bonds and other U.S. government agency securities, which management believes are subject to minimal credit and market risk. The carrying values of the Company’s cash and cash equivalents approximate fair value due to their short-term maturities. Marketable Securities Marketable securities consist primarily of investments which have expected average maturity dates in excess of three months, but not longer than 24 months. The Company invests in high-grade corporate obligations, including commercial paper, and U. S. government and government agency obligations that are classified as available-for-sale. Since these securities are available to fund current operations they are classified as current assets on the consolidated balance sheets. Marketable securities are stated at fair value, including accrued interest, with their unrealized gains and losses included as a component of accumulated other comprehensive income or loss, which is a separate component of stockholders’ equity. The fair value of these securities is based on quoted prices and observable inputs on a recurring basis. The cost of marketable securities is adjusted for amortization of premiums and accretion of discounts to maturity, with such amortization and accretion recorded as a component of interest expense, net. Realized gains and losses are determined on the specific identification method. Unrealized gains and losses are included in other comprehensive loss until realized, at which point they would be recorded as a component of interest expense, net. Below is a summary of cash, cash equivalents and marketable securities at December 31, 2017 and December 31, 2016: Amortized Cost Unrealized Gains Unrealized Losses Fair Value December 31, 2017 Cash and cash equivalents: Cash and money market funds $ 14,949 $ — $ — $ 14,949 Corporate debt securities — — — — Total cash and cash equivalents 14,949 — — 14,949 Marketable securities: Corporate debt securities due within 1 year $ 17,074 $ 1 $ (5 ) $ 17,070 US government agency securities due within 1 year 1,506 — — 1,506 Total marketable securities 18,580 1 (5 ) 18,576 Total cash, cash equivalents and marketable securities $ 33,529 $ 1 $ (5 ) $ 33,525 December 31, 2016 Cash and cash equivalents: Cash and money market funds $ 14,091 $ — $ — $ 14,091 Corporate debt securities 1,005 — — 1,005 Total cash and cash equivalents 15,096 — — 15,096 Marketable securities: Corporate debt securities due within 1 year 8,246 6 — 8,252 Total marketable securities 8,246 6 — 8,252 Total cash, cash equivalents and marketable securities $ 23,342 $ 6 $ — $ 23,348 Concentrations of Credit Risk Financial instruments that potentially subject the Company to credit risk primarily consist of cash and cash equivalents, marketable securities and accounts receivable. The Company maintains deposits in highly-rated, federally-insured financial institutions in excess of federally insured limits. The Company’s investment strategy is focused on capital preservation. The Company invests in instruments that meet the high credit quality standards outlined in the Company’s investment policy. This policy also limits the amount of credit exposure to any one issue or type of instrument. The Company’s accounts receivable primarily consists of amounts due to the Company from licensees and collaborators. The Company has not experienced any material losses related to accounts receivable from individual licensees or collaborators. Fair Value Measurements The fair value of the Company’s financial assets and liabilities reflects the Company’s estimate of amounts that it would have received in connection with the sale of the assets or paid in connection with the transfer of the liabilities in an orderly transaction between market participants at the measurement date. In connection with measuring the fair value of its assets and liabilities, the Company seeks to maximize the use of observable inputs (market data obtained from sources independent from the Company) and to minimize the use of unobservable inputs (the Company’s assumptions about how market participants would price assets and liabilities). The following fair value hierarchy is used to classify assets and liabilities based on the observable inputs and unobservable inputs used in order to value the assets and liabilities: Level 1: Quoted prices in active markets for identical assets or liabilities. An active market for an asset or liability is a market in which transactions for the asset or liability occur with sufficient frequency and volume to provide pricing information on an ongoing basis. Level 2: Observable inputs other than Level 1 inputs. Examples of Level 2 inputs include quoted prices in active markets for similar assets or liabilities and quoted prices for identical assets or liabilities in markets that are not active. Level 3: Unobservable inputs based on the Company’s assessment of the assumptions that market participants would use in pricing the asset or liability. Financial assets and liabilities are classified in their entirety within the fair value hierarchy based on the lowest level of input that is significant to the fair value measurement. The Company measures the fair value of its marketable securities by taking into consideration valuations obtained from third-party pricing sources. The pricing services utilize industry standard valuation models, including both income and market based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker-dealer quotes on the same or similar securities, issuer credit spreads, benchmark securities and other observable inputs. As of December 31, 2017, the Company’s financial assets valued based on Level 1 inputs consisted of cash and cash equivalents in a U.S. government money market fund and in addition, for 2016, high-grade corporate debt securities, including commercial paper, and its financial assets valued based on Level 2 inputs consisted of high-grade corporate debt securities, including commercial paper, and in addition, for 2017, U.S. government agency securities. During the years ended December 31, 2017 and 2016, the Company did not have any transfers of financial assets between Levels 1 and 2. As of December 31, 2017, the Company’s financial liabilities that were recorded at fair value consisted of warrant liabilities, including the PIPE warrant liability and the estimated fair value of the Settlement Warrants. The fair value of the Company’s loans payable at December 31, 2017 approximates its carrying value, computed pursuant to a discounted cash flow technique using a market interest rate and is considered a Level 3 fair value measurement. The effective interest rate, which reflects the current market rate, considers the fair value of the warrants issued in connection with the loan, loan issuance costs and the deferred financing charge. The following table summarizes the assets and liabilities measured at fair value on a recurring basis at December 31, 2017 and December 31, 2016: Fair Value Measurements as of December 31, 2017 Level 1 Level 2 Level 3 Total (in thousands) Financial assets carried at fair value: Cash and money market funds $ 14,949 $ — $ — $ 14,949 Corporate debt securities — — — — Total cash and cash equivalents $ 14,949 $ — $ — $ 14,949 Marketable securities: Corporate debt securities due within 1 year $ — $ 17,070 $ — $ 17,070 US government agency securities due within 1 year — 1,506 — 1,506 Total marketable securities $ — $ 18,576 $ — $ 18,576 Total cash, cash equivalents and marketable securities $ 14,949 $ 18,576 $ — $ 33,525 Financial liabilities carried at fair value: PIPE warrant liability $ — $ — $ 37,746 $ 37,746 Settlement warrant liability — — 2,073 2,073 Total warrant liabilities $ — $ — $ 39,819 $ 39,819 Fair Value Measurements as of December 31, 2016 Level 1 Level 2 Level 3 Total (in thousands) Financial assets carried at fair value: Cash and money market funds $ 14,091 $ — $ — $ 14,091 Corporate debt securities — 1,005 — 1,005 Total cash and cash equivalents $ 14,091 $ 1,005 $ — $ 15,096 Marketable securities: Corporate debt securities due within 1 year — $ 8,252 — $ 8,252 Total marketable securities $ — $ 8,252 $ — $ 8,252 Total cash, cash equivalents and marketable securities $ 14,091 $ 9,257 $ — $ 23,348 Financial liabilities carried at fair value: PIPE warrant liability $ — $ — $ 4,593 $ 4,593 Total warrant liability $ — $ — $ 4,593 $ 4,593 Property and Equipment Property and equipment are stated at cost and are depreciated using the straight-line method over the estimated useful lives of the respective assets. Maintenance and repair costs are charged to expense as incurred. Depreciation expense for the years ended December 31, 2017, 2016 and 2015 was $0, $30 thousand and $9.6 million, respectively. In September 2014, the Company entered into a Lease Termination Agreement (refer to Note 12). As a result, the Company revised the estimated useful life of its leasehold improvements related to this space. In February 2015, the Company provided notice that it would surrender the remaining space on May 29, 2015. Accordingly, the Company again revised the estimated useful life of its leasehold improvements related to this office space and amortized such assets through May 2015, resulting in an additional $2.9 million of depreciation expense during the year ended December 31, 2015. Long-lived Assets The Company reviews long-lived assets, including property and equipment, for impairment whenever changes in business circumstances indicate that the carrying amount of the asset may not be fully recoverable. The Company recognized $0, $0 and $0.2 million of impairment losses during the years ended December 31, 2017, 2016 and 2015, respectively, primarily related to leasehold improvements. Basic and Diluted Loss per Common Share Basic net loss per share is computed using the weighted average number of common shares outstanding during the period, excluding restricted stock that has been issued but is not yet vested. Diluted net loss per common share is computed using the weighted average number of common shares outstanding and the weighted average dilutive potential common shares outstanding using the treasury stock method. However, for the years ended December 31, 2017, 2016 and 2015, diluted net loss per share is the same as basic net loss per share as the inclusion of weighted average shares of unvested restricted common stock and common stock issuable upon the exercise of stock options and warrants would be anti-dilutive. The following table summarizes outstanding securities not included in the computation of diluted net loss per common share as their inclusion would be anti-dilutive for the years ended December 31, 2017, 2016 and 2015, respectively: Years Ended December 31, 2017 2016 2015 Outstanding stock options 7,537,958 4,858,678 4,796,005 Outstanding warrants 17,383,415 19,453,295 608,696 Unvested restricted stock — — 42,750 Total 24,921,373 24,311,973 5,447,451 Stock-Based Compensation Under the Company’s stock-based compensation programs, the Company periodically grants stock options and restricted stock to employees, directors and nonemployee consultants. The Company also issues shares under an employee stock purchase plan. The fair value of all awards is recognized in the Company’s statements of operations over the requisite service period for each award. Awards that vest as the recipient provides service are expensed on a straight-line basis over the requisite service period. Other awards, such as performance-based awards that vest upon the achievement of specified goals, are expensed using the accelerated attribution method if achievement of the specified goals is considered probable. The Company has also granted awards that vest upon the achievement of market conditions. Per Accounting Standards Codification (“ASC”) 718 Share-Based Payments, The Company uses the Black-Scholes option pricing model to value its stock option awards without market conditions, which require the Company to make certain assumptions regarding the expected volatility its common stock price, the expected term of the option grants, the risk-free interest rate and the dividend yield with respect to its common stock. In 2016, the Company began calculating volatility using its historical data. Previously, the Company did not have sufficient history to support a calculation of volatility using only its historical data. As such, prior to 2016, the Company used a weighted-average volatility considering the Company’s own volatility since March 2010 and the volatilities of several peer companies. For purposes of identifying similar entities, the Company considered characteristics such as industry, length of trading history, similar vesting terms and in-the-money option status. Due to the lack of the Company’s own historical data, the Company elected to use the “simplified” method for “plain vanilla” options to estimate the expected term of the Company’s stock option grants. Under this approach, the weighted-average expected life is presumed to be the average of the vesting term and the contractual term of the option. The risk-free interest rate used for each grant is based on the U.S. Treasury yield curve in effect at the time of grant for instruments with a similar expected life. The Company utilizes a dividend yield of zero based on the fact that the Company has never paid cash dividends and has no present intention to pay cash dividends. The fair value of equity-classified awards to employees and directors are measured at fair value on the date the awards are granted. Awards to nonemployee consultants are recorded at their fair values and are re-measured as of each balance sheet date until the recipient’s services are complete. During the years ended December 31, 2017, 2016 and 2015, the Company recorded the following stock-based compensation expense: Years Ended December 31, 2017 2016 2015 (in thousands) Research and development $ 290 $ 293 $ 298 General and administrative 799 706 765 Restructuring — — 69 Total stock-based compensation expense $ 1,089 $ 999 $ 1,132 Stock-based compensation expense is allocated to research and development and general and administrative expense based upon the department of the employee to whom each award was granted. Expenses recognized in connection with the modification of awards in connection with the Company’s strategic restructurings are allocated to restructuring expense. No related tax benefits of the stock-based compensation expense have been recognized. Income Taxes The Company provides for income taxes using the asset-liability method. Under this method, deferred tax assets and liabilities are recognized based on differences between financial reporting and tax bases of assets and liabilities, and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. The Company calculates its provision for income taxes on ordinary income based on its projected annual tax rate for the year. Uncertain tax positions are recognized if the position is more-likely-than-not to be sustained upon examination by a tax authority. Unrecognized tax benefits represent tax positions for which reserves have been established. Segment and Geographic Information Operating segments are defined as components of an enterprise engaging in business activities for which discrete financial information is available and regularly reviewed by the chief operating decision maker in deciding how to allocate resources and in assessing performance. The Company views its operations and manages its business in one operating segment principally in the United States. As of December 31, 2017 and 2016, the Company has $0 and $0.8 million, respectively, of net assets located in the United Kingdom. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect certain reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the , and the reported amounts of revenues and expenses during the reporting periods. Significant items subject to such estimates and assumptions in

Collaborations and License Agre

Collaborations and License Agreements	12 Months Ended
	Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaborations and License Agreements	(4) Collaborations and License Agreements Out-License Agreements CANbridge In March 2016, the Company entered into a collaboration and license agreement (the “CANbridge Agreement”) with CANbridge Life Sciences Ltd. (“CANbridge”). Under the terms of the CANbridge Agreement, the Company granted CANbridge the exclusive right to develop, manufacture and commercialize AV-203, the Company’s proprietary ErbB3 (HER3) inhibitory antibody, for the diagnosis, treatment and prevention of disease in humans and animals in all countries other than the United States, Canada and Mexico (the “CANbridge Licensed Territory”). The effective date of the CANbridge Agreement is March 16, 2016 (the “Effective Date”). Pursuant to the CANbridge Agreement, CANbridge made an upfront payment to the Company of $1.0 million in April 2016, net of $0.1 million in foreign withholding taxes. CANbridge agreed to reimburse the Company $1.0 million for certain manufacturing costs and expenses incurred by the Company prior to the Effective Date with respect to AV-203. CANbridge paid this manufacturing reimbursement in two installments of $0.5 million each, including one in March 2017 and one in September 2017, net of $0.1 million in foreign withholding taxes. The Company is also eligible to receive up to $42.0 million in potential development and regulatory milestone payments and up to $90.0 million in potential sales based milestone payments based on annual net sales of licensed products. In December 2017, CANbridge filed an IND with the China Food and Drug Administration for a Phase 1b / III clinical study of AV-203 in esophageal squamous cell cancer. CANbridge is obligated to use commercially reasonable efforts to develop and commercialize AV-203 in each of China, Japan, the United Kingdom, France, Italy, Spain, and Germany. CANbridge has responsibility for all activities and costs associated with the further development, manufacture, regulatory filings and commercialization of AV-203 in the CANbridge Licensed Territory. A percentage of any milestone and royalty payments received by the Company, excluding upfront and reimbursement payments, are due to Biogen Idec International GmbH (“Biogen”) as a sublicensing fee under the option and license agreement between the Company and Biogen dated March 18, 2009, as amended. Activities under the CANbridge Agreement were evaluated under ASC 605-25 Revenue Recognition—Multiple Element Arrangements de minimis The Company believes the development and regulatory milestones that may be achieved under the CANbridge Agreement are consistent with the definition of a milestone included in ASC 605-28, Revenue Recognition—Milestone Method The Company recognized the two $0.5 million payments by CANbridge for the reimbursement of manufacturing development activities conducted by the Company prior to the Effective Date as revenue during each of the three months ended March 31, 2017 and September 30, 2017, respectively, as the amounts were fixed and determinable and non-refundable. In addition, the Company has no further performance obligations. EUSA In December 2015, the Company entered into a license agreement with EUSA Pharma (UK) Limited (“EUSA”) under which the Company granted to EUSA the exclusive, sublicensable right to develop, manufacture and commercialize tivozanib in the territories of Europe (excluding Russia, Ukraine and the Commonwealth of Independent States), Latin America (excluding Mexico), Africa, Australasia and New Zealand (the “EUSA Licensed Territories”) for all diseases and conditions in humans, excluding non-oncologic diseases or conditions of the eye. Under the license agreement, EUSA made research and development reimbursement payments to the Company of $2.5 million upon the execution of the license agreement during the year ended December 31, 2015 and $4.0 million in September 2017 upon its receipt of marketing approval from the EMA for tivozanib (FOTIVDA) for the treatment of RCC. In September 2017, EUSA elected to opt-in to co-develop the ongoing TiNivo trial. As a result of exercising its opt-in right, EUSA made an additional research and development reimbursement payment to the Company of $2.0 million. This $2.0 million payment was received in October 2017, in advance of the completion of the TiNivo trial, and represents EUSA’s approximate 50% share of the total estimated costs of the TiNivo trial. The Company is also eligible to receive an additional research and development reimbursement payment from EUSA of fifty percent (50%) of the total costs for the Company’s TIVO-3 phase 3 study in third-line RCC, up to $20.0 million, if EUSA elects to opt-in to that study. The Company is entitled to receive milestone payments of $2.0 million per country upon reimbursement approval for RCC, if any, in each of France, Germany, Italy, Spain and the United Kingdom, and an additional $2.0 million for the grant of marketing approval, if any, in three of the five following countries: Argentina, Australia, Brazil, South Africa and Venezuela. In February 2018, EUSA obtained reimbursement approval from the NICE in the UK in first line RCC. Accordingly, the Company earned a $2.0 million milestone payment that was received in March 2018. The Company is also eligible to receive a payment of $2.0 million in connection with a filing by EUSA with the EMA for marketing approval, if any, for tivozanib for the treatment of each of up to three additional indications and $5.0 million per indication in connection with the EMA’s grant of marketing approval for each of up to three additional indications, as well as potentially up to $335.0 million upon EUSA’s achievement of certain sales thresholds. The Company is also eligible to receive tiered double-digit royalties on net sales, if any, of licensed products in the EUSA Licensed Territories ranging from a low double digit up to mid-twenty percent depending on the level of annual net sales. The research and development reimbursement payments under the EUSA license agreement are not subject to the 30% sublicensing payment to KHK, subject to certain limitations. The Company, however, would owe KHK 30% of other, non-research and development payments it may receive from EUSA pursuant to the EUSA license agreement, including EU reimbursement approval milestones in up to five specified EU countries, EU marketing approvals for up to three additional indications beyond RCC, marketing approvals in up to three specified licensed territories outside of the EU, sales-based milestones and royalties, as set forth above. The $2.0 million milestone the Company earned in February 2018 upon EUSA’s reimbursement approval from the NICE in the UK in first line RCC is subject to the 30% KHK sub-license fee, or $0.6 million. EUSA is obligated to use commercially reasonable efforts to seek regulatory approval for and commercialize tivozanib throughout the EUSA Licensed Territories in RCC. With the exception of certain support provided by the Company in connection with the application for marketing approval by the EMA, EUSA has responsibility for all activities and costs associated with the further development, manufacture, regulatory filings and commercialization of tivozanib in the EUSA Licensed Territories. Activities under the agreement were evaluated under ASC 605-25 to determine whether such activities represented a multiple element revenue arrangement. The agreement with EUSA includes the following non-contingent deliverables: (i) the Company’s grant of an exclusive license to develop and commercialize tivozanib in the EUSA Licensed Territories; (ii) the Company’s obligation to transfer all technical knowledge and data useful in the development and manufacture of tivozanib; (iii) the Company’s obligation to cooperate with EUSA and support its efforts to file for marketing approval in the EUSA Licensed Territories, (iv) the Company’s obligation to provide access to certain regulatory information resulting from the Company’s ongoing development activities outside of the EUSA Licensed Territories and (v) the Company’s participation in a joint steering committee. The Company determined that the delivered license did not have stand-alone value from the undelivered elements and have accounted for these items as a single bundled deliverable. The Company allocated the upfront consideration of $2.5 million to the bundled unit of accounting and is recognizing it over the Company’s performance period through April 2022, the remaining patent life of tivozanib. The Company recognized approximately $0.4 million, $0.4 million and $14 thousand as revenue during each of the years ended December 31, 2017, 2016 and 2015, respectively, related to the previously deferred upfront consideration. The Company believes the regulatory milestones that may be achieved under the EUSA agreement are consistent with the definition of a milestone included in ASC 605-28, Revenue Recognition—Milestone Method In August 2017, the European Commission (“EC”) approved tivozanib (FOTIVDA) for the treatment of adult patients with aRCC, as described above. Accordingly, the Company earned a $4.0 million research and development reimbursement payment upon the EMA approval in RCC that was paid by EUSA in September 2017. In accordance with ASC 605-28, Revenue Recognition—Milestone Method In September 2017, EUSA elected to opt-in to co-develop the TiNivo trial. As a result of EUSA’s exercise of its opt-in right, it became an active participant in the ongoing conduct of the TiNivo trial and is able to utilize the resulting data from the TiNivo trial for regulatory and commercial purposes in its Licensed Territories. Upon exercise of its opt-in right, EUSA became responsible for funding 50% of the total estimated costs of the TiNivo trial, up to $2.0 million. EUSA’s opt-in rights were identified as a contingent deliverable at the inception of the arrangement and, because they did not contain a significant incremental discount, were not considered as a deliverable in connection with the Company’s initial accounting for the EUSA arrangement. Accordingly, the Company evaluated EUSA’s exercise of its opt-in rights as a separate arrangement. The Company is accounting for the joint development activities relative to the TiNivo trial as a joint risk-sharing collaboration in accordance with ASC 808, Collaborative Arrangements because EUSA is an active participant in the ongoing TiNivo trial and is exposed to significant risk and rewards in connection with the activity. s the TiNivo trial was ongoing at the time EUSA made its opt-in election and EUSA paid the $2.0 million maximum amount of cost sharing per the license agreement in advance. The remaining $1.1 million in prepaid cost sharing was classified as deferred research and development reimbursements as of December 31, 2017 and will continue to be recognized as a reduction in research and development expenses as the related TiNivo trial costs are incurred over the duration of the trial. . Novartis In August 2015, the Company entered into a license agreement with Novartis. Under the license agreement, the Company granted to Novartis the exclusive right to develop and commercialize worldwide the Company’s proprietary antibody AV-380 and related AVEO antibodies that bind to growth differentiation factor 15 (“GDF15”) for the treatment and prevention of diseases and other conditions in all indications in humans (the “Product”). Pursuant to the license agreement, Novartis made an upfront payment to the Company of $15.0 million in September 2015. Novartis also acquired the Company’s inventory of clinical quality, AV-380 biological drug substance and reimbursed the Company for approximately $3.5 million for such existing inventory. As of December 31, 2017, the Company is eligible to receive up to $51.2 million in potential clinical and development milestone payments, up to $105.0 million in potential regulatory milestone payments tied to the commencement of clinical trials and to regulatory approvals of products developed under the license agreement in the United States, the European Union and Japan, and up to $150.0 million in potential commercial milestone payments based on annual net sales of such products. If the product is commercialized, the Company would be eligible to receive tiered royalties on net sales of approved products ranging from the high single digits to the low double-digits. Certain milestones achieved by Novartis or timelines associated with the development plan would trigger milestone payment obligations from the Company to St. Vincent’s Hospital Sydney Limited (“St. Vincent’s”) under the Company’s amended and restated license agreement with St. Vincent’s. In addition, specified royalties on approved products, if any, will be payable to St. Vincent’s, and the Company and Novartis will share that obligation equally. Novartis has responsibility under the license agreement for the development, manufacture and commercialization of the Company’s antibodies and any resulting approved therapeutic products. The Company has agreed that it will not directly or indirectly develop, manufacture or commercialize any GDF15 modulator as a human therapeutic during the term of the license agreement. Activities under the agreement with Novartis were evaluated under ASC 605-25 to determine whether such activities represented a multiple element revenue arrangement. The agreement with Novartis includes the following non-contingent deliverables: (i) the Company’s grant of an exclusive, worldwide license to develop and commercialize the Product; (ii) the Company’s obligation to transfer all technical knowledge and data useful in the development and manufacture of the Product; and (iii) the Company’s obligation to cooperate with Novartis’ requests for transition assistance during a 90-day period. The Company determined that the option to purchase the Company’s existing inventory was a contingent deliverable. The Company determined the delivered license and obligation to transfer technical knowledge and data have standalone value from the undelivered cooperation. The Company allocated the upfront consideration of $15.0 million to the delivered license and technical knowledge and recognized this amount as revenue during the year ended December 31, 2015. The relative selling price of the undelivered cooperation had de minimis The Company received a cash payment of $3.5 million related to the delivery of its inventory of clinical quality drug substance to Novartis during the three months ended March 31, 2016. In February 2017, Novartis paid the Company $1.8 million out of its future payment obligations under the license agreement. The funds were used to satisfy a $1.8 million time-based milestone obligation that the Company owed to St. Vincent’s in March 2017. Novartis will reduce any subsequent payment obligations to the Company, if any, by the $1.8 million. The Company recognized the $1.8 million of consideration as revenue during the three months ended March 31, 2017, as the amount was fixed and determinable and non-refundable, and the Company does not have any further performance obligations to Novartis in connection with the license agreement. This payment reduces the aggregate future amounts potentially payable by Novartis to the Company, if any, under the license agreement by the $1.8 million, but does not amend any other terms of the Novartis license agreement. No milestone payments have been earned as of December 31, 2017. Pharmstandard In August 2015, the Company entered into a license agreement with JSC “Pharmstandard-Ufimskiy Vitamin Plant,” a company registered under the laws of the Russian Federation (“Pharmstandard”). Pharmstandard is a subsidiary of Pharmstandard OJSC. Under the license agreement, the Company granted to Pharmstandard the right to develop, manufacture and commercialize tivozanib in the territories of Russia, Ukraine and the Commonwealth of Independent States for all diseases and conditions in humans, excluding non-oncologic ocular conditions. In June 2016, following unsuccessful efforts to renegotiate certain terms of the Pharmstandard license agreement, Pharmstandard notified the Company that due to economic and market changes in Russia it was exercising its right to terminate the license agreement effective September 9, 2016. Upon the effective date of the termination, the remaining deferred revenue of approximately $0.9 million was recognized. The Company recognized approximately $0, $0.9 million as revenue during the years ended December 31, 2017, 2016 and 2015, respectively. Ophthotech In November 2014, the Company entered into a research and exclusive option agreement (the “Option Agreement”), with Ophthotech Corporation (“Ophthotech”) pursuant to which the Company provided Ophthotech an exclusive option to enter into a definitive license agreement whereby the Company would grant Ophthotech the right to develop and commercialize tivozanib outside of Asia and the Middle East for the potential diagnosis, prevention and treatment of non-oncologic diseases or conditions of the eye in humans. Ophthotech paid the Company $0.5 million in consideration for the grant of the option. In January 2017, Ophthotech formally notified the Company that it would not be able to develop tivozanib and exercised its right to terminate the Option Agreement effective April 3, 2017. Under the Option Agreement, the Company received a cash payment of $0.5 million during the year ended December 31, 2014. The Company deferred the payment and was recording the deferred revenue over the Company’s period of performance, which was estimated to be through December 2017. Upon the effective date of the termination, the remaining deferred revenue of approximately $0.1 million was recognized. The Company recorded approximately $0.1 million, $0.1 million and $0.2 million of revenue during the years ended December 31, 2017, 2016 and 2015, respectively. Biodesix In April 2014, the Company entered into a worldwide co-development and collaboration agreement with Biodesix (the “Biodesix Agreement”) to develop and commercialize ficlatuzumab, the Company’s HGF inhibitory antibody. Under the Biodesix Agreement, the Company granted Biodesix perpetual, non-exclusive rights to certain intellectual property, including all clinical and biomarker data related to ficlatuzumab, to develop and commercialize VeriStrat ® ® Under the Biodesix Agreement, with the exception of the costs incurred for the FOCAL trial, the Company and Biodesix are each required to contribute 50% of all clinical, regulatory, manufacturing and other costs to develop ficlatuzumab. Pursuant to the Biodesix Agreement, Biodesix was obligated to fund all costs of the FOCAL trial up to a cap of $15 million, following which all costs of the FOCAL trial would be shared equally. In connection with the discontinuation of the FOCAL trial on October 14, 2016, the Company and Biodesix amended the Biodesix Agreement. Under the amendment, the Company agreed to share 50% of the shutdown costs for the FOCAL trial after August 1, 2016. In return for bearing these shutdown costs, the Company will be entitled to recover an agreed multiple of the additional costs borne by the Company out of any income Biodesix receives from the partnership in connection with the licensing or commercialization of ficlatuzumab. Following such recovery, the payment structure under the original Biodesix Agreement, which generally provides that the parties share equally in any costs and revenue, will resume without such modification. In addition, the Company and Biodesix are funding investigator-sponsored clinical trials, including ficlatuzumab in combination with ERBITUX ® Pending marketing approval or the sublicense of ficlatuzumab, and subject to the negotiation of a commercialization agreement, each party would share equally in commercialization profits and losses, subject to the Company’s right to be the lead commercialization party. Prior to the first commercial sale of ficlatuzumab, each party has the right to elect to discontinue participating in further development or commercialization efforts with respect to ficlatuzumab, which is referred to as an “Opt-Out”. If either AVEO or Biodesix elects to Opt-Out, with such party referred to as the “Opting-Out Party”, then the Opting-Out Party shall not be responsible for any future costs associated with developing and commercializing ficlatuzumab other than any ongoing clinical trials. If AVEO elects to Opt-Out, it will continue to make the existing supply of ficlatuzumab available to Biodesix for the purposes of enabling Biodesix to complete the development of ficlatuzumab, and Biodesix will have the right to commercialize ficlatuzumab. After election of an Opt-Out, the non-opting out party shall have sole decision-making authority with respect to further development and commercialization of ficlatuzumab. Additionally, the Opting-Out Party shall be entitled to receive, if ficlatuzumab is successfully developed and commercialized, a royalty equal to 10% of net sales of ficlatuzumab throughout the world, if any, subject to offsets under certain circumstances. Prior to any Opt-Out, the parties shall share equally in any payments received from a third-party licensee; provided, however, after any Opt-Out, the Opting-Out Party shall be entitled to receive only a reduced portion of such third-party payments. The agreement will remain in effect until the expiration of all payment obligations between the parties related to development and commercialization of ficlatuzumab, unless earlier terminated. Activities under the Biodesix Agreement were evaluated under ASC 605-25 to determine whether such activities represented a multiple element revenue arrangement. The Biodesix Agreement includes the following non-contingent deliverables: (i) the Company’s obligation to deliver perpetual, non-exclusive rights to certain intellectual property including clinical and biomarker data related to ficlatuzumab for use in developing and commercializing VeriStrat; (ii) the Company’s obligation to participate in the joint steering committee; and (iii) the Company’s obligation to provide its existing supply of ficlatuzumab for development purposes. The Company concluded that any deliverables that would be delivered after the FOCAL trial is complete were contingent deliverables because these services are contingent upon the results of the FOCAL trial. As these deliverables were contingent, and are not at an incremental discount, they are not evaluated as deliverables at the inception of the arrangement. These contingent deliverables will be evaluated and accounted for separately as each related contingency is resolved. As of December 31, 2017, no contingent deliverables had been provided by the Company. The Company determined that the perpetual, non-exclusive rights to certain intellectual property for use in developing and commercializing VeriStrat did not have standalone value from the remaining deliverables since Biodesix could not obtain the intended benefit of the license without the remaining deliverables. Since the remaining deliverables will be performed over the same period of performance, there is no difference in accounting for the deliverables as one unit or multiple units of accounting, and therefore, the Company is accounting for the deliverables as one unit of accounting. The Company recorded the consideration earned in connection with the FOCAL trial, which consisted of reimbursements from Biodesix for expenses related to the trial, as a reduction to research and development expense during the period that reimbursable expenses were incurred. As a result of the cost sharing provisions in the Biodesix Agreement, the Company reduced research and development expenses by approximately $0.1 million, $2.5 million and $3.5 million during the years ended December 31, 2017, 2016 and 2015, respectively. The amount due to the Company from Biodesix pursuant to the cost-sharing provision was approximately $0.1 million and $0.8 million at December 31, 2017 and 2016, respectively. Astellas Pharma In February 2011, the Company, together with its wholly-owned subsidiary AVEO Pharma Limited, entered into a collaboration and license agreement (the “Astellas Agreement”) with Astellas Pharma Inc. and certain of its subsidiaries (together, “Astellas”), pursuant to which the Company and Astellas intended to develop and commercialize tivozanib for the treatment of a broad range of cancers. Astellas elected to terminate the agreement effective on August 11, 2014, at which time the tivozanib rights were returned to the Company. In accordance with the Astellas Agreement, committed development costs, including the costs of completing certain tivozanib clinical development activities, continue to be shared equally. The Company accounted for the joint development and commercialization activities in North America and Europe as a joint risk-sharing collaboration in accordance with ASC 808, Collaborative Arrangements Under the agreement, the Company received cash payments related to reimbursable payments and milestone payments of $0 and $0.3 million during the years ended December 31, 2017 and 2016, respectively. Biogen Idec International GmbH In March 2009, the Company entered into an exclusive option and license agreement with Biogen regarding the development and commercialization of the Company’s discovery-stage ErbB3-targeted antibodies, AV-203, for the potential treatment and diagnosis of cancer and other diseases outside of North America. Under the agreement, the Company was responsible for developing ErbB3 antibodies through completion of the first phase 2 clinical trial designed in a manner that, if successful, will generate data sufficient to support advancement to a phase 3 clinical trial. In March 2014, the Company and Biogen amended the exclusive option and license agreement (the “Amendment”). Pursuant to the Amendment, Biogen agreed to the termination of its rights and obligations under the agreement, including Biogen’s option to (i) obtain a co-exclusive (with AVEO) worldwide license to develop and manufacture ErbB3 targeted antibodies and (ii) obtain exclusive commercialization rights to ErbB3 products in countries in the world other than North America. As a result, AVEO has worldwide rights to AV-203. Pursuant to the Amendment, the Company was obligated to use reasonable efforts to seek a collaboration partner for the purpose of funding further development and commercialization of ErbB3 targeted antibodies. The Company is also obligated to pay Biogen a percentage of milestone payments received by AVEO from future partnerships after March 28, 2016 and single digit royalty payments on net sales related to the sale of ErbB3 products, if any, up to cumulative maximum amount of $50 million. The Company concluded that the Amendment materially modified the terms of the agreement and, as a result, required the application of ASC 605-25. Based upon the terms of the Amendment, the remaining deliverables included the Company’s obligation to seek a collaboration partner to fund further development of the program and the Company’s obligation to continue development and commercialization of the licensed products if a collaboration partner is secured (“Development Deliverable”). The Company concluded that its obligation to use best efforts to seek a collaboration partner does not have standalone value from the Development Deliverable upon delivery and thus the deliverables should be treated as a single unit of accounting. Upon modifying the arrangement, the Company had $14.7 million of deferred revenue remaining to be amortized. The Company is not entitled to receive any further consideration from Biogen Idec under the agreement, as amended. The Company allocated a portion of the remaining deferred revenue to the undelivered unit of accounting based upon the Company’s best estimate of the selling price, as the Company determined that neither VSOE nor TPE were available. The Company determined the best estimate of selling price to be approximately $0.6 million and recognized the remaining $14.1 million as collaboration revenue in March 2014. The deferred revenue associated with the undelivered unit of accounting was recognized on a straight-line basis over the period of performance, or through March 2016, when the Company executed its agreement with CANbridge. Under the agreement, the Company recorded revenue of $0, $38 thousand and $0.3 million during the years ended December 31, 2017, 2016 and 2015, respectively. In March 2016, the Company entered into a collaboration and license agreement for AV-203 with CANbridge. See “—CANbridge” herein for a further description of that arrangement. In-License Agreements St. Vincent’s In July 2012, the Company entered into a license agreement with St. Vincent’s, under which the Company obtained an exclusive, worldwide license to research, develop, manufacture and commercialize products for human therapeutic, preventative and palliative applications that benefit from inhibition or decreased expression or activity of GDF15, which is also referred to as MIC-1. Under the agreement, the Company has the right to grant sublicenses subject to certain restrictions. Under the license agreement, St. Vincent’s also granted the Company non-exclusive rights for certain related diagnostic products and research tools. In order to sublicense certain necessary intellectual property rights to Novartis in August 2015, the Company and St. Vincent’s amended and restated the license agreement (the “Amended St. Vincent’s Agreement”). Under the Amended St. Vincent’s Agreement, the Company was required to make an upfront payment to St. Vincent’s of $1.5 million. St. Vincent’s is also eligible to receive up to approximately $16.7 million in connection with development and regulatory milestones and /or defined timelines under the Amended St. Vincent’s Agreement. Royalties for approved products resulting from the Amended St. Vincent’s Agreement will also be payable to St. Vincent’s, and the Company and Novartis will share that obligation equally. Under the license agreement with Novartis, the Company is required to maintain the Amended St. Vincent’s Agreement in effect, and not enter into any amendment that would adversely affect Novartis’ rights during the term of the license agreement with Novartis. During the year ended December 31, 2016, the Company recognized approximately $0.4 million in research and development expense in connection with a milestone obligation due to St. Vincent’s related to the selection of a development candidate. During the year ended December 31, 2017, the Company recognized $1.8 million in research and development expense in connection with a time-based milestone obligation due to St. Vincent’s. Kyowa Hakko Kirin (KHK) In December 2006, the Company entered into a license agreement with KHK under which it obtained an exclusive license, with the right to grant sublicenses subject to certain restrictions, to research, develop, manufacture and commercialize tivozanib, pharmaceutical compositions thereof and associated biomarkers in all potential indications. Its exclusive license covers all territories in the world except for Asia and the Middle East, where KHK has retained the rights to tivozanib. Under the license agreement, the Company obtained exclusive rights in its territory under certain KHK patents, patent applications and know-how related to tivozanib, to research, develop, make, have made, use, import, offer for sale, and sell tivozanib for the diagnosis, prevention and treatment of any and all human diseases and conditions. The Company and KHK each have access to and can benefit from the other party’s clinical data and regulatory filings with respect to tivozanib and biomarkers identified in the conduct of activities under the license agreement. Under the license agreement, the Company is obligated to use commercially reasonable efforts to develop and commercialize tivozanib in its territory. Prior to the first anniversary of the first post-marketing approval sale of tivozanib in its territory, neither the Company nor any of its subsidiaries has the right to conduct certain clinical trials of, seek marketing approval for or commercialize any other cancer product that also works by inhibiting the activity of a VEGF receptor. The Company has upfront, milestone and royalty payment obligations to KHK under the license agreement. Upon entering into the license agreement with KHK, the Company made an upfront payment in the amount of $5.0 million. In March 2010, the Comp

Other Accrued Liabilities

Other Accrued Liabilities	12 Months Ended
	Dec. 31, 2017
Payables And Accruals [Abstract]
Other Accrued Liabilities	(5) Other Accrued Liabilities Other accrued expenses consisted of the following: December 31, 2017 December 31, 2016 (in thousands) Professional fees $ 844 $ 464 Compensation and benefits 1,325 891 Other 289 176 Total $ 2,458 $ 1,531

Loans Payable

Loans Payable	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Loans Payable	(6) Loans Payable On May 28, 2010, the Company entered into a loan and security agreement with Hercules (the “First Loan Agreement”). The First Loan Agreement was subsequently amended in March 2012 (the “2012 Amendment”), September 2014 (the “2014 Amendment”), May 2016 (the “2016 Amendment”) and December 2017 (the “2017 Loan Agreement”). Amounts borrowed under the 2012 Amendment were repaid in full in 2015. Pursuant to the 2014 Amendment, the Company received additional loan proceeds from Hercules in the amount of $10.0 million and was not required to commence principal payments until May 1, 2016, with the last principal payment due on January 1, 2018. An end-of-term payment of approximately $0.5 million continued to be due on January 1, 2018 and was paid on the first business day of 2018. The Company incurred approximately $0.2 million in loan issuance costs paid directly to Hercules, which were offset against the loan proceeds and are accounted for as a loan discount. The 2014 Amendment was accounted for as a loan modification in accordance with ASC 470-50, Debt—Modifications and Extinguishments . In connection with the 2014 Amendment, the Company issued warrants to the lenders to purchase up to 608,696 shares of the Company’s common stock at an exercise price equal to $1.15 per share. The Company recorded the fair value of the warrants of approximately $0.4 million as stockholders’ equity and as a discount to the related loan outstanding and is amortizing the value of the discount to interest expense over the term of the loan using the effective interest method. In July 2017, Hercules exercised all 608,696 warrants. Pursuant to the terms of the warrant, Hercules, at their election, exercised the warrants via a non-cash “net share issuance.” The Company issued Hercules 369,297 shares of its common stock and did not receive any cash proceeds in connection with the warrant exercise. In May 2016, pursuant to the 2016 Amendment, the Company received additional loan proceeds from Hercules in the amount of $5.0 million, which increased the aggregate outstanding principal balance under the First Loan Agreement to $15.0 million. The Company was not required to commence principal payments on the $15 million loan until July 1, 2017, at which time the Company would have been required to make 30 equal monthly payments of principal and interest through December 2019. An end-of-term payment of approximately $0.2 million is due on December 1, 2019. The Company incurred approximately $0.1 million in loan issuance costs paid directly to Hercules, which were offset against the loan proceeds and are accounted for as a loan discount. The 2016 Amendment was accounted for as a loan modification in accordance with ASC 470-50 . Under the 2016 Amendment, from March 1, 2017 through June 30, 2017, the Company could draw down an additional $5.0 million in funding upon confirmation by Hercules, in its reasonable discretion, that the Company had achieved the following conditions: (i) satisfactory developmental progression on a minimum of two (2) clinical programs (other than the TIVO-3 trial) that are either managed directly by the Company or funded, in whole or in part, by the Company and (ii) having an unrestricted cash position greater than or equal to $25.0 million on the date of the draw down request. If the Company drew down the additional $5.0 million in funding, the commencement of principal payments on the aggregate $20.0 million loan balance would be deferred by six months from July 1, 2017 until January 1, 2018. In June 2017, pursuant to the 2016 Amendment, the Company received the additional $5.0 million in loan proceeds from Hercules, which increased the aggregate outstanding principal balance under the First Loan Agreement to $20.0 million and resulted in a six-month deferral in the commencement of principal payments. There was no change in the loan maturity date of December 2019. The Company was not required to commence principal payments on the $20.0 million loan until January 1, 2018, at which time the Company would have been required to make 23 equal monthly payments of principal and interest, in the approximate amount of $0.8 million, through November 2019 and an approximate $5.3 million payment of principal and interest in December 2019, which represented approximately 26% of the entire $20.0 million loan. An additional end-of-term payment of approximately $0.1 million is due on December 1, 2019, which increased the total end-of-term payments under the 2016 Amendment to $0.3 million. In connection with the 2016 Amendment, the Company issued warrants to Hercules to purchase up to 1,202,117 shares of the Company’s common stock at an exercise price equal to $0.87 per share. The Company recorded the fair value of the warrants of approximately $0.7 million as a component of stockholders’ equity and as a discount to the related loan outstanding and is amortizing the value of the discount to interest expense over the term of the loan using the effective interest method. In July 2017, Hercules exercised all 1,202,117 warrants. Pursuant to the terms of the warrant, Hercules, at their election, exercised the warrants via a non-cash “net share issuance.” The Company issued Hercules 846,496 shares of its common stock and did not receive any cash proceeds in connection with the warrant exercise. As part of the 2016 Agreement, Hercules also received an option, subject to the Company’s written consent, not to be unreasonably withheld, to purchase, either with cash or through conversion of outstanding principal under the loan, up to $2.0 million of equity of the Company sold in any sale by the Company to third parties of equity securities resulting in at least $10.0 million in net cash proceeds to the Company, subject to certain exceptions. In connection with the Company’s May 2016 private placement (refer to Note 7), Hercules purchased 259,067 units for cash proceeds of $0.2 million to the Company. This purchase was separate from the $2.0 million equity purchase option under the 2016 Amendment. Each unit in the May 2016 private placement included one share of the Company’s common stock and a PIPE Warrant to purchase one share of the Company’s common stock at an exercise price of $1.00 per share. In July 2017, Hercules exercised its PIPE Warrants with respect to all 259,067 shares of common stock underlying such PIPE Warrants. The Company issued Hercules 259,067 shares of its common stock and received approximately $0.3 million in cash proceeds. In December 2017, the Company entered into an amended and restated loan and security agreement with Hercules to refinance the $20.0 million First Loan Agreement (the “2017 Loan Agreement). The proceeds of the new loan facility were used to retire the existing $20.0 million in secured debt outstanding under the First Loan Agreement. Per the terms of the 2017 Loan Agreement, the new loan facility has a 42-month maturity from closing, no financial covenants, a lower interest rate and an interest-only period of no less than 12 months, which could be extended up to a maximum of 24 months, assuming the achievement of specified milestones relating to the development of tivozanib. Per the 2017 Loan Agreement, Hercules did not receive any additional warrants to purchase shares of the Company’s common stock and no longer has the option, subject to the Company’s written consent, to participate in its future equity financings up to $2.0 million through the purchase of the Company’s common stock either with cash or through the conversion of outstanding principal under the loan. The loan maturity date has been revised from December 2019 to July 2021. The Company is not required to make principal payments until February 1, 2019, at which time the Company will be required to make 29 equal monthly payments of principal and interest, in the approximate amount of $0.8 million, through July 2021. An additional end-of-term payment of approximately $0.8 million is due on July 1, 2021, which increases the total end-of-term payments under the 2014 Amendment, 2016 Amendment and 2017 Loan Agreement to approximately $1.6 million. The end-of-term payments under the 2014 Amendment, in the approximate amount of $0.5 million, and the 2016 Amendment, in the amount of $0.3 million, continue to be due on their original due dates of January 1, 2018 and December 1, 2019, respectively. The financial covenant per the 2016 Amendment to maintain an unrestricted cash position greater than or equal to $10.0 million through the date of completion of our TIVO-3 trial with results that are satisfactory to Hercules has been removed. Per the 2017 Loan Agreement, the current interest rate has been decreased from 11.9% to 9.45%. The Company incurred approximately $0.1 million in loan issuance costs paid directly to Hercules, which are accounted for as a loan discount. The 2017 Loan Agreement was accounted for as a loan modification in accordance with ASC 470-50. The interest-only period could be extended by two 6-month deferrals upon the achievement of specified milestones relating to the development of tizozanib, including (i) on or prior to September 30, 2018, the Company has received positive data with respect to its TIVO-3 trial for the treatment of RCC for patients in the third-line setting which positive data supports the filing for a new drug application with the FDA, subject to confirmation by Hercules at its reasonable discretion, and (ii) on or prior to June 28, 2019, the Company has received approval from the FDA for its tivozanib product for the treatment of RCC for patients in the third-line setting, subject to confirmation by Hercules at its reasonable discretion. The unamortized discount to be recognized over the remainder of the loan period was approximately $1.5 million and $1.0 million as of December 31, 2017 and 2016, respectively. The Company must make interest payments on the loan balance each month it remains outstanding. Per annum interest is payable on the principal balance of the loan each month it remains outstanding at the greater of 9.45% and an amount equal to 9.45% plus the prime rate minus 4.75% as determined daily, provided however, that the per annum interest rate shall not exceed 15.0% (9.45% as of December 31, 2017). The loans are secured by a lien on all the Company’s personal property (other than intellectual property), whether owned or acquired after the date of the First Loan Agreement. The 2017 Loan Agreement define events of default, including the occurrence of an event that results in a material adverse effect upon the Company’s business operations, properties, assets or condition (financial or otherwise), its ability to perform its obligations or upon the ability of the lenders to enforce any of their rights or remedies with respect to such obligations, or upon the collateral under the 2017 Loan Agreement, the related liens or the priority thereof. As of December 31, 2017, the Company was in compliance with all loan covenants, Hercules has not asserted any events of default and the Company does not believe that there has been a material adverse change as defined in the 2017 Loan Agreement. The Company has determined that the risk of subjective acceleration under the material adverse events clause is remote and therefore has classified the outstanding principal in current and long-term liabilities based on the timing of scheduled principal payments. Future minimum payments under the loans payable outstanding as of December 31, 2017 are as follows (amounts in thousands): Year Ending December 31: 2018 $ 2,493 2019 8,725 2020 9,013 2021 6,087 26,318 Less amount representing interest (4,688 ) Less unamortized discount (1,523 ) Less deferred charges (1,630 ) Less loans payable current, net of discount — Loans payable, net of current portion and discount $ 18,477

Common Stock

Common Stock	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Common Stock	(7) Common Stock As of December 31, 2017, the Company had 250,000,000 authorized shares of common stock, $0.001 par value, of which 118,325,396 shares were issued and outstanding. In June 2017, the Company amended its certificate of incorporation, which increased the number of authorized shares of common stock, $0.001 par value, by 50,000,000 from 200,000,000 shares to 250,000,000 shares. The amendment was adopted by the Board of Directors in April 2017 and approved by stockholders at the Annual Meeting of Stockholders held on June 21, 2017 ATM Sales Agreement with Leerink In February 2018, the Company entered into an at-the-market issuance sales agreement (the “Leerink Sales Agreement”), with Leerink Partners LLC (“Leerink”) pursuant to which the Company could issue and sell shares of its common stock from time to time up to an aggregate amount of $50 million, at its option, through Leerink as its sales agent, with any sales of common stock through Leerink being made by any method that is deemed an “at-the-market” offering as defined in Rule 415 promulgated under the Securities Act of 1933, as amended (the “Securities Act”) pursuant to an effective shelf registration statement on Form S-3. The Company agreed to pay Leerink a commission of up to 3% of the gross proceeds of any sales of common stock pursuant to the Leerink Sales Agreement. At the time of issuance of these financial statements, no shares of our common stock have been sold under the Leerink Sales Agreement. On November 30, 2017, the Company filed a shelf registration statement on Form S-3 with the Securities and Exchange Commission (the “SEC”), which covers the offering, issuance and sale of up to $200.0 million of its common stock, preferred stock, debt securities, warrants and/or units (the “2017 Shelf”). The 2017 Shelf (file No. 333-221873) was declared effective by the SEC on December 15, 2017 and was filed to replace the Company’s then existing 2015 Shelf, which was terminated. Public Offering On March 31, 2017, the Company closed an underwritten public offering of 34,500,000 shares of its common stock, including the exercise in full by the underwriter of its option to purchase 4,500,000 shares, at the public offering price of $0.50 per share for gross proceeds of approximately $17.3 million. Certain of the Company’s executive officers and a director purchased an aggregate of 420,000 shares and an entity affiliated with New Enterprise Associates, a greater than 5% stockholder of the Company, purchased 6,000,000 shares in this offering at the same public offering price per share as the other investors. The net offering proceeds to the Company were approximately $15.4 million after deducting underwriting discounts and estimated offering expenses payable by the Company. The Company sold these shares pursuant to the 2015 Shelf (as defined below). Private Placement / PIPE Warrants In May 2016, the Company entered into a securities purchase agreement with a select group of qualified institutional buyers, institutional accredited investors and accredited investors pursuant to which the Company sold 17,642,482 units, at a price of $0.965 per unit, for gross proceeds of approximately $17.0 million. Each unit consisted of one share of the Company’s common stock and a warrant to purchase one share of the Company’s common stock (the “PIPE Warrants”). The PIPE Warrants have an exercise price of $1.00 per share and are exercisable for a period of five years from the date of issuance. Certain of the Company’s directors and executive officers purchased an aggregate of 544,039 units in this offering at the same price as the other investors. The net offering proceeds to the Company were approximately $15.4 million after deducting placement agent fees and other offering expenses payable by the Company. In July 2017, Hercules exercised its PIPE Warrants with respect to all 259,067 shares of common stock underlying such PIPE Warrants, and the Company issued Hercules 259,067 shares of its common stock and received approximately $0.3 million in cash proceeds. As of December 31, 2017, there were PIPE Warrants outstanding and exercisable for 17,383,415 shares of common stock. ATM Sales Agreement with FBR In February 2015, the Company entered into an at-the-market issuance sales agreement (the “FBR Sales Agreement”) with FBR & Co. and MLV & Co. (together “FBR”), pursuant to which the Company could issue and sell shares of its common stock from time to time up to an aggregate amount of $17.9 million, at the Company’s option, through FBR as its sales agent, with any sales of common stock through FBR being made by any method that is deemed an “at-the-market” offering as defined in Rule 415 promulgated under the Securities Act pursuant to an effective shelf registration statement on Form S-3. The Company agreed to pay FBR a commission of up to 3% of the gross proceeds of any sales of common stock pursuant to the FBR Sales Agreement. On May 7, 2015, the Company filed a shelf registration statement on Form S-3 with the SEC, which covered the offering, issuance and sale by the Company of up to $100.0 million of its common stock, preferred stock, debt securities, warrants and/or units (the “2015 Shelf”). The 2015 Shelf was filed to replace the Company’s existing $250.0 million shelf registration statement (the “2012 Shelf”). On May 7, 2015, the Company also amended its FBR Sales Agreement to provide for the offering, issuance and sale by the Company of up to $15.0 million of its common stock under the 2015 Shelf, which replaced the Company’s existing $17.9 million offering that expired along with the expired 2012 Shelf. Through August 2015, the Company sold approximately 5.9 million shares pursuant to the FBR Sales Agreement, as amended, resulting in proceeds of approximately $10.2 million, net of commissions and issuance costs. In June 2017, the Company sold approximately 6.5 million shares pursuant to the FBR Sales Agreement, as amended, resulting in proceeds of approximately $8.8 million, net of commissions and issuance costs. No shares were sold between August 2015 and June 2017, and between July 2017 and December 15, 2017 under the FBR Sales Agreement. The FBR Sales Agreement has expired.

Stock-based Compensation

Stock-based Compensation	12 Months Ended
	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-based Compensation	(8) Stock-based Compensation Stock Incentive Plan The Company maintains the 2010 Stock Incentive Plan (the “Plan”) for employees, consultants, advisors, and directors, as amended in March 2013, June 2014 and June 2017. The Plan provides for the grant of equity awards such as stock options and restricted stock. In June 2017, the Company amended the Plan to increase the total number of shares reserved under the Plan by 3,500,000 from 8,500,000 shares to 12,000,000 shares. The amendment was adopted by the Board of Directors in February 2017 and approved by stockholders at the Annual Meeting of Stockholders held on June 21, 2017. The Plan provides that the exercise price of incentive stock options cannot be less than 100% of the fair market value of the common stock on the date of the award for participants who own less than 10% of the total combined voting power of stock of the Company and not less than 110% for participants who own more than 10% of the total combined voting power of the stock of the Company. Options and restricted stock granted under the Plan vest over periods as determined by the Board, which generally are equal to four years. Options generally expire ten years from the date of grant. As of December 31, 2017, there were 3,549,657 shares of common stock available for future issuance under the Plan. The following table summarizes stock option activity during the year ended December 31, 2017: Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term Aggregate Intrinsic Value Outstanding at January 1, 2017 4,858,678 $ 2.31 Granted 3,455,135 $ 1.40 Exercised (17,576 ) $ 0.87 Forfeited (758,279 ) $ 1.03 Outstanding at December 31, 2017 7,537,958 $ 2.00 7.49 $ 10,709,000 Exercisable at December 31, 2017 3,582,756 $ 2.67 6.06 $ 5,075,000 Stock options to purchase 178,564 shares of common stock contain performance-based milestone conditions, which were not deemed probable of vesting at December 31, 2017. The aggregate intrinsic value is based upon the Company’s closing stock price of $2.79 on December 29, 2017, the last trading day of the year. The fair value of stock options subject only to service or performance conditions that are granted to employees is estimated on the date of grant using the Black-Scholes option-pricing model using the assumptions noted in the following table: Years Ended December 31, 2017 2016 2015 Volatility factor 71.82% - 80.15% 72.18% - 74.47% 73.04% - 78.70% Expected term (in years) 5.50 - 6.25 3.00 - 6.25 5.50 - 6.25 Risk-free interest rates 1.84% - 2.22% 1.07% - 2.01% 1.54% - 1.93% Dividend yield — — — The risk-free interest rate is determined based upon the United States Treasury’s rates for U.S. Treasury zero-coupon bonds with maturities similar to those of the expected term of the options being valued. The Company does not expect to pay dividends in the foreseeable future. In July 2016, the Company began calculating volatility using its historical data. Previously, the Company did not have sufficient history to support a calculation of volatility using only its historical data. As such, prior to July 2016, the Company used a weighted-average volatility considering the Company’s own volatility since March 2010 and the volatilities of several peer companies. For purposes of identifying similar entities, the Company considered characteristics such as industry, length of trading history, similar vesting terms and in-the-money option status. Due to lack of available option activity data, the Company elected to use the “simplified” method for “plain vanilla” options to estimate the expected term of the stock option grants. Under this approach, the weighted-average expected life is presumed to be the average of the vesting term and the contractual term of the option. Based upon these assumptions, the weighted-average grant date fair value of stock options granted during the years ended December 31, 2017, 2016 and 2015 was $0.97, $0.65 and $0.75, respectively. On January 1, 2017, the Company adopted ASU No. 2016-09, Compensation–Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting As of December 31, 2017, there was $3.4 million of total unrecognized stock-based compensation expense related to stock options granted to employees under the Plan. The expense is expected to be recognized over a weighted-average period of 2.6 years. The intrinsic value of options exercised during the years ended December 31, 2017, 2016 and 2015 was $46,000, $6,000 and $58,000, respectively. Stock Incentive Plan—Restricted Stock The Company periodically grants awards of restricted stock to employees. These awards typically vest upon completion of the requisite service period or upon achievement of specified performance targets. The fair value of restricted stock awards that vested was $0 in the year ended December 31, 2017, and $0.1 million in each of the years ended December 31, 2016 and 2015. Employee Stock Purchase Plan In February 2010, the Board of Directors adopted the 2010 Employee Stock Purchase Plan (the “ESPP”) pursuant to which the Company may sell up to an aggregate of 250,000 shares of Common Stock, as amended in March 2013. The ESPP allows eligible employees to purchase common stock at a price per share equal to 85% of the lower of the fair market value of the common stock at the beginning or end of each six-month period during the term of the ESPP. The Company has reserved 764,000 shares of common stock under the ESPP. As of December 31, 2017, there were 307,282 shares available for future issuance under the ESPP. Pursuant to the ESPP, the Company did not sell any shares of common stock during the years ended December 31, 2017 and December 31, 2016. For the year ended December 31, 2015, the Company sold a total of 7,138 shares of common stock at purchase prices of $0.75 and $1.07, respectively, which represent 85% of the closing price of the Company’s common stock on June 30, 2015 and December 31, 2015, respectively. The total stock-based compensation expense recorded as a result of the ESPP was approximately $3 thousand, $2 thousand and $27 thousand during the years ended December 31, 2017, 2016 and 2015, respectively.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	( 9) Commitments and Contingencies Operating Leases The Company leases office and has leased lab space and equipment under various operating lease agreements. Rent expense under the operating leases amounted to $0.6 million, $0.6 million and $(9.1) million for the years ended December 31, 2017, 2016 and 2015, respectively. The net rent credit for the year ended December 31, 2015 was recorded within operating expenses and allocated to research and development and general and administrative expense based upon the use of the underlying facility space. Refer to the following paragraphs and Note 12 for further discussion of the net rent credit recognized in 2015. In May 2015, the Company began leasing office space under a cancellable arrangement. The Company recognized rent expense of approximately $0.2 million related to this lease during the year ended December 31, 2015. On May 9, 2012, the Company entered into a lease agreement with BMR-650 E KENDALL B LLC (“BMR”), under which the Company agreed to lease 126,065 square feet of space located at 650 East Kendall Street, Cambridge, Massachusetts to be used for office, research and laboratory space. The initial term of the lease agreement was approximately twelve years and seven months (the “initial term”). The Company has determined that the lease should be classified as an operating lease. In order to make the space usable for the Company’s operations, substantial improvements were made to the space. These improvements were planned, managed and carried out by the Company and the improvements were tailored to the Company’s needs. BMR agreed to reimburse the Company for up to $14.9 million of the improvements, and the Company bore all risks associated with any cost overruns that may be incurred. As such, the Company determined it was the owner of the improvements and, as such, the Company accounted for tenant improvement reimbursements from BMR as a lease incentive. The Company recorded a deferred lease incentive (included as a component of the deferred rent balance in the accompanying consolidated balance sheets) and the incentive was amortized as an offset to rent expense over the term of the lease. Rent expense, inclusive of the escalating rent payments, was recognized on a straight-line basis over the initial term of the lease agreement. Refer to Note 12 for further discussion regarding the termination of this lease. The Company recognized rent expense of approximately ($9.5) and $4.3 million related to the lease during the years ended December 31, 2015 and 2014, respectively. The expense recognized during the years ended December 31, 2015 and 2014 included the recognition of deferred rent credits totaling $10.6 million and $3.8 million, respectively, following the termination of the lease agreement. Employment Agreements Certain key executives are covered by severance and change in control agreements. Under these agreements, if the executive’s employment is terminated without cause or if the executive terminates his employment for good reason, such executive will be entitled to receive severance equal to his base salary, benefits and prorated bonuses for a period of time equal to either 12 months or 18 months, depending on the terms of such executive’s individual agreement. In addition, in December 2007, the Company approved a key employee change in control severance benefits plan, which was amended in November 2009, and which provides for severance and other benefits under certain qualifying termination events upon a change in control for a period of time ranging from 6 months to 18 months, depending upon the position of the key employee. Refer to Note 15 for further discussion of legal contingencies.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	( 10) Income Taxes The Company accounts for income taxes under the provisions of ASC 740. The Company recorded a $0.1 million tax provision for foreign withholding taxes in each of the years ended December 31, 2017 and 2016 in connection with the $1.0 million in reimbursement payments in 2017 related to manufacturing development activities conducted by the Company prior to the Effective Date and the $1.0 million upfront payment by CANbridge in March 2016 upon the execution of the collaboration and license agreement. For the year ended December 31, 2015, the Company did not have any federal, state, or foreign income tax expense as it generated taxable losses in all filing jurisdictions. A reconciliation of the expected income tax benefit computed using the federal statutory income tax rate to the Company’s effective income tax rate is as follows for the years ended December 31, 2017, 2016 and 2015: Years Ended December 31, 2017 2016 2015 Income tax computed at federal statutory tax rate 34.0% 34.0% 34.0% State taxes, net of federal benefit 5.3% 5.2% 5.3% Research and development credits 0.4% 1.4% 2.0% Other permanent differences (20.8)% 6.1% (2.0)% Foreign rate differential 0.0% (0.1)% (0.1)% Foreign withholding taxes (0.2)% (0.4)% — SEC settlement liability 0.0% — (9.1)% Excess benefit stock compensation 0.0% — — Tax reform - rate change (97.5)% — — Other 0.1% (6.6)% (3.8)% Change in valuation allowance 78.7% (39.6)% (26.3)% Total — — — With limited exceptions, the Company has incurred net operating losses from inception. At December 31, 2017, the Company had domestic federal, state, and United Kingdom (UK) net operating loss carryforwards of approximately $503.6 million, $394.3 million, and $6.0 million respectively, available to reduce future taxable income. The federal net operating loss carryforwards expire beginning in 2022 through 2037 and the state loss carryforwards begin to expire in 2030 and continue through 2037 The foreign net operating loss carryforwards in the UK do not expire. The Company also had federal and state research and development tax credit carryforwards of approximately $10.5 million and $4.3 million, respectively, available to reduce future tax liabilities and which expire at various dates. The federal credits expire beginning in 2022 through 2037 and the state credits expire beginning in 2019 through 2032. The net operating loss and research and development carryforwards are subject to review and possible adjustment by the Internal Revenue Service and may be limited in the event of certain changes in the ownership interest of significant stockholders. The Company’s net deferred tax assets as of December 31, 2017 and 2016 are as follows (in thousands): 2017 2016 Deferred tax assets: NOL carryforwards $ 131,683 $ 182,433 Research and development credits 13,913 13,060 Deferred revenue and R&D reimbursements 770 867 Estimated settlement liability 4,664 — Other temporary differences 4,420 4,570 Total deferred tax assets: 155,450 200,930 Deferred tax liabilities: Insurance recovery (4,098 ) — Total deferred tax liabilities: (4,098 ) — Valuation allowance (151,352 ) (200,930 ) Total $ — $ — A full valuation allowance has been recorded in the accompanying consolidated financial statements to offset these deferred tax assets because the future realizability of such assets is uncertain. This determination is based primarily on the Company’s historical losses. Accordingly, future favorable adjustments to the valuation allowance may be required, if and when circumstances change. The valuation allowance decreased by $49.6 million as of December 31, 2017 which was primarily related to the “Tax Cuts and Jobs Act”, which reduced the federal tax rate from 35% to 21%. The valuation allowance increased $10.6 million and $3.9 million during the years ended December 31, 2016 and 2015, respectively, primarily due to the generation of net operating loss carryforwards. As of December 31, 2016, the Company had federal and state net operating losses of approximately $4.1 million related to excess tax deductions that had been excluded from the above table. The benefit of these net operating losses would have been recognized as an increase in additional paid in capital when it resulted in a reduction of taxes payable. In January 2017, the Company adopted ASU 2016-09, Improvements to Employee Share-Based Payment Accounting. As part of the adoption, the Company recorded through retained earnings these additional deferred tax assets of $4.1 million related to previously unrecognized tax losses with an equal and offsetting adjustment to the Company's valuation allowance. The net impact of the adoption on the Company's deferred tax assets was $0. On December 22, 2017, President Trump signed into law The Tax Cuts and Jobs Act (“the Act”). The Act, among other things, contains significant changes to corporate taxation, including reduction of the corporate tax rate from a top marginal rate of 35% to a flat rate of 21%, limitation of the tax deduction for interest expense to 30% of adjusted earnings (except for certain small businesses), limitation of the deduction for net operating losses to 80% of current year taxable income and elimination of net operating loss carrybacks, one time taxation of offshore earnings at reduced rates regardless of whether they are repatriated, elimination of U.S. tax on foreign earnings (subject to certain important exceptions), immediate deductions for certain new investments instead of deductions for depreciation expense over time, and modifying or repealing many business deductions and credits. On December 22, 2017, the SEC issued guidance under Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act directing taxpayers to consider the impact of the U.S. legislation as “provisional” when it does not have the necessary information available, prepared or analyzed (including computations) in reasonable detail to complete its accounting for the change in tax law. The Company recognizes the changes in tax law, including the Act, in the period the law is enacted. Accordingly, the effects of the Act have been recognized in the financial statements for the year ended December 31, 2017. As a result of the change in law, the Company recorded a reduction to its deferred tax assets of $63.3 million and a corresponding reduction to its valuation allowance. As a result, there was no impact to the Company’s income statement due to the reduction in the U.S. corporate tax rate. At December 31, 2017, the Company has not completed its accounting for the tax effects of enactment of the Act; however in certain cases the Company has made a reasonable estimate of the effects of the Act. For the items for which we were able to determine a reasonable estimate and thus are considered provisional, we recorded a $63.3 million reduction to deferred tax assets. The Company’s preliminary estimate of the effects Act, including the remeasurement of deferred tax assets and liabilities, is subject to the finalization of management’s analysis related to certain matters, such as developing interpretations of the provisions of the Act and the filing of the Company’s tax returns. U.S. Treasury regulations, administrative interpretations or court decisions interpreting the Act may require further adjustments and changes in estimates. The final determination of the effects of the Act will be completed as additional information becomes available, but no later than one year from the enactment of the Act. In all cases, the Company will continue to make and refine its calculations as additional analysis is completed. In addition, the Company’s estimates may also be affected as it gains a more thorough understanding of the tax law. The Company applies FASB Interpretation No. 48, “ Accounting for Uncertainty in Income Taxes, an interpretation of FAS 109 Income Taxes The Company may from time to time be assessed interest or penalties by major tax jurisdictions. The Company recognizes interest and penalties related to uncertain tax positions in income tax expense. No interest and penalties have been recognized by the Company to date. The Company anticipates that the amount of unrecognized tax benefits recorded will not change in the next twelve months. The following is a reconciliation of the Company’s gross uncertain tax positions at December 31, 2017, 2016 and 2015: Years Ended December 31, 2017 2016 2015 (in thousands) Amount established upon adoption $ 1,200 $ 1,200 $ 1,200 Additions for current year tax provisions — — — Additions for prior year tax provisions — — — Reductions of prior year tax provisions — — — Balance as of end of year $ 1,200 $ 1,200 $ 1,200

Strategic Restructuring

Strategic Restructuring	12 Months Ended
	Dec. 31, 2017
Restructuring And Related Activities [Abstract]
Strategic Restructuring	(11) Strategic Restructuring On January 6, 2015, the Board of the Company approved a strategic restructuring of the Company that eliminated the Company’s internal research function and aligned the Company’s resources with the Company’s future strategic plans. As part of this restructuring, the Company eliminated approximately two-thirds of the Company’s workforce, or 40 positions across the organization. The Company substantially completed the restructuring during the quarter-ended March 31, 2015. The following table summarizes the components of the Company’s restructuring activity recorded in operating expenses and in accrued expenses in the accompanying consolidated balance sheet: Restructuring amounts at December 31, 2016 Restructuring expense incurred during the year ended December 31, 2017 Restructuring amounts paid during the year ended December 31, 2017 Restructuring amounts accrued at December 31, 2017 Employee severance, benefits and related costs. $ — $ — $ — $ — Restructuring amounts at December 31, 2015 Restructuring expense incurred during the year ended December 31, 2016 Restructuring amounts paid during the year ended December 31, 2016 Restructuring amounts accrued at December 31, 2016 Employee severance, benefits and related costs. $ 357 $ — $ (357 ) $ —

Facility Lease Exit

Facility Lease Exit	12 Months Ended
	Dec. 31, 2017
Facility Lease Exit [Abstract]
Facility Lease Exit	(12) Facility Lease Exit On May 9, 2012, the Company entered into a lease agreement with BMR-650 E KENDALL B LLC (“BMR”), under which the Company agreed to lease 126,065 square feet of space located at 650 East Kendall Street, Cambridge, Massachusetts to be used for office, research and laboratory space. The initial term of the lease agreement was approximately twelve years and seven months (the “initial term”). The Company had determined that the lease should be classified as an operating lease. In order to make the space usable for the Company’s operations, substantial improvements were made to the space. These improvements were planned, managed and carried out by the Company and the improvements were tailored to the Company’s needs. BMR agreed to reimburse the Company for up to $14.9 million of the improvements, and the Company bore all risks associated with any cost overruns that may be incurred. As such, the Company determined it was the owner of the improvements and, as such, the Company accounted for tenant improvement reimbursements from BMR as a lease incentive. The Company recorded a deferred lease incentive (included as a component of the deferred rent balance in the accompanying consolidated balance sheets) and the incentive was amortized as an offset to rent expense over the term of the lease. Rent expense, inclusive of the escalating rent payments, was recognized on a straight-line basis over the initial term of the lease agreement. In September 2014, the Company entered into the Lease Termination Agreement pursuant to which the Company immediately surrendered leased space at 650 East Kendall Street in Cambridge, Massachusetts that it had previously ceased using earlier in 2014. In connection with the Lease Termination Agreement, the Company agreed to pay the landlord a termination fee totaling $15.6 million. The Company also agreed to surrender its remaining leased space upon 90 days written notice prior to September 24, 2015. In February 2015, the Company provided notice that it would surrender the remaining space on May 29, 2015. Accordingly, the Company revised the estimated useful life of its leasehold improvements related to this office space and amortized such assets through May 2015, resulting in an additional $2.9 million of depreciation expense during the six months ended June 30, 2015. Similarly, the Company accelerated the amortization of its deferred rent and leasehold improvement allowance associated with this office space through May 2015, resulting in an additional $3.5 million of amortization during the six months ended June 30, 2015. The Company recognized rent expense of approximately ($9.5) million and $4.3 million related to the lease during the years ended December 31, 2015 and 2014, respectively. The net rent credit for the year ended December 31, 2015 and December 31, 2014 were recorded within operating expenses and allocated to research and development and general and administrative expense based upon the use of the underlying facility space. The expense recognized during the years ended December 31, 2015 and 2014 include the recognition of deferred rent credits totaling $10.6 million and $3.8 million, respectively, following the termination of the lease agreement. The following table summarizes the components of the Company’s lease exit activity recorded in current liabilities at December 31, 2015: Lease Exit amounts accrued at December 31, 2014 Accretion Expense incurred during the year ended December 31, 2015 Amounts paid during the year ended December 31, 2015 Additional expense incurred during the year ended December 31, 2015 Amounts accrued at December 31, 2015 Lease exit costs $ 4,981 224 $ (5,477 ) $ 272 $ — No costs were incurred during the year ended December 31, 2016 or 2017.

Employee Benefit Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2017
Compensation And Retirement Disclosure [Abstract]
Employee Benefit Plan	( 13) Employee Benefit Plan In 2002, the Company established the AVEO Pharmaceuticals, Inc. 401(k) Plan (the “401(k) Plan”) for its employees, which is designed to be qualified under Section 401(k) of the Internal Revenue Code. Eligible employees are permitted to contribute to the 401(k) Plan within statutory and 401(k) Plan limits. The Company makes matching contributions of 50% of the first 5% of employee contributions. The Company made matching contributions of $0.1 million for each of the years ended December 31, 2017, 2016 and 2015.

Quarterly Results (Unaudited)

Quarterly Results (Unaudited)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Quarterly Results (Unaudited)	( 14) Quarterly Results (Unaudited) Three Month Ended March 31, 2017 June 30, 2017 September 30, 2017 December 31, 2017 (in thousands, expect per share data) (unaudited) Collaboration and licensing revenue $ 2,532 $ 351 $ 4,614 $ 82 Operating expenses 10,287 9,183 6,767 10,153 Loss from operations (7,755 ) (8,832 ) (2,153 ) (10,071 ) Change in fair value of PIPE warrant liability (484 ) (23,925 ) (23,538 ) 14,207 Other expense, net (551 ) (530 ) (655 ) (637 ) Provision for income taxes (50 ) — (51 ) — Net income (loss) $ (8,840 ) $ (33,287 ) $ (26,397 ) $ 3,499 Basic net income (loss) per share Net income (loss) per share $ (0.12 ) $ (0.30 ) $ (0.22 ) $ 0.03 Weighted average number of common shares outstanding 76,246 110,550 118,006 118,323 Dilutive net income (loss) per share Net income (loss) per share $ (0.12 ) $ (0.30 ) $ (0.22 ) $ (0.08 ) Weighted average number of common shares and dilutive common share equivalents outstanding 76,246 110,550 118,006 130,108 Three Month Ended March 31, 2016 June 30, 2016 September 30, 2016 December 31, 2016 (in thousands, expect per share data) (unaudited) Collaboration and licensing revenue $ 1,203 $ 193 $ 992 $ 127 Operating expenses 8,435 7,335 6,585 9,553 Loss from operations (7,232 ) (7,142 ) (5,593 ) (9,426 ) Change in fair value of PIPE warrant liability — (996 ) 1,178 4,569 Other expense, net (377 ) (468 ) (551 ) (748 ) Provision for income taxes (101 ) — — — Net loss $ (7,710 ) $ (8,606 ) $ (4,966 ) $ (5,605 ) Net loss per share - basic and diluted $ (0.13 ) $ (0.13 ) $ (0.07 ) $ (0.07 ) Weighted average number of common shares outstanding 58,166 66,917 75,861 75,863

Legal Proceedings

Legal Proceedings	12 Months Ended
	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Legal Proceedings	(15) Legal Proceedings Two class action lawsuits have been filed against the Company and certain of its former officers and directors, (Tuan Ha-Ngoc, David N. Johnston, William Slichenmyer, and Ronald DePinho), in the United States District Court for the District of Massachusetts, one captioned Paul Sanders v. Aveo Pharmaceuticals, Inc., et al., No. 1:13-cv-11157-JLT, filed on May 9, 2013, and the other captioned Christine Krause v. AVEO Pharmaceuticals, Inc., et al., No. 1:13-cv-11320-JLT, filed on May 31, 2013. On December 4, 2013, the District Court consolidated the complaints as In re AVEO Pharmaceuticals, Inc. Securities Litigation et al The Company has agreed to use its best efforts to issue and deliver the Settlement Warrants within ten business days following the effective date of the final approval of the Stipulation. The Company evaluates developments in legal proceedings on a quarterly basis. The Company records an accrual for loss contingencies to the extent that the Company concludes that it is probable that a liability has been incurred and the amount of the related loss can be reasonably estimated. In December 2017, upon entering into the MOU, this settlement became estimable and probable. Accordingly, the Company recorded an estimated $17.1 million contingent liability, including $15.0 million for the cash portion of the settlement with a corresponding insurance recovery for the 100% portion to be paid directly by certain of the Company’s insurance carriers, and an approximate $2.1 million estimate for the warrant portion of the settlement with a corresponding non-cash charge to the Statement of Operations as a component of operating expenses. In February 2018, the insurance carriers funded the settlement escrow account for the $15.0 million cash settlement. Refer to Note 3, “Potential Class Action Settlement” for further discussion of the warrants. On July 3, 2013, the staff, or SEC Staff, of the SEC served a subpoena on the Company for documents and information concerning tivozanib, including related communications with the FDA, investors and others. In September 2015, the SEC Staff invited the Company to discuss the settlement of potential claims asserting that the Company violated federal securities laws by omitting to disclose to investors the recommendation by the staff of the FDA on May 11, 2012, that the Company conduct an additional clinical trial with respect to tivozanib. On March 29, 2016, the SEC filed a complaint against the Company and three of its former officers in the U.S. District Court for the District of Massachusetts alleging that the Company misled investors about its efforts to obtain FDA approval for tivozanib. Without admitting or denying the allegations in the SEC’s complaint, the Company consented to the entry of a final judgment pursuant to which the Company paid the SEC a $4.0 million civil penalty to settle the SEC’s claims against it. As this settlement was probable and estimable as of December 31, 2015, the Company recorded an estimated settlement liability of $4.0 million and recorded a corresponding loss in the Statement of Operations as a component of operating expenses. On March 31, 2016, the District Court entered a final judgment which (i) approved the settlement; (ii) permanently enjoined the Company from violating Section 17(a) of the Securities Act of 1933, as amended, Sections 10(b) and 13(a) of the Securities Exchange Act of 1934, as amended, and rules 10b-5, 12b-20, 13a-1, 13a-11 and 13a-13 promulgated thereunder; and (iii) ordered the Company to pay the agreed-to civil penalty. On September 15, 2017 and October 31, 2017, respectively, two of the Company’s former officers consented to entry of final judgment to settle the SEC’s claims against them. The Company is not a party to the litigation between the SEC and the remaining former officer, and the Company can make no assurance regarding the outcome of that action or the SEC’s claims against that individual.

Significant Accounting Polici24

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Revenue Recognition	Revenue Recognition The Company’s revenues are generated primarily through collaborative research, development and commercialization agreements. The terms of these agreements generally contain multiple elements, or deliverables, which may include (i) licenses, or options to obtain licenses, to the Company’s technology, (ii) research and development activities to be performed on behalf of the collaborative partner, and (iii) in certain cases, services in connection with the manufacturing of pre-clinical and clinical material. Payments to the Company under these arrangements typically include one or more of the following: non-refundable, upfront license fees; option exercise fees; funding of research and/or development efforts; milestone payments; and royalties on future product sales. The Company analyzes its collaboration arrangements to assess whether they are within the scope of ASC 808 to determine whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards dependent on the commercial success of such activities. This assessment is performed throughout the life of the arrangement based on changes in the responsibilities of all parties in the arrangement. For collaboration arrangements that are deemed to be within the scope of ASC 808, the Company first determines which elements of the collaboration are deemed to be within the scope of ASC 808 and those that are more reflective of a vendor-customer relationship and therefore within the scope of ASC 605. The Company’s policy is to recognized amounts received from collaborators in connection with joint operating activities that are within the scope of ASC 808 as a reduction to research and development expense. When evaluating multiple element arrangements under ASC 605, the Company considers whether the deliverables under the arrangement represent separate units of accounting. This evaluation requires subjective determinations and requires management to make judgments about the individual deliverables and whether such deliverables are separable from the other aspects of the contractual relationship. In determining the units of accounting, management evaluates certain criteria, including whether the deliverables have standalone value, based on the relevant facts and circumstances for each arrangement. The consideration received is allocated among the separate units of accounting using the relative selling price method, and the applicable revenue recognition criteria are applied to each of the separate units. The Company determines the estimated selling price for deliverables within each agreement using vendor-specific objective evidence (“VSOE”) of selling price, if available, third-party evidence (“TPE”) of selling price if VSOE is not available, or best estimate of selling price if neither VSOE nor TPE is available. Determining the best estimate of selling price for a deliverable requires significant judgment. The Company typically uses best estimate of selling price to estimate the selling price for licenses to the Company’s proprietary technology, since the Company often does not have VSOE or TPE of selling price for these deliverables. In those circumstances where the Company utilizes best estimate of selling price to determine the estimated selling price of a license to the Company’s proprietary technology, the Company considers market conditions as well as entity-specific factors, including those factors contemplated in negotiating the agreements and internally developed models that include assumptions related to the market opportunity, estimated development costs, probability of success and the time needed to commercialize a product candidate pursuant to the license. In validating the Company’s best estimate of selling price, the Company evaluates whether changes in the key assumptions used to determine the best estimate of selling price will have a significant effect on the allocation of arrangement consideration among multiple deliverables. The Company typically receives non-refundable, upfront payments when licensing its intellectual property in conjunction with a research and development agreement. When management believes the license to its intellectual property does not have stand-alone value from the other deliverables to be provided in the arrangement, the Company generally recognizes revenue attributed to the license on a straight-line basis over the Company’s contractual or estimated performance period, which is typically the term of the Company’s research and development obligations. If management cannot reasonably estimate when the Company’s performance obligation ends, then revenue is deferred until management can reasonably estimate when the performance obligation ends. When management believes the license to its intellectual property has stand-alone value, the Company generally recognizes revenue attributed to the license upon delivery. The periods over which revenue should be recognized are subject to estimates by management and may change over the course of the research and development agreement. Such a change could have a material impact on the amount of revenue the Company records in future periods. Payments or reimbursements resulting from the Company’s research and development efforts for those arrangements where such efforts are considered as deliverables are recognized as the services are performed and are presented on a gross basis so long as there is persuasive evidence of an arrangement, the fee is fixed or determinable, and collection of the related receivable is reasonably assured. Amounts received prior to satisfying the above revenue recognition criteria are recorded as deferred revenue in the accompanying balance sheets. At the inception of each agreement 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 (a) the consideration is commensurate with either (1) the entity’s performance to achieve the milestone, or (2) the enhancement of the value of the delivered item(s) as a result of a specific outcome resulting from the entity’s performance to achieve the milestone, (b) the consideration relates solely to past performance, and (c) the consideration is reasonable relative to all of the deliverables and payment terms within the arrangement. The Company evaluates factors such as the scientific, regulatory, commercial and other risks that must be overcome to achieve the respective milestone, the level of effort and investment required to achieve the respective milestone and whether the milestone consideration is reasonable relative to all deliverables and payment terms in the arrangement in making this assessment. The Company aggregates its milestones into four categories: (i) clinical and development milestones, (ii) regulatory milestones, (iii) commercial milestones, and (iv) patent-related milestones. Clinical and development milestones are typically achieved when a product candidate advances into a defined phase of clinical research or completes such phase. For example, a milestone payment may be due to the Company upon the initiation of a phase 3 clinical trial for a new indication, which is the last phase of clinical development and could eventually contribute to marketing approval by the FDA or other global regulatory authorities. Regulatory milestones are typically achieved upon acceptance of the submission for marketing approval of a product candidate or upon approval to market the product candidate by the FDA or other global regulatory authorities. For example, a milestone payment may be due to the Company upon the FDA’s acceptance of a New Drug Application (“NDA”). Commercial milestones are typically achieved when an approved pharmaceutical product reaches certain defined levels of net sales by the licensee, such as when a product first achieves global sales or annual sales of a specified amount. Patent-related milestones are typically achieved when a patent application is filed or a patent is issued with respect to certain intellectual property related to the applicable collaboration. Revenues from clinical and development, regulatory, and patent-related milestone payments, if the milestones are deemed substantive and the milestone payments are nonrefundable, are recognized upon successful accomplishment of the milestones. The Company has concluded that the clinical and development, regulatory and patent-related milestones pursuant to its current research and development arrangements are substantive. Milestones that are not considered substantive are accounted for as license payments and recognized on a straight-line basis over the remaining period of performance. Revenues from commercial milestone payments are accounted for as royalties and are recorded as revenue upon achievement of the milestone, assuming all other revenue recognition criteria are met.
Research and Development Expenses	Research and Development Expenses Research and development expenses are charged to expense as incurred. Research and development expenses consist of costs incurred in performing research and development activities, including internal costs for salaries, bonuses, benefits, stock-based compensation, facilities, and research-related overhead, and external costs for clinical trials, drug manufacturing and distribution, license fees, consultants and other contracted services.
Warrants Issued in Connection with Private Placement	Warrants Issued in Connection with Private Placement In May 2016, the Company issued PIPE warrants to purchase an aggregate of 17,642,482 shares of common stock in connection with a private placement financing and recorded the warrants as a liability (the “PIPE Warrants”). The Company accounts for warrant instruments that either conditionally or unconditionally obligate the issuer to transfer assets as liabilities regardless of the timing of the redemption feature or price, even though the underlying shares may be classified as permanent or temporary equity. As of December 31, 2017, PIPE Warrants exercisable for 259,067 shares of common stock had been exercised and PIPE Warrants exercisable for 17,383,415 shares of common stock were outstanding. In January 2018, PIPE Warrants with respect to 518,134 shares of common stock underlying such PIPE Warrants were exercised, and the Company issued 518,134 shares of its common stock and received approximately $0.5 million in cash proceeds. Refer to Note 7, “Common Stock—Private Placement / PIPE Warrants” for further discussion of the private placement financing. The PIPE Warrants contain a provision giving the warrant holder the option to receive cash, equal to the fair value of the remaining unexercised portion of the warrant, as cash settlement in the event that there is a fundamental transaction (contractually defined to include various merger, acquisition or stock transfer activities). Due to this provision, ASC 480, Distinguishing Liabilities from Equity The following table rolls forward the fair value of the Company’s PIPE warrant liability, the fair value of which is determined by Level 3 inputs for the year ended December 31, 2017 (in thousands): Issuance of warrants on May 13, 2016 $ 9,344 Decrease in fair value (4,751 ) Fair value at December 31, 2016 $ 4,593 Increase in fair value 33,740 Reduction in warrant liability for PIPE Warrant exercises (587 ) Fair value at December 31, 2017 $ 37,746 The key assumptions used to value the PIPE Warrants were as follows: Original Issuance December 31, 2016 December 31, 2017 Expected price volatility 76.25% 78.18% 84.86% Expected term (in years) 5.00 4.50 3.50 Risk-free interest rates 1.22% 1.93% 2.09% Stock price $ 0.89 $ 0.54 $ 2.79 Dividend yield — — —
Potential Class Action Settlement	Potential Class Action Settlement In December 2017, the Company entered into a binding memorandum of understanding (the “MOU”) with class representatives Bob Levine and William Windham (the “Plaintiffs”), regarding the settlement of a securities class action lawsuit (the “Class Action”) filed in 2013 and pending in the United States District Court for the District of Massachusetts (the “District Court”) against us and certain of our former officers (Tuan Ha-Ngoc, David Johnston, and William Slichenmyer, together, the “Individual Defendants”), In re AVEO Pharmaceuticals, Inc. Securities Litigation et al. , No. 1:13-cv-11157-DJC. As previously disclosed, the Class Action was purportedly brought on behalf of stockholders who purchased our common stock between May 16, 2012 and May 1, 2013 (the “Class”). In December 2017, upon entering into the MOU, this settlement became estimable and probable. Accordingly, the Company recorded an estimated $17.1 million contingent liability, including $15.0 million for the cash portion of the settlement with a corresponding insurance recovery for the 100% portion to be paid directly by certain of the Company’s insurance carriers, and an approximate $2.1 million estimate for the fair value on December 31, 2017 of 2.0 million warrants to purchase shares of its common stock exercisable from the date of issue until the expiration of a one-year period after the date of issue at an exercise price equal to the closing price on December 22, 2017, the trading day prior to the execution of the MOU, which was $3.00 per share (“the Settlement Warrants”) The settlement is subject to the execution of a definitive settlement agreement, notice to the Class, and final approval of the District Court and shall be effective on the date (the “Effective Date”) on which all of the following circumstances have occurred: (a) a final judgment containing the requisite release of claims has been entered by the District Court (“Final Judgment”); (b) no appeal is pending with respect to the Final Judgment; (c) the Final Judgment has not been reversed, modified, vacated or amended; (d) the time to file any appeal from the Final Judgment has expired without the filing of an appeal or an order dismissing the appeal or affirming the Final Judgment has been entered, and any time to file a further appeal (including a writ of certiorari or for reconsideration of the appeal) has expired; and (e) the MOU and any settlement agreement with respect to the claims released in the Final Judgment have not expired or been terminated. The Company as agreed to use its best efforts to issue and deliver the Settlement Warrants within ten business days following the Effective Date. In January 2018, the Company entered into a stipulation of settlement agreement (the “Stipulation”) that was preliminarily approved by the District Court in February 2018. A hearing by the District Court for final approval of the Stipulation has been scheduled for May 30, 2018. Refer to Note 15, “Legal Proceedings” for further discussion of this class action settlement. The estimated fair value of the Settlement Warrants to be issued on the Effective Date has been determined using the Black-Scholes pricing model. The estimated fair value of the Settlement Warrants to be issued on the Effective Date are subject to revaluation at each balance sheet date and any changes in fair value are recorded as a non-cash gain or (loss) in the Statement of Operations as a component of operating expenses until the Settlement Warrants are issued, at which point they will be recorded as equity or as a liability based upon the issuance terms The key assumptions used to estimate the fair value the Settlement Warrants were as follows: December 31, 2017 Expected price volatility 101.52% Expected term (in years) 1.00 Risk-free interest rates 1.76% Stock price $ 2.79 Dividend yield —
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less at the date of purchase and an investment in a U.S. government money market fund to be cash equivalents. Changes in the balance of cash and cash equivalents may be affected by changes in investment portfolio maturities, as well as actual cash disbursements to fund operations. The Company’s cash is deposited in highly-rated financial institutions in the United States. The Company invests in U.S. government money market funds, high-grade, short-term commercial paper, corporate bonds and other U.S. government agency securities, which management believes are subject to minimal credit and market risk. The carrying values of the Company’s cash and cash equivalents approximate fair value due to their short-term maturities.
Marketable Securities	Marketable Securities Marketable securities consist primarily of investments which have expected average maturity dates in excess of three months, but not longer than 24 months. The Company invests in high-grade corporate obligations, including commercial paper, and U. S. government and government agency obligations that are classified as available-for-sale. Since these securities are available to fund current operations they are classified as current assets on the consolidated balance sheets. Marketable securities are stated at fair value, including accrued interest, with their unrealized gains and losses included as a component of accumulated other comprehensive income or loss, which is a separate component of stockholders’ equity. The fair value of these securities is based on quoted prices and observable inputs on a recurring basis. The cost of marketable securities is adjusted for amortization of premiums and accretion of discounts to maturity, with such amortization and accretion recorded as a component of interest expense, net. Realized gains and losses are determined on the specific identification method. Unrealized gains and losses are included in other comprehensive loss until realized, at which point they would be recorded as a component of interest expense, net. Below is a summary of cash, cash equivalents and marketable securities at December 31, 2017 and December 31, 2016: Amortized Cost Unrealized Gains Unrealized Losses Fair Value December 31, 2017 Cash and cash equivalents: Cash and money market funds $ 14,949 $ — $ — $ 14,949 Corporate debt securities — — — — Total cash and cash equivalents 14,949 — — 14,949 Marketable securities: Corporate debt securities due within 1 year $ 17,074 $ 1 $ (5 ) $ 17,070 US government agency securities due within 1 year 1,506 — — 1,506 Total marketable securities 18,580 1 (5 ) 18,576 Total cash, cash equivalents and marketable securities $ 33,529 $ 1 $ (5 ) $ 33,525 December 31, 2016 Cash and cash equivalents: Cash and money market funds $ 14,091 $ — $ — $ 14,091 Corporate debt securities 1,005 — — 1,005 Total cash and cash equivalents 15,096 — — 15,096 Marketable securities: Corporate debt securities due within 1 year 8,246 6 — 8,252 Total marketable securities 8,246 6 — 8,252 Total cash, cash equivalents and marketable securities $ 23,342 $ 6 $ — $ 23,348
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially subject the Company to credit risk primarily consist of cash and cash equivalents, marketable securities and accounts receivable. The Company maintains deposits in highly-rated, federally-insured financial institutions in excess of federally insured limits. The Company’s investment strategy is focused on capital preservation. The Company invests in instruments that meet the high credit quality standards outlined in the Company’s investment policy. This policy also limits the amount of credit exposure to any one issue or type of instrument. The Company’s accounts receivable primarily consists of amounts due to the Company from licensees and collaborators. The Company has not experienced any material losses related to accounts receivable from individual licensees or collaborators.
Fair Value Measurements	Fair Value Measurements The fair value of the Company’s financial assets and liabilities reflects the Company’s estimate of amounts that it would have received in connection with the sale of the assets or paid in connection with the transfer of the liabilities in an orderly transaction between market participants at the measurement date. In connection with measuring the fair value of its assets and liabilities, the Company seeks to maximize the use of observable inputs (market data obtained from sources independent from the Company) and to minimize the use of unobservable inputs (the Company’s assumptions about how market participants would price assets and liabilities). The following fair value hierarchy is used to classify assets and liabilities based on the observable inputs and unobservable inputs used in order to value the assets and liabilities: Level 1: Quoted prices in active markets for identical assets or liabilities. An active market for an asset or liability is a market in which transactions for the asset or liability occur with sufficient frequency and volume to provide pricing information on an ongoing basis. Level 2: Observable inputs other than Level 1 inputs. Examples of Level 2 inputs include quoted prices in active markets for similar assets or liabilities and quoted prices for identical assets or liabilities in markets that are not active. Level 3: Unobservable inputs based on the Company’s assessment of the assumptions that market participants would use in pricing the asset or liability. Financial assets and liabilities are classified in their entirety within the fair value hierarchy based on the lowest level of input that is significant to the fair value measurement. The Company measures the fair value of its marketable securities by taking into consideration valuations obtained from third-party pricing sources. The pricing services utilize industry standard valuation models, including both income and market based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker-dealer quotes on the same or similar securities, issuer credit spreads, benchmark securities and other observable inputs. As of December 31, 2017, the Company’s financial assets valued based on Level 1 inputs consisted of cash and cash equivalents in a U.S. government money market fund and in addition, for 2016, high-grade corporate debt securities, including commercial paper, and its financial assets valued based on Level 2 inputs consisted of high-grade corporate debt securities, including commercial paper, and in addition, for 2017, U.S. government agency securities. During the years ended December 31, 2017 and 2016, the Company did not have any transfers of financial assets between Levels 1 and 2. As of December 31, 2017, the Company’s financial liabilities that were recorded at fair value consisted of warrant liabilities, including the PIPE warrant liability and the estimated fair value of the Settlement Warrants. The fair value of the Company’s loans payable at December 31, 2017 approximates its carrying value, computed pursuant to a discounted cash flow technique using a market interest rate and is considered a Level 3 fair value measurement. The effective interest rate, which reflects the current market rate, considers the fair value of the warrants issued in connection with the loan, loan issuance costs and the deferred financing charge. The following table summarizes the assets and liabilities measured at fair value on a recurring basis at December 31, 2017 and December 31, 2016: Fair Value Measurements as of December 31, 2017 Level 1 Level 2 Level 3 Total (in thousands) Financial assets carried at fair value: Cash and money market funds $ 14,949 $ — $ — $ 14,949 Corporate debt securities — — — — Total cash and cash equivalents $ 14,949 $ — $ — $ 14,949 Marketable securities: Corporate debt securities due within 1 year $ — $ 17,070 $ — $ 17,070 US government agency securities due within 1 year — 1,506 — 1,506 Total marketable securities $ — $ 18,576 $ — $ 18,576 Total cash, cash equivalents and marketable securities $ 14,949 $ 18,576 $ — $ 33,525 Financial liabilities carried at fair value: PIPE warrant liability $ — $ — $ 37,746 $ 37,746 Settlement warrant liability — — 2,073 2,073 Total warrant liabilities $ — $ — $ 39,819 $ 39,819 Fair Value Measurements as of December 31, 2016 Level 1 Level 2 Level 3 Total (in thousands) Financial assets carried at fair value: Cash and money market funds $ 14,091 $ — $ — $ 14,091 Corporate debt securities — 1,005 — 1,005 Total cash and cash equivalents $ 14,091 $ 1,005 $ — $ 15,096 Marketable securities: Corporate debt securities due within 1 year — $ 8,252 — $ 8,252 Total marketable securities $ — $ 8,252 $ — $ 8,252 Total cash, cash equivalents and marketable securities $ 14,091 $ 9,257 $ — $ 23,348 Financial liabilities carried at fair value: PIPE warrant liability $ — $ — $ 4,593 $ 4,593 Total warrant liability $ — $ — $ 4,593 $ 4,593
Property and Equipment	Property and Equipment Property and equipment are stated at cost and are depreciated using the straight-line method over the estimated useful lives of the respective assets. Maintenance and repair costs are charged to expense as incurred. Depreciation expense for the years ended December 31, 2017, 2016 and 2015 was $0, $30 thousand and $9.6 million, respectively. In September 2014, the Company entered into a Lease Termination Agreement (refer to Note 12). As a result, the Company revised the estimated useful life of its leasehold improvements related to this space. In February 2015, the Company provided notice that it would surrender the remaining space on May 29, 2015. Accordingly, the Company again revised the estimated useful life of its leasehold improvements related to this office space and amortized such assets through May 2015, resulting in an additional $2.9 million of depreciation expense during the year ended December 31, 2015.
Long-lived Assets	Long-lived Assets The Company reviews long-lived assets, including property and equipment, for impairment whenever changes in business circumstances indicate that the carrying amount of the asset may not be fully recoverable. The Company recognized $0, $0 and $0.2 million of impairment losses during the years ended December 31, 2017, 2016 and 2015, respectively, primarily related to leasehold improvements.
Basic and Diluted Loss per Common Share	Basic and Diluted Loss per Common Share Basic net loss per share is computed using the weighted average number of common shares outstanding during the period, excluding restricted stock that has been issued but is not yet vested. Diluted net loss per common share is computed using the weighted average number of common shares outstanding and the weighted average dilutive potential common shares outstanding using the treasury stock method. However, for the years ended December 31, 2017, 2016 and 2015, diluted net loss per share is the same as basic net loss per share as the inclusion of weighted average shares of unvested restricted common stock and common stock issuable upon the exercise of stock options and warrants would be anti-dilutive. The following table summarizes outstanding securities not included in the computation of diluted net loss per common share as their inclusion would be anti-dilutive for the years ended December 31, 2017, 2016 and 2015, respectively: Years Ended December 31, 2017 2016 2015 Outstanding stock options 7,537,958 4,858,678 4,796,005 Outstanding warrants 17,383,415 19,453,295 608,696 Unvested restricted stock — — 42,750 Total 24,921,373 24,311,973 5,447,451
Stock-Based Compensation	Stock-Based Compensation Under the Company’s stock-based compensation programs, the Company periodically grants stock options and restricted stock to employees, directors and nonemployee consultants. The Company also issues shares under an employee stock purchase plan. The fair value of all awards is recognized in the Company’s statements of operations over the requisite service period for each award. Awards that vest as the recipient provides service are expensed on a straight-line basis over the requisite service period. Other awards, such as performance-based awards that vest upon the achievement of specified goals, are expensed using the accelerated attribution method if achievement of the specified goals is considered probable. The Company has also granted awards that vest upon the achievement of market conditions. Per Accounting Standards Codification (“ASC”) 718 Share-Based Payments, The Company uses the Black-Scholes option pricing model to value its stock option awards without market conditions, which require the Company to make certain assumptions regarding the expected volatility its common stock price, the expected term of the option grants, the risk-free interest rate and the dividend yield with respect to its common stock. In 2016, the Company began calculating volatility using its historical data. Previously, the Company did not have sufficient history to support a calculation of volatility using only its historical data. As such, prior to 2016, the Company used a weighted-average volatility considering the Company’s own volatility since March 2010 and the volatilities of several peer companies. For purposes of identifying similar entities, the Company considered characteristics such as industry, length of trading history, similar vesting terms and in-the-money option status. Due to the lack of the Company’s own historical data, the Company elected to use the “simplified” method for “plain vanilla” options to estimate the expected term of the Company’s stock option grants. Under this approach, the weighted-average expected life is presumed to be the average of the vesting term and the contractual term of the option. The risk-free interest rate used for each grant is based on the U.S. Treasury yield curve in effect at the time of grant for instruments with a similar expected life. The Company utilizes a dividend yield of zero based on the fact that the Company has never paid cash dividends and has no present intention to pay cash dividends. The fair value of equity-classified awards to employees and directors are measured at fair value on the date the awards are granted. Awards to nonemployee consultants are recorded at their fair values and are re-measured as of each balance sheet date until the recipient’s services are complete. During the years ended December 31, 2017, 2016 and 2015, the Company recorded the following stock-based compensation expense: Years Ended December 31, 2017 2016 2015 (in thousands) Research and development $ 290 $ 293 $ 298 General and administrative 799 706 765 Restructuring — — 69 Total stock-based compensation expense $ 1,089 $ 999 $ 1,132 Stock-based compensation expense is allocated to research and development and general and administrative expense based upon the department of the employee to whom each award was granted. Expenses recognized in connection with the modification of awards in connection with the Company’s strategic restructurings are allocated to restructuring expense. No related tax benefits of the stock-based compensation expense have been recognized.
Income Taxes	Income Taxes The Company provides for income taxes using the asset-liability method. Under this method, deferred tax assets and liabilities are recognized based on differences between financial reporting and tax bases of assets and liabilities, and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. The Company calculates its provision for income taxes on ordinary income based on its projected annual tax rate for the year. Uncertain tax positions are recognized if the position is more-likely-than-not to be sustained upon examination by a tax authority. Unrecognized tax benefits represent tax positions for which reserves have been established.
Segment and Geographic Information	Segment and Geographic Information Operating segments are defined as components of an enterprise engaging in business activities for which discrete financial information is available and regularly reviewed by the chief operating decision maker in deciding how to allocate resources and in assessing performance. The Company views its operations and manages its business in one operating segment principally in the United States. As of December 31, 2017 and 2016, the Company has $0 and $0.8 million, respectively, of net assets located in the United Kingdom.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect certain reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the , and the reported amounts of revenues and expenses during the reporting periods. Significant items subject to such estimates and assumptions include revenue recognition, contract research accruals, measurement of the PIPE warrant liability, estimated settlement liabilities and measurement of stock-based compensation. The Company bases its estimates on historical experience and various other assumptions that management believes to be reasonable under the circumstances. Changes in estimates are recorded in the period in which they become known
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) The Company , as well as identifying any appropriate changes to its revenue recognition policies and internal controls. Under ASU 2014-09, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of ASU 2014-09, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. ASU 2014-09 also impacts certain other areas, such as the accounting for costs to obtain or fulfill a contract. The standard also requires disclosure of the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. To date, the Company has identified the following differences in accounting treatment for its collaboration agreements under ASU 2014-09: • The Company expects the accounting for contingent milestone payments under its collaboration agreements to change under ASU 2014-09. Under ASC 605, the Company generally considers non-refundable preclinical research and development, clinical development and regulatory milestones that the Company expects to be achieved as a result of the Company’s efforts during the period of the Company’s performance obligations under its collaboration and license agreements to be substantive and recognizes them as revenue upon the achievement of the milestone, assuming all other revenue recognition criteria are met. ASU 2014-09 does not contain guidance specific to milestone payments, thereby requiring contingent milestone payments to be considered in accordance with the overall model of ASU 2014-09. Revenue from contingent milestone payments may be recognized earlier under ASU 2014-09 than under ASC 605, based on an assessment of the probability of achievement of the milestone event and the likelihood of a significant reversal of such milestone revenue at each reporting date. This assessment may result in the recognition of revenue related to a contingent milestone payment before the milestone event has been achieved. • ASU 2014-09 requires more robust disclosures than required by previous guidance, including disclosures related to disaggregation of revenue into appropriate categories, performance obligations, the judgments made in revenue recognition determinations, adjustments to revenue which relate to activities from previous quarters or years, any significant reversals of revenue, and costs to obtain or fulfill contracts. The Company has not yet completed its assessment of the impact the adoption of this standard may have on its consolidated financial statements and internal control. With regard to the arrangements with CANbridge and Novartis, the Company currently does not expect the impact of adoption of this standard to be material. The Company is continuing to evaluate the effects of the adoption of the standard on its arrangement with EUSA. Expected impacts from the adoption of this standard could differ upon the final adoption and implementation of the standard. In connection with the adoption of this standard, the Company is implementing several new internal controls, including controls to monitor the probability of achievement of contingent milestone payments. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments contingent consideration payments made after a business combination, proceeds from the settlement of insurance claims, proceeds from the settlement of corporate-owned life insurance policies, distributions received from equity method investees and beneficial interests in securitization transactions. The new standard also clarifies that an entity should determine each separately identifiable source or use within the cash receipts and cash payments on the basis of the nature of the underlying cash flows. In situations in which cash receipts and payments have aspects of more than one class of cash flows and cannot be separated by source or use, the appropriate classification should depend on the activity that is likely to be the predominant source or use of cash flows for the item. The new standard will be effective for the Company on January 1, 2018. The adoption of this standard is not expected to have a material impact on the Company’s consolidated statements of cash flows. In May 2017, the FASB issued ASU 2017-09, Compensation-Stock Compensation (Topic 718): Scope of Modification Accounting , which clarifies when to account for a change to the terms or conditions of a share-based payment award as a modification. The new standard does not change the accounting for modifications but clarifies that modification accounting guidance should only be applied if the fair value, vesting conditions, or classification of the award changes as a result of the change in terms or conditions. The new standard is effective for fiscal years, and interim periods within, beginning after December 15, 2017. Early adoption is permitted. A reporting entity must apply the amendments in the ASU prospectively to an award modified on or after the adoption date. The adoption of ASU 2017-09 is not expected to have a material effect on the Company’s consolidated financial statements or disclosures.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In March 2016, the FASB issued ASU No. 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting

Significant Accounting Polici25

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
Summary of Cash, Cash Equivalents and Marketable Securities	Below is a summary of cash, cash equivalents and marketable securities at December 31, 2017 and December 31, 2016: Amortized Cost Unrealized Gains Unrealized Losses Fair Value December 31, 2017 Cash and cash equivalents: Cash and money market funds $ 14,949 $ — $ — $ 14,949 Corporate debt securities — — — — Total cash and cash equivalents 14,949 — — 14,949 Marketable securities: Corporate debt securities due within 1 year $ 17,074 $ 1 $ (5 ) $ 17,070 US government agency securities due within 1 year 1,506 — — 1,506 Total marketable securities 18,580 1 (5 ) 18,576 Total cash, cash equivalents and marketable securities $ 33,529 $ 1 $ (5 ) $ 33,525 December 31, 2016 Cash and cash equivalents: Cash and money market funds $ 14,091 $ — $ — $ 14,091 Corporate debt securities 1,005 — — 1,005 Total cash and cash equivalents 15,096 — — 15,096 Marketable securities: Corporate debt securities due within 1 year 8,246 6 — 8,252 Total marketable securities 8,246 6 — 8,252 Total cash, cash equivalents and marketable securities $ 23,342 $ 6 $ — $ 23,348
Summary of Assets And Liabilities Measured at Fair Value on Recurring Basis	The following table summarizes the assets and liabilities measured at fair value on a recurring basis at December 31, 2017 and December 31, 2016: Fair Value Measurements as of December 31, 2017 Level 1 Level 2 Level 3 Total (in thousands) Financial assets carried at fair value: Cash and money market funds $ 14,949 $ — $ — $ 14,949 Corporate debt securities — — — — Total cash and cash equivalents $ 14,949 $ — $ — $ 14,949 Marketable securities: Corporate debt securities due within 1 year $ — $ 17,070 $ — $ 17,070 US government agency securities due within 1 year — 1,506 — 1,506 Total marketable securities $ — $ 18,576 $ — $ 18,576 Total cash, cash equivalents and marketable securities $ 14,949 $ 18,576 $ — $ 33,525 Financial liabilities carried at fair value: PIPE warrant liability $ — $ — $ 37,746 $ 37,746 Settlement warrant liability — — 2,073 2,073 Total warrant liabilities $ — $ — $ 39,819 $ 39,819 Fair Value Measurements as of December 31, 2016 Level 1 Level 2 Level 3 Total (in thousands) Financial assets carried at fair value: Cash and money market funds $ 14,091 $ — $ — $ 14,091 Corporate debt securities — 1,005 — 1,005 Total cash and cash equivalents $ 14,091 $ 1,005 $ — $ 15,096 Marketable securities: Corporate debt securities due within 1 year — $ 8,252 — $ 8,252 Total marketable securities $ — $ 8,252 $ — $ 8,252 Total cash, cash equivalents and marketable securities $ 14,091 $ 9,257 $ — $ 23,348 Financial liabilities carried at fair value: PIPE warrant liability $ — $ — $ 4,593 $ 4,593 Total warrant liability $ — $ — $ 4,593 $ 4,593
Summary of Outstanding Securities Not Included in Computation of Diluted Net Loss Per Common Share	The following table summarizes outstanding securities not included in the computation of diluted net loss per common share as their inclusion would be anti-dilutive for the years ended December 31, 2017, 2016 and 2015, respectively: Years Ended December 31, 2017 2016 2015 Outstanding stock options 7,537,958 4,858,678 4,796,005 Outstanding warrants 17,383,415 19,453,295 608,696 Unvested restricted stock — — 42,750 Total 24,921,373 24,311,973 5,447,451
Stock-Based Compensation Expense	During the years ended December 31, 2017, 2016 and 2015, the Company recorded the following stock-based compensation expense: Years Ended December 31, 2017 2016 2015 (in thousands) Research and development $ 290 $ 293 $ 298 General and administrative 799 706 765 Restructuring — — 69 Total stock-based compensation expense $ 1,089 $ 999 $ 1,132
Settlement Warrants
Key Assumptions Used to Value the Warrants	The key assumptions used to estimate the fair value the Settlement Warrants were as follows: December 31, 2017 Expected price volatility 101.52% Expected term (in years) 1.00 Risk-free interest rates 1.76% Stock price $ 2.79 Dividend yield —
PIPE Warrants
Summary of Fair Value of Company's Warrant Liability	The following table rolls forward the fair value of the Company’s PIPE warrant liability, the fair value of which is determined by Level 3 inputs for the year ended December 31, 2017 (in thousands): Issuance of warrants on May 13, 2016 $ 9,344 Decrease in fair value (4,751 ) Fair value at December 31, 2016 $ 4,593 Increase in fair value 33,740 Reduction in warrant liability for PIPE Warrant exercises (587 ) Fair value at December 31, 2017 $ 37,746
Key Assumptions Used to Value the Warrants	The key assumptions used to value the PIPE Warrants were as follows: Original Issuance December 31, 2016 December 31, 2017 Expected price volatility 76.25% 78.18% 84.86% Expected term (in years) 5.00 4.50 3.50 Risk-free interest rates 1.22% 1.93% 2.09% Stock price $ 0.89 $ 0.54 $ 2.79 Dividend yield — — —

Other Accrued Liabilities (Tabl

Other Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2017
Payables And Accruals [Abstract]
Other Accrued Liabilities	Other accrued expenses consisted of the following: December 31, 2017 December 31, 2016 (in thousands) Professional fees $ 844 $ 464 Compensation and benefits 1,325 891 Other 289 176 Total $ 2,458 $ 1,531

Loans Payable (Tables)

Loans Payable (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Future Minimum Payments Under Loans Payable	Future minimum payments under the loans payable outstanding as of December 31, 2017 are as follows (amounts in thousands): Year Ending December 31: 2018 $ 2,493 2019 8,725 2020 9,013 2021 6,087 26,318 Less amount representing interest (4,688 ) Less unamortized discount (1,523 ) Less deferred charges (1,630 ) Less loans payable current, net of discount — Loans payable, net of current portion and discount $ 18,477

Stock-based Compensation (Table

Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Option Activity	The following table summarizes stock option activity during the year ended December 31, 2017: Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term Aggregate Intrinsic Value Outstanding at January 1, 2017 4,858,678 $ 2.31 Granted 3,455,135 $ 1.40 Exercised (17,576 ) $ 0.87 Forfeited (758,279 ) $ 1.03 Outstanding at December 31, 2017 7,537,958 $ 2.00 7.49 $ 10,709,000 Exercisable at December 31, 2017 3,582,756 $ 2.67 6.06 $ 5,075,000
Assumptions used in Black-Scholes Pricing Model for New Grants	The fair value of stock options subject only to service or performance conditions that are granted to employees is estimated on the date of grant using the Black-Scholes option-pricing model using the assumptions noted in the following table: Years Ended December 31, 2017 2016 2015 Volatility factor 71.82% - 80.15% 72.18% - 74.47% 73.04% - 78.70% Expected term (in years) 5.50 - 6.25 3.00 - 6.25 5.50 - 6.25 Risk-free interest rates 1.84% - 2.22% 1.07% - 2.01% 1.54% - 1.93% Dividend yield — — —

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Reconciliation of Expected Income Tax Benefit	A reconciliation of the expected income tax benefit computed using the federal statutory income tax rate to the Company’s effective income tax rate is as follows for the years ended December 31, 2017, 2016 and 2015: Years Ended December 31, 2017 2016 2015 Income tax computed at federal statutory tax rate 34.0% 34.0% 34.0% State taxes, net of federal benefit 5.3% 5.2% 5.3% Research and development credits 0.4% 1.4% 2.0% Other permanent differences (20.8)% 6.1% (2.0)% Foreign rate differential 0.0% (0.1)% (0.1)% Foreign withholding taxes (0.2)% (0.4)% — SEC settlement liability 0.0% — (9.1)% Excess benefit stock compensation 0.0% — — Tax reform - rate change (97.5)% — — Other 0.1% (6.6)% (3.8)% Change in valuation allowance 78.7% (39.6)% (26.3)% Total — — —
Company Net Deferred Tax Assets	The Company’s net deferred tax assets as of December 31, 2017 and 2016 are as follows (in thousands): 2017 2016 Deferred tax assets: NOL carryforwards $ 131,683 $ 182,433 Research and development credits 13,913 13,060 Deferred revenue and R&D reimbursements 770 867 Estimated settlement liability 4,664 — Other temporary differences 4,420 4,570 Total deferred tax assets: 155,450 200,930 Deferred tax liabilities: Insurance recovery (4,098 ) — Total deferred tax liabilities: (4,098 ) — Valuation allowance (151,352 ) (200,930 ) Total $ — $ —
Reconciliation of Gross Uncertain Tax Positions	The following is a reconciliation of the Company’s gross uncertain tax positions at December 31, 2017, 2016 and 2015: Years Ended December 31, 2017 2016 2015 (in thousands) Amount established upon adoption $ 1,200 $ 1,200 $ 1,200 Additions for current year tax provisions — — — Additions for prior year tax provisions — — — Reductions of prior year tax provisions — — — Balance as of end of year $ 1,200 $ 1,200 $ 1,200

Strategic Restructuring (Tables

Strategic Restructuring (Tables)	12 Months Ended
	Dec. 31, 2017
Restructuring And Related Activities [Abstract]
Restructuring Activity Recorded in Operating Expenses and in Accrued Expenses	The following table summarizes the components of the Company’s restructuring activity recorded in operating expenses and in accrued expenses in the accompanying consolidated balance sheet: Restructuring amounts at December 31, 2016 Restructuring expense incurred during the year ended December 31, 2017 Restructuring amounts paid during the year ended December 31, 2017 Restructuring amounts accrued at December 31, 2017 Employee severance, benefits and related costs. $ — $ — $ — $ — Restructuring amounts at December 31, 2015 Restructuring expense incurred during the year ended December 31, 2016 Restructuring amounts paid during the year ended December 31, 2016 Restructuring amounts accrued at December 31, 2016 Employee severance, benefits and related costs. $ 357 $ — $ (357 ) $ —

Facility Lease Exit (Tables)

Facility Lease Exit (Tables)	12 Months Ended
	Dec. 31, 2017
Facility Lease Exit [Abstract]
Components of Lease Exit Activity Recorded in Current Liabilities	The following table summarizes the components of the Company’s lease exit activity recorded in current liabilities at December 31, 2015: Lease Exit amounts accrued at December 31, 2014 Accretion Expense incurred during the year ended December 31, 2015 Amounts paid during the year ended December 31, 2015 Additional expense incurred during the year ended December 31, 2015 Amounts accrued at December 31, 2015 Lease exit costs $ 4,981 224 $ (5,477 ) $ 272 $ —

Quarterly Results (Unaudited) (

Quarterly Results (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Summary of Quarterly Results	Three Month Ended March 31, 2017 June 30, 2017 September 30, 2017 December 31, 2017 (in thousands, expect per share data) (unaudited) Collaboration and licensing revenue $ 2,532 $ 351 $ 4,614 $ 82 Operating expenses 10,287 9,183 6,767 10,153 Loss from operations (7,755 ) (8,832 ) (2,153 ) (10,071 ) Change in fair value of PIPE warrant liability (484 ) (23,925 ) (23,538 ) 14,207 Other expense, net (551 ) (530 ) (655 ) (637 ) Provision for income taxes (50 ) — (51 ) — Net income (loss) $ (8,840 ) $ (33,287 ) $ (26,397 ) $ 3,499 Basic net income (loss) per share Net income (loss) per share $ (0.12 ) $ (0.30 ) $ (0.22 ) $ 0.03 Weighted average number of common shares outstanding 76,246 110,550 118,006 118,323 Dilutive net income (loss) per share Net income (loss) per share $ (0.12 ) $ (0.30 ) $ (0.22 ) $ (0.08 ) Weighted average number of common shares and dilutive common share equivalents outstanding 76,246 110,550 118,006 130,108 Three Month Ended March 31, 2016 June 30, 2016 September 30, 2016 December 31, 2016 (in thousands, expect per share data) (unaudited) Collaboration and licensing revenue $ 1,203 $ 193 $ 992 $ 127 Operating expenses 8,435 7,335 6,585 9,553 Loss from operations (7,232 ) (7,142 ) (5,593 ) (9,426 ) Change in fair value of PIPE warrant liability — (996 ) 1,178 4,569 Other expense, net (377 ) (468 ) (551 ) (748 ) Provision for income taxes (101 ) — — — Net loss $ (7,710 ) $ (8,606 ) $ (4,966 ) $ (5,605 ) Net loss per share - basic and diluted $ (0.13 ) $ (0.13 ) $ (0.07 ) $ (0.07 ) Weighted average number of common shares outstanding 58,166 66,917 75,861 75,863

Organization - Additional Infor

Organization - Additional Information (Detail)

1 Months Ended

2 Months Ended

3 Months Ended

12 Months Ended

Feb. 28, 2018USD ($)shares

Jan. 31, 2018USD ($)shares

Jul. 31, 2017USD ($)shares

Jun. 30, 2017USD ($)shares

Mar. 31, 2017USD ($)shares

May 31, 2016USD ($)shares

Aug. 31, 2015USD ($)shares

Mar. 31, 2010USD ($)

Mar. 08, 2018USD ($)

Mar. 31, 2019USD ($)

Dec. 31, 2017USD ($)SubsidiaryIndicationshares

Mar. 31, 2018USD ($)

Dec. 31, 2016USD ($)shares

Organization [Line Items]

Number of subsidiaries | Subsidiary

2

Cash, cash equivalents and marketable securities

$ 33,529,000

$ 23,342,000

Working capital

18,100,000

Accumulated deficit

586,969,000

$ 521,916,000

Net proceeds from public offering

$ 29,500,000

Common stock, shares issued | shares

118,325,396

75,863,000

Scenario Forecast

Organization [Line Items]

Net proceeds from public offering

$ 0

Research and development funding received

0

Collaborations and license agreements, milestone payment

0

Milestone payment to be received

0

Proceeds from debt financing

0

EUSA

Organization [Line Items]

Research and development funding received

$ 2,500,000

Collaborations and license agreements, potential future payment as percentage of certain amounts the Company receives under sublicense agreements

30.00%

Payments received in connection with indications

$ 2,000,000

Eligible number of indications | Indication

3

Percentage of additional proceeds from research and development funding

50.00%

EUSA | Scenario Forecast

Organization [Line Items]

Milestone payment to be received

$ 2,000,000

EUSA | Maximum

Organization [Line Items]

Payments received in connection with indications

$ 8,000,000

EUSA | Marketing Approval in France, Germany, Italy, Spain and the United Kingdom

Organization [Line Items]

Milestone payment to be received

2,000,000

EUSA | Marketing Approval in Argentina, Australia, Brazil, South Africa and Venezuela

Organization [Line Items]

Milestone payment to be received

2,000,000

Kyowa Hakko Kirin | Maximum

Organization [Line Items]

Research and development reimbursement payment not required to be paid

$ 20,000,000

Kyowa Hakko Kirin | Licensing Agreements

Organization [Line Items]

Collaborations and license agreements, milestone payment

$ 10,000,000

Collaborations and license agreements, potential future payment as percentage of certain amounts the Company receives under sublicense agreements

30.00%

Subsequent Event

Organization [Line Items]

Net proceeds from public offering

$ 1,900,000

Subsequent Event | EUSA | Licensing Agreements

Organization [Line Items]

Research and development funding received

$ 1,400,000

Collaborations and license agreements, milestone payment

$ 2,000,000

Subsequent Event | Kyowa Hakko Kirin | Licensing Agreements

Organization [Line Items]

Collaborations and license agreements, potential future payment as percentage of certain amounts the Company receives under sublicense agreements

30.00%

PIPE Warrants | Scenario Forecast

Organization [Line Items]

Proceeds from warrant exercises

0

PIPE Warrants | Subsequent Event

Organization [Line Items]

Number of warrants exercised | shares

500,000

Proceeds from warrant exercises

$ 500,000

Loans Payable | Hercules May 2016 Loan Agreement

Organization [Line Items]

Proceeds from additional borrowing capacity

$ 5,000,000

$ 5,000,000

F B R Co

Organization [Line Items]

Proceeds from additional borrowing capacity

$ 8,800,000

$ 10,200,000

$ 8,800,000

Common stock, shares issued | shares

6,500,000

5,900,000

6,500,000

Leerink | Scenario Forecast

Organization [Line Items]

Proceeds from sale of equity

$ 0

Leerink | Subsequent Event

Organization [Line Items]

Common stock, shares issued | shares

0

Underwritten Public Offering

Organization [Line Items]

Net proceeds from public offering

$ 15,400,000

$ 15,400,000

Common stock, shares issued | shares

34,500,000

Common stock, shares issued | shares

34,500,000

Proceeds from sale of equity

$ 17,300,000

Private Placement | PIPE Warrants

Organization [Line Items]

Common stock, shares issued | shares

259,067

17,642,482

Cash proceeds

$ 300,000

Number of warrants exercised | shares

259,067

Significant Accounting Polici34

Significant Accounting Policies - Additional Information (Detail)	Jan. 29, 2018$ / shares	Feb. 28, 2018USD ($)	Jan. 31, 2018USD ($)shares	Sep. 30, 2017USD ($)	Jun. 30, 2015USD ($)	Dec. 31, 2017USD ($)Segment$ / sharesshares	Dec. 31, 2016USD ($)shares	Dec. 31, 2015USD ($)	May 31, 2016shares
Significant Accounting Policies [Line Items]
Common stock, shares issued | shares						118,325,396	75,863,000
Increase (decrease) in the fair value of warrant liability						$ 2,073,000
Reserve for settlement of fines						17,073,000		$ 4,000,000
Estimated insurance recoveries						15,000,000
Transfers of financial assets from Level 1 to Level 2						0	$ 0
Transfers of financial assets from Level 2 to Level 1						0	0
Depreciation expense						0	30,000	9,600,000
Impairment losses						0	0	200,000
Tax benefits of the stock based compensation expenses recognized						$ 0
Number of operating segments | Segment						1
United Kingdom
Significant Accounting Policies [Line Items]
Net assets located in the United Kingdom						$ 0	800,000
3rd Amendment, Lease exit costs associated with 650 E. Kendall.
Significant Accounting Policies [Line Items]
Leased space surrendering date						May 29, 2015
3rd Amendment, Lease exit costs associated with 650 E. Kendall. | Leasehold Improvements
Significant Accounting Policies [Line Items]
Additional charge to depreciation expense due to revision of estimated useful life					$ 2,900,000			$ 2,900,000
Minimum
Significant Accounting Policies [Line Items]
Marketable securities maturity term						3 months
Maximum
Significant Accounting Policies [Line Items]
Marketable securities maturity term						24 months
Subsequent Event
Significant Accounting Policies [Line Items]
Cash settlement from insurance carriers		$ 15,000,000
PIPE Warrants
Significant Accounting Policies [Line Items]
Warrant liability						$ 9,300,000
Increase (decrease) in the fair value of warrant liability				$ (600,000)		$ 33,740,000	$ (4,751,000)
PIPE Warrants | Subsequent Event
Significant Accounting Policies [Line Items]
Warrants exercisable shares of common stock exercised | shares			518,134
Number of warrants exercised | shares			518,134
Cash proceeds			$ 500,000
PIPE Warrants | Private Placement
Significant Accounting Policies [Line Items]
Common stock, shares issued | shares									17,642,482
Warrants exercisable shares of common stock exercised | shares						259,067
Warrants exercisable shares of common stock outstanding | shares						17,383,415
Settlement Warrants
Significant Accounting Policies [Line Items]
Reserve for settlement of fines						$ 17,100,000
Estimated insurance recoveries						15,000,000
Estimated fair value of warrants						$ 2,100,000
Warrants to purchase of common stock shares | shares						2,000,000
Warrants exercisable expiration period						1 year
Warrants exercise price | $ / shares						$ 3
Settlement agreement date						May 30, 2018
Settlement Warrants | Subsequent Event
Significant Accounting Policies [Line Items]
Warrants exercisable expiration period	1 year
Warrants exercise price | $ / shares	$ 3
Cash settlement from insurance carriers		$ 15,000,000

Summary of Fair Value of Compan

Summary of Fair Value of Company's Warrant Liability (Detail) - PIPE Warrants - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	$ 4,593
Issuance of warrants on May 13, 2016		$ 9,344
Increase (decrease) in fair value	33,740	(4,751)
Reduction in warrant liability for PIPE Warrant exercises	(587)
Fair value, end of period	$ 37,746	$ 4,593

Key Assumptions Used to Value t

Key Assumptions Used to Value the Warrants (Detail) - $ / shares	1 Months Ended	12 Months Ended
	May 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 29, 2017
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Stock price				$ 2.79
Settlement Warrants
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Expected price volatility		101.52%
Expected term (in years)		1 year
Risk-free interest rates		1.76%
Stock price		$ 2.79
Dividend yield		0.00%
PIPE Warrants
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Expected price volatility	76.25%	84.86%	78.18%
Expected term (in years)	5 years	3 years 6 months	4 years 6 months
Risk-free interest rates	1.22%	2.09%	1.93%
Stock price	$ 0.89	$ 2.79	$ 0.54
Dividend yield	0.00%	0.00%	0.00%

Summary of Cash, Cash Equivalen

Summary of Cash, Cash Equivalents and Marketable Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	$ 33,529	$ 23,342
Unrealized Gains	1	6
Unrealized Losses	(5)
Fair Value	33,525	23,348
Amortized Cost	14,949	15,096	$ 26,634	$ 52,306
Fair Value	14,949	15,096
Amortized Cost	18,580	8,246
Unrealized Gains	1	6
Unrealized Losses	(5)
Fair Value	18,576	8,252
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost		1,005
Fair Value		1,005
Amortized Cost	17,074	8,246
Unrealized Gains	1	6
Unrealized Losses	(5)
Fair Value	17,070	8,252
US government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	1,506
Fair Value	1,506
Cash and money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	14,949	14,091
Fair Value	$ 14,949	$ 14,091

Summary of Assets And Liabiliti

Summary of Assets And Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 14,949	$ 15,096
Marketable securities	18,576	8,252
Total cash, cash equivalents and marketable securities	33,525	23,348
Settlement Warrants
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant liability	2,100
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents		1,005
Marketable securities	17,070	8,252
US government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	1,506
Cash and money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	14,949	14,091
Fair Value Measurements Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	14,949	15,096
Marketable securities	18,576	8,252
Total cash, cash equivalents and marketable securities	33,525	23,348
Total warrant liabilities	39,819	4,593
Fair Value Measurements Recurring | Settlement Warrants
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant liability	2,073
Fair Value Measurements Recurring | PIPE Warrants
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant liability	37,746	4,593
Fair Value Measurements Recurring | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents		1,005
Marketable securities	17,070	8,252
Fair Value Measurements Recurring | US government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	1,506
Fair Value Measurements Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	14,949	14,091
Total cash, cash equivalents and marketable securities	14,949	14,091
Fair Value Measurements Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents		1,005
Marketable securities	18,576	8,252
Total cash, cash equivalents and marketable securities	18,576	9,257
Fair Value Measurements Recurring | Level 2 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents		1,005
Marketable securities	17,070	8,252
Fair Value Measurements Recurring | Level 2 | US government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	1,506
Fair Value Measurements Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total warrant liabilities	39,819	4,593
Fair Value Measurements Recurring | Level 3 | Settlement Warrants
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant liability	2,073
Fair Value Measurements Recurring | Level 3 | PIPE Warrants
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant liability	37,746	4,593
Fair Value Measurements Recurring | Cash and money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	14,949	14,091
Fair Value Measurements Recurring | Cash and money market funds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 14,949	$ 14,091

Summary of Outstanding Securiti

Summary of Outstanding Securities Not Included in Computation of Diluted Net Loss Per Common Share (Detail) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount, outstanding	24,921,373	24,311,973	5,447,451
Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount, outstanding	7,537,958	4,858,678	4,796,005
Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount, outstanding	17,383,415	19,453,295	608,696
Unvested Restricted Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount, outstanding			42,750

Stock Based Compensation Expens

Stock Based Compensation Expense for Equity-Classified Awards (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 1,089	$ 999	$ 1,132
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	290	293	298
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 799	$ 706	765
Restructuring
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense			$ 69

Collaborations and License Ag41

Collaborations and License Agreements - Additional Information (Detail)

1 Months Ended

3 Months Ended

12 Months Ended

Feb. 28, 2018USD ($)

Oct. 31, 2017USD ($)

Sep. 30, 2017USD ($)

Mar. 31, 2017USD ($)

Apr. 30, 2016USD ($)

Dec. 31, 2015USD ($)

Sep. 30, 2015USD ($)

Aug. 31, 2015USD ($)

Nov. 30, 2014USD ($)

Mar. 31, 2014USD ($)

Dec. 31, 2012USD ($)

Mar. 31, 2010USD ($)

Dec. 31, 2006USD ($)

Mar. 31, 2019USD ($)

Dec. 31, 2017USD ($)

Sep. 30, 2017USD ($)

Jun. 30, 2017USD ($)

Mar. 31, 2017USD ($)

Dec. 31, 2016USD ($)

Sep. 30, 2016USD ($)

Jun. 30, 2016USD ($)

Mar. 31, 2016USD ($)

Dec. 31, 2017USD ($)IndicationInstallment

Dec. 31, 2016USD ($)

Dec. 31, 2015USD ($)

Dec. 31, 2014USD ($)

Mar. 31, 2018USD ($)

Oct. 14, 2016

Apr. 30, 2014USD ($)

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaboration revenue

$ 82,000

$ 4,614,000

$ 351,000

$ 2,532,000

$ 127,000

$ 992,000

$ 193,000

$ 1,203,000

$ 7,579,000

$ 2,515,000

$ 19,024,000

Amounts due from pursuant to the cost-sharing provisions

$ 402,000

1,027,000

402,000

1,027,000

Research and development

25,179,000

23,703,000

12,875,000

Credited against amounts due the Company for tenant improvements

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Development and sales-based milestones payment

22,500,000

Will be paid in nine equal monthly installments

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Development and sales-based milestones payment

5,500,000

Scenario 3

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Development and sales-based milestones payment

4,200,000

Scenario Forecast

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Milestone payment to be received

$ 0

Research and development funding received

0

Collaborations and license agreements, milestone payment

$ 0

Opt-in to Co-develop TiNivo Trial

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborations and license agreements, expected milestone receivable

$ 2,000,000

Other License Agreements

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Research and development

25,000

License payment per product

1,000,000

License expense

$ 0

0

0

Other License Agreements | Maximum

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborations and license agreements, royalties payment on net sales

1.50%

1.50%

Other License Agreements | Minimum

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborations and license agreements, royalties payment on net sales

0.50%

0.50%

CANbridge

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

License agreement date

Mar. 16, 2016

Revenue recognized from reimbursement of manufacturing development activities

$ 500,000

500,000

CANbridge | Licensing Agreements

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborations and license agreements, expected milestone receivable

$ 1,000,000

$ 1,000,000

Upfront payment, withholding taxes

$ 100,000

100,000

100,000

100,000

Reimbursable amount for manufacturing costs and expenses

$ 1,000,000

Number of installments paid | Installment

2

Revenue recognized from reimbursement of manufacturing development activities

500,000

$ 500,000

Collaborations and license agreements, time period from first commercial sale of certain product upon which the agreement expires

10 years

Description of royalty percentage receivable on net sales

Upon commercialization, the Company is eligible to receive a tiered royalty, with a percentage range in the low double-digits, on net sales of approved licensed products.

Allocation of upfront payment

1,000,000

Collaboration revenue

1,000,000

CANbridge | Licensing Agreements | Sales Based Milestone Payments

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborations and license agreements, expected milestone receivable

$ 90,000,000

CANbridge | Licensing Agreements | Development and Regulatory Milestone Events

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborations and license agreements, expected milestone receivable

42,000,000

Collaborations and license agreements, expected milestone receivable

0

CANbridge | Licensing Agreements | Foreign

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Upfront payment, withholding taxes

$ 100,000

$ 100,000

100,000

EUSA

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborations and license agreements, expected milestone receivable

4,000,000

$ 2,500,000

Collaborations and license agreements, expected milestone receivable

$ 400,000

400,000

14,000

Description of royalty percentage receivable on net sales

The Company is also eligible to receive tiered double-digit royalties on net sales, if any, of licensed products in the EUSA Licensed Territories ranging from a low double digit up to mid-twenty percent depending on the level of annual net sales.

Research and development reimbursement received

$ 4,000,000

2,500,000

Percentage of additional proceeds from research and development funding

50.00%

Payments received in connection with indications

$ 2,000,000

Eligible number of indications | Indication

3

Payments received in connection with additional indications

$ 5,000,000

Potential payments received in connection with additional indications

$ 335,000,000

Collaborations and license agreements, potential future payment as percentage of certain amounts the Company receives under sublicense agreements

30.00%

30.00%

Research and development funding received

$ 2,500,000

Sales royalties revenue recognized

$ 19,000

EUSA | Maximum

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Payments received in connection with indications

8,000,000

EUSA | Subsequent Event

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborations and license agreements, expected milestone receivable

$ 2,000,000

Allocation of upfront payment

600,000

EUSA | Scenario Forecast

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Milestone payment to be received

$ 2,000,000

EUSA | Opt-in to Planned Phase Three Study

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Milestone payment to be received

20,000,000

20,000,000

EUSA | Marketing Approval in France, Germany, Italy, Spain and the United Kingdom

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Milestone payment to be received

2,000,000

2,000,000

EUSA | Marketing Approval in Argentina, Australia, Brazil, South Africa and Venezuela

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Milestone payment to be received

2,000,000

2,000,000

EUSA | Research and Development Reimbursement Milestone Payment

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborations and license agreements, expected milestone receivable

4,000,000

EUSA | Licensing Agreements | Subsequent Event

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Research and development funding received

1,400,000

Collaborations and license agreements, milestone payment

$ 2,000,000

EUSA | TiNivo trial

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Research and development reimbursement received

$ 2,000,000

Collaborations and license agreements, deferred research and development reimbursements

1,100,000

1,100,000

EUSA | TiNivo trial | Research and development

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Payments received and recorded as an increased (decreased) to expense pursuant to cost-sharing provisions

900,000

Novartis

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborations and license agreements, expected milestone receivable

$ 15,000,000

$ 0

Description of royalty percentage receivable on net sales

If the product is commercialized, the Company would be eligible to receive tiered royalties on net sales of approved products ranging from the high single digits to the low double-digits.

Collaboration revenue

$ 1,800,000

Reimbursable inventory

$ 3,500,000

License and service revenue

3,500,000

Research and development

$ 1,800,000

Novartis | Sales Based Milestone Payments

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborations and license agreements, expected milestone receivable

150,000,000

Novartis | Clinical Efficacy Milestone

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborations and license agreements, expected milestone receivable

51,200,000

Novartis | Regulatory Milestone Events

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborations and license agreements, expected milestone receivable

105,000,000

Novartis | License and Technical Knowledge

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaboration revenue

15,000,000

Pharmstandard

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaboration revenue

0

900,000

61,000

Collaborations and license agreements, deferred revenue

$ 900,000

900,000

Ophthotech Corporation | Option and License Agreement

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Upfront license payment

$ 500,000

Collaborations and license agreements, payment received

$ 500,000

Collaborations and license agreements, revenue recognized

100,000

100,000

200,000

Remaining deferred revenue to be recognized

100,000

Biodesix | FOCAL study

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Contribution percentage of clinical, regulatory, manufacturing and other costs

50.00%

Percentage of closeout project cost

50.00%

Biodesix | FOCAL study | Maximum

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Funding

$ 15,000,000

Biodesix | FOCAL trial

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborations and license agreements, royalties payment on net sales

10.00%

Amounts due from pursuant to the cost-sharing provisions

100,000

800,000

100,000

800,000

Cash received related to cost reimbursements

800,000

2,800,000

Biodesix | FOCAL trial | Research and development

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Payments received and recorded as an increased (decreased) to expense pursuant to cost-sharing provisions

100,000

2,500,000

3,500,000

Astellas Pharma Inc. | Astellas Agreement

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Amounts due from pursuant to the cost-sharing provisions

$ 200,000

$ 100,000

200,000

100,000

Astellas Pharma Inc. | Astellas Agreement | Research and development

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Payments received and recorded as an increased (decreased) to expense pursuant to cost-sharing provisions

200,000

300,000

700,000

Astellas Pharma Inc. | Collaboration and License Agreement

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborations and license agreements, payment received

0

300,000

Biogen Idec International GmbH

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborations and license agreements, deferred revenue

$ 14,700,000

Collaborations and license agreements, revenue recognized

14,100,000

Collaborations and license agreements, relative selling price of the deliverable

$ 600,000

Biogen Idec International GmbH | Maximum

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Royalty payments

50,000,000

Biogen Idec International GmbH | Option and License Agreement

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborations and license agreements, revenue recognized

$ 0

38,000

$ 300,000

St Vincent's Hospital Sydney Limited

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Amendment agreement date

2015-08

License fees payable

$ 16,700,000

Collaborations and license agreements, milestone payment

$ 400,000

St Vincent's Hospital Sydney Limited | Licensing Agreements | Up-front Payment Arrangement

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborations and license agreements, cash payment

$ 1,500,000

Kyowa Hakko Kirin | Maximum

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Research and development reimbursement payment not required to be paid

$ 20,000,000

Kyowa Hakko Kirin | Opt-in to Planned Phase Three Study | Maximum

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Research and development reimbursement payment not required to be paid

$ 20,000,000

Kyowa Hakko Kirin | Licensing Agreements

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborations and license agreements, potential future payment as percentage of certain amounts the Company receives under sublicense agreements

30.00%

30.00%

Collaborations and license agreements, cash payment

$ 5,000,000

Collaborations and license agreements, milestone payment

$ 10,000,000

Collaborations and license agreements, potential future milestone payments, maximum amount

$ 18,000,000

Term of royalty payment obligations

12 years

Kyowa Hakko Kirin | Licensing Agreements | Subsequent Event

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborations and license agreements, potential future payment as percentage of certain amounts the Company receives under sublicense agreements

30.00%

Kyowa Hakko Kirin | Licensing Agreements | FDA Marketing Approval

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborations and license agreements, milestone payment

$ 12,000,000

Other Accrued Liabilities (Deta

Other Accrued Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Payables And Accruals [Abstract]
Professional fees	$ 844	$ 464
Compensation and benefits	1,325	891
Other	289	176
Total	$ 2,458	$ 1,531

Loans Payable - Additional Info

Loans Payable - Additional Information (Detail)	1 Months Ended					12 Months Ended
	Dec. 31, 2017USD ($)Installment$ / sharesshares	Jul. 31, 2017USD ($)shares	Jun. 30, 2017USD ($)Installment	May 31, 2016USD ($)Installment$ / sharesshares	Sep. 30, 2014USD ($)$ / sharesshares	Dec. 31, 2017USD ($)Installment$ / sharesshares	Dec. 31, 2016USD ($)shares
Debt Instrument [Line Items]
Loan payable, end-of-term payment due	$ 1,630,000					$ 1,630,000
Warrants issued to lenders as part of new loan agreement, shares of common stock to purchase | shares				1,202,117	608,696
Warrants issued to lenders as part of new loan agreement, exercise price | $ / shares				$ 0.87	$ 1.15
Warrants issued to lenders as part of new loan agreement, fair value				$ 700,000	$ 400,000		$ 667,000
Number of common stock shared issued | shares	118,325,396					118,325,396	75,863,000
Approximate payment of principle and interest	$ 9,013,000					$ 9,013,000
Maximum amount of debt conversion	2,000,000					2,000,000
Unamortized discount recognized	$ 1,523,000					$ 1,523,000	$ 1,000,000
Private Placement | PIPE Warrants
Debt Instrument [Line Items]
Warrants issued to lenders as part of new loan agreement, shares of common stock to purchase | shares						259,067
Number of warrants exercised | shares		259,067
Number of common stock shared issued | shares		259,067		17,642,482
Cash proceeds from issue of units						$ 200,000
Exchange of unit to share | shares				1		1
Common stock warrant exercise price | $ / shares	$ 1			$ 1		$ 1
Cash proceeds		$ 300,000
Private Placement | PIPE Warrants | Director and Executive Officer
Debt Instrument [Line Items]
Number of common stock shared issued | shares		259,067		544,039
Cash proceeds		$ 300,000
Loans Payable | Minimum
Debt Instrument [Line Items]
Option to purchase equity, net cash proceeds of equity securities	$ 10,000,000					$ 10,000,000
Hercules Amended Loan Agreement | Loans Payable
Debt Instrument [Line Items]
Proceeds from additional borrowing capacity					$ 10,000,000
Loan payable, Commencement date					May 1, 2016
Loan payable, due date						Jan. 1, 2018
Loan payable, end-of-term payment due	$ 500,000					$ 500,000
Loan issuance costs paid						$ 200,000
Loan payable, interest rate	11.90%					11.90%
Hercules September Two Thousand Fourteen Loan Agreement | Amendment One
Debt Instrument [Line Items]
Number of warrants exercised | shares		608,696
Number of common stock shared issued | shares					369,297
Cash proceeds in connection with warrants exercised					$ 0
Hercules May 2016 Loan Agreement | Loans Payable
Debt Instrument [Line Items]
Proceeds from additional borrowing capacity			$ 5,000,000	$ 5,000,000
Loan payable, Commencement date			Jan. 1, 2018			Jul. 1, 2017
Loan payable, due date			Dec. 1, 2019			Dec. 1, 2019
Loan payable, end-of-term payment due			$ 300,000	200,000
Loan issuance costs paid				100,000
Loan outstanding principal amount			$ 20,000,000	$ 15,000,000
Loan payable, number of installments of principal and interest | Installment			23	30
Loan payable, frequency of installments of principal and interest			Monthly payments of principal and interest	Monthly payments of principal and interest
Unrestricted and unencumbered cash and cash equivalents			$ 25,000,000
Debt instrument, covenant description						The Company had achieved the following conditions: (i) satisfactory developmental progression on a minimum of two (2) clinical programs (other than the TIVO-3 trial) that are either managed directly by the Company or funded, in whole or in part, by the Company and (ii) having an unrestricted cash position greater than or equal to $25.0 million on the date of the draw down request.
Additional borrowing capacity			5,000,000
Loan payable, Commencement date deferred by six months						Jan. 1, 2018
Additional, end-of-term payment			$ 100,000
Percentage of loan outstanding			26.00%
Hercules May 2016 Loan Agreement | Loans Payable | November 2019
Debt Instrument [Line Items]
Approximate payment of principle and interest			$ 800,000
Hercules May 2016 Loan Agreement | Loans Payable | December 2019
Debt Instrument [Line Items]
Approximate payment of principle and interest			$ 5,300,000
Hercules May 2016 Loan Agreement | Loans Payable | Minimum | Financial covenant
Debt Instrument [Line Items]
Unrestricted and unencumbered cash and cash equivalents				$ 10,000,000
Hercules May 2016 Loan Agreement | Amendment Two
Debt Instrument [Line Items]
Number of warrants exercised | shares		1,202,117
Number of common stock shared issued | shares		846,496
Cash proceeds in connection with warrants exercised		$ 0
2017 Loan Agreement with Hercules
Debt Instrument [Line Items]
Proceeds from additional borrowing capacity	$ 20,000,000
Warrants issued to lenders as part of new loan agreement, shares of common stock to purchase | shares	0
Maximum amount of debt conversion	$ 2,000,000					$ 2,000,000
Refinancing amount	$ 20,000,000					$ 20,000,000
Loan facility maturity period	42 months
Loan facility extension period	24 months
2017 Loan Agreement with Hercules | Loans Payable
Debt Instrument [Line Items]
Loan payable, due date						Jul. 1, 2021
Loan payable, end-of-term payment due	$ 1,600,000					$ 1,600,000
Loan issuance costs paid	$ 100,000
Loan payable, number of installments of principal and interest | Installment	29					29
Loan payable, frequency of installments of principal and interest	Monthly payments of principal and interest
Loan payable, Commencement date deferred by six months						Feb. 1, 2019
Additional, end-of-term payment	$ 800,000
Loan payable, interest rate	9.45%					9.45%
Loan payable, interest rate, base rate	9.45%					9.45%
Loan payable, interest rate, additional rate deducted from base rate	4.75%					4.75%
Loan payable, description of interest rate terms						Per annum interest is payable on the principal balance of the loan each month it remains outstanding at the greater of 9.45% and an amount equal to 9.45% plus the prime rate minus 4.75% as determined daily, provided however, that the per annum interest rate shall not exceed 15.0% (9.45% as of December 31, 2017).
2017 Loan Agreement with Hercules | Loans Payable | July 2021
Debt Instrument [Line Items]
Approximate payment of principle and interest	$ 800,000					$ 800,000
2017 Loan Agreement with Hercules | Loans Payable | Minimum
Debt Instrument [Line Items]
Loan payable, interest rate	9.45%					9.45%
2017 Loan Agreement with Hercules | Loans Payable | Minimum | Financial covenant
Debt Instrument [Line Items]
Unrestricted and unencumbered cash and cash equivalents	$ 10,000,000					$ 10,000,000
2017 Loan Agreement with Hercules | Loans Payable | Maximum
Debt Instrument [Line Items]
Loan payable, interest rate	15.00%					15.00%

Future Minimum Payments Under L

Future Minimum Payments Under Loans Payable (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
2,018	$ 2,493
2,019	8,725
2,020	9,013
2,021	6,087
Long-term Debt, Gross, Total	26,318
Less amount representing interest	(4,688)
Less unamortized discount	(1,523)	$ (1,000)
Less deferred charges	(1,630)
Less loans payable current, net of discount		(2,124)
Loans payable, net of current portion and discount	$ 18,477	$ 11,879

Common Stock - Additional Infor

Common Stock - Additional Information (Detail) - USD ($)	1 Months Ended					2 Months Ended	5 Months Ended	12 Months Ended	23 Months Ended
	Jul. 31, 2017	Jun. 30, 2017	Mar. 31, 2017	May 31, 2016	Aug. 31, 2015	Mar. 08, 2018	Dec. 15, 2017	Dec. 31, 2017	Jun. 30, 2017	Feb. 28, 2018	Nov. 30, 2017	Dec. 31, 2016	May 07, 2015	Mar. 31, 2015	Feb. 28, 2015
Class Of Stock [Line Items]
Common stock, shares authorized		250,000,000						250,000,000	250,000,000			200,000,000
Common stock, par value		$ 0.001						$ 0.001	$ 0.001			$ 0.001
Common stock, shares issued								118,325,396				75,863,000
Common stock, shares outstanding								118,325,396				75,863,000
Common stock, additional shares authorized		50,000,000							50,000,000
Common stock sales agreement, aggregate offering amount								$ 118,000				$ 76,000
Offering, issuance and sale of stocks and securities, shelf registration														$ 250,000,000
Underwriters' option to purchase shares								17,576
Net proceeds from public offering								$ 29,500,000
Sale of stock							0		0
Underwritten Public Offering
Class Of Stock [Line Items]
Common stock, shares issued			34,500,000
Underwriters' option to purchase shares			4,500,000
Gross proceeds from public offering			$ 17,300,000
Percentage of affiliates stock holders			5.00%
Net proceeds from public offering			$ 15,400,000					$ 15,400,000
Private Placement | PIPE Warrants
Class Of Stock [Line Items]
Common stock, shares issued	259,067			17,642,482
Shares issued, price per share				$ 0.965
Gross proceeds from issuance of private placement				$ 17,000,000
Exchange of unit to share				1				1
Warrants exercise price				$ 1				$ 1
Warrants exercisable period				5 years
Warrants exercisable shares of common stock outstanding								17,383,415
Warrants exercisable shares of common stock exercised	259,067
Cash proceeds	$ 300,000
Private Placement | PIPE Warrants | Director and Executive Officer
Class Of Stock [Line Items]
Common stock, shares issued	259,067			544,039
Net offering proceeds to the company				$ 15,400,000
Cash proceeds	$ 300,000
Subsequent Event
Class Of Stock [Line Items]
Net proceeds from public offering						$ 1,900,000
Leerink | Subsequent Event
Class Of Stock [Line Items]
Common stock, shares issued										0
New Enterprise Associates | Underwritten Public Offering
Class Of Stock [Line Items]
Common stock, shares issued			420,000
Other Investors | Underwritten Public Offering
Class Of Stock [Line Items]
Common stock, shares issued			6,000,000
F B R Co
Class Of Stock [Line Items]
Common stock, shares issued		6,500,000			5,900,000			6,500,000	6,500,000
proceeds from sale of shares		$ 8,800,000			$ 10,200,000			$ 8,800,000
Maximum
Class Of Stock [Line Items]
Offering, issuance and sale of stocks and securities, shelf registration											$ 200,000,000		$ 100,000,000
Maximum | Leerink | Subsequent Event
Class Of Stock [Line Items]
Common stock sales agreement, aggregate offering amount										$ 50,000,000
Common stock sales agreement commission, percentage										3.00%
Maximum | F B R Co
Class Of Stock [Line Items]
Common stock sales agreement, aggregate offering amount													$ 15,000,000		$ 17,900,000
Common stock sales agreement commission, percentage															3.00%
Minimum | Underwritten Public Offering
Class Of Stock [Line Items]
Shares issued, price per share			$ 0.50

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($)	1 Months Ended			6 Months Ended	12 Months Ended
	Jun. 30, 2017	Mar. 31, 2013	Feb. 28, 2010	Jun. 30, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 29, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance	3,500,000
Shares of common stock available for future issuance under the Plan					3,549,657
Stock options issued to purchase common stock					7,537,958	4,858,678
Stock price								$ 2.79
Total unrecognized stock-based compensation expense related to stock options granted					$ 3,400,000
Stock-based compensation expense					$ 1,089,000	$ 999,000	$ 1,132,000
Employee Stock Purchase Plan, 2010
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance					764,000
Shares of common stock available for future issuance under the Plan					307,282
Employee stock purchase plan, number of shares authorized to sell			250,000
Common stock price per share percentage as of lower of fair market value of the common stock			85.00%	85.00%			85.00%
Employee stock purchase plan, each offering period		6 months
Employee stock purchase plan, number of share sold					0	0	7,138
Price per share of shares sold to employees					$ 0.75	$ 1.07
Stock-based compensation expense					$ 3,000	$ 2,000	$ 27,000
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Awards, vesting period	4 years
Awards, Expiration period	10 years
Weighted-average grant date fair value of stock options granted					$ 0.97	$ 0.65	$ 0.75
Share based payment award forfeiture rates					0.00%	76.00%	71.00%
Total unrecognized stock-based compensation expense, weighted-average period Recognition					2 years 7 months 6 days
Intrinsic value of options exercised					$ 46,000	$ 6,000	$ 58,000
Awards With Performance-Based Milestone Conditions
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options issued to purchase common stock					178,564
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair value of restricted stock awards vested					$ 0	$ 100,000	$ 100,000
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance	8,500,000
Minimum | Stock Options | Participants Who Own Less than 10% of Total Combined Voting Power
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Exercise price of incentive stock options as percentage of fair market value of common stock on the date of the award	100.00%
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance	12,000,000
Maximum | Stock Options | Participants Who Own More than 10% of Total Combined Voting Power
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Exercise price of incentive stock options as percentage of fair market value of common stock on the date of the award	110.00%

Stock Option Activity (Detail)

Stock Option Activity (Detail)	12 Months Ended
	Dec. 31, 2017USD ($)$ / sharesshares
Options
Outstanding at beginning of period | shares	4,858,678
Granted | shares	3,455,135
Exercised | shares	(17,576)
Forfeited | shares	(758,279)
Outstanding at end of period | shares	7,537,958
Exercisable at December 31, 2017 | shares	3,582,756
Weighted-Average Exercise Price
Outstanding at beginning of period | $ / shares	$ 2.31
Granted | $ / shares	1.40
Exercised | $ / shares	0.87
Forfeited | $ / shares	1.03
Outstanding at end of period | $ / shares	2
Exercisable at December 31, 2017 | $ / shares	$ 2.67
Weighted-Average Remaining Contractual Term
Outstanding at December 31, 2017	7 years 5 months 26 days
Exercisable at December 31, 2017	6 years 21 days
Aggregate Intrinsic Value
Outstanding at end of year | $	$ 10,709,000
Exercisable at end of year | $	$ 5,075,000

Assumptions Used in Black Schol

Assumptions Used in Black Scholes Pricing Model for New Grants (Detail)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Volatility factor, minimum	71.82%	72.18%	73.04%
Volatility factor, maximum	80.15%	74.47%	78.70%
Risk-free interest rates, minimum	1.84%	1.07%	1.54%
Risk-free interest rates, maximum	2.22%	2.01%	1.93%
Dividend yield	0.00%	0.00%	0.00%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	5 years 6 months	3 years	5 years 6 months
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	6 years 3 months	6 years 3 months	6 years 3 months

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	May 09, 2012USD ($)ft²	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Commitment And Contingencies [Line Items]
Rent expense		$ 600,000	$ 600,000
Rent credit				$ (9,100,000)
Maximum
Commitment And Contingencies [Line Items]
Severance and bonus payment period		18 months
Severance and bonus payment period		18 months
Minimum
Commitment And Contingencies [Line Items]
Severance and bonus payment period		12 months
Severance and bonus payment period		6 months
BMR-650 E KENDALL B LLC
Commitment And Contingencies [Line Items]
Lease agreement, square feet of property leased | ft²	126,065
Lease agreement, initial term	12 years 7 months
Operating lease, maximum lease improvements reimbursement amount	$ 14,900,000
Operating lease, rent expense				(9,500,000)	$ 4,300,000
Recognition of deferred rent credits				10,600,000	$ 3,800,000
Lease Cancellable Arrangement
Commitment And Contingencies [Line Items]
Rent expense				$ 200,000

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Apr. 30, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jan. 31, 2017
Income Taxes [Line Items]
Operating loss carryforwards, net				$ 4,100
Decrease in valuation allowance			$ 49,600
Increase in valuation allowance				$ 10,600	$ 3,900
Additional deferred tax assets related to previously unrecognized tax losses						$ 4,100
Deferred tax assets						$ 0
Federal statutory tax rate			34.00%	34.00%	34.00%
Decrease in deferred tax assets			$ 63,300
Scenario Plan
Income Taxes [Line Items]
Federal statutory tax rate		21.00%
Maximum
Income Taxes [Line Items]
Federal statutory tax rate			35.00%
Tax deduction for interest expense of adjusted earnings			30.00%
Tax deduction for net operating losses			80.00%
State and Local Jurisdiction
Income Taxes [Line Items]
Operating loss carryforwards, net			$ 394,300
Research and development tax credit carryforwards			$ 4,300
State and Local Jurisdiction | Minimum
Income Taxes [Line Items]
Operating loss carryforwards, expiration year			2,030
Research and development tax credit, expiration year			2,019
State and Local Jurisdiction | Maximum
Income Taxes [Line Items]
Operating loss carryforwards, expiration year			2,037
Research and development tax credit, expiration year			2,032
Internal Revenue Service (IRS)
Income Taxes [Line Items]
Operating loss carryforwards, net			$ 503,600
Research and development tax credit carryforwards			$ 10,500
Internal Revenue Service (IRS) | Minimum
Income Taxes [Line Items]
Operating loss carryforwards, expiration year			2,022
Research and development tax credit, expiration year			2,022
Internal Revenue Service (IRS) | Maximum
Income Taxes [Line Items]
Operating loss carryforwards, expiration year			2,037
Research and development tax credit, expiration year			2,037
United Kingdom
Income Taxes [Line Items]
Operating loss carryforwards, net			$ 6,000
CANbridge | Licensing Agreements
Income Taxes [Line Items]
Upfront payment, withholding taxes			100	$ 100
Reimbursement payments related to manufacturing development activities			1,000
Collaborations and license agreements, expected milestone receivable	$ 1,000		$ 1,000

Reconciliation of Expected Inco

Reconciliation of Expected Income Tax Benefit (Detail)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income tax computed at federal statutory tax rate	34.00%	34.00%	34.00%
State taxes, net of federal benefit	5.30%	5.20%	5.30%
Research and development credits	0.40%	1.40%	2.00%
Other permanent differences	(20.80%)	6.10%	(2.00%)
Foreign rate differential	0.00%	(0.10%)	(0.10%)
Foreign withholding taxes	(0.20%)	(0.40%)
SEC settlement liability	0.00%		(9.10%)
Excess benefit stock compensation	0.00%
Tax reform - rate change	(97.50%)
Other	0.10%	(6.60%)	(3.80%)
Change in valuation allowance	78.70%	(39.60%)	(26.30%)
Total	0.00%	0.00%	0.00%

Company Net Deferred Tax Assets

Company Net Deferred Tax Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
NOL carryforwards	$ 131,683	$ 182,433
Research and development credits	13,913	13,060
Deferred revenue and R&D reimbursements	770	867
Estimated settlement liability	4,664
Other temporary differences	4,420	4,570
Total deferred tax assets:	155,450	200,930
Deferred tax liabilities:
Insurance recovery	(4,098)
Total deferred tax liabilities:	(4,098)
Valuation allowance	(151,352)	(200,930)
Total	$ 0	$ 0

Reconciliation of Gross Uncerta

Reconciliation of Gross Uncertain Tax Positions (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Amount established upon adoption	$ 1,200	$ 1,200	$ 1,200
Additions for current year tax provisions	0	0	0
Additions for prior year tax provisions	0	0	0
Reductions of prior year tax provisions	0	0	0
Balance as of end of year	$ 1,200	$ 1,200	$ 1,200

Strategic Restructuring - Addit

Strategic Restructuring - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2017Position
Restructuring And Related Activities [Abstract]
Restructuring plan, completion date	Mar. 31, 2015
Restructuring plan, percentage of number of positions eliminated	66.67%
Restructuring plan, number of positions eliminated	40

Restructuring Activity Recorded

Restructuring Activity Recorded in Operating Expenses and Accrued Expenses (Detail) - Employee Severance $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)
Restructuring Cost And Reserve [Line Items]
Restructuring amounts accrued, beginning balance	$ 357
Restructuring amounts paid	$ (357)

Facility Lease Exit - Additiona

Facility Lease Exit - Additional Information (Detail)	May 09, 2012USD ($)ft²	Sep. 30, 2014USD ($)	Jun. 30, 2015USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Facility Lease Exit Disclosure [Line Items]
Lease exit expense incurred				$ 0	$ 0
Notice period to surrender remaining leased space				90 days
3rd Amendment, Lease exit costs associated with 650 E. Kendall.
Facility Lease Exit Disclosure [Line Items]
Lease exit expense incurred		$ 15,600,000
Leased space surrendering date				May 29, 2015
3rd Amendment, Lease exit costs associated with 650 E. Kendall. | Leasehold Improvements
Facility Lease Exit Disclosure [Line Items]
Additional charge to depreciation expense due to revision of estimated useful life			$ 2,900,000			$ 2,900,000
3rd Amendment, Lease exit costs associated with 650 E. Kendall. | Deferred Rent And Leasehold Improvement
Facility Lease Exit Disclosure [Line Items]
Additional charge to depreciation expense due to revision of estimated useful life			$ 3,500,000
BMR-650 E KENDALL B LLC
Facility Lease Exit Disclosure [Line Items]
Lease agreement, square feet of property leased | ft²	126,065
Lease agreement, initial term	12 years 7 months
Operating lease, maximum lease improvements reimbursement amount	$ 14,900,000
Operating lease, rent expense						(9,500,000)	$ 4,300,000
Recognition of deferred rent credits						$ 10,600,000	$ 3,800,000

Components of Lease Exit Activi

Components of Lease Exit Activity Recorded in Current Liabilities (Detail) - Lease exit costs $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)
Facility Lease Exit Disclosure [Line Items]
Lease Exit amounts accrued	$ 4,981
Accretion Expense incurred	224
Amounts paid	(5,477)
Additional expense incurred	$ 272

Employee Benefit Plan - Additio

Employee Benefit Plan - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Compensation And Retirement Disclosure [Abstract]
401(k) Plan, matching employer contribution percentage	50.00%
401(k) Plan, employee contributions percentage	5.00%
Contributions made under the plan	$ 0.1	$ 0.1	$ 0.1

Summary of Quarterly Results (D

Summary of Quarterly Results (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Collaboration and licensing revenue	$ 82	$ 4,614	$ 351	$ 2,532	$ 127	$ 992	$ 193	$ 1,203	$ 7,579	$ 2,515	$ 19,024
Operating expenses	10,153	6,767	9,183	10,287	9,553	6,585	7,335	8,435
Loss from operations	(10,071)	(2,153)	(8,832)	(7,755)	(9,426)	(5,593)	(7,142)	(7,232)	(28,811)	(29,393)	(12,426)
Change in fair value of PIPE warrant liability	14,207	(23,538)	(23,925)	(484)	4,569	1,178	(996)		(33,740)	4,751
Other expense, net	(637)	(655)	(530)	(551)	(748)	(551)	(468)	(377)	(36,113)	2,607	(2,575)
Provision for income taxes		(51)		(50)				(101)	(101)	(101)
Net loss	$ 3,499	$ (26,397)	$ (33,287)	$ (8,840)	$ (5,605)	$ (4,966)	$ (8,606)	$ (7,710)	$ (65,025)	$ (26,887)	$ (15,001)
Basic net income (loss) per share
Net income (loss) per share	$ 0.03	$ (0.22)	$ (0.30)	$ (0.12)
Weighted average number of common shares outstanding	118,323	118,006	110,550	76,246
Dilutive net income (loss) per share
Net income (loss) per share	$ (0.08)	$ (0.22)	$ (0.30)	$ (0.12)
Weighted average number of common shares and dilutive common share equivalents outstanding	130,108	118,006	110,550	76,246
Net loss per share - basic and diluted					$ (0.07)	$ (0.07)	$ (0.13)	$ (0.13)	$ (0.61)	$ (0.39)	$ (0.27)
Weighted average number of common shares outstanding					75,863	75,861	66,917	58,166	105,930,000	69,268,000	55,701,000

Legal Proceedings -Additional I

Legal Proceedings -Additional Information (Detail) $ / shares in Units, $ in Thousands, shares in Millions	Jan. 29, 2018USD ($)$ / sharesshares	Mar. 29, 2016USD ($)	Feb. 28, 2018USD ($)	Dec. 31, 2017USD ($)LegalMatter$ / shares	Dec. 31, 2015USD ($)
Loss Contingencies [Line Items]
Class action lawsuits | LegalMatter				2
Reserve for settlement of fines				$ 17,073	$ 4,000
Estimated insurance recoveries				15,000
Non-cash charge for Settlement warrants				2,073
Litigation settlement amount paid by company		$ 4,000
Settlement fees				$ 2,073	$ 4,000
Settlement Warrants
Loss Contingencies [Line Items]
Warrants exercisable period				1 year
Warrants exercise price | $ / shares				$ 3
Reserve for settlement of fines				$ 17,100
Estimated insurance recoveries				$ 15,000
Subsequent Event
Loss Contingencies [Line Items]
Attorney fees cost and expenses	$ 15,000
Cash settlement from insurance carriers			$ 15,000
Subsequent Event | Settlement Warrants
Loss Contingencies [Line Items]
Warrants to purchase of common stock shares | shares	2
Warrants exercisable period	1 year
Warrants exercise price | $ / shares	$ 3
Cash settlement from insurance carriers			$ 15,000