Aveo Pharmaceuticals (AVEO) 10-Q7 May 142014 Q1 Quarterly reportFinancial data

Company Profile

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
Document and Entity Information	Mar. 31, 2014	1-May-14
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	31-Mar-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Trading Symbol	'AVEO	'
Entity Registrant Name	'AVEO PHARMACEUTICALS INC	'
Entity Central Index Key	'0001325879	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	52,266,461

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Current assets:	'	'
Cash and cash equivalents	$46,335	$50,826
Marketable securities	41,987	67,680
Accounts receivable	1,254	984
Tenant improvement allowance receivable	13,321	5,833
Restricted cash	636	598
Prepaid expenses and other current assets	2,044	2,998
Total current assets	105,577	128,919
Property and equipment, net	19,011	14,140
Other assets	258	290
Restricted cash	2,959	2,997
Total assets	127,805	146,346
Current liabilities:	'	'
Accounts payable	4,031	4,238
Accrued expenses	12,351	13,263
Loans payable, net of discount	10,730	10,383
Deferred revenue	2,897	1,294
Other liabilities	1,238	1,238
Deferred rent	1,397	992
Total current liabilities	32,644	31,408
Loans payable, net of current portion and discount	6,001	8,822
Deferred revenue, net of current portion	204	17,098
Deferred rent, net of current portion	21,198	19,080
Lease exit obligation, net of current portion	3,492	'
Stockholders' equity:	'	'
Preferred stock, $.001 par value: 5,000 shares authorized; no shares issued and outstanding	'	'
Common stock, $.001 par value: 100,000 shares authorized; 52,262 and 51,809 shares issued and outstanding at March 31, 2014 and December 31, 2013, respectively	52	52
Additional paid-in capital	497,946	497,177
Accumulated other comprehensive income (loss)	7	-2
Accumulated deficit	-433,739	-427,289
Total stockholders' equity	64,266	69,938
Total liabilities and stockholders' equity	$127,805	$146,346

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Preferred stock, par value	$0.00	$0.00
Preferred stock, shares authorized	5,000	5,000
Preferred stock, shares issued	'	'
Preferred stock, shares outstanding	'	'
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	100,000	100,000
Common stock, shares issued	52,262	51,809
Common stock, shares outstanding	52,262	51,809

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Collaboration revenue	$15,289	$323
Operating expenses:	'	'
Research and development	11,767	20,962
General and administrative	5,555	12,449
Restructuring and lease exit	3,859	67
Operating Expenses, Total	21,181	33,478
Loss from operations	-5,892	-33,155
Other income and expense:	'	'
Other income (expense), net	7	-101
Interest expense	-581	-870
Interest income	16	41
Other expense, net	-558	-930
Net loss	($6,450)	($34,085)
Net loss per share - basic and diluted	($0.12)	($0.69)
Weighted average number of common shares outstanding	51,634	49,380

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Loss (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Net loss	($6,450)	($34,085)
Other comprehensive income:	'	'
Unrealized gains on available-for-sale securities	8	7
Foreign currency translation adjustment	'	26
Comprehensive loss	($6,442)	($34,052)

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Operating activities	'	'
Net loss	($6,450)	($34,085)
Adjustments to reconcile net loss to net cash used in operating activities:	'	'
Impairment of property, and equipment	2,502	'
Depreciation and amortization	838	900
Net loss on disposal of fixed assets	'	50
Stock-based compensation	718	2,588
Non-cash interest expense	54	81
Amortization of premium and discount on investments	120	339
Changes in operating assets and liabilities:	'	'
Accounts receivable	-270	11,468
Tenant improvement allowance receivable	-7,488	-300
Prepaid expenses and other current assets	951	-17
Other noncurrent assets	32	-46
Restricted cash	'	42
Accounts payable	-1,618	-2,545
Accrued expenses	71	-2,128
Deferred revenue	-15,291	-324
Other liabilities	3,492	'
Deferred rent	2,523	2,369
Net cash used in operating activities	-19,816	-21,608
Investing activities	'	'
Purchases of property and equipment	-7,754	-762
Purchases of marketable securities	-33,054	-48,951
Proceeds from maturities and sales of marketable securities	58,628	27,351
Net cash provided by (used in) investing activities	17,820	-22,362
Financing activities	'	'
Proceeds from issuance of common stock, net of issuance costs	'	53,638
Proceeds from exercise of stock options	29	70
Principal payments on loans payable	-2,524	'
Net cash (used in) provided by financing activities	-2,495	53,708
Net (decrease) increase in cash and cash equivalents	-4,491	9,738
Effect of exchange rate changes on cash and cash equivalents	'	26
Cash and cash equivalents at beginning of period	50,826	76,134
Cash and cash equivalents at end of period	46,335	85,898
Supplemental cash flow information	'	'
Cash paid for interest	$553	$788

Organization

Organization	3 Months Ended
Organization	Mar. 31, 2014
Organization	'
	(1) Organization
	AVEO Pharmaceuticals, Inc. (the “Company”) is a biopharmaceutical company committed to discovering and developing targeted therapies designed to provide substantial impact in the lives of people with cancer by addressing unmet medical needs. The Company’s proprietary Human Response Platform™ provides the Company with unique insights into cancer biology and is leveraged in the discovery and clinical development of therapeutics.
	The Company has a pipeline of monoclonal antibodies, including ficlatuzumab, a product candidate for which the Company has completed a phase 2 clinical study, and AV-203, an anti-ErbB3 monoclonal antibody that has high ErbB3 affinity and potent anti-tumor activity in mouse models, for which the Company has completed a phase 1 dose escalation study.

	The Company and Astellas Pharma, Inc. (“Astellas”) were developing tivozanib for the treatment of various types of cancers such as renal cell carcinoma, colorectal cancer and breast cancer pursuant to a worldwide collaboration and license agreement. Astellas notified the Company in February 2014 that it has elected to terminate the license agreement. This termination will become effective in August 2014, at which time the tivozanib rights will be returned to the Company.

	In 2012, the Company initiated a program focusing on cachexia, a serious and common complication of advanced cancer and a number of chronic diseases. Cachexia is characterized by symptoms of unintentional weight loss, progressive muscle wasting, and a loss of appetite. The program’s primary research focus is in the area of cancer cachexia, where there is a major unmet need. AV-380, the Company’s lead drug candidate, is a potent humanized IgG1 inhibitory monoclonal antibody targeting growth differentiating factor-15, or GDF-15, a divergent member of the TGF-ß family.

	As used throughout these condensed consolidated financial statements, the terms “AVEO,” and the “Company” refer to the business of AVEO Pharmaceuticals, Inc. and its subsidiaries, AVEO Pharma Limited and AVEO Securities Corporation, both of which are wholly-owned.

	The Company has an accumulated deficit as of March 31, 2014 of approximately $433.7 million, and will require substantial additional capital for research and product development.

Basis_of_Presentation

Basis of Presentation	3 Months Ended
Basis of Presentation	Mar. 31, 2014
Basis of Presentation	'
	(2) Basis of Presentation
	These condensed 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.
	The accompanying condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements. In the opinion of management, all adjustments, consisting of normal recurring accruals and revisions of estimates, considered necessary for a fair presentation of the condensed consolidated financial statements have been included. Interim results for the three months ended March 31, 2014 are not necessarily indicative of the results that may be expected for the fiscal year ending December 31, 2014 or any other future period.
	The information presented in the condensed consolidated financial statements and related footnotes at March 31, 2014, and for the three months ended March 31, 2014 and 2013, is unaudited and the condensed consolidated balance sheet amounts and related footnotes at December 31, 2013 have been derived from the Company’s audited financial statements. For further information, refer to the consolidated financial statements and accompanying footnotes included in the Company’s annual report on Form 10-K for the fiscal year ended December 31, 2013, which was filed with the U.S. Securities and Exchange Commission (“SEC”) on March 13, 2014.

Significant_Accounting_Policie

Significant Accounting Policies	3 Months Ended
Significant Accounting Policies	Mar. 31, 2014
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, up-front license fees; option exercise fees; funding of research and/or development efforts; milestone payments; and royalties on future product sales.

	When evaluating multiple element arrangements, 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, up-front 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 U.S. Food and Drug Administration (“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 personnel-related costs such as salaries and stock-based compensation, facilities, research-related overhead, clinical trial costs, manufacturing costs and costs of other contracted services, license fees, and other external costs. Nonrefundable advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received.
	Cash and Cash Equivalents
	The Company considers highly liquid investments with a maturity of three months or less when purchased to be cash equivalents. Cash equivalents at March 31, 2014 consisted of money market funds and corporate debt securities, including commercial paper, maintained by an investment manager totaling $34.3 million and $4.8 million, respectively. Cash equivalents at December 31, 2013 consisted of money market funds and corporate debt securities, including commercial paper, maintained by an investment manager totaling $29.9 million and $15.9 million, respectively. The carrying values of our cash equivalent securities approximate fair value due to their short term maturities.
	Marketable Securities
	Marketable securities at March 31, 2014 consisted of asset-backed securities and corporate debt securities, including commercial paper, maintained by an investment manager. Marketable securities at December 31, 2013 consisted of municipal bonds, asset-backed securities, and corporate debt securities, including commercial paper, maintained by an investment manager. Credit risk is reduced as a result of the Company’s policy to limit the amount invested in any one issue. 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 classifies these investments as available-for-sale. Unrealized gains and losses are included in other comprehensive (loss) income until realized. The cost of securities sold is based on the specific identification method. There were no realized gains or losses recognized on the sale or maturity of securities during the three months ended March 31, 2014 and 2013.

	Available-for-sale securities at March 31, 2014 and December 31, 2013 consist of the following:


			Amortized			Unrealized				Unrealized				Fair
			Cost			Gains				Losses				Value
			(in thousands)
	March 31, 2014:
	Corporate debt securities (Due within 1 year)		$	29,178		$	10			$	(3	)		$	29,185
	Asset-backed securities (Due within 1 year)			12,802			1				(1	)			12,802

			$	41,980		$	11			$	(4	)		$	41,987

	December 31, 2013:
	Corporate debt securities (Due within 1 year)		$	52,156		$	4			$	(4	)		$	52,156
	Municipal bonds (Due within 1 year)			7,519			—				—				7,519
	Asset-backed securities (Due within 1 year)			8,007			—				(2	)			8,005

			$	67,682		$	4			$	(6	)		$	67,680

	The aggregate fair value of securities in an unrealized loss position for less than 12 months at March 31, 2014 was $22.3 million, representing twelve securities. There were no securities that were in an unrealized loss position for greater than 12 months at March 31, 2014. The unrealized loss was caused by a temporary change in the market for those securities primarily caused by changes in market interest rates. There was no change in the credit risk of the securities. To determine whether an other-than-temporary impairment exists, the Company performs an analysis to assess whether it intends to sell, or whether it would more likely than not be required to sell, the security before the expected recovery of the amortized cost basis. Where the Company intends to sell a security, or may be required to do so, the security’s decline in fair value is deemed to be other-than-temporary and the full amount of the unrealized loss is recorded in the statement of operations as an other-than-temporary impairment charge. When this is not the case, the Company performs additional analyses on all securities with unrealized losses to evaluate losses associated with the creditworthiness of the security. Credit losses are identified where the Company does not expect to receive cash flows, based on using a single best estimate, sufficient to recover the amortized cost basis of a security and these are recognized in other income (expense), net. The Company does not believe an other-than-temporary impairment exists with respect to those securities in an unrealized loss position at March 31, 2014.
	Marketable securities in an unrealized loss position at March 31, 2014 and December 31, 2013 consist of the following:


			Aggregate			Unrealized
			Fair Value			Losses
			(in thousands)
	March 31, 2014:
	Corporate debt securities		$	11,034		$	(3	)
	Asset-backed securities			11,300			(1	)

			$	22,334		$	(4	)

	December 31, 2013:
	Corporate debt securities		$	30,106		$	(4	)
	Government agency securities			7,519			—
	Asset-backed securities			8,005			(2	)

			$	45,630		$	(6	)

	Concentrations of Credit Risk
	Financial instruments that potentially subject the Company to credit risk primarily consist of cash, cash equivalents and available-for-sale marketable securities. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits.
	Management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held.
	The Company’s credit risk related to marketable securities is reduced as a result of the Company’s policy to limit the amount invested in any one issue.

Fair Value Measurements
The Company records cash equivalents and marketable securities at fair value. The accounting standards for fair value measurements establish a hierarchy that distinguishes between fair value measurements based on market data (observable inputs) and those based on the Company’s own assumptions (unobservable inputs). The hierarchy consists of three levels:

	•		Level 1—Quoted market prices in active markets for identical assets or liabilities. Assets that are valued utilizing only Level 1 inputs include money market funds.

	•		Level 2—Inputs other than Level 1 inputs that are either directly or indirectly observable, such as quoted market prices, interest rates and yield curves. Assets that are valued utilizing Level 2 inputs include U.S. government agency securities, asset-backed securities, and corporate bonds, including commercial paper. These investments have been initially valued at the transaction price and are subsequently valued, at the end of each reporting period, utilizing third party pricing services or other observable market data. The pricing services utilize industry standard valuation models, including both income and market based approaches and observable market inputs to determine value. These observable market inputs include reportable trades, benchmark yields, credit spreads, broker/dealer quotes, bids, offers, current spot rates, and other industry and economic events. The Company validates the prices provided by third party pricing services by reviewing their pricing methods and matrices, obtaining market values from other pricing sources, analyzing pricing data in certain instances and confirming that the relevant markets are active. After completing its validation procedures, the Company did not adjust or override any fair value measurements provided by pricing services as of March 31, 2014 or December 31, 2013.

	•		Level 3—Unobservable inputs developed using estimates and assumptions developed by the Company, which reflect those that a market participant would use. The Company made one nonrecurring fair value measurement associated with a lease exit liability. The Company currently has no assets or liabilities measured at fair value on a recurring basis that utilize Level 3 inputs.
The following tables summarize the cash equivalents and marketable securities measured at fair value on a recurring basis in the accompanying consolidated balance sheets as of March 31, 2014 and December 31, 2013.


		Fair Value Measurements of Cash Equivalents and
		Marketable Securities as of March 31, 2014
		Level 1			Level 2				Level 3				Total
		(in thousands)
Cash equivalents		$	34,266		$	4,829			$	—			$	39,095
Marketable securities			—			41,987				—				41,987

		$	34,266		$	46,816			$	—			$	81,082



		Fair Value Measurements of Cash Equivalents and
		Marketable Securities as of December 31, 2013
		Level 1			Level 2				Level 3				Total
		(in thousands)
Cash equivalents		$	29,865		$	15,958			$	—			$	45,823
Marketable securities			—			67,680				—				67,680

		$	29,865		$	83,638			$	—			$	113,503

The Company recorded a liability totaling $6.0 million associated with the exit of a portion of its leased facilities. The Company measured the fair value of the liability based on the present value of the remaining lease payments less the amount of sublease income the Company estimates it could reasonably obtain. The Company estimated its future rental and operating expense payment obligations using the terms of its lease agreement and its historical share of the building’s expenses, adjusting for the effects of inflation. The estimated sublease income to be received is based upon market rates for comparable spaces in the Cambridge area. The net cash outflows over the remaining life of the lease were discounted using a credit-risk adjusted risk-free rate. The Company has classified this lease liability as a Level 3 fair value measurement.
The fair value of the Company’s loans payable at March 31, 2014, computed pursuant to a discounted cash flow technique using the effective interest rate under the loan, is $17.8 million and is considered a Level 2 fair value measurement. The effective interest rate considers the fair value of the warrant issued in connection with the loan, loan issuance costs and the deferred charge.

Tenant Improvement Allowance Receivable
The Company is entitled to be reimbursed by the Company’s landlord for certain expenditures associated with improvements made to its leased facility at 650 E. Kendall Street in Cambridge, Massachusetts. These receivables are recorded in the period that the improvements are made and the reimbursement is earned.
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.
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 $2.5 million of impairment losses for the three months ended March 31, 2014 related to leasehold improvements (refer to Footnote 9). During the year ended December 31, 2013, the Company recognized $0.1 million of impairment losses.
Basic and Diluted Loss per Common Share
Basic (loss) earnings per share is computed by dividing net (loss) income available to common stockholders by the weighted-average number of common shares outstanding during the period. Diluted (loss) earnings per share is computed by dividing net (loss) income available to common stockholders by the weighted-average number of common shares and dilutive common share equivalents then outstanding. Potential common share equivalents consist of restricted stock awards and the incremental common shares issuable upon the exercise of stock options and warrants. Since the Company had a net loss for all periods presented, the effect of all potentially dilutive securities is anti-dilutive. Accordingly, basic and diluted net loss per common share is the same. Under the treasury stock method, unexercised “in-the-money” stock options are assumed to be exercised at the beginning of the period or at issuance, if later. The assumed proceeds are then used to purchase common shares at the average market price during the period. Stock-based payment awards that entitle their holders to receive non-forfeitable dividends before vesting are considered participating securities and are included in the calculation of basic and diluted earnings per share. Common share equivalents have not been included in the net loss per share computation for the three months ended March 31, 2014 and March 31, 2013 because their effect is anti-dilutive.
The following table sets forth for the periods presented the potential common shares (prior to consideration of the treasury stock method) excluded from the calculation of net loss per common share because their inclusion would have been anti-dilutive:


		Three Months Ended
		March 31,
		2014			2013
		(in thousands)
Options outstanding			4,163			5,393
Warrants outstanding			—			10

			4,163			5,403

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 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 re-measured fair value as of each balance sheet date until the recipient’s services are complete. During the three months ended March 31, 2014 and March 31, 2013, the Company recorded the following stock-based compensation expense:


		Three Months Ended
		March 31,
		2014			2013
		(in thousands)
Research and development		$	318		$	1,114
General and administrative			400			1,474

Total stock-based compensation expense		$	718		$	2,588

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. 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. 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. The Company has $1.0 million of net assets located in the United Kingdom.
Use of Estimates
The preparation of financial statements in conformity with accounting principles generally accepted in the United States (“GAAP”) requires the Company’s management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.
Recently Adopted Accounting Pronouncements
For a discussion of recent accounting pronouncements adopted by the Company, please refer to Note 2, “Significant Accounting Policies,” included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2013, filed with the SEC on March 13, 2014. The Company did not adopt any new accounting pronouncements during the three months ended March 31, 2014 that had a material effect on the Company’s condensed consolidated financial statements.
Reclassifications
The Company has reclassified the tenant improvement allowance receivable from prepaid expenses and other current assets on the consolidated balance sheets to a separate financial statement line to conform to the current period presentation.
Subsequent Events
The Company has evaluated all events or transactions that occurred after March 31, 2014 through the date the Company issued these financial statements.

Collaborations_and_License_Agr

Collaborations and License Agreements	3 Months Ended
	Mar. 31, 2014
Collaborations and License Agreements	'
	(4) Collaborations and License Agreements
	Astellas Pharma
	In February 2011, the Company, together with its wholly-owned subsidiary AVEO Pharma Limited, entered into a Collaboration and License Agreement with Astellas (the “Astellas Agreement”), pursuant to which the Company and Astellas intended to develop and commercialize tivozanib for the treatment of a broad range of cancers. Under the terms of the Astellas Agreement, the Company and Astellas shared responsibility for continued development and commercialization of tivozanib in North America and in Europe under a joint development plan and a joint commercialization plan, respectively. Throughout the rest of the world (the “Royalty Territory”), excluding Asia, where Kyowa Hakko Kirin (“KHK”) has retained all development and commercialization rights, Astellas has an exclusive, royalty-bearing license to develop and commercialize tivozanib. The terms of the Astellas Agreement are subject to the Company’s obligations to KHK under a license agreement entered into with KHK in 2006 pursuant to which the Company acquired exclusive rights to develop and commercialize tivozanib worldwide outside of Asia.


	In June 2013, the Company received a complete response letter from the FDA informing the Company that the FDA will not approve in its present form the Company’s NDA for tivozanib for the treatment of patients with advanced renal cell carcinoma, or RCC. In January 2014, AVEO and Astellas jointly decided to discontinue a Phase 2 breast cancer clinical trial due to insufficient enrollment. Further, Astellas elected in February 2014 to terminate the Astellas Agreement as a result of the limited scope of development for tivozanib moving forward. This termination will be effective in August 2014, at which time the tivozanib rights will be returned to the Company. In accordance with the Astellas Agreement, committed development costs, including the costs of winding down discontinued tivozanib clinical development programs, will be shared equally. There are no refund provisions in the Astellas Agreement.

	Under the Astellas Agreement, the Company received an initial cash payment of $125.0 million, comprised of a $75.0 million license fee and $50.0 million in research and development funding. The Company retained net proceeds of approximately $97.6 million of the initial cash payment from Astellas, after payments to KHK and strategic, legal and financial advisors. In December 2012, the Company received a $15.0 million milestone payment from Astellas in connection with the acceptance by the FDA of the NDA filing for tivozanib. The milestone was considered substantive and revenue was recognized upon achievement of the milestone.

	The Company is accounting 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. In addition, these activities were not deemed to be separate deliverables under the Astellas Agreement.

	Payments from Astellas with respect to Astellas’ share of tivozanib development and commercialization costs incurred by the Company pursuant to the joint development plan are recorded as a reduction to research and development expense and general and administrative expense in the accompanying consolidated financial statements due to the joint risk-sharing nature of the activities in North America and Europe. As a result of the cost-sharing provisions in the Astellas Agreement, the Company reduced research and development expense by $1.2 million and $6.3 million during the three months ended March 31, 2014 and 2013, respectively. The Company also reduced general and administrative expense by $0.1 million and $1.3 million during the three months ended March 31, 2014 and 2013, respectively, as a result of the cost-sharing provisions in the Astellas Agreement. The net amount due to the Company from Astellas pursuant to the cost-sharing provisions was $1.3 million at March 31, 2014.

	Activities under the Astellas Agreement outside of the joint development and commercialization activities in North America and Europe, including the co-exclusive license to develop and commercialize tivozanib in North America and Europe that was delivered prior to the initiation of the collaborative activities in North America and Europe, were evaluated under ASC 605-25, Revenue Recognition—Multiple Element Arrangements (“ASC 605-25”) (as amended by ASU 2009-13, Revenue Recognition (“ASU 2009-13”)) to determine if they represented a multiple element revenue arrangement. The Astellas Agreement includes the following deliverables: (1) a co-exclusive license to develop and commercialize tivozanib in North America and Europe (the “License Deliverable”); (2) a combined deliverable comprised of an exclusive royalty-bearing license to develop and commercialize tivozanib in the Royalty Territory and the Company’s obligation to provide access to clinical and regulatory information resulting from the activities in North America and Europe to Astellas for its development and commercialization of tivozanib in the Royalty Territory (the “Royalty Territory Deliverable”); and (3) the Company’s obligation to supply clinical material to Astellas for development of tivozanib in the Royalty Territory (the “Clinical Material Deliverable”). All of these deliverables were deemed to have stand-alone value and to meet the criteria to be accounted for as separate units of accounting under ASC 605-25. Factors considered in this determination included, among other things, the subject of the licenses and the research and development and commercial capabilities of Astellas.

	The Company allocated the up-front consideration of $125.0 million to the deliverables based on management’s best estimate of selling price of each deliverable using the relative selling price method as the Company did not have VSOE or TPE of selling price for such deliverables. The Company’s best estimate of selling price considered discounted cash flow models, the key assumptions of which included the market opportunity for commercialization of tivozanib in North America and Europe and the Royalty Territory, the probability of successfully developing and commercializing tivozanib, the remaining development costs for tivozanib, and the estimated time to commercialization of tivozanib. The Company allocated up-front consideration of $120.2 million to the License Deliverable and up-front consideration of $4.8 million to the Royalty Territory Deliverable. The relative selling price of the Company’s obligation under the Clinical Material Deliverable had de minimis value.

	The Company recorded the $120.2 million relative selling price of the License Deliverable as collaboration revenue during the three months ended March 31, 2011 upon delivery of the license, and deferred approximately $4.8 million of revenue representing the relative selling price of the Royalty Territory Deliverable. The Company was recording the $4.8 million of revenue attributed to the Royalty Territory Deliverable ratably over the Company’s period of performance through April 2022, the remaining patent life of tivozanib. Upon being notified that the collaboration would be terminated effective August 2014, the Company reassessed the period of performance associated with the Royalty Territory Deliverable and accelerated the recognition of the remaining deferred revenue such that the balance would be recognized through August 2014. This change in estimate resulted in the recognition of an additional $0.9 million during the three months ended March 31, 2014. The Company recorded approximately $1.0 million and $0.1 million of revenue associated with the Royalty Territory Deliverable during the three month periods ended March 31, 2014 and 2013, respectively.



	Under the agreement, the Company received cash payments related to up-front license fees, reimbursable payments and milestone payments of $1.0 million and $18.6 million during the three months ended March 31, 2014 and 2013, respectively.

	Biogen Idec International GmbH

	In March 2009, the Company entered into an exclusive option and license agreement with Biogen Idec International GmbH, a subsidiary of Biogen Idec Inc., (collectively “Biogen Idec”) regarding the development and commercialization of the Company’s discovery-stage ErbB3-targeted antibodies for the potential treatment and diagnosis of cancer and other diseases outside of North America. Under the agreement, the Company is 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 Idec 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, AVEO is obligated to use reasonable efforts to seek a collaboration partner for the purpose of funding further development and commercialization of ErbB3 targeted antibodies. AVEO 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 deliverables under the original arrangement included an option for a co-exclusive, worldwide license to develop and manufacture ErbB3 antibody products and an option for an exclusive license to commercialize ErbB3 antibody products in all countries in the world other than North America. The Company determined that these deliverables did not have standalone value due to the fact that the program was still in preclinical development and required the Company’s experience to advance development of the product candidates. As such, the Company determined that the original agreement should be accounted for as one unit of accounting.

	Biogen Idec paid the Company an up-front cash payment of $5.0 million in March 2009, which was being amortized over the Company’s period of substantial involvement, defined as the patent life of the development candidate. In addition, Biogen Idec purchased 7,500,000 shares of Series E Convertible Preferred Stock at a per share price of $4.00, resulting in gross proceeds to the Company of $30.0 million. In connection with the initial public offering consummated by the Company in March 2010 and the related 1:4 reverse stock split of the common stock, each four shares of outstanding Series E Convertible Preferred Stock were converted into one share of common stock. The Company determined that the per share price of $4.00 paid by Biogen Idec included a premium of $1.09 per share over the fair value of the Series E Convertible Preferred Stock of $2.91 as calculated by the Company in its retrospective stock valuation. Accordingly, the Company is recognizing the premium of $8.2 million as revenue on a straight-line basis over the period of substantial involvement. The Company earned a $5.0 million milestone payment for achievement of the first pre-clinical discovery milestone under the agreement in June 2009 which was not considered at risk and was therefore deferred and is being recognized over the period of substantial involvement. The Company earned a second $5.0 million milestone payment upon selection of a development candidate in March 2010. This milestone was considered substantive and was included in revenue for the quarter ended March 31, 2010. The Company earned a third $5.0 million milestone payment based on achieving the Good Laboratory Practices toxicology initiation milestone in June 2011. This milestone was considered substantive and was included in revenue for the quarter ended June 30, 2011. The Company did not earn any milestones under the Biogen arrangement during the three months ended March 31, 2014 or 2013.

	The Company concluded that the Amendment materially modified the terms of the agreement and, as a result, required application of the guidance included in FASB Accounting Standards Codification section 605-25, Multiple-Element Arrangements. 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 amended arrangement. 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 or 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 the three months ended March 31, 2014. The deferred revenue associated with the undelivered unit of accounting is being recognized on a straight-line basis over the expected period of performance, or through December 2015 based upon the Company’s historical experience with marketing its product candidates to potential partners.

	The best estimate of selling price was based upon a cost approach pursuant to which the Company estimated the costs expected to be incurred in executing a partnership agreement and then applied a reasonable markup. The Company estimated future cash outflows for several possible outcomes, including the execution of a partnership at different times within a reasonable range and partnerships of differing complexity. The Company estimated its cash outflows for each scenario based upon the expected costs associated with the relevant employees and the expected level of effort to be expended to seek and execute a partnership. The Company’s analysis also considered the legal charges that it anticipates it will incur. Changes to the Company’s assumptions within the reasonable range of possible values would not have a material impact on the amounts recorded in current or future periods.

	Under the agreement, the Company recorded revenue of $14.3 million and $0.2 million for the three months ended March 31, 2014 and 2013, respectively.

	Kirin Brewery

	In December 2006, the Company entered into an exclusive license agreement, with the right to grant sublicenses, subject to certain restrictions, with Kirin Brewery Co. Ltd. (now Kyowa Hakko Kirin) (“KHK”) to research, develop, manufacture and commercialize tivozanib, pharmaceutical compositions thereof and associated biomarkers in all territories in the world except for Asia (the “KHK Agreement”). Upon entering into the KHK Agreement, the Company made a cash payment in the amount of $5.0 million.

	In March 2010, the Company made a $10.0 million milestone payment to KHK in connection with the dosing of the first patient in the Company’s phase 3 clinical trial of tivozanib. The Company recorded $22.5 million of research and development expense during the year ended December 31, 2011 associated with a payment made to KHK related to the up-front license payment received under the Astellas Agreement. In December 2012, the Company made a $12.0 million milestone payment to KHK in connection with the acceptance by the FDA of the Company’s NDA filing for tivozanib, all of which was expensed as research and development expense during the year ended December 31, 2012. In connection with this payment, $6.0 million was reimbursed from Astellas and recorded as a reduction of research and development expense.

	Under the KHK Agreement, the Company may be required to (i) make future milestone payments upon the achievement of specified regulatory milestones and (ii) pay tiered royalty payments on net sales it makes of tivozanib in its territory ranging from the low to mid-teens as a percentage of the Company’s net sales of tivozanib. In the event the Company sublicenses the rights licensed to the Company under the KHK Agreement (after the termination of the agreement with Astellas in August 2014), the Company is required to pay KHK a specified percentage of any amounts the Company receives from any third party sublicensees, other than amounts the Company receives in respect of research and development funding or equity investments, subject to certain limitations.

	St. Vincent’s Hospital

	In July 2012, the Company entered into a license agreement with St. Vincent’s Hospital Sydney Limited (“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 MIC-1, which is also referred to as GDF-15. The Company believes GDF-15 is a novel target for cachexia and the Company is exploiting this license in its AV-380 program for cachexia. Under the agreement, the Company has the right to grant sublicenses subject to certain restrictions. The Company has a right of first negotiation to obtain an exclusive license to certain improvements that St. Vincent’s or third parties may make to licensed therapeutic products. Under the license agreement, St. Vincent’s also granted the Company non-exclusive rights for certain related diagnostic products and research tools.

	Under the license agreement, the Company is obligated to use diligent efforts to conduct research and clinical development and commercially launch at least one licensed therapeutic product, and to maximize profits from licensed therapeutic products for the benefit of the Company and St. Vincent’s. Subject to certain conditions, the Company has also agreed to achieve specified research, development and regulatory milestones by specified dates. If the Company does not achieve a given milestone by the agreed date, the Company has the option of paying the amount the Company would have been obligated to pay had the Company timely achieved the milestone, and, if the Company does so, St. Vincent’s will not have the right to terminate the license agreement based on its failure to timely achieve such milestone.

	The Company has also agreed that, for as long as there is a valid claim in the licensed patents, the Company will not, and the Company will ensure that its affiliates and its sublicensees do not, develop or commercialize any product, other than a licensed therapeutic product, for the treatment, prevention or prophylaxis of cachexia, decreased appetite or body weight, that binds to GDF-15 or the GDF-15 receptor and that is a GDF-15 antagonist, and will not license or induce any other person to do the same.

	In connection with entering into the license agreement with St. Vincent’s, the Company paid St. Vincent’s an upfront license fee of $0.7 million and a low five-figure amount to reimburse St. Vincent’s for patent-related expenses it incurred with respect to a specified licensed patent.



	Under the Company’s license agreement with St. Vincent’s, the Company may be required to:



	•	make milestone payments, up to an aggregate total of $9.2 million, upon achievement of specified research, development and regulatory milestones for the first three indications for licensed therapeutic products, some of which payments may be increased by a mid to high double-digit percentage rate for milestones payments made after the Company grants any sublicense under the license agreement, depending on the sublicensed territory or territories;


	•	pay tiered royalty payments equal to a low-single-digit percentage of any net sales the Company or its sublicensees make of licensed therapeutic products. The royalty rate escalates within the low-single-digit range during each calendar year based on increasing licensed therapeutic product sales during such calendar year. The Company’s royalty payment obligations for a licensed therapeutic product in a particular country end on the later of 10 years after the date of first commercial sale of such licensed therapeutic product in such country or expiration of the last-to-expire valid claim of the licensed patents covering such licensed therapeutic product in such country, and are subject to offsets under certain circumstances;


	•	pay St. Vincent’s sublicensing fees of up to an aggregate amount in the low-to-mid six-digits, depending on the sublicensed territory or territories, at the time the Company grants any sublicense; and


	•	reimburse St. Vincent’s for some or all of the reasonable costs and expenses it incurs in patent management, filing, prosecuting and maintaining the licensed patents.
The license agreement will remain in effect until the later of 10 years after the date of first commercial sale of licensed therapeutic products in the last country in which a commercial sale is made, or expiration of the last-to-expire valid claim of the licensed patents, unless the Company elects, or St. Vincent’s elects, to terminate the license agreement earlier.

Either party has the right to terminate the agreement in connection with a material breach of the agreement by the other party that remains uncured for a specified cure period, or in connection with events relating to the other party’s insolvency or bankruptcy, or if a force majeure event continues for more than four months.

St. Vincent’s has the right to terminate the agreement due to any patent-related challenge by the Company, its affiliates or any sublicensee, or if the Company or its affiliates or any sublicensee cause or induce any other person to make a patent-related challenge, and such challenge continues after a specified cure period.

The Company has the right to terminate the agreement on six months’ notice if the Company terminates its GDF-15 research and development programs as a result of the failure of a licensed therapeutic product in pre-clinical or clinical development, or if the Company forms the reasonable view that further GDF-15 research and development is not commercially viable, and the Company is not then in breach of any of its obligations under the agreement. If the Company forms the reasonable view that further GDF-15 research and development is not commercially viable and terminate the agreement before the Company starts a phase 1 clinical trial on a licensed therapeutic product, the Company will be required to pay St. Vincent’s a low-to-mid six-figure termination payment.

The Company may also terminate the agreement on 60 days’ notice if certain licensed patents become invalid or unenforceable prior to July 2014, the Company is not in breach of any of the Company’s obligations under the agreement, and the Company, its affiliates and sublicensees have not made a patent-related challenge.

Any termination of the agreement, in whole or in part, will result in a loss of the Company’s rights to the relevant licensed patents and know-how. If St. Vincent’s terminates the agreement in its entirety due to the Company’s breach, insolvency or a patent-related challenge, or the Company terminates the agreement due to a development failure or lack of commercial viability, as described above, St. Vincent’s will have a non-exclusive license from the Company to certain intellectual property rights and know-how relating to the licensed therapeutic products, and the Company must transfer to St. Vincent’s certain then-existing regulatory approvals and related documents for the licensed therapeutic products.

Accrued_Expenses

Accrued Expenses	3 Months Ended
Accrued Expenses	Mar. 31, 2014
Accrued Expenses	'
	(5) Accrued Expenses
	Accrued expenses consisted of the following as of March 31, 2014 and December 31, 2013:


		March 31,		December 31,
		2014		2013
		(in thousands)
	Clinical expenses	$	3,729	$	5,319
	Facility lease exit		2,499		—
	Salaries and benefits		2,047		2,027
	Property and equipment		946		1,905
	Professional fees		804		811
	Manufacturing and distribution		715		1,362
	Restructuring		207		587
	Other		1,404		1,252

		$	12,351	$	13,263

Loans_Payable

Loans Payable	3 Months Ended
Loans Payable	Mar. 31, 2014
Loans Payable	'
	(6) Loans Payable
	On May 28, 2010, the Company entered into a 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”), pursuant to which the Company received a loan in the aggregate principal amount of $25.0 million. The Company was initially required to repay the aggregate principal balance under the Loan Agreement in 30 equal monthly installments of principal starting on April 1, 2011. However, the Loan Agreement provided that such date would be extended under certain circumstances. During 2011, the Company triggered two possible extensions to the date from which principal payments were to be made and, as a result, the initial date for principal repayment was extended to January 1, 2012. On March 31, 2012, the Company entered into an amendment to the Loan Agreement, pursuant to which the Company increased the principal amount under the Loan Agreement to $26.5 million. Under the amendment to the Loan Agreement, the date on which the Company was required to begin repaying the aggregate principal balance was extended to April 1, 2013, at which point the Company began repaying such balance in 30 equal monthly installments. The Company accounted for this amendment as a loan modification in accordance with ASC 470-50, Debt—Modifications and Extinguishments.
	Per annum interest is payable on the principal balance of the loan at the greater of 11.9% and an amount equal to 11.9% plus the prime rate of interest minus 4.75%, provided however, that the per annum interest shall not exceed 15.0%. The Company must make interest payments on the loan each month following the date of borrowing under the Loan Agreement. The unpaid principal balance and all accrued but unpaid interest will be due and payable on September 1, 2015. The loan is secured by a lien on all of the Company’s personal property as of, or acquired after, the date of the Loan Agreement, except for intellectual property.
	The Loan Agreement required a deferred charge of $1.3 million which was paid in May 2012 related to the amendment of the Loan Agreement. The Loan Agreement also includes an additional deferred charge of $1.2 million due in June 2014 which has been recorded as a loan discount and is being amortized to interest expense over the term of the Loan Agreement using the effective interest rate method. The Company recorded a long-term liability for the full amount of the charge since the payment of such amount is not contingent on any future event. The Company incurred approximately $0.2 million in loan issuance costs paid directly to the lenders under the Loan Agreement, which were offset against the loan proceeds and are accounted for as a loan discount. As part of the Loan Agreement, the Company issued warrants to the lenders on June 2, 2010 to purchase up to 156,641 shares of the Company’s common stock at an exercise price equal to $7.98 per share. The Company recorded the relative fair value of the warrants of approximately $0.8 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. The relative fair value of the warrants was calculated using the Black-Scholes option-pricing model with the following assumptions: volatility of 64.12%, an expected term equal to the contractual life of the warrant (seven years), a risk-free interest rate of 2.81% and no dividend yield. The resulting effective interest rate for the loans outstanding under the Loan Agreement is approximately 13.1%.
	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. The Company has evaluated the embedded conversion option, and has concluded that it does not need to be bifurcated and separately accounted for. No amount will be recognized for the conversion feature until such time as the conversion feature is exercised and it can be determined whether a beneficial conversion feature exists. As of March 31, 2014, the principal balance outstanding was $16.9 million.

	The Loan Agreement defines 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 under and in accordance with the terms of the Loan Agreement, 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 Loan Agreement, the related liens or the priority thereof. As of March 31, 2014, the lenders have not asserted any events of default under the loan. While the Company does not believe that there has been a material adverse change, as defined in the Loan Agreement, it is possible that Hercules could take the position that the adverse outcome relating to the development and commercialization of tivozanib for RCC, including the FDA informing the Company that it would not approve the NDA for tivozanib for the treatment of patients with advanced RCC and the related shareholder litigation described below in footnote 10 —Legal Proceedings, and Astellas’ decision to terminate its collaboration with the Company, collectively constitutes a material adverse change, and, accordingly, an event of default, which could trigger a repayment of all principal and interest due under the loan unless such event of default is waived by Hercules. The Company has classified the principal amount of the loan as current and non-current on its consolidated balance sheet based upon the expected timing of the remaining payments.
	Future minimum payments under the loans payable outstanding as of March 31, 2014 are as follows (amounts in thousands):


	Years Ending December 31:
	2014 (9 months remaining)	$	10,469
	2015		9,309

			19,778
	Less amount representing interest		(1,669	)
	Less discount		(140	)
	Less deferred charges		(1,238	)
	Less current portion		(10,730	)

	Loans payable, net of current portion and discount	$	6,001

Stockbased_Compensation

Stock-based Compensation	3 Months Ended
Stock-based Compensation	Mar. 31, 2014
Stock-based Compensation	'
	(7) Stock-based Compensation
	Stock Plans
	The Company issued stock options and restricted stock awards during the three months ended March 31, 2014 and 2013.
	A summary of the status of the Company’s stock option activity at March 31, 2014 and changes during the three months then ended is presented in the table and narrative below:


		Options			Weighted-			Weighted-		Aggregate
					Average			Average		Intrinsic Value
					Exercise Price			Remaining
								Contractual
								Term
	Outstanding at December 31, 2013		4,296,694		$	7.36
	Granted		498,400		$	1.77
	Exercised		—			—
	Forfeited		(631,874	)	$	8.11

	Outstanding at March 31, 2014		4,163,220		$	6.57			6.78	$	46,107

	Vested or expected to vest at March 31, 2014		3,399,735		$	7.26			6.22	$	46,107

	Exercisable at March 31, 2014		2,323,560		$	8.36			4.95	$	46,107

	The fair value of each employee stock option granted is estimated on the date of grant using the Black-Scholes option-pricing model using the assumptions noted in the following table:


		Three Months Ended
		March 31,
		2014			2013
	Volatility factor		73.53	%		64.22	%
	Expected term (in years)		6.25			6.25
	Risk-free interest rates		2.02	%		1.01	%
	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.
	The Company does not have sufficient history to support a calculation of volatility and expected term using only its historical data. As such, the Company has 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. Additionally, the Company is required to include an estimate of the value of the awards that will be forfeited in calculating compensation costs, which the Company estimates based upon actual historical forfeitures. The forfeiture estimates are recognized over the requisite service period of the awards on a straight-line basis. Based upon these assumptions, the weighted-average grant date fair value of stock options granted to employees during the three months ended March 31, 2014 and 2013 was $1.17 and $4.58 per share, respectively.
	As of March 31, 2014, there was $2.8 million of total unrecognized stock-based compensation expense related to stock options granted to employees under the Company’s 2002 Stock Incentive Plan and 2010 Stock Incentive Plan (collectively, the “Plans”). The expense is expected to be recognized over a weighted-average period of 1.9 years. No options were exercised during the three months ended March 31, 2014. The intrinsic value of options exercised was $0.3 million for the three months ended March 31, 2013.
	The restricted stock activity for the three months ended March 31, 2014 is as follows:


		Number of Shares			Weighted-
					Average
					Fair-Value
	Unvested at December 31, 2013		241,500		$	2.5
	Granted		501,000			1.62
	Cancelled		(64,720	)		2.09
	Expired		—			—
	Vested/Released		(73,280	)		2.5

	Unvested at March 31, 2014		604,500		$	1.81

	As of March 31, 2014, there was $0.3 million of total unrecognized stock-based compensation expense related to restricted stock awards granted under the plans. The expense is expected to be recognized over a weighted-average period of 1.7 years.

Strategic_Restructuring

Strategic Restructuring

3 Months Ended

Mar. 31, 2014

Strategic Restructuring

(8) Strategic Restructuring

In connection with the receipt of a Complete Response Letter from the FDA informing the Company that the FDA would not approve the Company’s NDA for tivozanib for the treatment of patients with advanced RCC, the Company announced a strategic restructuring in June 2013 to refocus the Company’s efforts on the then on-going clinical development of tivozanib in colorectal and breast cancer and on the advancement of key pipeline and preclinical assets. As part of this restructuring, the Company decided not to pursue the development of tivozanib in RCC. This restructuring was completed as of December 31, 2013 and resulted in costs totaling $8.0 million, which includes impairment charges of $0.3 million.

The following table summarizes the components of the Company’s restructuring activity recorded in operating expenses and in current liabilities:

Restructuring

amounts accrued at

expense

amounts

December 31,

incurred

paid

accrued at

2013

during the three

March 31,

months ended

2014

March 31,

2014

(in thousands)

Employee severance, benefits and related costs.

587

—

(380

)

207

Total

587

—

(380

)

207

All remaining accrued amounts are current and are reflected within accrued expenses on the consolidated balance sheet.

Facility_Lease_Exit

Facility Lease Exit

3 Months Ended

Mar. 31, 2014

Facility Lease Exit

(9) Facility Lease Exit

During the three months ending March 31, 2014, the Company completed the planned build-out of a portion of the office space it currently leases at its 650 E. Kendall Street facility. Upon completion of the build-out, the Company ceased use of the space and recorded a $6.0 million liability accordingly. The fair value of the liability was determined using the credit-adjusted risk-free rate to discount the estimated future net cash outflows associated with the space that met the cease use criteria. The estimate of future net cash outflows included the Company’s expected minimum rental payments and incremental operating, utility and tax payments to the landlord less the amount of sublease income that the Company estimates it could reasonably expect to obtain during the remainder of the lease period.

The following table summarizes the components of the Company’s lease exit activity recorded in current and long-term liabilities:

Expense

Amounts

incurred

paid

accrued at

during the three

March 31,

months ended

2014

March 31,

2014

(in thousands)

Lease exit costs.

5,991

—

5,991

Total

5,991

—

5,991

The total expense associated with recording the fair value of the lease exit liability of $6.0 million for the three months ending March 31, 2014 has been recorded within Restructuring and Lease Exit expense on the Condensed Consolidated Statements of Operations. The Company wrote-off $4.6 million of deferred rent and $2.5 million of leasehold improvements associated with the portion of the facility that met the cease use criteria under ASC 420-10, resulting in a net charge of $3.9 million being recorded during the quarter ended March 31, 2014. Approximately $2.5 million of the amounts are reflected within accrued expenses on the consolidated balance sheet and the remaining $3.5 million has been recorded within other noncurrent liabilities on the consolidated balance sheet.

Legal_Proceedings

Legal Proceedings	3 Months Ended
Legal Proceedings	Mar. 31, 2014
Legal Proceedings	'
	(10) Legal Proceedings
	Two class action lawsuits have been filed against the Company and certain present and former officers and members of the Company’s board of 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., No. 1:13-cv-11157-DJC, and an amended complaint was filed on February 3, 2014. The amended complaint purports to be brought on behalf of shareholders who purchased the Company’s common stock between January 3, 2012 and May 1, 2013. The amended complaint generally alleges that the Company and certain of its present and former officers and directors violated Sections 10(b) and/or 20(a) of the Securities Exchange Act of 1934 and Rule 10b-5 promulgated thereunder by making allegedly false and/or misleading statements concerning the phase 3 trial design and results for our TIVO-1 study in an effort to lead investors to believe that the drug would receive approval from the FDA. The amended complaint seeks unspecified damages, interest, attorneys’ fees, and other costs. On April 4, 2014, the Company filed a motion to dismiss the consolidated class action complaint with prejudice. The Company denies any allegations of wrongdoing and intends to vigorously defend against this lawsuit. However, there is no assurance that the Company will be successful in our defense or that insurance will be available or adequate to fund any settlement or judgment or the litigation costs of the action. Moreover, the Company is unable to predict the outcome or reasonably estimate a range of possible loss at this time.
	On July 3, 2013, the Company received a subpoena from the SEC, requesting documents and information concerning tivozanib, including related communications with the FDA, investors and others. The Company is fully cooperating with the SEC regarding this fact-finding inquiry. The SEC has informed the Company that this inquiry should not be construed as an indication that any violations of law have occurred or that the SEC has any negative opinion of any person, entity or security.
	See Note 11 below for information regarding additional legal proceedings.

Subsequent_Events

Subsequent Events	3 Months Ended
Subsequent Events	Mar. 31, 2014
Subsequent Events	'
	(11) Subsequent Events
	Biodesix
	In April 2014, the Company entered into a worldwide agreement with Biodesix to develop and commercialize its hepatocyte growth factor (“HGF”) inhibitory antibody ficlatuzumab, with Biodesix’s proprietary companion diagnostic test, VeriStrat^®, a serum protein test that is commercially available to help physicians guide treatment decisions for patients with advanced non-small cell lung cancer (“NSCLC”).
	Under the 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. Biodesix granted the Company perpetual, non-exclusive rights to certain intellectual property, including diagnostic data related to VeriStrat, with respect to the development and commercialization of ficlatuzumab; each license includes the right to sublicense, subject to certain exceptions. Pursuant to a joint development plan to be agreed upon by a joint steering committee, the Company retains primary responsibility for clinical development of ficlatuzumab in a proof of concept (“POC”) clinical study of ficlatuzumab for NSCLC, in which VeriStrat will be used to select clinical trial subjects, referred to as NSCLC POC Trial. The NSCLC POC Trial will be fully funded by Biodesix up to a maximum of $15 million, referred to as the “Cap”. After the Cap is reached, the Company and Biodesix will share equally in the costs of the NSCLC trial, and the Company and Biodesix will each be responsible for 50% of development and regulatory costs associated with all future clinical trials agreed-upon by Biodesix and the Company, including all milestone payments and royalties payable to third parties, if any.
	Pending marketing approval of ficlatuzumab and subject to a commercialization agreement to be entered into after receipt of results from the NSCLC POC Trial, each party will share equally in commercialization profits and losses, subject to the Company’s right to be the lead commercialization party and to book worldwide sales of ficlatuzumab.
	Biodesix is solely responsible for the VeriStrat development costs, as well as VeriStrat sales and marketing costs. Following the approval of the VeriStrat test as a companion diagnostic for ficlatuzumab, Biodesix will make the VeriStrat test available and use commercially reasonable efforts to seek reimbursement in all geographies where ficlatuzumab is approved. The Company will reimburse Biodesix a pre-specified amount, under certain circumstances for VeriStrat tests performed.
	Prior to the first commercial sale of ficlatuzumab and after the earlier of (i) the Cap being reached or (ii) the completion of the NSCLC POC Trial, 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, referred to as the “Opting -Out Party”, then the Opting-Out Party shall not be responsible for any future costs associated in developing and commercializing ficlatuzumab other than any ongoing clinical studies. 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.
	If Biodesix elects to Opt-Out, it will continue to be responsible for its development and commercialization obligations with respect to VeriStrat. 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.
	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.
	The Company is in the process of evaluating the accounting treatment for the arrangement.
	Legal Matters
	On April 4, 2014, Karen J. van Ingen, a purported purchaser of AVEO stock, filed a derivative complaint allegedly on behalf of AVEO in the United States District Court for the District of Massachusetts, Civil Action No. 1:14-cv-11672-DJC, naming AVEO, as a nominal defendant and also naming as defendants present and former members of the Company’s board of directors, including Tuan Ha-Ngoc, Henri A. Termeer, Kenneth M. Bate, Anthony B. Evnin, Robert Epstein, Raju Kucherlapati, Robert C. Young, and Kenneth E. Weg. The complaint alleges breach of fiduciary duty and abuse of control between January 2012 and May 2013 with respect to allegedly misleading statements and omissions regarding tivozanib. The complaint seeks, among other relief, unspecified damages, costs and expenses, including attorneys’ fees, an order requiring the Company to implement certain corporate governance reforms, restitution from the defendants and such other relief as the court might find just and proper. The Company denies any allegations of wrongdoing and intends to vigorously defend this lawsuit. However, there is no assurance that the Company will be successful in its defense or that insurance will be available or adequate to fund any settlement or judgment or the litigation costs of this action. Moreover, the Company is unable to predict the outcome or reasonably estimate a range of possible loss at this time.

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)	3 Months Ended
Significant Accounting Policies (Policies)	Mar. 31, 2014
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, up-front license fees; option exercise fees; funding of research and/or development efforts; milestone payments; and royalties on future product sales.

	When evaluating multiple element arrangements, 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, up-front 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 U.S. Food and Drug Administration (“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 personnel-related costs such as salaries and stock-based compensation, facilities, research-related overhead, clinical trial costs, manufacturing costs and costs of other contracted services, license fees, and other external costs. Nonrefundable advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received.
Cash and Cash Equivalents	'
	Cash and Cash Equivalents
	The Company considers highly liquid investments with a maturity of three months or less when purchased to be cash equivalents. Cash equivalents at March 31, 2014 consisted of money market funds and corporate debt securities, including commercial paper, maintained by an investment manager totaling $34.3 million and $4.8 million, respectively. Cash equivalents at December 31, 2013 consisted of money market funds and corporate debt securities, including commercial paper, maintained by an investment manager totaling $29.9 million and $15.9 million, respectively. The carrying values of our cash equivalent securities approximate fair value due to their short term maturities.
Marketable Securities	'
	Marketable Securities
	Marketable securities at March 31, 2014 consisted of asset-backed securities and corporate debt securities, including commercial paper, maintained by an investment manager. Marketable securities at December 31, 2013 consisted of municipal bonds, asset-backed securities, and corporate debt securities, including commercial paper, maintained by an investment manager. Credit risk is reduced as a result of the Company’s policy to limit the amount invested in any one issue. 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 classifies these investments as available-for-sale. Unrealized gains and losses are included in other comprehensive (loss) income until realized. The cost of securities sold is based on the specific identification method. There were no realized gains or losses recognized on the sale or maturity of securities during the three months ended March 31, 2014 and 2013.

	Available-for-sale securities at March 31, 2014 and December 31, 2013 consist of the following:


			Amortized		Unrealized			Unrealized			Fair
			Cost		Gains			Losses			Value
			(in thousands)
	March 31, 2014:
	Corporate debt securities (Due within 1 year)		$	29,178	$	10		$	(3	)	$	29,185
	Asset-backed securities (Due within 1 year)			12,802		1			(1	)		12,802

			$	41,980	$	11		$	(4	)	$	41,987

	December 31, 2013:
	Corporate debt securities (Due within 1 year)		$	52,156	$	4		$	(4	)	$	52,156
	Municipal bonds (Due within 1 year)			7,519		—			—			7,519
	Asset-backed securities (Due within 1 year)			8,007		—			(2	)		8,005

			$	67,682	$	4		$	(6	)	$	67,680

	The aggregate fair value of securities in an unrealized loss position for less than 12 months at March 31, 2014 was $22.3 million, representing twelve securities. There were no securities that were in an unrealized loss position for greater than 12 months at March 31, 2014. The unrealized loss was caused by a temporary change in the market for those securities primarily caused by changes in market interest rates. There was no change in the credit risk of the securities. To determine whether an other-than-temporary impairment exists, the Company performs an analysis to assess whether it intends to sell, or whether it would more likely than not be required to sell, the security before the expected recovery of the amortized cost basis. Where the Company intends to sell a security, or may be required to do so, the security’s decline in fair value is deemed to be other-than-temporary and the full amount of the unrealized loss is recorded in the statement of operations as an other-than-temporary impairment charge. When this is not the case, the Company performs additional analyses on all securities with unrealized losses to evaluate losses associated with the creditworthiness of the security. Credit losses are identified where the Company does not expect to receive cash flows, based on using a single best estimate, sufficient to recover the amortized cost basis of a security and these are recognized in other income (expense), net. The Company does not believe an other-than-temporary impairment exists with respect to those securities in an unrealized loss position at March 31, 2014.
	Marketable securities in an unrealized loss position at March 31, 2014 and December 31, 2013 consist of the following:


			Aggregate		Unrealized
			Fair Value		Losses
			(in thousands)
	March 31, 2014:
	Corporate debt securities		$	11,034	$	(3	)
	Asset-backed securities			11,300		(1	)

			$	22,334	$	(4	)

	December 31, 2013:
	Corporate debt securities		$	30,106	$	(4	)
	Government agency securities			7,519		—
	Asset-backed securities			8,005		(2	)

			$	45,630	$	(6	)

Concentrations of Credit Risk	'
	Concentrations of Credit Risk
	Financial instruments that potentially subject the Company to credit risk primarily consist of cash, cash equivalents and available-for-sale marketable securities. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits.
	Management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held.
	The Company’s credit risk related to marketable securities is reduced as a result of the Company’s policy to limit the amount invested in any one issue.
Fair Value Measurements	'
	Fair Value Measurements
	The Company records cash equivalents and marketable securities at fair value. The accounting standards for fair value measurements establish a hierarchy that distinguishes between fair value measurements based on market data (observable inputs) and those based on the Company’s own assumptions (unobservable inputs). The hierarchy consists of three levels:

		•		Level 1—Quoted market prices in active markets for identical assets or liabilities. Assets that are valued utilizing only Level 1 inputs include money market funds.

		•		Level 2—Inputs other than Level 1 inputs that are either directly or indirectly observable, such as quoted market prices, interest rates and yield curves. Assets that are valued utilizing Level 2 inputs include U.S. government agency securities, asset-backed securities, and corporate bonds, including commercial paper. These investments have been initially valued at the transaction price and are subsequently valued, at the end of each reporting period, utilizing third party pricing services or other observable market data. The pricing services utilize industry standard valuation models, including both income and market based approaches and observable market inputs to determine value. These observable market inputs include reportable trades, benchmark yields, credit spreads, broker/dealer quotes, bids, offers, current spot rates, and other industry and economic events. The Company validates the prices provided by third party pricing services by reviewing their pricing methods and matrices, obtaining market values from other pricing sources, analyzing pricing data in certain instances and confirming that the relevant markets are active. After completing its validation procedures, the Company did not adjust or override any fair value measurements provided by pricing services as of March 31, 2014 or December 31, 2013.

		•		Level 3—Unobservable inputs developed using estimates and assumptions developed by the Company, which reflect those that a market participant would use. The Company made one nonrecurring fair value measurement associated with a lease exit liability. The Company currently has no assets or liabilities measured at fair value on a recurring basis that utilize Level 3 inputs.
	The following tables summarize the cash equivalents and marketable securities measured at fair value on a recurring basis in the accompanying consolidated balance sheets as of March 31, 2014 and December 31, 2013.


			Fair Value Measurements of Cash Equivalents and
			Marketable Securities as of March 31, 2014
			Level 1		Level 2			Level 3			Total
			(in thousands)
	Cash equivalents		$	34,266	$	4,829		$	—		$	39,095
	Marketable securities			—		41,987			—			41,987

			$	34,266	$	46,816		$	—		$	81,082



			Fair Value Measurements of Cash Equivalents and
			Marketable Securities as of December 31, 2013
			Level 1		Level 2			Level 3			Total
			(in thousands)
	Cash equivalents		$	29,865	$	15,958		$	—		$	45,823
	Marketable securities			—		67,680			—			67,680

			$	29,865	$	83,638		$	—		$	113,503

	The Company recorded a liability totaling $6.0 million associated with the exit of a portion of its leased facilities. The Company measured the fair value of the liability based on the present value of the remaining lease payments less the amount of sublease income the Company estimates it could reasonably obtain. The Company estimated its future rental and operating expense payment obligations using the terms of its lease agreement and its historical share of the building’s expenses, adjusting for the effects of inflation. The estimated sublease income to be received is based upon market rates for comparable spaces in the Cambridge area. The net cash outflows over the remaining life of the lease were discounted using a credit-risk adjusted risk-free rate. The Company has classified this lease liability as a Level 3 fair value measurement.
	The fair value of the Company’s loans payable at March 31, 2014, computed pursuant to a discounted cash flow technique using the effective interest rate under the loan, is $17.8 million and is considered a Level 2 fair value measurement. The effective interest rate considers the fair value of the warrant issued in connection with the loan, loan issuance costs and the deferred charge.
Tenant Improvement Allowance Receivable	'
	Tenant Improvement Allowance Receivable
	The Company is entitled to be reimbursed by the Company’s landlord for certain expenditures associated with improvements made to its leased facility at 650 E. Kendall Street in Cambridge, Massachusetts. These receivables are recorded in the period that the improvements are made and the reimbursement is earned.
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.
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 $2.5 million of impairment losses for the three months ended March 31, 2014 related to leasehold improvements (refer to Footnote 9). During the year ended December 31, 2013, the Company recognized $0.1 million of impairment losses.
Basic and Diluted Loss per Common Share	'
	Basic and Diluted Loss per Common Share
	Basic (loss) earnings per share is computed by dividing net (loss) income available to common stockholders by the weighted-average number of common shares outstanding during the period. Diluted (loss) earnings per share is computed by dividing net (loss) income available to common stockholders by the weighted-average number of common shares and dilutive common share equivalents then outstanding. Potential common share equivalents consist of restricted stock awards and the incremental common shares issuable upon the exercise of stock options and warrants. Since the Company had a net loss for all periods presented, the effect of all potentially dilutive securities is anti-dilutive. Accordingly, basic and diluted net loss per common share is the same. Under the treasury stock method, unexercised “in-the-money” stock options are assumed to be exercised at the beginning of the period or at issuance, if later. The assumed proceeds are then used to purchase common shares at the average market price during the period. Stock-based payment awards that entitle their holders to receive non-forfeitable dividends before vesting are considered participating securities and are included in the calculation of basic and diluted earnings per share. Common share equivalents have not been included in the net loss per share computation for the three months ended March 31, 2014 and March 31, 2013 because their effect is anti-dilutive.
	The following table sets forth for the periods presented the potential common shares (prior to consideration of the treasury stock method) excluded from the calculation of net loss per common share because their inclusion would have been anti-dilutive:


			Three Months Ended
			March 31,
			2014		2013
			(in thousands)
	Options outstanding			4,163		5,393
	Warrants outstanding			—		10

				4,163		5,403

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 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 re-measured fair value as of each balance sheet date until the recipient’s services are complete. During the three months ended March 31, 2014 and March 31, 2013, the Company recorded the following stock-based compensation expense:


			Three Months Ended
			March 31,
			2014		2013
			(in thousands)
	Research and development		$	318	$	1,114
	General and administrative			400		1,474

	Total stock-based compensation expense		$	718	$	2,588

	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. 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. 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. The Company has $1.0 million of net assets located in the United Kingdom.
Use of Estimates	'
	Use of Estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States (“GAAP”) requires the Company’s management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.
Recently Adopted Accounting Pronouncements	'
	Recently Adopted Accounting Pronouncements
	For a discussion of recent accounting pronouncements adopted by the Company, please refer to Note 2, “Significant Accounting Policies,” included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2013, filed with the SEC on March 13, 2014. The Company did not adopt any new accounting pronouncements during the three months ended March 31, 2014 that had a material effect on the Company’s condensed consolidated financial statements.
Reclassifications	'
	Reclassifications
	The Company has reclassified the tenant improvement allowance receivable from prepaid expenses and other current assets on the consolidated balance sheets to a separate financial statement line to conform to the current period presentation.
Subsequent Events	'
	Subsequent Events
	The Company has evaluated all events or transactions that occurred after March 31, 2014 through the date the Company issued these financial statements.

Significant_Accounting_Policie2

Significant Accounting Policies (Tables)	3 Months Ended
Significant Accounting Policies (Tables)	Mar. 31, 2014
Available-For-Sale Securities	'
	Available-for-sale securities at March 31, 2014 and December 31, 2013 consist of the following:


		Amortized		Unrealized			Unrealized			Fair
		Cost		Gains			Losses			Value
		(in thousands)
	March 31, 2014:
	Corporate debt securities (Due within 1 year)	$	29,178	$	10		$	(3	)	$	29,185
	Asset-backed securities (Due within 1 year)		12,802		1			(1	)		12,802

		$	41,980	$	11		$	(4	)	$	41,987

	December 31, 2013:
	Corporate debt securities (Due within 1 year)	$	52,156	$	4		$	(4	)	$	52,156
	Municipal bonds (Due within 1 year)		7,519		—			—			7,519
	Asset-backed securities (Due within 1 year)		8,007		—			(2	)		8,005

		$	67,682	$	4		$	(6	)	$	67,680

Marketable Securities in Unrealized Loss Position	'
	Marketable securities in an unrealized loss position at March 31, 2014 and December 31, 2013 consist of the following:


		Aggregate		Unrealized
		Fair Value		Losses
		(in thousands)
	March 31, 2014:
	Corporate debt securities	$	11,034	$	(3	)
	Asset-backed securities		11,300		(1	)

		$	22,334	$	(4	)

	December 31, 2013:
	Corporate debt securities	$	30,106	$	(4	)
	Government agency securities		7,519		—
	Asset-backed securities		8,005		(2	)

		$	45,630	$	(6	)

Summary of Cash Equivalents and Marketable Securities Measured at Fair Value on Recurring Basis	'
	The following tables summarize the cash equivalents and marketable securities measured at fair value on a recurring basis in the accompanying consolidated balance sheets as of March 31, 2014 and December 31, 2013.


		Fair Value Measurements of Cash Equivalents and
		Marketable Securities as of March 31, 2014
		Level 1		Level 2			Level 3			Total
		(in thousands)
	Cash equivalents	$	34,266	$	4,829		$	—		$	39,095
	Marketable securities		—		41,987			—			41,987

		$	34,266	$	46,816		$	—		$	81,082



		Fair Value Measurements of Cash Equivalents and
		Marketable Securities as of December 31, 2013
		Level 1		Level 2			Level 3			Total
		(in thousands)
	Cash equivalents	$	29,865	$	15,958		$	—		$	45,823
	Marketable securities		—		67,680			—			67,680

		$	29,865	$	83,638		$	—		$	113,503

Potential Common Shares Excluded from Calculation of Net Loss Per Common Share	'
	The following table sets forth for the periods presented the potential common shares (prior to consideration of the treasury stock method) excluded from the calculation of net loss per common share because their inclusion would have been anti-dilutive:


		Three Months Ended
		March 31,
		2014		2013
		(in thousands)
	Options outstanding		4,163		5,393
	Warrants outstanding		—		10

			4,163		5,403

Equity-classified awards	'
Stock-Based Compensation Expense	'
	During the three months ended March 31, 2014 and March 31, 2013, the Company recorded the following stock-based compensation expense:


		Three Months Ended
		March 31,
		2014		2013
		(in thousands)
	Research and development	$	318	$	1,114
	General and administrative		400		1,474

	Total stock-based compensation expense	$	718	$	2,588

Accrued_Expenses_Tables

Accrued Expenses (Tables)	3 Months Ended
Accrued Expenses (Tables)	Mar. 31, 2014
Accrued Expenses	'
	Accrued expenses consisted of the following as of March 31, 2014 and December 31, 2013:


		March 31,		December 31,
		2014		2013
		(in thousands)
	Clinical expenses	$	3,729	$	5,319
	Facility lease exit		2,499		—
	Salaries and benefits		2,047		2,027
	Property and equipment		946		1,905
	Professional fees		804		811
	Manufacturing and distribution		715		1,362
	Restructuring		207		587
	Other		1,404		1,252

		$	12,351	$	13,263

Loans_Payable_Tables

Loans Payable (Tables)	3 Months Ended
Loans Payable (Tables)	Mar. 31, 2014
Future Minimum Payments Under Loans Payable	'
	Future minimum payments under the loans payable outstanding as of March 31, 2014 are as follows (amounts in thousands):


	Years Ending December 31:
	2014 (9 months remaining)	$	10,469
	2015		9,309

			19,778
	Less amount representing interest		(1,669	)
	Less discount		(140	)
	Less deferred charges		(1,238	)
	Less current portion		(10,730	)

	Loans payable, net of current portion and discount	$	6,001

Stockbased_Compensation_Tables

Stock-based Compensation (Tables)	3 Months Ended
Stock-based Compensation (Tables)	Mar. 31, 2014
Stock Option Activity	'
	A summary of the status of the Company’s stock option activity at March 31, 2014 and changes during the three months then ended is presented in the table and narrative below:


		Options			Weighted-			Weighted-		Aggregate
					Average			Average		Intrinsic Value
					Exercise Price			Remaining
								Contractual
								Term
	Outstanding at December 31, 2013		4,296,694		$	7.36
	Granted		498,400		$	1.77
	Exercised		—			—
	Forfeited		(631,874	)	$	8.11

	Outstanding at March 31, 2014		4,163,220		$	6.57			6.78	$	46,107

	Vested or expected to vest at March 31, 2014		3,399,735		$	7.26			6.22	$	46,107

	Exercisable at March 31, 2014		2,323,560		$	8.36			4.95	$	46,107

Assumptions used in Black-Scholes Pricing Model for New Grants	'
	The fair value of each employee stock option granted is estimated on the date of grant using the Black-Scholes option-pricing model using the assumptions noted in the following table:


		Three Months Ended
		March 31,
		2014			2013
	Volatility factor		73.53	%		64.22	%
	Expected term (in years)		6.25			6.25
	Risk-free interest rates		2.02	%		1.01	%
	Dividend yield		—			—
Restricted Stock Activity	'
	The restricted stock activity for the three months ended March 31, 2014 is as follows:


		Number of Shares			Weighted-
					Average
					Fair-Value
	Unvested at December 31, 2013		241,500		$	2.5
	Granted		501,000			1.62
	Cancelled		(64,720	)		2.09
	Expired		—			—
	Vested/Released		(73,280	)		2.5

	Unvested at March 31, 2014		604,500		$	1.81

Strategic_Restructuring_Tables

Strategic Restructuring (Tables)

3 Months Ended

Mar. 31, 2014

Restructuring Activity Recorded in Operating Expenses and in Current Liabilities

The following table summarizes the components of the Company’s restructuring activity recorded in operating expenses and in current liabilities:

Restructuring

amounts accrued at

expense

amounts

December 31,

incurred

paid

accrued at

2013

during the three

March 31,

months ended

2014

March 31,

2014

(in thousands)

Employee severance, benefits and related costs.

587

—

(380

)

207

Total

587

—

(380

)

207

Facility_Lease_Exit_Tables

Facility Lease Exit (Tables)

3 Months Ended

Mar. 31, 2014

Components of Lease Exit Activity Recorded in Current and Long-Term Liabilities

The following table summarizes the components of the Company’s lease exit activity recorded in current and long-term liabilities:

Expense

Amounts

incurred

paid

accrued at

during the three

March 31,

months ended

2014

March 31,

2014

(in thousands)

Lease exit costs.

5,991

—

5,991

Total

5,991

—

5,991

Organization_Additional_Inform

Organization - Additional Information (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Organization [Line Items]	'	'
Accumulated deficit	($433,739)	($427,289)

Significant_Accounting_Policie3

Significant Accounting Policies - Additional Information (Detail) (USD $)

3 Months Ended

12 Months Ended

3 Months Ended

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Segment

Money Market Funds

Corporate Debt Securities, Including Commercial Paper

Level 2

Lease exit costs associated with 650 E. Kendall.

Minimum

Maximum

United Kingdom

Securities

Restructuring and Lease Exit

Investment

Significant Accounting Policies [Line Items]

Cash equivalents

$34,300,000

$29,900,000

$4,800,000

$15,900,000

Marketable securities maturity term

'3 months

'24 months

Gain (loss) recognized on sale security

Available for sale securities, aggregate fair value of securities in an unrealized loss position for less than 12 months

22,300,000

Available for sale securities, number of securities in an unrealized loss position

Available for sale securities, aggregate fair value of securities

Lease exit cost

5,991,000

Fair value of loan payable

17,800,000

Impairment losses

2,500,000

100,000

Number of operating segments

Net assets located in the United Kingdom

$1,000,000

Available_for_Sale_Securities_

Available for Sale Securities (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	$41,980	$67,682
Unrealized Gains	11	4
Unrealized Losses	-4	-6
Fair Value	41,987	67,680
Corporate debt securities \| Due within 1 year	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	29,178	52,156
Unrealized Gains	10	4
Unrealized Losses	-3	-4
Fair Value	29,185	52,156
Asset-backed Securities \| Due within 1 year	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	12,802	8,007
Unrealized Gains	1	'
Unrealized Losses	-1	-2
Fair Value	12,802	8,005
Municipal Bonds \| Due within 1 year	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	'	7,519
Fair Value	'	$7,519

Marketable_Securities_in_Unrea

Marketable Securities in Unrealized Loss Position (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Investments, Unrealized Loss Position [Line Items]	'	'
Aggregate Fair Value	$22,334	$45,630
Unrealized Losses	-4	-6
Corporate debt securities	'	'
Investments, Unrealized Loss Position [Line Items]	'	'
Aggregate Fair Value	11,034	30,106
Unrealized Losses	-3	-4
Asset-backed Securities	'	'
Investments, Unrealized Loss Position [Line Items]	'	'
Aggregate Fair Value	11,300	8,005
Unrealized Losses	-1	-2
Government agency securities	'	'
Investments, Unrealized Loss Position [Line Items]	'	'
Aggregate Fair Value	'	$7,519

Summary_of_Cash_Equivalents_an

Summary of Cash Equivalents and Marketable Securities Measured at Fair Value on Recurring Basis (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Marketable securities	$41,987	$67,680
Fair Value, Measurements, Recurring	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash equivalents	39,095	45,823
Marketable securities	41,987	67,680
Cash Equivalents, and Marketable Securities Fair Value Disclosure, Total	81,082	113,503
Fair Value, Measurements, Recurring \| Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash equivalents	34,266	29,865
Cash Equivalents, and Marketable Securities Fair Value Disclosure, Total	34,266	29,865
Fair Value, Measurements, Recurring \| Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash equivalents	4,829	15,958
Marketable securities	41,987	67,680
Cash Equivalents, and Marketable Securities Fair Value Disclosure, Total	$46,816	$83,638

Potential_Common_Shares_Exclud

Potential Common Shares Excluded from Calculation of Net Loss Per Common Share (Detail)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Antidilutive securities excluded from computation of earnings per share amount, outstanding	4,163	5,403
Stock Option	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Antidilutive securities excluded from computation of earnings per share amount, outstanding	4,163	5,393
Warrant	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Antidilutive securities excluded from computation of earnings per share amount, outstanding	'	10

Stock_Based_Compensation_Expen

Stock Based Compensation Expense for Equity-Classified Awards (Detail) (Equity-classified awards, USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'
Stock-based compensation expense	$718	$2,588
Research and development	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'
Stock-based compensation expense	318	1,114
General and administrative	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'
Stock-based compensation expense	$400	$1,474

Collaborations_and_License_Agr1

Collaborations and License Agreements - Additional Information (Detail) (USD $)

3 Months Ended

1 Months Ended

3 Months Ended

1 Months Ended

3 Months Ended

1 Months Ended

3 Months Ended

1 Months Ended

12 Months Ended

1 Months Ended

3 Months Ended

1 Months Ended

0 Months Ended

3 Months Ended

Mar. 31, 2014

Mar. 31, 2013

Dec. 31, 2013

Mar. 31, 2014

Mar. 31, 2013

Feb. 28, 2011

Mar. 31, 2011

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Mar. 31, 2013

Feb. 28, 2011

Dec. 31, 2012

Mar. 31, 2014

Mar. 31, 2011

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2011

Jul. 30, 2011

Mar. 31, 2010

Jun. 30, 2009

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2009

Mar. 31, 2010

Dec. 31, 2006

Dec. 31, 2011

Dec. 31, 2012

Mar. 31, 2014

Jul. 31, 2012

Mar. 18, 2014

Mar. 31, 2014

Astellas Pharma Inc.

Biogen Idec International GmbH

Kirin Brewery Co. Ltd.

St Vincent's Hospital Sydney Limited

Biogen Idec

Collaboration and License Agreement

Collaborative Arrangements, Co-promotion Agreement, Agreement

Option and License Agreement

Series E Convertible Preferred Stock

Up-front Payment Arrangement

Premium on Sale of Stock

Licensing Agreements

Collaboration and License Agreement

Licensing Agreements

Up-front Payment Arrangement

MIC-1 research and development programs

Licensed Patents

Maximum

Research and development

General and administrative

Up-front Payment Arrangement

research and development funding

Regulatory Milestone Events

License Deliverable

Royalty Territory Deliverable

Option and License Agreement

Series E Convertible Preferred Stock

Licensing Agreements

Option and License Agreement

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Collaborations and license agreements, payment received

$1,000,000

$18,600,000

$125,000,000

$75,000,000

$50,000,000

$15,000,000

$5,000,000

Collaborations and license agreements, net proceeds

97,600,000

Payments received and recorded as a reduction to expense pursuant to cost-sharing provisions

1,200,000

6,300,000

100,000

1,300,000

Amounts due from Astellas pursuant to the cost-sharing provisions

1,254,000

984,000

1,300,000

Collaborations and license agreements, relative selling price of the deliverable

125,000,000

120,200,000

4,800,000

600,000

Collaborations and license agreements, revenue recognized

120,200,000

1,000,000

100,000

14,300,000

200,000

14,100,000

Collaborations and license agreements, deferred revenue

4,800,000

8,200,000

Collaborations and license agreements, deferred revenue recognition period

'Through April 2022

Collaborations and license agreements, revenue recognized

900,000

Royalty payments

50,000,000

Shares of stock sold, number of shares

7,500,000

Shares of stock sold, price per shares

Proceeds from issuance of Convertible Preferred Stock

30,000,000

Reverse stock split, ratio

0.25

Shares of stock sold, discount (premium) over the fair value per share

$1.09

Fair value of stock calculated in retrospective stock valuation

$2.91

Collaborations and license agreements, milestone payment received

5,000,000

Amortization of deferred revenue

14,700,000

Collaborations and license agreements, cash payment

5,000,000

700,000

Collaborations and license agreements, milestone payment

10,000,000

12,000,000

Research and development expense

11,767,000

20,962,000

22,500,000

Reimbursement cost

6,000,000

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

$9,200,000

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

'10 years

Termination period in case of breach of contract

'4 months

Collaborations and license agreements, written notice period for at will termination

'6 months

'60 days

Invalidation date of licensed patents

'2014-07

Accrued_Expenses_Detail

Accrued Expenses (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Schedule of Accrued Liabilities [Line Items]	'	'
Clinical expenses	$3,729	$5,319
Facility lease exit	2,499	'
Salaries and benefits	2,047	2,027
Property and equipment	946	1,905
Professional fees	804	811
Manufacturing and distribution	715	1,362
Restructuring	207	587
Other	1,404	1,252
Accrued expenses	$12,351	$13,263

Loans_Payable_Additional_Infor

Loans Payable - Additional Information (Detail) (USD $)	0 Months Ended		1 Months Ended		3 Months Ended
	Jun. 02, 2010	28-May-10	Mar. 31, 2012	Jun. 30, 2010	Mar. 31, 2014	Dec. 31, 2013
	Jun. 02, 2010	Installment	Installment	Jun. 30, 2010	Mar. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]	'	'	'	'	'	'
Loan payable, aggregate principal amount	'	$25,000,000	$26,500,000	'	'	'
Loan payable, number of installments of principal	'	30	30	'	'	'
Loan payable, start date of first principal payment	'	1-Apr-11	1-Apr-13	'	'	'
Loan payable, description of interest rate terms	'	'Per annum interest is payable on the principal balance of the loan at the greater of 11.9% and an amount equal to 11.9% plus the prime rate of interest minus 4.75%,	'	'	'	'
Loan payable, interest rate, base rate	'	11.90%	'	'	'	'
Loan payable, interest rate, additional rate deducted from base rate	'	4.75%	'	'	'	'
Loan payable, maximum per annum interest rate	'	15.00%	'	'	'	'
Loan payable, due date	'	1-Sep-15	'	'	'	'
Deferred charge related to loan	'	'	1,300,000	'	1,238,000	1,238,000
Loan issuance costs paid	'	200,000	'	'	'	'
Warrants issued to lenders as part of the new loan agreement, shares of common stock to purchase	156,641	'	'	'	'	'
Warrants issued to lenders as part of the new loan agreement, exercise price	7.98	'	'	'	'	'
Warrants issued to lenders as part of the new loan agreement, expiration period (in years)	'7 years	'	'	'	'	'
Warrants issued to lenders as part of the new loan agreement, fair value	'	'	'	800,000	'	'
Assumptions used in the Black-Scholes pricing model for warrant, volatility	64.12%	'	'	'	'	'
Assumptions used in the Black-Scholes pricing model for warrant, expected term	'7 years	'	'	'	'	'
Assumptions used in the Black-Scholes pricing model for warrant, risk-free interest rate	2.81%	'	'	'	'	'
Assumptions used in the Black-Scholes pricing model for warrant, risk-free interest rate	0.00%	'	'	'	'	'
Loan payable, effective interest rate	'	'	'	'	13.10%	'
Option to purchase equity, description	'	'	'	'	'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.	'
Option to purchase equity, maximum amount	'	'	'	'	2,000,000	'
Loan outstanding	'	'	'	'	16,900,000	'
Minimum	'	'	'	'	'	'
Debt Instrument [Line Items]	'	'	'	'	'	'
Loan payable, interest rate	'	11.90%	'	'	'	'
Option to purchase equity, net cash proceeds of equity securities	'	'	'	'	$10,000,000	'

Future_Minimum_Payments_Under_

Future Minimum Payments Under Loans Payable (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]	'	'
2014 (9 months remaining)	$10,469	'
2015	9,309	'
Long-term Debt, Gross, Total	19,778	'
Less amount representing interest	-1,669	'
Less discount	-140	'
Less deferred charges	-1,238	'
Less current portion Loans Payable Current	-10,730	-10,383
Loans payable, net of current portion and discount	$6,001	$8,822

Stock_Option_Activity_Detail

Stock Option Activity (Detail) (USD $)	3 Months Ended
Stock Option Activity (Detail) (USD $)	Mar. 31, 2014
Options	'
Outstanding at beginning of period	4,296,694
Granted	498,400
Exercised	'
Forfeited	-631,874
Outstanding at end of period	4,163,220
Vested or expected to vest at March 31, 2014	3,399,735
Exercisable at March 31, 2014	2,323,560
Weighted-Average Exercise Price	'
Outstanding at beginning of period	$7.36
Granted	$1.77
Exercised	'
Forfeited	$8.11
Outstanding at end of period	$6.57
Vested or expected to vest at March 31, 2014	$7.26
Exercisable at March 31, 2014	$8.36
Weighted-Average Remaining Contractual Term	'
Outstanding at March 31, 2014	'6 years 9 months 11 days
Vested or expected to vest at March 31, 2014	'6 years 2 months 19 days
Exercisable at March 31, 2014	'4 years 11 months 12 days
Aggregate Intrinsic Value	'
Outstanding at March 31, 2014	$46,107
Vested or expected to vest at March 31, 2014	46,107
Exercisable at March 31, 2014	$46,107

Assumptions_Used_in_Black_Scho

Assumptions Used in Black Scholes Pricing Model for New Grants (Detail)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Volatility factor	73.53%	64.22%
Expected term (in years)	'6 years 3 months	'6 years 3 months
Risk-free interest rates	2.02%	1.01%
Dividend yield	'	'

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Stock Options	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Weighted-average grant date fair value of stock options granted	$1.17	$4.58
Total unrecognized stock-based compensation expense	$2.80	'
Total unrecognized stock-based compensation expense, weighted-average period Recognition	'1 year 10 months 24 days	'
Intrinsic value of options exercised	0	0.3
Restricted Stock	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Total unrecognized stock-based compensation expense	$0.30	'
Total unrecognized stock-based compensation expense, weighted-average period Recognition	'1 year 8 months 12 days	'

Restricted_Stock_Activity_Deta

Restricted Stock Activity (Detail) (Restricted Stock, USD $)	3 Months Ended
	Mar. 31, 2014
Restricted Stock	'
Number of Shares	'
Unvested at beginning of period	241,500
Granted	501,000
Cancelled	-64,720
Vested/Released	-73,280
Unvested at end of period	604,500
Expired	'
Weighted-Average Grant-Date Fair Value	'
Unvested at beginning of period	$2.50
Granted	$1.62
Cancelled	$2.09
Expired	'
Vested/Released	$2.50
Unvested at end of period	$1.81

Strategic_Restructuring_Additi

Strategic Restructuring - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Restructuring Cost and Reserve [Line Items]	'	'
Restructuring expense incurred	'	$8
Restructuring expense including impairment charges	'	$0.30

Restructuring_Activity_Recorde

Restructuring Activity Recorded in Operating Expenses and Accrued Expenses (Detail) (USD $)	3 Months Ended	12 Months Ended	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014	Dec. 31, 2012
	Mar. 31, 2014	Dec. 31, 2013	Employee Severance	Employee Severance
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Restructuring amounts accrued, beginning balance	'	$587,000	'	$587,000
Restructuring expense incurred	'	8,000,000	'	'
Restructuring amounts paid	-380,000	'	-380,000	'
Restructuring amounts accrued, ending balance	$207,000	'	$207,000	$587,000

Facility_Lease_Exit_Additional

Facility Lease Exit - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Operating Lease Obligations [Line Items]	'	'
Lease exit liability	$5,991,000	'
Restructuring and lease exit	3,859,000	67,000
Amounts accrued	5,991,000	'
Lease exit costs associated with 650 E. Kendall.	'	'
Operating Lease Obligations [Line Items]	'	'
Lease exit liability	5,991,000	'
Restructuring and lease exit	3,859,000	'
Amounts accrued	5,991,000	'
Lease exit costs associated with 650 E. Kendall. \| Deferred rent	'	'
Operating Lease Obligations [Line Items]	'	'
Lease exit write-off cost	4,600,000	'
Lease exit costs associated with 650 E. Kendall. \| Leasehold improvement	'	'
Operating Lease Obligations [Line Items]	'	'
Lease exit write-off cost	2,500,000	'
Lease exit costs associated with 650 E. Kendall. \| Accrued expenses	'	'
Operating Lease Obligations [Line Items]	'	'
Amounts accrued	2,500,000	'
Lease exit costs associated with 650 E. Kendall. \| Other liabilities	'	'
Operating Lease Obligations [Line Items]	'	'
Amounts accrued	3,500,000	'
Lease exit costs associated with 650 E. Kendall. \| Restructuring and Lease Exit	'	'
Operating Lease Obligations [Line Items]	'	'
Lease exit liability	$5,991,000	'

Components_of_Lease_Exit_Activ

Components of Lease Exit Activity Recorded in Current and Long-Term Liabilities (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014
Operating Lease Obligations [Line Items]	'
Expense incurred	$5,991
Amounts paid	'
Amounts accrued	5,991
Lease exit costs associated with 650 E. Kendall.	'
Operating Lease Obligations [Line Items]	'
Expense incurred	5,991
Amounts paid	'
Amounts accrued	$5,991

Legal_Proceedings_Additional_I

Legal Proceedings -Additional Information (Detail)	3 Months Ended
	Mar. 31, 2014
	LegalMatter
Legal Proceedings [Line Items]	'
Class action lawsuits	2

Subsequent_Events_Additional_I

Subsequent Events - Additional Information (Detail) (Subsequent Event, Biodesix, NSCLC POC Trial, USD $)	Apr. 30, 2014
In Millions, unless otherwise specified	Apr. 30, 2014
Subsequent Event [Line Items]	'
Responsible percentage of development and regulatory costs after cap reached	50.00%
Royalty rate to net sales of ficlatuzumab	10.00%
Maximum	'
Subsequent Event [Line Items]	'
Funding	15