Immunogen (IMGN) 10-Q 2 May 14 2014 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Mar. 31, 2014	Apr. 23, 2014
Document and Entity Information	'	'
Entity Registrant Name	'IMMUNOGEN INC	'
Entity Central Index Key	'0000855654	'
Document Type	'10-Q	'
Document Period End Date	31-Mar-14	'
Amendment Flag	'false	'
Current Fiscal Year End Date	'--06-30	'
Entity Current Reporting Status	'Yes	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	85,813,733
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q3	'

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Mar. 31, 2014	Jun. 30, 2013
In Thousands, unless otherwise specified
ASSETS	'	'
Cash and cash equivalents	$164,076	$194,960
Accounts receivable	36	'
Unbilled revenue	1,987	2,121
Inventory	2,484	703
Restricted cash	319	319
Prepaid and other current assets	3,442	2,581
Total current assets	172,344	200,684
Property and equipment, net of accumulated depreciation	12,046	10,783
Long-term restricted cash	1,912	1,912
Other assets	392	217
Total assets	186,694	213,596
LIABILITIES AND SHAREHOLDERS' EQUITY	'	'
Accounts payable	4,743	4,498
Accrued compensation	6,396	6,153
Other accrued liabilities	7,221	6,049
Current portion of deferred lease incentive	1,016	979
Current portion of deferred revenue	1,821	1,494
Total current liabilities	21,197	19,173
Deferred lease incentive, net of current portion	5,079	5,626
Deferred revenue, net of current portion	59,348	63,384
Other long-term liabilities	3,136	3,566
Total liabilities	88,760	91,749
Commitments and contingencies (Note E)	'	'
Shareholders' equity:	'	'
Preferred stock, $0.01 par value; authorized 5,000 shares; no shares issued and outstanding	'	'
Common stock, $0.01 par value; authorized 150,000 shares; issued and outstanding 85,807 and 84,725 shares as of March 31, 2014 and June 30, 2013, respectively	858	847
Additional paid-in capital	718,708	697,767
Accumulated deficit	-621,632	-576,767
Total shareholders' equity	97,934	121,847
Total liabilities and shareholders' equity	$186,694	$213,596

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Mar. 31, 2014	Jun. 30, 2013
In Thousands, except Per Share data, unless otherwise specified
CONSOLIDATED BALANCE SHEETS	'	'
Preferred stock, par value (in dollars per share)	$0.01	$0.01
Preferred stock, authorized shares	5,000	5,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$0.01	$0.01
Common stock, authorized shares	150,000	150,000
Common stock, issued shares	85,807	84,725
Common stock, outstanding shares	85,807	84,725

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
Revenues:	'	'	'	'
License and milestone fees	$305	$22,010	$39,150	$23,372
Royalty revenue	2,558	'	6,946	'
Research and development support	1,948	2,257	5,860	5,670
Clinical materials revenue	2,064	734	2,197	2,662
Total revenues	6,875	25,001	54,153	31,704
Operating Expenses:	'	'	'	'
Research and development	38,280	21,318	81,171	66,674
General and administrative	6,040	4,995	18,013	16,098
Total operating expenses	44,320	26,313	99,184	82,772
Loss from operations	-37,445	-1,312	-45,031	-51,068
Other (expense) income, net	-7	-39	166	132
Net loss	-37,452	-1,351	-44,865	-50,936
Basic and diluted net loss per common share (in dollars per share)	($0.44)	($0.02)	($0.53)	($0.61)
Basic and diluted weighted average common shares outstanding (in shares)	85,684	84,279	85,375	83,923
Total comprehensive loss	($37,452)	($1,351)	($44,865)	($50,936)

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:	'	'
Net loss	($44,865)	($50,936)
Adjustments to reconcile net loss to net cash used for operating activities:	'	'
Depreciation and amortization	3,428	3,509
Loss (gain) on sale/disposal of fixed assets	20	-22
Gain on forward contracts	-2	-150
Non-cash licensing fee	12,830	'
Stock and deferred share unit compensation	12,395	9,839
Deferred rent	92	-81
Changes in operating assets and liabilities:	'	'
Accounts receivable	-36	-5,317
Unbilled revenue	134	-909
Inventory	-1,781	1,176
Prepaid and other current assets	-613	777
Other assets	-113	-9
Accounts payable	245	-672
Accrued compensation	243	121
Other accrued liabilities	-84	1,088
Deferred revenue, net of non-cash upfront license payment	-16,849	-7,101
Proceeds from landlord for tenant improvements	227	'
Net cash used for operating activities	-34,729	-48,687
Cash flows from investing activities:	'	'
Purchases of property and equipment, net	-4,711	-2,415
Payments (proceeds) from settlement of forward contracts	-1	58
Net cash used for investing activities	-4,712	-2,357
Cash flows from financing activities:	'	'
Proceeds from common stock issuance, net	'	93,991
Proceeds from stock options exercised	8,557	2,218
Net cash provided by financing activities	8,557	96,209
Net change in cash and cash equivalents	-30,884	45,165
Cash and cash equivalents, beginning balance	194,960	160,938
Cash and cash equivalents, ending balance	$164,076	$206,103

Summary_of_Significant_Account

Summary of Significant Accounting Policies	9 Months Ended
	Mar. 31, 2014
Summary of Significant Accounting Policies	'
Summary of Significant Accounting Policies	'
	A.                                    Summary of Significant Accounting Policies
	Basis of Presentation
	The accompanying unaudited consolidated financial statements at March 31, 2014 and June 30, 2013 and for the three and nine months ended March 31, 2014 and 2013 include the accounts of ImmunoGen, Inc., or the Company, and its wholly owned subsidiaries, ImmunoGen Securities Corp. and ImmunoGen Europe Limited. The consolidated financial statements include all of the adjustments, consisting only of normal recurring adjustments, which management considers necessary for a fair presentation of the Company’s financial position in accordance with accounting principles generally accepted in the U.S. for interim financial information. Certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted. The preparation of interim financial statements requires the use of management’s estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the interim financial statements and the reported amounts of revenues and expenditures during the reported periods. The results of the interim periods are not necessarily indicative of the results for the entire year. Accordingly, the interim financial statements should be read in conjunction with the audited financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended June 30, 2013.
	Subsequent Events
	The Company has evaluated all events or transactions that occurred after March 31, 2014 up through the date the Company issued these financial statements.  In April 2014, the Company modified its lease agreement at 830 Winter Street, Waltham , MA to extend the lease from 2020 to 2026.  The Company may extend the lease for two additional terms of five years. As part of this lease amendment, the Company will receive a construction allowance of approximately $1.1 million to build out office space to the Company’s specifications. The Company did not have any other material recognizable or unrecognizable subsequent events during this period.
	Revenue Recognition
	The Company enters into licensing and development agreements with collaborative partners for the development of monoclonal antibody-based anticancer therapeutics. The terms of these agreements contain multiple deliverables which may include (i) licenses, or options to obtain licenses, to the Company’s antibody-drug conjugate, or ADC, technology, (ii) rights to future technological improvements, (iii) research activities to be performed on behalf of the collaborative partner, (iv) delivery of cytotoxic agents and (v) the manufacture of preclinical or clinical materials for the collaborative partner. Payments to the Company under these agreements may include upfront fees, option fees, exercise fees, payments for research activities, payments for the manufacture of preclinical or clinical materials, payments based upon the achievement of certain milestones and royalties on product sales. The Company follows the provisions of the Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) Topic 605-25, “Revenue Recognition—Multiple-Element Arrangements,” and ASC Topic 605-28, “Revenue Recognition—Milestone Method,” in accounting for these agreements. In order to account for these agreements, the Company must identify the deliverables included within the agreement and evaluate which deliverables represent separate units of accounting based on whether certain criteria are met, including whether the delivered element has stand-alone value to the collaborator. The consideration received is allocated among the separate units of accounting, and the applicable revenue recognition criteria are applied to each of the separate units.
	At March 31, 2014, the Company had the following two types of agreements with the parties identified below:
	·                  Development and commercialization licenses to use the Company’s ADC technology and/or certain other intellectual property to develop compounds to a specified target antigen (referred to as development and commercialization licenses, as distinguished from the Company’s right-to-test agreements described elsewhere):
	Amgen (four exclusive single-target licenses)
	Bayer HealthCare (one exclusive single-target license)
	Biotest (one exclusive single-target license)
	Lilly (one exclusive single-target license)
	Novartis (two exclusive single-target licenses and one license to two related targets: one target on an exclusive basis and the second target on a non-exclusive basis)
	Roche, through its Genentech unit (five exclusive single-target licenses)
	Sanofi (one exclusive single-target license and one exclusive license to multiple individual targets)
	·                  Option/research agreement for a defined period of time to secure development and commercialization licenses to use the Company’s ADC technology to develop anticancer compounds to specified targets on established terms (referred to herein as right-to-test agreements):
	Sanofi
	Novartis
	Lilly
	CytomX
	There are no performance, cancellation, termination or refund provisions in any of the arrangements that contain material financial consequences to the Company.
	Development and Commercialization Licenses
	The deliverables under a development and commercialization license agreement generally include the license to the Company’s ADC technology with respect to a specified antigen target, and may also include deliverables related to rights to future technological improvements, research activities to be performed on behalf of the collaborative partner and the manufacture of preclinical or clinical materials for the collaborative partner.
	Generally, development and commercialization licenses contain non-refundable terms for payments and, depending on the terms of the agreement, provide that the Company will (i) at the collaborator’s request, provide research services at negotiated prices which are generally consistent with what other third parties would charge, (ii) at the collaborator’s request, manufacture and provide to it preclinical and clinical materials or deliver cytotoxic agents at negotiated prices which are generally consistent with what other third parties would charge, (iii) earn payments upon the achievement of certain milestones and (iv) earn royalty payments, generally until the later of the last applicable patent expiration or 10 to 12 years after product launch. In the case of Roche’s Kadcyla®, however, the minimum royalty term is 10 years and the maximum royalty term is 12 years on a country-by-country basis. Royalty rates may vary over the royalty term depending on the Company’s intellectual property rights. The Company may provide technical assistance and share any technology improvements with its collaborators during the term of the collaboration agreements. The Company does not directly control when or whether any collaborator will request research or manufacturing services, achieve milestones or become liable for royalty payments. As a result, the Company cannot predict when or if it will recognize revenues in connection with any of the foregoing.
	In determining the units of accounting, management evaluates whether the license has stand-alone value from the undelivered elements to the collaborative partner based on the consideration of the relevant facts and circumstances for each arrangement. Factors considered in this determination include the research capabilities of the partner and the availability of ADC technology research expertise in the general marketplace. If the Company concludes that the license has stand-alone value and therefore will be accounted for as a separate unit of accounting, the Company then determines the estimated selling prices of the license and all other units of accounting based on market conditions, similar arrangements entered into by third parties, and entity-specific factors such as the terms of the Company’s previous collaborative agreements, recent preclinical and clinical testing results of therapeutic products that use the Company’s ADC technology, the Company’s pricing practices and pricing objectives, the likelihood that technological improvements will be made, the likelihood that technological improvements made will be used by the Company’s collaborators and the nature of the research services to be performed on behalf of its collaborators and market rates for similar services.
	Upfront payments on development and commercialization licenses are deferred if facts and circumstances dictate that the license does not have stand-alone value. Prior to the adoption of Accounting Standards Update (ASU) No. 2009-13, “Revenue Arrangements with Multiple Deliverables” on July 1, 2010, the Company determined that its licenses lacked stand-alone value and were combined with other elements of the arrangement and any amounts associated with the license were deferred and amortized over a certain period, which the Company refers to as the Company’s period of substantial involvement. The determination of the length of the period over which to defer revenue is subject to judgment and estimation and can have an impact on the amount of revenue recognized in a given period. Historically the Company’s involvement with the development of a collaborator’s product candidate has been significant at the early stages of development, and lessens as it progresses into clinical trials. Also, as a drug candidate gets closer to commencing pivotal testing the Company’s collaborators have sought an alternative site to manufacture their products, as the Company’s facility does not produce pivotal or commercial drug product. Accordingly, the Company generally estimates this period of substantial involvement to begin at the inception of the collaboration agreement and conclude at the end of non-pivotal Phase II testing. The Company believes this period of substantial involvement is, depending on the nature of the license, on average six and one-half years. Quarterly, the Company reassesses its periods of substantial involvement over which the Company amortizes its upfront license fees and makes adjustments as appropriate. In the event a collaborator elects to discontinue development of a specific product candidate under a development and commercialization license, but retains its right to use the Company’s technology to develop an alternative product candidate to the same target or a target substitute, the Company would cease amortization of any remaining portion of the upfront fee until there is substantial preclinical activity on another product candidate and its remaining period of substantial involvement can be estimated. In the event that a development and commercialization license were to be terminated, the Company would recognize as revenue any portion of the upfront fee that had not previously been recorded as revenue, but was classified as deferred revenue, at the date of such termination.
	Subsequent to the adoption of ASU No. 2009-13, the Company determined that its research licenses lack stand-alone value and are considered for aggregation with the other elements of the arrangement and accounted for as one unit of accounting.
	Upfront payments on development and commercialization licenses may be recognized upon delivery of the license if facts and circumstances dictate that the license has stand-alone value from the undelivered elements, which generally include rights to future technological improvements, research services, delivery of cytotoxic agents and the manufacture of preclinical and clinical materials.
	The Company recognizes revenue related to research services that represent separate units of accounting as they are performed, as long as there is persuasive evidence of an arrangement, the fee is fixed or determinable, and collection of the related receivable is probable. The Company recognizes revenue related to the rights to future technological improvements over the estimated term of the applicable license.
	The Company may also provide cytotoxic agents to its collaborators or produce preclinical and clinical materials at negotiated prices which are generally consistent with what other third parties would charge. The Company recognizes revenue on cytotoxic agents and on preclinical and clinical materials when the materials have passed all quality testing required for collaborator acceptance and title and risk of loss have transferred to the collaborator. Arrangement consideration allocated to the manufacture of preclinical and clinical materials in a multiple-deliverable arrangement is below the Company’s full cost, and the Company’s full cost is not expected to be below its contract selling prices for its existing collaborations for the foreseeable future. During the nine months ended March 31, 2014 and 2013, the difference between the Company’s full cost to manufacture preclinical and clinical materials on behalf of its collaborators as compared to total amounts received from collaborators for the manufacture of preclinical and clinical materials was $1.6 million and $755,000, respectively. The majority of the Company’s costs to produce these preclinical and clinical materials are fixed and then allocated to each batch based on the number of batches produced during the period. Therefore, the Company’s costs to produce these materials are significantly impacted by the number of batches produced during the period. The volume of preclinical and clinical materials the Company produces is directly related to the number of clinical trials for which the Company and its collaborators are preparing or currently have underway, the speed of enrollment in those trials, the dosage schedule of each clinical trial and the time period such trials last. Accordingly, the volume of preclinical and clinical materials produced, and therefore the Company’s per batch costs to manufacture these preclinical and clinical materials, may vary significantly from period to period.
	The Company may also produce research material for potential collaborators under material transfer agreements. Additionally, the Company performs research activities, including developing antibody specific conjugation processes, on behalf of its collaborators and potential collaborators during the early evaluation and preclinical testing stages of drug development. The Company records amounts received for research materials produced or services performed as a component of research and development support revenue. The Company also develops conjugation processes for materials for later stage testing and commercialization for certain collaborators. The Company is compensated at negotiated rates and may receive milestone payments for developing these processes which are recorded as a component of research and development support revenue.
	The Company’s development and commercialization license agreements have milestone payments which for reporting purposes are aggregated into three categories: (i) development milestones, (ii) regulatory milestones, and (iii) sales milestones. Development milestones are typically payable when a product candidate first moves into clinical testing or advances into different clinical trial phases. Regulatory milestones are typically payable upon submission for marketing approval with the U.S. Food and Drug Administration, or FDA, or other countries’ regulatory authorities or on receipt of actual marketing approvals for the compound or for additional indications. Sales milestones are typically payable when annual sales reach certain levels.
	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.
	Non-refundable development and regulatory milestones that are expected to be achieved as a result of the Company’s efforts during the period of substantial involvement are considered substantive and are recognized as revenue upon the achievement of the milestone, assuming all other revenue recognition criteria are met. Milestones that are not considered substantive because we do not contribute effort to the achievement of such milestones are generally achieved after the period of substantial involvement and are recognized as revenue upon achievement of the milestone, as there are no undelivered elements remaining and no continuing performance obligations, assuming all other revenue recognition criteria are met.
	Under the Company’s development and commercialization license agreements, the Company receives royalty payments based upon its licensees’ net sales of covered products. Generally, under these agreements the Company is to receive royalty reports and payments from its licensees approximately one quarter in arrears, that is, generally in the second month of the quarter after the licensee has sold the royalty-bearing product or products. The Company recognizes royalty revenues when it can reliably estimate such amounts and collectability is reasonably assured. As such, the Company generally recognizes royalty revenues in the quarter reported to the Company by its licensees, or one quarter following the quarter in which sales by the Company’s licensees occurred.
	Right-to-Test Agreements
	The Company’s right-to-test agreements generally provide collaborators the right to (a) test the Company’s ADC technology for a defined period of time through a research, or right-to-test, license, (b) take options, for a defined period of time, to specified targets and (c) upon exercise of those options, secure or “take” licenses to develop and commercialize products for the specified targets on established terms. Under these agreements, fees may be due to the Company (i) at the inception of the arrangement (referred to as “upfront” fees or payments), (ii) upon taking an option with respect to a specific target (referred to as option fees or payments earned, if any, when the option is “taken”), (iii) upon the exercise of a previously taken option to acquire a development and commercialization license(s) (referred to as exercise fees or payments earned, if any, when the development and commercialization license is “taken”), or (iv) some combination of all of these fees.
	The accounting for right-to-test agreements is dependent on the nature of the options granted to the collaborative partner. Options are considered substantive if, at the inception of a right-to-test agreement, the Company is at risk as to whether the collaborative partner will choose to exercise the options to secure development and commercialization licenses. Factors that are considered in evaluating whether options are substantive include the overall objective of the arrangement, the benefit the collaborator might obtain from the agreement without exercising the options, the cost to exercise the options relative to the total upfront consideration, and the additional financial commitments or economic penalties imposed on the collaborator as a result of exercising the options.
	For right-to-test agreements where the options to secure development and commercialization licenses to the Company’s ADC technology are considered substantive, the Company does not consider the development and commercialization licenses to be a deliverable at the inception of the agreement. For those right-to-test agreements entered into prior to the adoption of ASU No. 2009-13 where the options to secure development and commercialization licenses are considered substantive, the Company has deferred the upfront payments received and recognizes this revenue over the period during which the collaborator could elect to take options for development and commercialization licenses. These periods are specific to each collaboration agreement. If a collaborator takes an option to acquire a development and commercialization license under these agreements, any substantive option fee is deferred and recognized over the life of the option, generally 12 to 18 months. If a collaborator exercises an option and takes a development and commercialization license to a specific target, the Company attributes the exercise fee to the development and commercialization license. Upon exercise of an option to acquire a development and commercialization license, the Company would also attribute any remaining deferred option fee to the development and commercialization license and apply the multiple-element revenue recognition criteria to the development and commercialization license and any other deliverables to determine the appropriate revenue recognition, which will be consistent with the Company’s accounting policy for upfront payments on single-target licenses. In the event a right-to-test agreement were to be terminated, the Company would recognize as revenue any portion of the upfront fee that had not previously been recorded as revenue, but was classified as deferred revenue, at the date of such termination. None of the Company’s right-to-test agreements entered into subsequent to the adoption of ASU No. 2009-13 has been determined to contain substantive options.
	For right-to-test agreements where the options to secure development and commercialization licenses to the Company’s ADC technology are not considered substantive, the Company considers the development and commercialization licenses to be a deliverable at the inception of the agreement and applies the multiple-element revenue recognition criteria to determine the appropriate revenue recognition. None of the Company’s right-to-test agreements entered into prior to the adoption of ASU No. 2009-13 has been determined to contain non-substantive options.
	The Company does not directly control when or if any collaborator will exercise its options for development and commercialization licenses. As a result, the Company cannot predict when or if it will recognize revenues in connection with any of the foregoing.
	Fair Value of Financial Instruments
	Fair value is defined under ASC Topic 820, “Fair Value Measurements and Disclosures,” as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date.  Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs.  The standard describes a fair value hierarchy to measure fair value which is based on three levels of inputs, of which the first two are considered observable and the last unobservable, as follows:
	·                           Level 1 - Quoted prices in active markets for identical assets or liabilities.
	·                           Level 2 - Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.
	·                           Level 3 - Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.
	As of March 31, 2014, the Company held certain assets that are required to be measured at fair value on a recurring basis.  The following table represents the fair value hierarchy for the Company’s financial assets measured at fair value on a recurring basis as of March 31, 2014 (in thousands):
		Fair Value Measurements at March 31, 2014 Using
					Quoted Prices in		Significant Other		Significant
					Active Markets for		Observable Inputs		Unobservable
					Identical Assets				Inputs
		Total			(Level 1)		(Level 2)		(Level 3)
	Cash, cash equivalents and restricted cash	$	166,307		$	166,307	$	—	$	—
	As of June 30, 2013, the Company held certain assets that are required to be measured at fair value on a recurring basis. The following table represents the fair value hierarchy for the Company’s financial assets measured at fair value on a recurring basis as of June 30, 2013 (in thousands):
		Fair Value Measurements at June 30, 2013 Using
					Quoted Prices in		Significant Other		Significant
					Active Markets for		Observable Inputs		Unobservable
					Identical Assets				Inputs
		Total			(Level 1)		(Level 2)		(Level 3)
	Cash, cash equivalents and restricted cash	$	197,191		$	197,191	$	—	$	—
	The fair value of the Company’s cash equivalents is based primarily on quoted prices from active markets.
	Unbilled Revenue
The majority of the Company’s unbilled revenue at March 31, 2014 and June 30, 2013 represents research funding earned prior to those dates based on actual resources utilized under the Company’s agreements with various collaborators.
Inventory
Inventory costs relate to clinical trial materials being manufactured for sale to the Company’s collaborators. Inventory is stated at the lower of cost or market as determined on a first-in, first-out (FIFO) basis.
Inventory at March 31, 2014 and June 30, 2013 is summarized below (in thousands):
	March 31,			June 30,
	2014			2013
Raw materials	$	547		$	75
Work in process	1,937			628
Total	$	2,484		$	703
Raw materials inventory consists entirely of DM1 and DM4, proprietary cell-killing agents the Company developed as part of its ADC technology. The Company considers more than a twelve month supply of raw materials that is not supported by firm, fixed orders and/or projections from its collaborators to be excess and establishes a reserve to reduce to zero the value of any such excess raw material inventory with a corresponding charge to research and development expense. In accordance with this policy, the Company recorded $236,000 and $798,000 of expense related to excess inventory during the nine-month periods ended March 31, 2014 and 2013, respectively. The Company recorded $32,000 of expense related to excess inventory during the three-month period ended March 31, 2014. There were no expenses recorded for excess inventory during the same period last year.
Work in process inventory consists of conjugate manufactured for sale to the Company’s collaborators to be used in preclinical and clinical studies.  All conjugate is made to order at the request of the collaborators and subject to the terms and conditions of respective supply agreements.  As such, no reserve for work in process inventory is required.
Computation of Net Loss per Common Share
Basic and diluted net loss per share is calculated based upon the weighted average number of common shares outstanding during the period. During periods of income, participating securities are allocated a proportional share of income determined by dividing total weighted average participating securities by the sum of the total weighted average common shares and participating securities (the “two-class method”). The Company’s restricted stock participates in any dividends declared by the Company and are therefore considered to be participating securities. Participating securities have the effect of diluting both basic and diluted earnings per share during periods of income. During periods of loss, no loss is allocated to participating securities since they have no contractual obligation to share in the losses of the Company. Diluted (loss) income per share is computed after giving consideration to the dilutive effect of stock options that are outstanding during the period, except where such non-participating securities would be anti-dilutive.
The Company’s common stock equivalents, as calculated in accordance with the treasury-stock method, are shown in the following table (in thousands):
	Three Months Ended				Nine Months Ended
	March 31,				March 31,
	2014		2013		2014	2013
Options outstanding to purchase common stock and unvested restricted stock	8,605		7,945		8,605	7,945
Common stock equivalents under treasury stock method	1,814		2,433		1,956	2,302
The Company’s common stock equivalents have not been included in the net loss per share calculation because their effect is anti-dilutive due to the Company’s net loss position.
Stock-Based Compensation
As of March 31, 2014, the Company is authorized to grant future awards under one employee share-based compensation plan, which is the ImmunoGen, Inc. 2006 Employee, Director and Consultant Equity Incentive Plan, or the 2006 Plan. At the annual meeting of shareholders on November 13, 2012, an amendment to the 2006 Plan was approved and an additional 3,500,000 shares were authorized for issuance under this plan.  As amended, the 2006 Plan provides for the issuance of Stock Grants, the grant of Options and the grant of Stock-Based Awards for up to 12,000,000 shares of the Company’s common stock, as well as any shares of common stock that are represented by awards granted under the previous stock option plan, the ImmunoGen, Inc. Restated Stock Option Plan, or the Former Plan, that are forfeited, expire or are cancelled without delivery of shares of common stock; provided, however, that no more than 5,900,000 shares shall be added to the 2006 Plan from the Former Plan, pursuant to this provision. Option awards are granted with an exercise price equal to the market price of the Company’s stock at the date of grant. Options vest at various periods of up to four years and may be exercised within ten years of the date of grant.
The stock-based awards are accounted for under ASC Topic 718, “Compensation—Stock Compensation.” Pursuant to Topic 718, the estimated grant date fair value of awards is charged to the statement of operations and comprehensive loss over the requisite service period, which is the vesting period. Such amounts have been reduced by an estimate of forfeitures of all unvested awards. The fair value of each stock option is estimated on the date of grant using the Black-Scholes option-pricing model with the assumptions noted in the following table. As the Company has not paid dividends since inception, nor does it expect to pay any dividends for the foreseeable future, the expected dividend yield assumption is zero. Expected volatility is based exclusively on historical volatility data of the Company’s stock. The expected term of stock options granted is based exclusively on historical data and represents the period of time that stock options granted are expected to be outstanding. The expected term is calculated for and applied to one group of stock options as the Company does not expect substantially different exercise or post-vesting termination behavior among its option recipients. The risk-free rate of the stock options is based on the U.S. Treasury rate in effect at the time of grant for the expected term of the stock options.
	Three Months Ended				Nine Months Ended
	March 31,				March 31,
	2014		2013		2014	2013
Dividend	None		None		None	None
Volatility	60.44%		60.44%		60.44%	60.44%
Risk-free interest rate	1.94%		1.13%		1.74%	0.85%
Expected life (years)	6.3		6.3		6.3	6.3
Using the Black-Scholes option-pricing model, the weighted average grant date fair values of options granted during the three months ended March 31, 2014 and 2013 were $9.52 and $8.28 per share, respectively, and $10.54 and $8.67 per share for options granted during the nine months ended March 31, 2013 and 2012, respectively.
Stock compensation expense related to stock options and restricted stock awards granted under the 2006 Plan was $3.7 million and $12.1 million during the three and nine months ended March 31, 2014, respectively, compared to stock compensation expense of $2.9 million and $9.6 million for the three and nine months ended March 31, 2013, respectively. As of March 31, 2014, the estimated fair value of unvested employee awards was $25.5 million, net of estimated forfeitures. The weighted-average remaining vesting period for these awards is approximately two and a quarter years.
During the nine months ended March 31, 2014, holders of options issued under the Company’s equity plans exercised their rights to acquire an aggregate of approximately 1.0 million shares of common stock at prices ranging from $3.19 to $15.83 per share.  The total proceeds to the Company from these option exercises were approximately $8.6 million.
Financial Instruments and Concentration of Credit Risk
The Company’s cash equivalents consist of money market funds with underlying investments primarily being U.S. Government-issued securities and high quality, short-term commercial paper. All of the Company’s cash and cash equivalents are maintained with three financial institutions in the U.S.  The Company uses a Euro-denominated bank account to manage the foreign currency exposures that exist as part of our ongoing business operations. Our foreign currency risk management strategy is principally designed to mitigate the future potential financial impact of changes in the value of transactions, anticipated transactions and balances denominated in foreign currency, resulting from changes in foreign currency exchange rates.
Segment Information
During the nine months ended March 31, 2014, the Company continued to operate in one operating segment which is the business of discovery of monoclonal antibody-based anticancer therapeutics.
The percentages of revenues recognized from significant customers of the Company in the three and nine months ended March 31, 2014 and 2013 are included in the following table:
	Three Months Ended				Nine Months Ended
	March 31,				March 31,
Collaborative Partner:	2014		2013		2014	2013
Biotest	13%		1%		3%	5%
Lilly	15%		1%		18%	2%
Novartis	22%		51%		40%	48%
Roche	37%		42%		31%	33%
There were no other customers of the Company with significant revenues in the three and nine months ended March 31, 2014 and 2013.
Recent Accounting Pronouncements
In July 2013, the FASB issued guidance to address the diversity in practice related to the financial statement presentation of unrecognized tax benefits as either a reduction of a deferred tax asset or a liability when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. This guidance is effective prospectively for fiscal years, and interim periods within those years, beginning after December 15, 2013. The adoption of this guidance is not expected to have a material impact on the Company’s consolidated financial statements.

Collaborative_Agreements

Collaborative Agreements	9 Months Ended
	Mar. 31, 2014
Collaborative Agreements	'
Collaborative Agreements	'
	B.            Collaborative Agreements
	Roche
	In May 2000, the Company granted Genentech, now a unit of Roche, an exclusive license to use the Company’s maytansinoid ADC technology with antibodies, such as trastuzumab, or other proteins that target HER2. Under the terms of this agreement, Roche has exclusive worldwide rights to develop and commercialize maytansinoid ADC compounds targeting HER2. In February 2013, the U.S. FDA granted marketing approval to the HER2-targeting ADC compound, Kadcyla. Roche received marketing approval for Kadcyla in Japan and in the European Union (EU) in September 2013 and November 2013, respectively. Roche is responsible for the manufacturing, product development and marketing of Kadcyla and any other products resulting from the agreement. The Company received a $2 million non-refundable upfront payment from Roche upon execution of the agreement. The Company is also entitled to receive up to a total of $44 million in milestone payments, plus royalties on the commercial sales of Kadcyla or any other resulting products. Total milestones are categorized as follows: development milestones—$13.5 million; and regulatory milestones—$30.5 million. The Company received two $5 million regulatory milestone payments in connection with marketing approval of Kadcyla in Japan and in the EU. Based on an evaluation of the effort contributed to the achievement of these milestones, the Company determined these milestones were not substantive. In consideration that there were no undelivered elements remaining, no continuing performance obligations and all other revenue recognition criteria had been met, the Company recognized the $10 million non-refundable payments as revenue upon achievement of the milestones, which is included in license and milestone fees for the nine months ended March 31, 2014. Through March 31, 2014, the Company has received and recognized $13.5 million and $20.5 million in development and regulatory milestone payments, respectively, related to Kadcyla. The next potential milestone the Company will be entitled to receive will be a $5 million regulatory milestone for marketing approval of Kadcyla for a first extended indication as defined in the agreement. Based on an evaluation of the effort contributed towards the achievement of this future milestone, the Company determined this milestone is not substantive.
	The Company receives royalty reports and payments related to sales of Kadcyla from Roche one quarter in arrears. In accordance with the Company’s revenue recognition policy, $2.6 million of royalties on net sales of Kadcyla for the three-month period ended December 31, 2013 were recorded and included in royalty revenue for the three months ended March 31, 2014 and $6.9 million of royalties on net sales of Kadcyla for the nine-month period ended December 31, 2013 is included in royalty revenue for the nine months ended March 31, 2014.  No such royalties were recorded in the prior year period.
	Amgen
	Under a now-expired right-to-test agreement entered into with Abgenix (now Amgen) in December 2000, in September 2009, November 2009 and December 2012, Amgen took three exclusive development and commercialization licenses, for which the Company received an exercise fee of $1 million for each license taken.  Under the same now-expired right-to-test agreement, in May 2013, Amgen took one non-exclusive development and commercialization license, for which the Company received an exercise fee of $500,000. In October 2013, the non-exclusive license was amended and converted to an exclusive license, for which Amgen paid an additional $500,000 fee to the Company. For each of these development and commercialization licenses, the Company is entitled to receive up to a total of $34 million in milestone payments, plus royalties on the commercial sales of any resulting products. The total milestones per development and commercialization license are categorized as follows: development milestones—$9 million; regulatory milestones—$20 million; and sales milestones—$5 million. Amgen is responsible for the manufacturing, product development and marketing of any products resulting from the agreement. Amgen no longer has the right to take additional development and commercialization licenses under the agreement.
	Since a deliverable to the original right-to-test agreement was determined to be materially modified at the time the non-exclusive license was converted to exclusive in October 2013, the Company accounted for the multiple-element agreement in accordance with ACS 605-25 (as amended by ASU No. 2009-13).  As a result, all of the deferred revenue recorded on the date of the modification and the new consideration received as part of the modification was allocated to all of the remaining deliverables at the time of amendment of the right-to-test agreement based on the estimated selling price of each element.  The remaining amount represents consideration for previously delivered elements and was recognized upon the execution of the modification.
	The outstanding licenses, including the exclusive license delivered upon the signing of the amendment, contain the rights to future technological improvements as well as options to purchase materials and research and development services. The Company concluded that additional materials and research and development services would be paid at a contractual price equal to the estimated selling price based estimated prices that would be charged by third parties for similar services.  The estimated selling price of the right to technological improvements is the Company’s best estimate of selling price and was determined by estimating the probability that technological improvements will be made and the probability that such technological improvements made will be used by Amgen. In estimating these probabilities, we considered factors such as the technology that is the subject of the development and commercialization licenses, our history of making technological improvements, and when such improvements, if any, were likely to occur relative to the stage of development of any product candidates pursuant to the development and commercialization licenses. The Company’s estimate of probability considered the likely period of time that any improvements would be utilized, which was estimated to be ten years following delivery of a commercialization and development license. The value of any technological improvements made available after this ten year period was considered to be de minimis due to the significant additional costs that would be incurred to incorporate such technology into any existing product candidates. The estimate of probability was multiplied by the estimated selling price of the development and commercialization licenses and the resulting cash flow was discounted at a rate of 13%, representing the Company’s estimate of its cost of capital at the time of amendment of the right-to-test agreement.
	The $430,000 determined to be the estimated selling price of the future technological improvements is being recognized as revenue ratably over the period the Company is obligated to make available any technological improvements, which is equivalent to the estimated term of the agreement. The Company estimates the term of a development and commercialization license to be approximately 25 years, which reflects management’s estimate of the time necessary to develop and commercialize products pursuant to the license plus the estimated royalty term. The Company reassesses the estimated term at the end of each reporting period.
	After accounting for the undelivered elements at the estimated selling price, the Company had $2.2 million of remaining allocable consideration which was determined to represent consideration for the previously delivered elements, including the exclusive license that was delivered upon the execution of the modification.  This amount was recorded as revenue and is included in license and milestone fees for the nine months ended March 31, 2014.
	The next potential milestone the Company will be entitled to receive under the September 2009 and November 2009 development and commercialization licenses will be a development milestone for the first dosing of a patient in a Phase II clinical trial, which will result in a $3 million payment being due. The next potential milestones the Company will be entitled to receive under the December 2012 and May 2013 development and commercialization licenses will be a development milestone for IND approval which will result in a $1 million payment being due to the Company.  At the time of execution of each of these development and commercialization licenses, there was significant uncertainty as to whether these milestones would be achieved. In consideration of this, as well as the Company’s past involvement in the research and manufacturing of these product candidates, these milestones were deemed substantive.
	Sanofi
	In December 2006, the Company entered into a right-to-test agreement with Sanofi. The agreement provides Sanofi with the right to (a) test the Company’s maytansinoid ADC technology with Sanofi’s antibodies to targets under a right-to-test, or research, license, (b) take exclusive options, with certain restrictions, to specified targets for specified option periods and (c) upon exercise of those options, take exclusive licenses to use the Company’s maytansinoid ADC technology to develop and commercialize products directed to the specified targets on terms agreed upon at the inception of the right-to-test agreement. For each development and commercialization license taken, the Company is entitled to receive an exercise fee of $2 million and up to a total of $30 million in milestone payments, plus royalties on the commercial sales of any resulting products. The total milestones are categorized as follows: development milestones—$10 million; and regulatory milestones—$20 million. In December 2013, Sanofi took its first exclusive development and commercialization license under the right-to-test agreement, for which the Company received an exercise fee of $2 million. The Company has deferred the exercise fee and is recognizing the $2 million as revenue ratably over the Company’s estimated period of its substantial involvement.  The next payment the Company could receive would either be a $2 million development milestone payment with the initiation of a Phase I clinical trial under the first development and commercialization license taken, or a $2 million exercise fee for the execution of a second license. At the time of execution of this agreement, there was significant uncertainty as to whether the milestone related to initiation of a Phase I clinical trial under the first development and commercialization license would be achieved. In consideration of this, as well as the Company’s expected involvement in the research and manufacturing of these product candidates, this milestone was deemed substantive. Sanofi is responsible for the manufacturing, product development and marketing of any products resulting from the agreement.
	In addition to the $2 million exercise fee received for the development and commercialization license taken, the Company received upfront payments of $4 million under the right-to-test agreement, of which $500,000 was received in December 2006 upon execution of the agreement and $3.5 million was received in August 2008 upon Sanofi’s activation of its rights under the agreement. The right-to-test agreement had a three-year original term from the activation date and was renewed by Sanofi in August 2011 for its final three-year term by payment of a $2 million fee. The Company has deferred the $2 million extension fee and is recognizing this amount as revenue over the period during which Sanofi can take additional options for development and commercialization licenses.
	Novartis
	In October 2010, the Company entered into a three-year right-to-test agreement with Novartis Institutes for BioMedical Research, Inc. (Novartis). The agreement provides Novartis with the right to (a) test the Company’s ADC technology with individual antibodies selected by Novartis under a right-to-test, or research, license, (b) take exclusive options, with certain restrictions, to individual targets selected by Novartis for specified option periods and (c) upon exercise of those options, take exclusive licenses to use the Company’s ADC technology to develop and commercialize products for a specified number of individual targets on terms agreed upon at the inception of the right-to-test agreement. The initial three-year term of the right-to-test agreement was extended by Novartis in October 2013 for an additional one-year period by payment of a $5 million fee to the Company. In addition to the one-year extension taken in October 2013, the terms of the right-to-test agreement allow Novartis to extend the research term for one additional one-year period by payment of additional consideration. The terms of the right-to-test agreement require Novartis to exercise its options for the development and commercialization licenses by the end of the term of the research license. The Company received a $45 million upfront payment in connection with the execution of the right-to-test agreement, and for each development and commercialization license for a specific target, the Company is entitled to receive an exercise fee of $1 million and up to a total of $199.5 million in milestone payments, plus royalties on the commercial sales of any resulting products. The total milestones are categorized as follows: development milestones—$22.5 million; regulatory milestones—$77 million; and sales milestones—$100 million. The Company also is entitled to receive payments for research and development activities performed on behalf of Novartis. Novartis is responsible for the manufacturing, product development and marketing of any products resulting from this agreement.
	In March 2013, the Company and Novartis amended the right-to-test agreement so that Novartis can take a license to develop and commercialize products directed at two pre-defined and related undisclosed targets, one target licensed on an exclusive basis and the other target initially licensed on a non-exclusive basis. The target licensed on a non-exclusive basis may be converted to an exclusive target by notice and payment to the Company of an agreed-upon fee of at least $5 million, depending on specific circumstances. The Company received a $3.5 million fee in connection with the execution of the amendment to the agreement. The Company may be required to credit this fee against future milestone payments if Novartis discontinues the development of a specified product under certain circumstances.
	In connection with the amendment, in March 2013, Novartis took the license referenced above under the right-to-test agreement, as amended, enabling it to develop and commercialize products directed at the two targets. The Company received a $1 million upfront fee with the execution of this license. Additionally, the execution of this license provides the Company the opportunity to receive milestone payments totaling $199.5 million (development milestones—$22.5 million; regulatory milestones—$77 million; and sales milestones—$100 million) or $238 million (development milestones—$22.5 million; regulatory milestones—$115.5 million; and sales milestones—$100 million), depending on the composition of any resulting products.
	In October 2013 and November 2013, Novartis took its second and third exclusive licenses to single targets, each triggering a $1 million payment to the Company and the opportunity to receive milestone payments totaling $199.5 million for each license taken, as outlined above, plus royalties on the commercial sales of any resulting products. The next payment the Company could receive would either be a $5 million development milestone for commencement of a Phase I clinical trial under any of these three licenses, or a $1 million exercise fee for the execution of a fourth license. At the time of execution of these agreements, there was significant uncertainty as to whether these milestones would be achieved. In consideration of this, as well as the Company’s past involvement in the research and manufacturing of these product candidates, these milestones were deemed substantive. Additionally, the Company is entitled to receive royalties on product sales, if any. Novartis also has the right to convert the noted non-exclusive license to an exclusive license, in which case the Company would be entitled to receive, depending on the composition of resultant products, an upward adjustment on milestone payments.
	In accordance with ACS 605-25 (as amended by ASU No. 2009-13), the Company identified all of the deliverables at the inception of the right-to-test agreement and subsequently when amended. The significant deliverables were determined to be the right-to-test, or research, license, the development and commercialization licenses, rights to future technological improvements, and the research services. The options to obtain development and commercialization licenses in the right-to-test agreement were determined not to be substantive and, as a result, the exclusive development and commercialization licenses were considered deliverables at the inception of the right-to-test agreement. Factors that were considered in determining the options were not substantive included (i) the overall objective of the agreement was for Novartis to obtain development and commercialization licenses, (ii) the size of the exercise fee of $1 million for each development and commercialization license obtained is not significant relative to the $45 million upfront payment that was due at the inception of the right-to-test agreement, (iii) the limited economic benefit that Novartis could obtain from the right-to-test agreement unless it exercised its options to obtain development and commercialization licenses, and (iv) the lack of economic penalties as a result of exercising the options.
	The Company has determined that the research license together with the development and commercialization licenses represent one unit of accounting as the research license does not have stand-alone value from the development and commercialization licenses due to the lack of transferability of the research license and the limited economic benefit Novartis would derive if they did not obtain any development and commercialization licenses. The Company has also determined that this unit of accounting does have stand-alone value from the rights to future technological improvements and the research services. The rights to future technological improvements and the research services are considered separate units of accounting as each of these was determined to have stand-alone value. The rights to future technological improvements have stand-alone value as Novartis would be able to use those items for their intended purpose without the undelivered elements. The research services have stand-alone value as similar services are sold separately by other vendors.
	The estimated selling prices for the development and commercialization licenses are the Company’s best estimate of selling price and were determined based on market conditions, similar arrangements entered into by third parties, including the Company’s understanding of pricing terms offered by its competitors for single-target development and commercialization licenses that utilize ADC technology, and entity-specific factors such as the pricing terms of the Company’s previous single-target development and commercialization licenses, recent preclinical and clinical testing results of therapeutic products that use the Company’s ADC technology, and the Company’s pricing practices and pricing objectives. The estimated selling price of the right to technological improvements is the Company’s best estimate of selling price and was determined by estimating the probability that technological improvements will be made and the probability that such technological improvements made will be used by Novartis. In estimating these probabilities, we considered factors such as the technology that is the subject of the development and commercialization licenses, our history of making technological improvements, and when such improvements, if any, were likely to occur relative to the stage of development of any product candidates pursuant to the development and commercialization licenses. The Company’s estimate of probability considered the likely period of time that any improvements would be utilized, which was estimated to be ten years following delivery of a commercialization and development license. The value of any technological improvements made available after this ten year period was considered to be de minimis due to the significant additional costs that would be incurred to incorporate such technology into any existing product candidates. The estimate of probability was multiplied by the estimated selling price of the development and commercialization licenses and the resulting cash flow was discounted at a rate of 16%, representing the Company’s estimate of its cost of capital at the time. The estimated selling price of the research services was based on third-party evidence given the nature of the research services to be performed for Novartis and market rates for similar services.
	Upon payment of the extension fee in October 2013, the total arrangement consideration of $60.2 million (which comprises the $45 million upfront payment, the amendment fee of $3.5 million, the $5 million extension fee, the exercise fee for each license, and the expected fees for the research services to be provided under the remainder of the arrangement) was reallocated to the deliverables based on the relative selling price method as follows: $55 million to the delivered and undelivered development and commercialization licenses; $4.5 million to the rights to future technological improvements; and $710,000 to the research services. The Company recorded $17.2 million of the $55 million of the arrangement consideration outlined above for the two development and commercialization licenses taken by Novartis in October 2013 and November 2013, which is included in license and milestone fee revenue for the nine months ended March 31, 2014.  The Company also recorded a cumulative catch-up of $1 million for the license delivered in March 2013 and the delivered portion of the license covering future technological improvements, which is included in license and milestone fee revenue for the nine months ended March 31, 2014.
	Since execution of the first development and commercialization license taken in March 2013, the amount of the total arrangement consideration allocated to future technological improvements is being recognized as revenue ratably over the period the Company is obligated to make available any technological improvements, which is equivalent to the estimated term of the agreement. The Company estimates the term of a development and commercialization license to be approximately 25 years, which reflects management’s estimate of the time necessary to develop and commercialize products pursuant to the license plus the estimated royalty term. The Company reassesses the estimated term at the end of each reporting period. The Company does not control when Novartis will exercise its options for development and commercialization licenses. As a result, the Company cannot predict when it will recognize the related remaining license revenue except that it will be within the term of the research license. The Company will recognize research services revenue as the related services are delivered.
	Lilly
	In December 2011, the Company entered into a three-year right-to-test agreement with Eli Lilly and Company (Lilly). The agreement provides Lilly with the right to (a) take exclusive options, with certain restrictions, to individual targets selected by Lilly for specified option periods, (b) test the Company’s maytansinoid ADC technology with Lilly’s antibodies directed to the optioned targets under a right-to-test, or research, license, and (c) upon exercise of those options, take exclusive licenses to use the Company’s maytansinoid ADC technology to develop and commercialize products for a specified number of individual targets on terms agreed upon at the inception of the right-to-test agreement. The terms of the right-to-test agreement require Lilly to exercise its options for the development and commercialization licenses by the end of the term of the research license. In August 2013, Lilly took its first development and commercialization license to a single target.
	The Company received a $20 million upfront payment in connection with the execution of the right-to-test agreement, and for the first development and commercialization license taken in August 2013 and amended in December 2013, the Company received an exercise fee in the amount of $2 million and is entitled to receive up to a total of $199 million in milestone payments, plus royalties on the commercial sales of any resulting products. Lilly has the right to elect, at its discretion, which of the two additional development and commercialization licenses it has a right to take under the right-to-test agreement will have no exercise fee and which will have an exercise fee of $2 million. With respect to any subsequent development and commercialization license taken, if Lilly elects that the $2 million exercise fee is payable, the Company is entitled to receive, in addition to the  exercise fee, up to a total of $199 million in milestone payments, plus royalties on the commercial sales of any resulting products. If Lilly elects that no exercise fee is payable when it takes a development and commercialization license, the Company is entitled to receive up to a total of $200.5 million in milestone payments, plus royalties on the commercial sales of any resulting products. The total milestones are categorized as follows: development milestones—$29 million for the development and commercialization licenses with respect to which the $2 million exercise fee is paid, and $30.5 million for the development and commercialization license with respect to which no exercise fee is payable; regulatory milestones—$70 million in all cases; and sales milestones—$100 million in all cases. The next payment the Company could receive would either be a $5 million development milestone payment with the initiation of a Phase I clinical trial under the first development and commercialization license taken, or a $2 million exercise fee for the execution of an additional license if Lilly elects to pay the exercise fee with respect to such license. At the time of execution of this agreement, there was significant uncertainty as to whether the milestone related to initiation of a Phase I clinical trial under the first development and commercialization license would be achieved. In consideration of this, as well as the Company’s expected involvement in the research and manufacturing of these product candidates, this milestone was deemed substantive. The Company also is entitled to receive payments for delivery of cytotoxic agents to Lilly and research and development activities performed on behalf of Lilly. Lilly is responsible for the manufacturing, product development and marketing of any products resulting from this collaboration.
	In accordance with ASC 605-25 (as amended by ASU No. 2009-13), the Company identified all of the deliverables at the inception of the right-to-test agreement. The significant deliverables were determined to be the right-to-test, or research, license, the exclusive development and commercialization licenses, rights to future technological improvements, delivery of cytotoxic agents and the research services. The options to obtain development and commercialization licenses in the right-to-test agreement were determined not to be substantive and, as a result, the exclusive development and commercialization licenses were considered deliverables at the inception of the right-to-test agreement. Factors that were considered in determining the options were not substantive included (i) the overall objective of the agreement was for Lilly to obtain development and commercialization licenses, (ii) the size of the exercise fees of $2 million for each development and commercialization license taken beyond the first license is not significant relative to the $20 million upfront payment that was due at the inception of the right-to-test agreement, (iii) the limited economic benefit that Lilly could obtain from the right-to-test agreement unless it exercised its options to obtain development and commercialization licenses, and (iv) the lack of economic penalties as a result of exercising the options.
	The Company has determined that the research license together with the development and commercialization licenses represent one unit of accounting as the research license does not have stand-alone value from the development and commercialization licenses due to the lack of transferability of the research license and the limited economic benefit Lilly would derive if they did not obtain any development and commercialization licenses. The Company has also determined that this unit of accounting has stand-alone value from the rights to future technological improvements, the delivery of cytotoxic agents and the research services. The rights to future technological improvements, delivery of cytotoxic agents and the research services are considered separate units of accounting as each of these was determined to have stand-alone value. The rights to future technological improvements have stand-alone value as Lilly would be able to use those items for their intended purpose without the undelivered elements. The research services and cytotoxic agents have stand-alone value as similar services and products are sold separately by other vendors.
	The estimated selling prices for the development and commercialization licenses are the Company’s best estimate of selling price and were determined based on market conditions, similar arrangements entered into by third parties, including pricing terms offered by our competitors for single-target development and commercialization licenses that utilize antibody-drug conjugate technology, and entity-specific factors such as the pricing terms of the Company’s previous single-target development and commercialization licenses, recent preclinical and clinical testing results of therapeutic products that use the Company’s ADC technology, and the Company’s pricing practices and pricing objectives. The estimated selling price of the rights to technological improvements is the Company’s best estimate of selling price and was determined by estimating the probability that technological improvements will be made, and the probability that technological improvements made will be used by Lilly. In estimating these probabilities, we considered factors such as the technology that is the subject of the development and commercialization licenses, our history of making technological improvements, and when such improvements, if any, were likely to occur relative to the stage of development of any product candidates pursuant to the development and commercialization licenses. The company’s estimate of probability considered the likely period of time that any improvements would be utilized, which was estimated to be ten years following delivery of a commercialization and development license. The value of any technological improvements made available after this ten year period was considered to be de minimis due to the significant additional costs that would be incurred to incorporate such technology into any existing product candidates. The estimate of probability was multiplied by the estimated selling price of the development and commercialization licenses and the resulting cash flow was discounted at a rate of 16%, representing the Company’s estimate of its cost of capital at the time. The estimated selling price of the cytotoxic agent was based on third-party evidence given market rates for the manufacture of such cytotoxic agents. The estimated selling price of the research services was based on third-party evidence given the nature of the research services to be performed for Lilly and market rates for similar services.
	The total arrangement consideration of $28.2 million (which comprises the $20 million upfront payment, the exercise fee, if any, for each license, the expected fees for the research services to be provided and the cytotoxic agent to be delivered under the arrangement) was allocated to the deliverables based on the relative selling price method as follows: $23.5 million to the development and commercialization licenses; $0.6 million to the rights to future technological improvements, $0.8 million to the sale of cytotoxic agent; and $3.3 million to the research services. Upon execution of the development and commercialization license taken by Lilly in August 2013, the Company recorded $7.8 million of the $23.5 million of the arrangement consideration outlined above, which is included in license and milestone fee revenue for the nine month period ended March 31, 2014. With this first development and commercialization license taken, the amount of the total arrangement consideration allocated to future technological improvements will commence to be recognized as revenue ratably over the period the Company is obligated to make available any technological improvements, which is the equivalent to the estimated term of the license. The Company estimates the term of a development and commercialization license to be approximately 25 years, which reflects management’s estimate of the time necessary to develop and commercialize therapeutic products pursuant to the license plus the estimated royalty term. The Company will reassess the estimated term at each subsequent reporting period. The Company will recognize as license revenue an equal amount of the total remaining $15.7 million of arrangement consideration allocated to the development and commercialization licenses as each individual license is delivered to Lilly upon Lilly’s exercise of its remaining options to such licenses. The Company does not control when Lilly will exercise its options for development and commercialization licenses. As a result, the Company cannot predict when it will recognize the related license revenue except that it will be within the term of the research license. The Company will recognize research services revenue and revenue from the delivery of cytotoxic agents as the related services and cytotoxic agents are delivered.
	In December 2013, the Company and Lilly amended the right-to-test agreement and the first development and commercialization license. Under these amendments, Lilly now has the right to extend the three-year research period under the right-to-test agreement for up to two nine-month periods by payment to the Company of additional consideration prior to the expiration of both the original term or the first extended term of that agreement. In addition, Lilly retroactively paid the Company an exercise fee of $2 million for the first development and commercialization license, and has the right to elect, at its discretion, which of the additional development and commercialization licenses, if any, taken under the right-to-test agreement will have no exercise fee and which will have an exercise fee of $2 million. The application of the $2 million exercise fee to the first license granted under the arrangement did not impact the total arrangement consideration, only the timing of payment of the consideration.  Due to the contingent nature of the extension fees, the lack of overall change in the total consideration for the licenses and the Company’s conclusion that there has been no change in the relative selling prices originally used in the allocation of the consideration, there was no accounting impact upon the execution of the amendment.
	CytomX
	In January 2014, the Company entered into a reciprocal right-to-test agreement with CytomX Therapeutics, Inc. (CytomX). The agreement provides CytomX with the right to test the Company’s ADC technology with CytomX Probodies™ to create Probody-drug conjugates (PDCs) directed to a specified number of targets under a right-to-test, or research, license, and to subsequently take an exclusive, worldwide license to use the Company’s ADC technology to develop and commercialize PDCs directed to the specified targets on terms agreed upon at the inception of the right-to-test agreement.  The Company received no upfront cash payment in connection with the execution of the right-to-test agreement.  Instead, the Company received reciprocal rights to CytomX’s Probody technology whereby the Company was provided the right to test CytomX’s Probody technology to create PDCs directed to a specified number of targets and to subsequently take exclusive, worldwide licenses to develop and commercialize PDCs directed to the specified targets on terms agreed upon at the inception of the right-to-test agreement. The terms of the right-to-test agreement require the Company and CytomX to take their respective development and commercialization licenses by the end of the term of the research licenses.  In addition, both the Company and CytomX are required to perform specific research activities under the right-to-test agreement on behalf of the other party for no monetary consideration.
	With respect to the development and commercialization license that may be taken by CytomX, the Company is entitled to receive up to a total of $160 million in milestone payments plus royalties on the commercial sales of any resulting product. The total milestones are categorized as follows: development milestones—$10 million; regulatory milestones—$50 million; and sales milestones—$100 million. Assuming no annual maintenance fee is payable as described below, the next payment the Company could receive would be a $1 million development milestone payment with commencement of a Phase I clinical trial.  At the time of execution of the right-to-test agreement, there was significant uncertainty as to whether the milestone related to the Phase I clinical trial would be achieved. In consideration of this, as well as the Company’s expected involvement in the research and manufacturing of any product candidate, this milestone was deemed substantive. CytomX is responsible for the manufacturing, product development and marketing of any PDC resulting from the development and commercialization license taken by CytomX under this collaboration.
	With respect to any development and commercialization license that may be taken by the Company, the Company will potentially be required to pay up to a total of $80 million in milestone payments per license, plus royalties on the commercial sales of any resulting product. The total milestones per license are categorized as follows: development milestones—$7 million; regulatory milestones—$23 million; and sales milestones—$50 million. Assuming no annual maintenance fee is payable as described below, the next payment the Company could be required to make is a $1 million development milestone payment with commencement of a Phase I clinical trial. The Company is responsible for the manufacturing, product development and marketing of any PDC resulting from any development and commercialization license taken by the Company under this collaboration.
	In addition, each party may be liable to pay annual maintenance fees to the other party if the licensed PDC product candidate covered under each development and commercialization license has not progressed to a specified stage of development within a specified time frame.
	The arrangement was accounted for based on the fair value of the items exchanged. The items to be delivered to CytomX under the arrangement are accounted for under the Company’s revenue recognition policy. The items to be received from CytomX are recorded as research and development expenses as incurred.
	In accordance with ASC 605-25 (as amended by ASU No. 2009-13), the Company identified all of the deliverables at the inception of the right-to-test agreement. The significant deliverables were determined to be the right-to-test, or research, license, the exclusive development and commercialization license, rights to future technological improvements, and the research services. The research license in the right-to-test agreement was determined not to be substantive and, as a result, the exclusive development and commercialization license was considered a deliverable at the inception of the right-to-test agreement. Factors that were considered in determining the research license was not substantive included (i) the overall objective of the agreement is for CytomX to obtain a development and commercialization license, (ii)  there are no exercise fees payable upon taking the development and commercialization license, (iii) the limited economic benefit that CytomX could obtain from the right-to-test agreement unless CytomX was able to take the development and commercialization license, and (iv) the lack of economic penalties as a result of taking the license.
	The Company has determined that the research license from the Company to CytomX together with the development and commercialization license from the Company to CytomX represent one unit of accounting as the research license does not have stand-alone value from the development and commercialization license due to the lack of transferability of the research license and the limited economic benefit CytomX would derive if they did not obtain any development and commercialization license. The Company has also determined that this unit of accounting has stand-alone value from the rights to future technological improvements and the research services.  The rights to future technological improvements and the research services are considered separate units of accounting as each of these was determined to have stand-alone value. The rights to future technological improvements have stand-alone value as CytomX would be able to use those items for their intended purpose without the undelivered elements. The research services have stand-alone value as similar services are sold separately by other vendors.
	The estimated selling price for the development and commercialization license is the Company’s best estimate of selling price and was determined based on market conditions, similar arrangements entered into by third parties, including pricing terms offered by the Company’s competitors for single-target development and commercialization licenses that utilize antibody-drug conjugate technology, and entity-specific factors such as the pricing terms of the Company’s previous single-target development and commercialization licenses, recent preclinical and clinical testing results of therapeutic products that use the Company’s ADC technology, and the Company’s pricing practices and pricing objectives. In order to determine the best estimate of selling price, the Company determined the overall value of a license by calculating a risk-adjusted net present value of a recent, comparable transaction the Company entered into with another collaborator.  This overall value was then decreased by risk-adjusting the net present value of the contingent consideration (the milestones and royalties) payable by CytomX under the development and commercialization license. This amount represents the value that a third party would be willing to pay as an upfront payment for this license to the Company’s technology.
	The estimated selling price of the rights to technological improvements is the Company’s best estimate of selling price and was determined by estimating the probability that technological improvements will be made, and the probability that technological improvements made will be used by CytomX. In estimating these probabilities, the Company considered factors such as the technology that is the subject of the development and commercialization license, the Company’s history of making technological improvements, and when such improvements, if any, were likely to occur relative to the stage of development of the product candidate pursuant to the development and commercialization license. The Company’s estimate of probability considered the likely period of time that any improvements would be utilized, which was estimated to be ten years following delivery of the commercialization and development license. The value of any technological improvements made available after this ten year period was considered to be de minimis due to the significant additional costs that would be incurred to incorporate such technology into any existing product candidate. The estimate of probability was multiplied by the estimated selling price of the development and commercialization license and the resulting cash flow was discounted at a rate of 13%, representing the Company’s estimate of its cost of capital at the time.
	The estimated selling price of the research services was based on third-party evidence given the nature of the research services to be performed for CytomX and market rates for similar services.
	The total allocable consideration of $13.1 million (which comprises the $13.0 million that a third party would be willing to pay as an upfront payment for this license to the Company’s technology plus $140,000 for the fair value of fees for the research services to be provided) was allocated to the deliverables based on the relative selling price method as follows: $12.7 million to the development and commercialization license; $350,000 to the rights to future technological improvements and $140,000 million to the research services. The Company will recognize as license revenue the amount of the total allocable consideration allocated to the development and commercialization license when the development and commercialization license is delivered to CytomX.  At the time the license is taken, the amount of the total allocable consideration allocated to future technological improvements will commence to be recognized as revenue ratably over the period the Company is obligated to make available any technological improvements, which is the equivalent to the estimated term of the license. The Company estimates the term of a development and commercialization license to be approximately 25 years, which reflects management’s estimate of the time necessary to develop and commercialize therapeutic products pursuant to the license plus the estimated royalty term. The Company will be required to reassess the estimated term at each subsequent reporting period. The Company does not control when CytomX will take the development and commercialization license. As a result, the Company cannot predict when it will recognize the related license revenue except that it will be within the term of the research license. The Company will recognize research services revenue as the related services are delivered.
	No license fee revenue has been recognized related to this agreement through March 31, 2014 as the research license was not considered to be substantive and the development and commercialization license had not been delivered at this time. Accordingly, $13.0 million of allocated arrangement consideration is included in long-term deferred revenue at March 31, 2014.
	The $13.1 million of total allocable consideration to be accounted for as revenue described above is also the amount that was used to account for the expense of the licenses and research services the Company received or will receive from CytomX.  Based on an estimate of the research services that CytomX will be providing to the Company for no monetary consideration, $310,000 was allocated to such services and will be expensed over the period the services are provided.  The balance of $12.8 million pertains to technology rights received and these amounts have been charged to research and development expense during the three months ended March 31, 2014 upon execution of the research agreement.
	For additional information related to these agreements, as well as the Company’s other significant collaborative agreements, please read Note C, Agreements to our consolidated financial statements included within the Company’s 2013 Form 10-K.

Capital_Stock

Capital Stock	9 Months Ended
	Mar. 31, 2014
Capital Stock	'
Capital Stock	'
	C.     Capital Stock
	2001 Non-Employee Director Stock Plan
	During the three and nine months ended March 31, 2014, the Company recorded approximately $2,000 and $(11,000) in expense and expense reduction, respectively, related to stock units outstanding under the Company’s 2001 Non-Employee Director Stock Plan, or the 2001 Plan, compared to $21,000 and $(4,000) in expense and expense reduction recorded during the three and nine months ended March 31, 2013, respectively. The value of the stock units are classified as a liability and adjusted to market value at each reporting period as the redemption amount of stock units for this plan will be paid in cash.  No stock units have been issued under the 2001 Plan subsequent to June 30, 2004.
	Compensation Policy for Non-Employee Directors
	On November 12, 2013, the Board amended the Compensation Policy for Non-Employee Directors to make certain changes to the compensation of its non-employee directors, including an increase in the fees paid in cash to the non-employee directors. Under the terms of the amended policy, the redemption amount of deferred share units issued will continue to be paid in shares of common stock of the Company on the date a director ceases to be a member of the Board. Annual retainers vest quarterly over approximately one year from the date of grant, contingent upon the individual remaining a director of ImmunoGen as of each vesting date.  The number of deferred share units awarded is now fixed per the plan on the date of the award and is no longer based on the market price of the Company’s common stock on the date of the award. All unvested deferred stock awards will automatically vest immediately prior to the occurrence of a change of control.
	In addition to the deferred share units, the Non-Employee Directors are now also entitled to receive a fixed number of stock options instead of a fixed grant date fair value of options, determined using the Black-Scholes option pricing model measured on the date of grant, which would be the date of the annual meeting of shareholders.  These options vest quarterly over approximately one year from the date of grant.  Any new directors will receive a pro-rated award, depending on their date of election to the Board.  The directors received a total of 80,000, 41,805 and 33,187 options in the nine months ended March 31, 2014, and fiscal years ended 2013 and 2012, respectively, and the related compensation expense for the three and nine months ended March 31, 2014 and 2013 is included in the amounts discussed in the “Stock-Based Compensation” section of footnote A above.
	During the three and nine months ended March 31, 2014, the Company recorded approximately $118,000 and $315,000 in compensation expense, respectively, related to deferred share units issued and outstanding under the Company’s Compensation Policy for Non-Employee Directors, compared to $98,000 and $253,000 in compensation expense recorded during the three and nine months ended March 31, 2013, respectively. Pursuant to the Compensation Policy for Non-Employee Directors, in November 2013, the Company issued a retiring director 43,615 shares of common stock of the Company to settle outstanding deferred share units.

Cash_and_Cash_Equivalents

Cash and Cash Equivalents	9 Months Ended
	Mar. 31, 2014
Cash and Cash Equivalents	'
Cash and Cash Equivalents	'
	D.    Cash and Cash Equivalents
	As of March 31, 2014 and June 30, 2013, the Company held $164.1 million and $195.0 million, respectively, in cash and money market funds consisting principally of U.S. Government-issued securities and high quality, short-term commercial paper which were classified as cash and cash equivalents.

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Mar. 31, 2014
Commitments and Contingencies	'
Commitments and Contingencies	'
	E.     Commitments and Contingencies
	Leases
	Effective July 27, 2007, the Company entered into a lease agreement with Intercontinental Fund III for the rental of approximately 89,000 square feet of laboratory and office space at 830 Winter Street, Waltham, MA through March 2020. The Company uses this space for its corporate headquarters, research and other operations. In December 2013, the Company modified its lease agreement at 830 Winter Street, Waltham, MA to include approximately 19,000 square feet of additional office space through 2020, concurrent with the remainder of the original lease term. As part of the lease amendment, the Company will receive a construction allowance of approximately $746,000 to build out office space to the Company’s specifications. The Company obtained physical control of the additional space to begin construction in January 2014.  In April, 2014, the Company again modified its lease agreement at this site to extend the lease to 2026. The Company may extend the lease for two additional terms of five years. As part of this lease amendment, the Company will receive a construction allowance of approximately $1.1 million to build out office space to the Company’s specifications. The Company is required to pay certain operating expenses for the leased premises subject to escalation charges for certain expense increases over a base amount. The Company entered into a sublease in December 2009 for 14,100 square feet of this space in Waltham through January 2015, with the sublessee having a conditional option to extend the term for an additional two years. However, the Company has notified the sublessee that it does not intend to allow them to extend the term beyond January 2015.
	Effective April 2012, the Company entered into a sublease agreement for the rental of 7,310 square feet of laboratory and office space at 830 Winter Street, Waltham, MA from Histogenics Corporation. The term of the sublease is for three years and the Company is required to pay certain operating expenses for the leased premises subject to escalation charges for certain expense increases over a base amount.
	The Company also leases 43,850 square feet of manufacturing and office space at 333 Providence Highway, Norwood, MA under an agreement through 2018 with an option to extend the lease for an additional term of five years. The Company is required to pay certain operating expenses for the leased premises subject to escalation charges for certain expense increases over a base amount.
	Effective April 2013, the Company entered into a lease agreement with River Ridge Limited Partnership for the rental of 7,507 square feet of additional office space at 100 River Ridge Drive, Norwood, MA. The initial term of the lease is for five years and two months commencing in August 2013 with an option for the Company to extend the lease for an additional term of five years. The Company is required to pay certain operating expenses for the leased premises subject to escalation charges for certain expense increases over a base amount.
	The minimum rental commitments for the Company’s facilities, including real estate taxes and other expenses, for the next five fiscal years and thereafter under the non-cancelable operating lease agreements discussed above are as follows (in thousands):
	2014 (three months remaining)	$	1,537
	2015	7,053
	2016	6,831
	2017	6,848
	2018	6,954
	Thereafter	12,267
	Total minimum lease payments	$	41,490
	Total minimum rental payments from sublease	(573		)
	Total minimum lease payments, net	$	40,917
	Collaborations
	The Company is contractually obligated to make potential future success-based development, regulatory or sales milestone payments in conjunction with certain collaborative agreements. These payments are contingent upon the occurrence of certain future events and, given the nature of these events, it is unclear when, if ever, the Company may be required to pay such amounts. Further, the timing of any future payment is not reasonably estimable. As of March 31, 2014, the maximum amount that may be payable in the future under the Company’s current collaborative agreements is $162 million, $1.4 million of which is reimbursable by a third party under a separate agreement.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Mar. 31, 2014
Summary of Significant Accounting Policies	'
Basis of Presentation	'
	Basis of Presentation
	The accompanying unaudited consolidated financial statements at March 31, 2014 and June 30, 2013 and for the three and nine months ended March 31, 2014 and 2013 include the accounts of ImmunoGen, Inc., or the Company, and its wholly owned subsidiaries, ImmunoGen Securities Corp. and ImmunoGen Europe Limited. The consolidated financial statements include all of the adjustments, consisting only of normal recurring adjustments, which management considers necessary for a fair presentation of the Company’s financial position in accordance with accounting principles generally accepted in the U.S. for interim financial information. Certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted. The preparation of interim financial statements requires the use of management’s estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the interim financial statements and the reported amounts of revenues and expenditures during the reported periods. The results of the interim periods are not necessarily indicative of the results for the entire year. Accordingly, the interim financial statements should be read in conjunction with the audited financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended June 30, 2013.
Subsequent Events	'
	Subsequent Events
	The Company has evaluated all events or transactions that occurred after March 31, 2014 up through the date the Company issued these financial statements.  In April 2014, the Company modified its lease agreement at 830 Winter Street, Waltham , MA to extend the lease from 2020 to 2026.  The Company may extend the lease for two additional terms of five years. As part of this lease amendment, the Company will receive a construction allowance of approximately $1.1 million to build out office space to the Company’s specifications. The Company did not have any other material recognizable or unrecognizable subsequent events during this period.
Revenue Recognition	'
	Revenue Recognition
	The Company enters into licensing and development agreements with collaborative partners for the development of monoclonal antibody-based anticancer therapeutics. The terms of these agreements contain multiple deliverables which may include (i) licenses, or options to obtain licenses, to the Company’s antibody-drug conjugate, or ADC, technology, (ii) rights to future technological improvements, (iii) research activities to be performed on behalf of the collaborative partner, (iv) delivery of cytotoxic agents and (v) the manufacture of preclinical or clinical materials for the collaborative partner. Payments to the Company under these agreements may include upfront fees, option fees, exercise fees, payments for research activities, payments for the manufacture of preclinical or clinical materials, payments based upon the achievement of certain milestones and royalties on product sales. The Company follows the provisions of the Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) Topic 605-25, “Revenue Recognition—Multiple-Element Arrangements,” and ASC Topic 605-28, “Revenue Recognition—Milestone Method,” in accounting for these agreements. In order to account for these agreements, the Company must identify the deliverables included within the agreement and evaluate which deliverables represent separate units of accounting based on whether certain criteria are met, including whether the delivered element has stand-alone value to the collaborator. The consideration received is allocated among the separate units of accounting, and the applicable revenue recognition criteria are applied to each of the separate units.
	At March 31, 2014, the Company had the following two types of agreements with the parties identified below:
	·                  Development and commercialization licenses to use the Company’s ADC technology and/or certain other intellectual property to develop compounds to a specified target antigen (referred to as development and commercialization licenses, as distinguished from the Company’s right-to-test agreements described elsewhere):
	Amgen (four exclusive single-target licenses)
	Bayer HealthCare (one exclusive single-target license)
	Biotest (one exclusive single-target license)
	Lilly (one exclusive single-target license)
	Novartis (two exclusive single-target licenses and one license to two related targets: one target on an exclusive basis and the second target on a non-exclusive basis)
	Roche, through its Genentech unit (five exclusive single-target licenses)
	Sanofi (one exclusive single-target license and one exclusive license to multiple individual targets)
	·                  Option/research agreement for a defined period of time to secure development and commercialization licenses to use the Company’s ADC technology to develop anticancer compounds to specified targets on established terms (referred to herein as right-to-test agreements):
	Sanofi
	Novartis
	Lilly
	CytomX
	There are no performance, cancellation, termination or refund provisions in any of the arrangements that contain material financial consequences to the Company.
	Development and Commercialization Licenses
	The deliverables under a development and commercialization license agreement generally include the license to the Company’s ADC technology with respect to a specified antigen target, and may also include deliverables related to rights to future technological improvements, research activities to be performed on behalf of the collaborative partner and the manufacture of preclinical or clinical materials for the collaborative partner.
	Generally, development and commercialization licenses contain non-refundable terms for payments and, depending on the terms of the agreement, provide that the Company will (i) at the collaborator’s request, provide research services at negotiated prices which are generally consistent with what other third parties would charge, (ii) at the collaborator’s request, manufacture and provide to it preclinical and clinical materials or deliver cytotoxic agents at negotiated prices which are generally consistent with what other third parties would charge, (iii) earn payments upon the achievement of certain milestones and (iv) earn royalty payments, generally until the later of the last applicable patent expiration or 10 to 12 years after product launch. In the case of Roche’s Kadcyla®, however, the minimum royalty term is 10 years and the maximum royalty term is 12 years on a country-by-country basis. Royalty rates may vary over the royalty term depending on the Company’s intellectual property rights. The Company may provide technical assistance and share any technology improvements with its collaborators during the term of the collaboration agreements. The Company does not directly control when or whether any collaborator will request research or manufacturing services, achieve milestones or become liable for royalty payments. As a result, the Company cannot predict when or if it will recognize revenues in connection with any of the foregoing.
	In determining the units of accounting, management evaluates whether the license has stand-alone value from the undelivered elements to the collaborative partner based on the consideration of the relevant facts and circumstances for each arrangement. Factors considered in this determination include the research capabilities of the partner and the availability of ADC technology research expertise in the general marketplace. If the Company concludes that the license has stand-alone value and therefore will be accounted for as a separate unit of accounting, the Company then determines the estimated selling prices of the license and all other units of accounting based on market conditions, similar arrangements entered into by third parties, and entity-specific factors such as the terms of the Company’s previous collaborative agreements, recent preclinical and clinical testing results of therapeutic products that use the Company’s ADC technology, the Company’s pricing practices and pricing objectives, the likelihood that technological improvements will be made, the likelihood that technological improvements made will be used by the Company’s collaborators and the nature of the research services to be performed on behalf of its collaborators and market rates for similar services.
	Upfront payments on development and commercialization licenses are deferred if facts and circumstances dictate that the license does not have stand-alone value. Prior to the adoption of Accounting Standards Update (ASU) No. 2009-13, “Revenue Arrangements with Multiple Deliverables” on July 1, 2010, the Company determined that its licenses lacked stand-alone value and were combined with other elements of the arrangement and any amounts associated with the license were deferred and amortized over a certain period, which the Company refers to as the Company’s period of substantial involvement. The determination of the length of the period over which to defer revenue is subject to judgment and estimation and can have an impact on the amount of revenue recognized in a given period. Historically the Company’s involvement with the development of a collaborator’s product candidate has been significant at the early stages of development, and lessens as it progresses into clinical trials. Also, as a drug candidate gets closer to commencing pivotal testing the Company’s collaborators have sought an alternative site to manufacture their products, as the Company’s facility does not produce pivotal or commercial drug product. Accordingly, the Company generally estimates this period of substantial involvement to begin at the inception of the collaboration agreement and conclude at the end of non-pivotal Phase II testing. The Company believes this period of substantial involvement is, depending on the nature of the license, on average six and one-half years. Quarterly, the Company reassesses its periods of substantial involvement over which the Company amortizes its upfront license fees and makes adjustments as appropriate. In the event a collaborator elects to discontinue development of a specific product candidate under a development and commercialization license, but retains its right to use the Company’s technology to develop an alternative product candidate to the same target or a target substitute, the Company would cease amortization of any remaining portion of the upfront fee until there is substantial preclinical activity on another product candidate and its remaining period of substantial involvement can be estimated. In the event that a development and commercialization license were to be terminated, the Company would recognize as revenue any portion of the upfront fee that had not previously been recorded as revenue, but was classified as deferred revenue, at the date of such termination.
	Subsequent to the adoption of ASU No. 2009-13, the Company determined that its research licenses lack stand-alone value and are considered for aggregation with the other elements of the arrangement and accounted for as one unit of accounting.
	Upfront payments on development and commercialization licenses may be recognized upon delivery of the license if facts and circumstances dictate that the license has stand-alone value from the undelivered elements, which generally include rights to future technological improvements, research services, delivery of cytotoxic agents and the manufacture of preclinical and clinical materials.
	The Company recognizes revenue related to research services that represent separate units of accounting as they are performed, as long as there is persuasive evidence of an arrangement, the fee is fixed or determinable, and collection of the related receivable is probable. The Company recognizes revenue related to the rights to future technological improvements over the estimated term of the applicable license.
	The Company may also provide cytotoxic agents to its collaborators or produce preclinical and clinical materials at negotiated prices which are generally consistent with what other third parties would charge. The Company recognizes revenue on cytotoxic agents and on preclinical and clinical materials when the materials have passed all quality testing required for collaborator acceptance and title and risk of loss have transferred to the collaborator. Arrangement consideration allocated to the manufacture of preclinical and clinical materials in a multiple-deliverable arrangement is below the Company’s full cost, and the Company’s full cost is not expected to be below its contract selling prices for its existing collaborations for the foreseeable future. During the nine months ended March 31, 2014 and 2013, the difference between the Company’s full cost to manufacture preclinical and clinical materials on behalf of its collaborators as compared to total amounts received from collaborators for the manufacture of preclinical and clinical materials was $1.6 million and $755,000, respectively. The majority of the Company’s costs to produce these preclinical and clinical materials are fixed and then allocated to each batch based on the number of batches produced during the period. Therefore, the Company’s costs to produce these materials are significantly impacted by the number of batches produced during the period. The volume of preclinical and clinical materials the Company produces is directly related to the number of clinical trials for which the Company and its collaborators are preparing or currently have underway, the speed of enrollment in those trials, the dosage schedule of each clinical trial and the time period such trials last. Accordingly, the volume of preclinical and clinical materials produced, and therefore the Company’s per batch costs to manufacture these preclinical and clinical materials, may vary significantly from period to period.
	The Company may also produce research material for potential collaborators under material transfer agreements. Additionally, the Company performs research activities, including developing antibody specific conjugation processes, on behalf of its collaborators and potential collaborators during the early evaluation and preclinical testing stages of drug development. The Company records amounts received for research materials produced or services performed as a component of research and development support revenue. The Company also develops conjugation processes for materials for later stage testing and commercialization for certain collaborators. The Company is compensated at negotiated rates and may receive milestone payments for developing these processes which are recorded as a component of research and development support revenue.
	The Company’s development and commercialization license agreements have milestone payments which for reporting purposes are aggregated into three categories: (i) development milestones, (ii) regulatory milestones, and (iii) sales milestones. Development milestones are typically payable when a product candidate first moves into clinical testing or advances into different clinical trial phases. Regulatory milestones are typically payable upon submission for marketing approval with the U.S. Food and Drug Administration, or FDA, or other countries’ regulatory authorities or on receipt of actual marketing approvals for the compound or for additional indications. Sales milestones are typically payable when annual sales reach certain levels.
	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.
	Non-refundable development and regulatory milestones that are expected to be achieved as a result of the Company’s efforts during the period of substantial involvement are considered substantive and are recognized as revenue upon the achievement of the milestone, assuming all other revenue recognition criteria are met. Milestones that are not considered substantive because we do not contribute effort to the achievement of such milestones are generally achieved after the period of substantial involvement and are recognized as revenue upon achievement of the milestone, as there are no undelivered elements remaining and no continuing performance obligations, assuming all other revenue recognition criteria are met.
	Under the Company’s development and commercialization license agreements, the Company receives royalty payments based upon its licensees’ net sales of covered products. Generally, under these agreements the Company is to receive royalty reports and payments from its licensees approximately one quarter in arrears, that is, generally in the second month of the quarter after the licensee has sold the royalty-bearing product or products. The Company recognizes royalty revenues when it can reliably estimate such amounts and collectability is reasonably assured. As such, the Company generally recognizes royalty revenues in the quarter reported to the Company by its licensees, or one quarter following the quarter in which sales by the Company’s licensees occurred.
	Right-to-Test Agreements
	The Company’s right-to-test agreements generally provide collaborators the right to (a) test the Company’s ADC technology for a defined period of time through a research, or right-to-test, license, (b) take options, for a defined period of time, to specified targets and (c) upon exercise of those options, secure or “take” licenses to develop and commercialize products for the specified targets on established terms. Under these agreements, fees may be due to the Company (i) at the inception of the arrangement (referred to as “upfront” fees or payments), (ii) upon taking an option with respect to a specific target (referred to as option fees or payments earned, if any, when the option is “taken”), (iii) upon the exercise of a previously taken option to acquire a development and commercialization license(s) (referred to as exercise fees or payments earned, if any, when the development and commercialization license is “taken”), or (iv) some combination of all of these fees.
	The accounting for right-to-test agreements is dependent on the nature of the options granted to the collaborative partner. Options are considered substantive if, at the inception of a right-to-test agreement, the Company is at risk as to whether the collaborative partner will choose to exercise the options to secure development and commercialization licenses. Factors that are considered in evaluating whether options are substantive include the overall objective of the arrangement, the benefit the collaborator might obtain from the agreement without exercising the options, the cost to exercise the options relative to the total upfront consideration, and the additional financial commitments or economic penalties imposed on the collaborator as a result of exercising the options.
	For right-to-test agreements where the options to secure development and commercialization licenses to the Company’s ADC technology are considered substantive, the Company does not consider the development and commercialization licenses to be a deliverable at the inception of the agreement. For those right-to-test agreements entered into prior to the adoption of ASU No. 2009-13 where the options to secure development and commercialization licenses are considered substantive, the Company has deferred the upfront payments received and recognizes this revenue over the period during which the collaborator could elect to take options for development and commercialization licenses. These periods are specific to each collaboration agreement. If a collaborator takes an option to acquire a development and commercialization license under these agreements, any substantive option fee is deferred and recognized over the life of the option, generally 12 to 18 months. If a collaborator exercises an option and takes a development and commercialization license to a specific target, the Company attributes the exercise fee to the development and commercialization license. Upon exercise of an option to acquire a development and commercialization license, the Company would also attribute any remaining deferred option fee to the development and commercialization license and apply the multiple-element revenue recognition criteria to the development and commercialization license and any other deliverables to determine the appropriate revenue recognition, which will be consistent with the Company’s accounting policy for upfront payments on single-target licenses. In the event a right-to-test agreement were to be terminated, the Company would recognize as revenue any portion of the upfront fee that had not previously been recorded as revenue, but was classified as deferred revenue, at the date of such termination. None of the Company’s right-to-test agreements entered into subsequent to the adoption of ASU No. 2009-13 has been determined to contain substantive options.
	For right-to-test agreements where the options to secure development and commercialization licenses to the Company’s ADC technology are not considered substantive, the Company considers the development and commercialization licenses to be a deliverable at the inception of the agreement and applies the multiple-element revenue recognition criteria to determine the appropriate revenue recognition. None of the Company’s right-to-test agreements entered into prior to the adoption of ASU No. 2009-13 has been determined to contain non-substantive options.
	The Company does not directly control when or if any collaborator will exercise its options for development and commercialization licenses. As a result, the Company cannot predict when or if it will recognize revenues in connection with any of the foregoing.
Fair Value of Financial Instruments	'
	Fair Value of Financial Instruments
	Fair value is defined under ASC Topic 820, “Fair Value Measurements and Disclosures,” as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date.  Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs.  The standard describes a fair value hierarchy to measure fair value which is based on three levels of inputs, of which the first two are considered observable and the last unobservable, as follows:
	·                           Level 1 - Quoted prices in active markets for identical assets or liabilities.
	·                           Level 2 - Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.
	·                           Level 3 - Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.
	As of March 31, 2014, the Company held certain assets that are required to be measured at fair value on a recurring basis.  The following table represents the fair value hierarchy for the Company’s financial assets measured at fair value on a recurring basis as of March 31, 2014 (in thousands):
		Fair Value Measurements at March 31, 2014 Using
					Quoted Prices in		Significant Other		Significant
					Active Markets for		Observable Inputs		Unobservable
					Identical Assets				Inputs
		Total			(Level 1)		(Level 2)		(Level 3)
	Cash, cash equivalents and restricted cash	$	166,307		$	166,307	$	—	$	—
	As of June 30, 2013, the Company held certain assets that are required to be measured at fair value on a recurring basis. The following table represents the fair value hierarchy for the Company’s financial assets measured at fair value on a recurring basis as of June 30, 2013 (in thousands):
		Fair Value Measurements at June 30, 2013 Using
					Quoted Prices in		Significant Other		Significant
					Active Markets for		Observable Inputs		Unobservable
					Identical Assets				Inputs
		Total			(Level 1)		(Level 2)		(Level 3)
	Cash, cash equivalents and restricted cash	$	197,191		$	197,191	$	—	$	—
	The fair value of the Company’s cash equivalents is based primarily on quoted prices from active markets.
Unbilled Revenue	'
	Unbilled Revenue
	The majority of the Company’s unbilled revenue at March 31, 2014 and June 30, 2013 represents research funding earned prior to those dates based on actual resources utilized under the Company’s agreements with various collaborators.
Inventory	'
	Inventory
	Inventory costs relate to clinical trial materials being manufactured for sale to the Company’s collaborators. Inventory is stated at the lower of cost or market as determined on a first-in, first-out (FIFO) basis.
	Inventory at March 31, 2014 and June 30, 2013 is summarized below (in thousands):
		March 31,			June 30,
		2014			2013
	Raw materials	$	547		$	75
	Work in process	1,937			628
	Total	$	2,484		$	703
	Raw materials inventory consists entirely of DM1 and DM4, proprietary cell-killing agents the Company developed as part of its ADC technology. The Company considers more than a twelve month supply of raw materials that is not supported by firm, fixed orders and/or projections from its collaborators to be excess and establishes a reserve to reduce to zero the value of any such excess raw material inventory with a corresponding charge to research and development expense. In accordance with this policy, the Company recorded $236,000 and $798,000 of expense related to excess inventory during the nine-month periods ended March 31, 2014 and 2013, respectively. The Company recorded $32,000 of expense related to excess inventory during the three-month period ended March 31, 2014. There were no expenses recorded for excess inventory during the same period last year.
	Work in process inventory consists of conjugate manufactured for sale to the Company’s collaborators to be used in preclinical and clinical studies.  All conjugate is made to order at the request of the collaborators and subject to the terms and conditions of respective supply agreements.  As such, no reserve for work in process inventory is required.
Computation of Net Loss per Common Share	'
	Computation of Net Loss per Common Share
	Basic and diluted net loss per share is calculated based upon the weighted average number of common shares outstanding during the period. During periods of income, participating securities are allocated a proportional share of income determined by dividing total weighted average participating securities by the sum of the total weighted average common shares and participating securities (the “two-class method”). The Company’s restricted stock participates in any dividends declared by the Company and are therefore considered to be participating securities. Participating securities have the effect of diluting both basic and diluted earnings per share during periods of income. During periods of loss, no loss is allocated to participating securities since they have no contractual obligation to share in the losses of the Company. Diluted (loss) income per share is computed after giving consideration to the dilutive effect of stock options that are outstanding during the period, except where such non-participating securities would be anti-dilutive.
	The Company’s common stock equivalents, as calculated in accordance with the treasury-stock method, are shown in the following table (in thousands):
		Three Months Ended				Nine Months Ended
		March 31,				March 31,
		2014		2013		2014	2013
	Options outstanding to purchase common stock and unvested restricted stock	8,605		7,945		8,605	7,945
	Common stock equivalents under treasury stock method	1,814		2,433		1,956	2,302
	The Company’s common stock equivalents have not been included in the net loss per share calculation because their effect is anti-dilutive due to the Company’s net loss position.
Stock-Based Compensation	'
	Stock-Based Compensation
	As of March 31, 2014, the Company is authorized to grant future awards under one employee share-based compensation plan, which is the ImmunoGen, Inc. 2006 Employee, Director and Consultant Equity Incentive Plan, or the 2006 Plan. At the annual meeting of shareholders on November 13, 2012, an amendment to the 2006 Plan was approved and an additional 3,500,000 shares were authorized for issuance under this plan.  As amended, the 2006 Plan provides for the issuance of Stock Grants, the grant of Options and the grant of Stock-Based Awards for up to 12,000,000 shares of the Company’s common stock, as well as any shares of common stock that are represented by awards granted under the previous stock option plan, the ImmunoGen, Inc. Restated Stock Option Plan, or the Former Plan, that are forfeited, expire or are cancelled without delivery of shares of common stock; provided, however, that no more than 5,900,000 shares shall be added to the 2006 Plan from the Former Plan, pursuant to this provision. Option awards are granted with an exercise price equal to the market price of the Company’s stock at the date of grant. Options vest at various periods of up to four years and may be exercised within ten years of the date of grant.
	The stock-based awards are accounted for under ASC Topic 718, “Compensation—Stock Compensation.” Pursuant to Topic 718, the estimated grant date fair value of awards is charged to the statement of operations and comprehensive loss over the requisite service period, which is the vesting period. Such amounts have been reduced by an estimate of forfeitures of all unvested awards. The fair value of each stock option is estimated on the date of grant using the Black-Scholes option-pricing model with the assumptions noted in the following table. As the Company has not paid dividends since inception, nor does it expect to pay any dividends for the foreseeable future, the expected dividend yield assumption is zero. Expected volatility is based exclusively on historical volatility data of the Company’s stock. The expected term of stock options granted is based exclusively on historical data and represents the period of time that stock options granted are expected to be outstanding. The expected term is calculated for and applied to one group of stock options as the Company does not expect substantially different exercise or post-vesting termination behavior among its option recipients. The risk-free rate of the stock options is based on the U.S. Treasury rate in effect at the time of grant for the expected term of the stock options.
		Three Months Ended				Nine Months Ended
		March 31,				March 31,
		2014		2013		2014	2013
	Dividend	None		None		None	None
	Volatility	60.44%		60.44%		60.44%	60.44%
	Risk-free interest rate	1.94%		1.13%		1.74%	0.85%
	Expected life (years)	6.3		6.3		6.3	6.3
	Using the Black-Scholes option-pricing model, the weighted average grant date fair values of options granted during the three months ended March 31, 2014 and 2013 were $9.52 and $8.28 per share, respectively, and $10.54 and $8.67 per share for options granted during the nine months ended March 31, 2013 and 2012, respectively.
	Stock compensation expense related to stock options and restricted stock awards granted under the 2006 Plan was $3.7 million and $12.1 million during the three and nine months ended March 31, 2014, respectively, compared to stock compensation expense of $2.9 million and $9.6 million for the three and nine months ended March 31, 2013, respectively. As of March 31, 2014, the estimated fair value of unvested employee awards was $25.5 million, net of estimated forfeitures. The weighted-average remaining vesting period for these awards is approximately two and a quarter years.
	During the nine months ended March 31, 2014, holders of options issued under the Company’s equity plans exercised their rights to acquire an aggregate of approximately 1.0 million shares of common stock at prices ranging from $3.19 to $15.83 per share.  The total proceeds to the Company from these option exercises were approximately $8.6 million.
Financial Instruments and Concentration of Credit Risk	'
	Financial Instruments and Concentration of Credit Risk
	The Company’s cash equivalents consist of money market funds with underlying investments primarily being U.S. Government-issued securities and high quality, short-term commercial paper. All of the Company’s cash and cash equivalents are maintained with three financial institutions in the U.S.  The Company uses a Euro-denominated bank account to manage the foreign currency exposures that exist as part of our ongoing business operations. Our foreign currency risk management strategy is principally designed to mitigate the future potential financial impact of changes in the value of transactions, anticipated transactions and balances denominated in foreign currency, resulting from changes in foreign currency exchange rates.
Segment Information	'
	Segment Information
	During the nine months ended March 31, 2014, the Company continued to operate in one operating segment which is the business of discovery of monoclonal antibody-based anticancer therapeutics.
	The percentages of revenues recognized from significant customers of the Company in the three and nine months ended March 31, 2014 and 2013 are included in the following table:
		Three Months Ended				Nine Months Ended
		March 31,				March 31,
	Collaborative Partner:	2014		2013		2014	2013
	Biotest	13%		1%		3%	5%
	Lilly	15%		1%		18%	2%
	Novartis	22%		51%		40%	48%
	Roche	37%		42%		31%	33%
	There were no other customers of the Company with significant revenues in the three and nine months ended March 31, 2014 and 2013.
Recent Accounting Pronouncements	'
	Recent Accounting Pronouncements
	In July 2013, the FASB issued guidance to address the diversity in practice related to the financial statement presentation of unrecognized tax benefits as either a reduction of a deferred tax asset or a liability when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. This guidance is effective prospectively for fiscal years, and interim periods within those years, beginning after December 15, 2013. The adoption of this guidance is not expected to have a material impact on the Company’s consolidated financial statements.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Mar. 31, 2014
Summary of Significant Accounting Policies	'
Schedule of assets that are required to be measured at fair value on a recurring basis	'
	As of March 31, 2014, the Company held certain assets that are required to be measured at fair value on a recurring basis.  The following table represents the fair value hierarchy for the Company’s financial assets measured at fair value on a recurring basis as of March 31, 2014 (in thousands):
		Fair Value Measurements at March 31, 2014 Using
					Quoted Prices in		Significant Other		Significant
					Active Markets for		Observable Inputs		Unobservable
					Identical Assets				Inputs
		Total			(Level 1)		(Level 2)		(Level 3)
	Cash, cash equivalents and restricted cash	$	166,307		$	166,307	$	—	$	—
	As of June 30, 2013, the Company held certain assets that are required to be measured at fair value on a recurring basis. The following table represents the fair value hierarchy for the Company’s financial assets measured at fair value on a recurring basis as of June 30, 2013 (in thousands):
		Fair Value Measurements at June 30, 2013 Using
					Quoted Prices in		Significant Other		Significant
					Active Markets for		Observable Inputs		Unobservable
					Identical Assets				Inputs
		Total			(Level 1)		(Level 2)		(Level 3)
	Cash, cash equivalents and restricted cash	$	197,191		$	197,191	$	—	$	—
Schedule of inventory	'
	Inventory at March 31, 2014 and June 30, 2013 is summarized below (in thousands):
		March 31,			June 30,
		2014			2013
	Raw materials	$	547		$	75
	Work in process	1,937			628
	Total	$	2,484		$	703
Schedule of common stock equivalents, as calculated in accordance with the treasury-stock method	'
	The Company’s common stock equivalents, as calculated in accordance with the treasury-stock method, are shown in the following table (in thousands):
		Three Months Ended				Nine Months Ended
		March 31,				March 31,
		2014		2013		2014	2013
	Options outstanding to purchase common stock and unvested restricted stock	8,605		7,945		8,605	7,945
	Common stock equivalents under treasury stock method	1,814		2,433		1,956	2,302
Schedule of weighted-average assumptions used to estimate the fair value of each stock option	'
		Three Months Ended				Nine Months Ended
		March 31,				March 31,
		2014		2013		2014	2013
	Dividend	None		None		None	None
	Volatility	60.44%		60.44%		60.44%	60.44%
	Risk-free interest rate	1.94%		1.13%		1.74%	0.85%
	Expected life (years)	6.3		6.3		6.3	6.3
Schedule of percentage of total revenue recognized from each significant customer	'
		Three Months Ended				Nine Months Ended
		March 31,				March 31,
	Collaborative Partner:	2014		2013		2014	2013
	Biotest	13%		1%		3%	5%
	Lilly	15%		1%		18%	2%
	Novartis	22%		51%		40%	48%
	Roche	37%		42%		31%	33%

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	9 Months Ended
	Mar. 31, 2014
Commitments and Contingencies	'
Minimum rental commitments for the next five fiscal years and thereafter under the non-cancelable operating lease agreements	'
	The minimum rental commitments for the Company’s facilities, including real estate taxes and other expenses, for the next five fiscal years and thereafter under the non-cancelable operating lease agreements discussed above are as follows (in thousands):
	2014 (three months remaining)	$	1,537
	2015	7,053
	2016	6,831
	2017	6,848
	2018	6,954
	Thereafter	12,267
	Total minimum lease payments	$	41,490
	Total minimum rental payments from sublease	(573		)
	Total minimum lease payments, net	$	40,917

Summary_of_Significant_Account3

Summary of Significant Accounting Policies (Details) (USD $)

9 Months Ended

40 Months Ended

1 Months Ended

9 Months Ended

1 Months Ended

9 Months Ended

1 Months Ended

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Dec. 31, 2012

31-May-13

Mar. 31, 2014

Mar. 31, 2014

Dec. 31, 2011

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Dec. 31, 2013

Apr. 30, 2014

item

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Right-to-Test Agreements

Right-to-Test Agreements

Amgen

Amgen

Amgen

Amgen

Bayer HealthCare

Biotest

Lilly

Lilly

Novartis

Roche

Sanofi

830 Winter Street, Waltham, MA

Subsequent event

item

Minimum

Maximum

Roche's Kadcyla

Roche's Kadcyla

Minimum

Maximum

Exclusive license

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

830 Winter Street, Waltham, MA

Minimum

Maximum

item

Exclusive license

Exclusive license

Non-exclusive license

Exclusive license

Exclusive license

item

Exclusive license

Exclusive license

Exclusive license

Exclusive license

item

item

item

item

item

item

item

item

item

item

Summary of Significant Accounting Policies

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of additional terms for which lease agreement can be extended

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2

Additional term period for which lease agreement can be extended

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'5 years

Construction allowance receivable

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$746,000

$1,100,000

Number of types of licensing and development agreements with collaborative partners

2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of single-target licenses

'

'

'

'

'

'

'

'

'

1

4

3

1

1

1

2

1

2

5

1

'

'

Number of licenses to multiple individual targets

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1

'

'

Number of licenses to two related targets

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1

'

'

'

'

Number of related targets

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2

'

'

'

'

Period after product launch in which the company will earn royalty payments

'

'

'

'10 years

'12 years

'10 years

'12 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Average involvement period over which the upfront payments on single-target licenses are amortized

'

'6 years 6 months

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Difference between the full cost to manufacture and amounts received from collaborators for preclinical and clinical materials

'

$1,600,000

$755,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of types of milestone payments under collaborative arrangements

'

3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Average period over which upfront payments are deferred and recognized

'

'

'

'

'

'

'

'12 months

'18 months

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of quarters in arrear for revenue recognition

'

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Summary_of_Significant_Account4

Summary of Significant Accounting Policies (Details 2) (Recurring basis, USD $)	Mar. 31, 2014	Jun. 30, 2013
In Thousands, unless otherwise specified
Total	'	'
Fair value hierarchy for the Company's financial assets measured at fair value	'	'
Cash, cash equivalents and restricted cash	$166,307	$197,191
Quoted Prices in Active Markets for Identical Assets (Level 1)	'	'
Fair value hierarchy for the Company's financial assets measured at fair value	'	'
Cash, cash equivalents and restricted cash	$166,307	$197,191

Summary_of_Significant_Account5

Summary of Significant Accounting Policies (Details 3) (USD $)	3 Months Ended		9 Months Ended
Share data in Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013	Jun. 30, 2013
Inventory	'	'	'	'	'
Raw materials	$547,000	'	$547,000	'	$75,000
Work in process	1,937,000	'	1,937,000	'	628,000
Total	2,484,000	'	2,484,000	'	703,000
Minimum supply period of raw materials that is not supported by firm, fixed orders and/or projections from collaborators considered to expense inventory	'	'	'12 months	'	'
Charges to research and development expense related to raw material inventory identified as excess	$32,000	$0	$236,000	$798,000	'
Computation of Net Income (Loss) per Common Share	'	'	'	'	'
Options outstanding to purchase common stock and unvested restricted stock (in shares)	8,605	7,945	8,605	7,945	'
Common stock equivalents under treasury stock method (in shares)	1,814	2,433	1,956	2,302	'

Summary_of_Significant_Account6

Summary of Significant Accounting Policies (Details 4) (USD $)	0 Months Ended	3 Months Ended		9 Months Ended
	Nov. 13, 2012	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
				item
Additional disclosure for options	'	'	'	'	'
Cash received for exercise of stock options	'	'	'	$8,557,000	$2,218,000
Financial Instruments and Concentration of Credit Risk	'	'	'	'	'
Number of financial institutions in the U.S. in which cash and cash equivalents are primarily maintained	'	'	'	3	'
2006 Plan	'	'	'	'	'
Stock-Based Compensation	'	'	'	'	'
Number of employee share-based compensation plans	'	'	'	1	'
Additional number of shares authorized for issuance	3,500,000	'	'	'	'
Common stock authorized for issuance (in shares)	12,000,000	'	'	'	'
Additional disclosure for options	'	'	'	'	'
Stock compensation expense	'	3,700,000	2,900,000	12,100,000	9,600,000
Estimated fair value of unvested employee awards, net of estimated forfeitures	'	'	'	25,500,000	'
Weighted average vesting period of unvested employee awards	'	'	'	'2 years 3 months	'
2006 Plan | Maximum	'	'	'	'	'
Stock-Based Compensation	'	'	'	'	'
Number of shares of common stock added to the Plan from the Former Plan	'	'	'	5,900,000	'
2006 Plan | Stock options	'	'	'	'	'
Weighted-average assumptions used to estimate the fair value of each stock option	'	'	'	'	'
Number of group of awards for which expected term is calculated for and applied	'	'	'	1	'
Dividend (as a percent)	'	0.00%	0.00%	0.00%	0.00%
Volatility (as a percent)	'	60.44%	60.44%	60.44%	60.44%
Risk-free interest rate (as a percent)	'	1.94%	1.13%	1.74%	0.85%
Expected life	'	'6 years 3 months 18 days	'6 years 3 months 18 days	'6 years 3 months 18 days	'6 years 3 months 18 days
Weighted-average grant date fair values of options granted (in dollars per share)	'	$9.52	$8.28	$10.54	$8.67
Additional disclosure for options	'	'	'	'	'
Exercised (in shares)	'	'	'	1,000,000	'
Cash received for exercise of stock options	'	'	'	$8,600,000	'
2006 Plan | Stock options | Maximum	'	'	'	'	'
Stock-Based Compensation	'	'	'	'	'
Vesting period	'	'	'	'4 years	'
Exercise period	'	'	'	'10 years	'
Additional disclosure for options	'	'	'	'	'
Exercised (in dollars per share)	'	'	'	$15.83	'
2006 Plan | Stock options | Minimum	'	'	'	'	'
Additional disclosure for options	'	'	'	'	'
Exercised (in dollars per share)	'	'	'	$3.19	'

Summary_of_Significant_Account7

Summary of Significant Accounting Policies (Details 5)	3 Months Ended		9 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting	'	'	'	'
Number of operating segments	'	'	1	'
Biotest | Revenues	'	'	'	'
Collaborative Partner:	'	'	'	'
Percentages of revenue recognized	13.00%	1.00%	3.00%	5.00%
Lilly | Revenues	'	'	'	'
Collaborative Partner:	'	'	'	'
Percentages of revenue recognized	15.00%	1.00%	18.00%	2.00%
Novartis | Revenues	'	'	'	'
Collaborative Partner:	'	'	'	'
Percentages of revenue recognized	22.00%	51.00%	40.00%	48.00%
Roche | Revenues	'	'	'	'
Collaborative Partner:	'	'	'	'
Percentages of revenue recognized	37.00%	42.00%	31.00%	33.00%

Collaborative_Agreements_Detai

Collaborative Agreements (Details) (USD $)

3 Months Ended

9 Months Ended

1 Months Ended

3 Months Ended

9 Months Ended

167 Months Ended

3 Months Ended

9 Months Ended

167 Months Ended

1 Months Ended

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Mar. 31, 2013

31-May-00

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Mar. 31, 2013

31-May-00

Mar. 31, 2014

31-May-00

Nov. 30, 2013

Mar. 31, 2014

Mar. 31, 2014

31-May-00

Sep. 30, 2013

Nov. 30, 2013

Roche

Roche

Roche

Roche

Roche

Roche

Roche

Roche

Roche

Roche

Roche

Roche

Roche

Roche

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Exclusive license

Exclusive license

Exclusive license

Exclusive license

Exclusive license

Exclusive license

Exclusive license

Exclusive license

Exclusive license

Exclusive license

Exclusive license

Exclusive license

Exclusive license

Exclusive license

Kadcyla

Kadcyla

Kadcyla

Kadcyla

Kadcyla

Kadcyla

Kadcyla

Kadcyla

Kadcyla

Kadcyla

Kadcyla

Kadcyla

Kadcyla

Kadcyla

Maximum

Development milestones

Development milestones

Regulatory milestones

Regulatory milestones

Regulatory milestones

Regulatory milestones

Regulatory milestones in Japan

Regulatory milestones in Europe

item

Collaborative Agreements disclosures

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Payments received under collaboration agreement

'

'

'

'

$2,000,000

'

'

'

'

'

$13,500,000

'

'

'

$20,500,000

'

$5,000,000

$5,000,000

Potential milestone payments

'

'

'

'

'

'

'

'

'

44,000,000

'

13,500,000

'

5,000,000

5,000,000

30,500,000

'

'

Number of milestone payments received

'

'

'

'

'

'

'

'

'

'

'

'

2

'

'

'

'

'

Amount of arrangement consideration included in license and milestone fees

305,000

22,010,000

39,150,000

23,372,000

'

'

'

'

'

'

'

'

'

10,000,000

'

'

'

'

Period in arrears to receive royalty reports and payments related to sales of Kadcyla

'

'

'

'

'

'

'

'3 months

'

'

'

'

'

'

'

'

'

'

Royalties on net sales of Kadcyla

$2,558,000

'

$6,946,000

'

'

$2,600,000

$0

$6,900,000

$0

'

'

'

'

'

'

'

'

'

Collaborative_Agreements_Detai1

Collaborative Agreements (Details 2) (Amgen, USD $)

9 Months Ended

1 Months Ended

9 Months Ended

40 Months Ended

1 Months Ended

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Oct. 31, 2013

Oct. 31, 2013

Mar. 31, 2014

Mar. 31, 2014

Oct. 31, 2013

Oct. 31, 2013

Oct. 31, 2013

Dec. 31, 2012

Nov. 30, 2009

Sep. 30, 2009

Mar. 31, 2014

Dec. 31, 2012

31-May-13

Future Technological Improvements

Exclusive license

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

item

Maximum

Development milestones

Development milestones

Development milestones

Regulatory milestones

Sales milestones

Exclusive license

Exclusive license

Exclusive license

Exclusive license

Exclusive license

Exclusive license

Non-exclusive license

Phase II clinical trial

IND application effective

item

item

item

Collaborative Agreements disclosures

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of single-target licenses

'

1

'

'

'

'

'

'

'

'

'

'

'

4

3

1

Fee received per license

'

'

'

'

'

'

'

'

'

'

$1,000,000

$1,000,000

$1,000,000

'

'

$500,000

Fee received on conversion of non-exclusive license agreement to an exclusive license

'

'

'

'

'

'

'

'

'

500,000

'

'

'

'

'

'

Potential milestone payments

'

'

'

34,000,000

9,000,000

3,000,000

1,000,000

20,000,000

5,000,000

'

'

'

'

'

'

'

Estimated utilization period after commercialization

'

'

'10 years

'

'

'

'

'

'

'

'

'

'

'

'

'

Discount rate (as a percent)

'

'

13.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

Remaining arrangement consideration to be recognized as license revenue

$430,000

'

$2,200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Estimated term of development and commercialization license

'25 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Collaborative_Agreements_Detai2

Collaborative Agreements (Details 3) (Sanofi, USD $)	1 Months Ended			21 Months Ended							1 Months Ended
	Aug. 31, 2011	Aug. 31, 2008	Dec. 31, 2006	Aug. 31, 2008	Mar. 31, 2014	Dec. 31, 2006	Dec. 31, 2006	Dec. 31, 2006	Mar. 31, 2014	Dec. 31, 2006	Dec. 31, 2013
	Right-to-test agreement	Right-to-test agreement	Right-to-test agreement	Right-to-test agreement	Development and Commercialization License	Development and Commercialization License	Development and Commercialization License	Development and Commercialization License	Development and Commercialization License	Development and Commercialization License	Development and Commercialization License
							Maximum	Development milestones	Development milestones	Regulatory milestones	Exclusive license
									Phase I clinical trial
Collaborative Agreements disclosures	'	'	'	'	'	'	'	'	'	'	'
License exercise fee, per license	'	'	'	'	'	$2,000,000	'	'	'	'	'
Potential milestone payments	'	'	'	'	2,000,000	'	30,000,000	10,000,000	2,000,000	20,000,000	'
Fee received per license	'	'	'	'	'	'	'	'	'	'	2,000,000
Payments received under collaboration agreement	'	3,500,000	500,000	4,000,000	'	'	'	'	'	'	'
Term of agreement	'	'	'3 years	'	'	'	'	'	'	'	'
Term of extension of the agreement	'3 years	'	'	'	'	'	'	'	'	'	'
Payments for extension of agreement	$2,000,000	'	'	'	'	'	'	'	'	'	'

Collaborative_Agreements_Detai3

Collaborative Agreements (Details 4) (USD $)

3 Months Ended

9 Months Ended

24 Months Ended

1 Months Ended

1 Months Ended

9 Months Ended

24 Months Ended

9 Months Ended

9 Months Ended

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Mar. 31, 2013

Oct. 31, 2012

Oct. 31, 2012

Oct. 31, 2012

Nov. 30, 2013

Oct. 31, 2013

Mar. 31, 2013

Oct. 31, 2010

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2013

Mar. 31, 2013

Mar. 31, 2014

Oct. 31, 2012

Oct. 31, 2010

Nov. 30, 2013

Oct. 31, 2013

Mar. 31, 2013

Oct. 31, 2010

Mar. 31, 2013

Oct. 31, 2010

Mar. 31, 2014

Mar. 31, 2013

Oct. 31, 2010

Mar. 31, 2013

Oct. 31, 2010

Mar. 31, 2014

Novartis

Novartis

Novartis

Novartis

Novartis

Novartis

Novartis

Novartis

Novartis

Novartis

Novartis

Novartis

Novartis

Novartis

Novartis

Novartis

Novartis

Novartis

Novartis

Novartis

Novartis

Novartis

Novartis

Novartis

Novartis

Novartis

Future Technological Improvements

Research Services

Right-to-test agreement

Right-to-test agreement

Right-to-test agreement

Right-to-test agreement

Right-to-test agreement

Right-to-test agreement

Right-to-test agreement

Right-to-test agreement

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

item

Undisclosed Target

Minimum

Exclusive license

Maximum

Maximum

Maximum

Maximum

Development milestones

Development milestones

Development milestones

Regulatory milestones

Regulatory milestones

Sales milestones

Sales milestones

Exclusive license

item

Undisclosed Target

Undisclosed Target

Phase I clinical trial

item

item

item

Collaborative Agreements disclosures

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Term of agreement

'

'

'

'

'

'

'

'

'

'

'3 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Term of extension of the agreement

'

'

'

'

'

'

'

'

'1 year

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Payments for extension of agreement

'

'

'

'

'

'

'

'

$5,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of extension terms

'

'

'

'

'

'

'

'

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Additional term of extension of the agreement

'

'

'

'

'

'

'

'

'1 year

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Payments received under collaboration agreement

'

'

'

'

60,200,000

4,500,000

710,000

1,000,000

1,000,000

1,000,000

45,000,000

'

'

'

'

'

55,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

License exercise fee, per license

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,000,000

'

'

'

'

'

'

'

'

'

'

'

'

Potential milestone payments

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

199,500,000

199,500,000

199,500,000

199,500,000

22,500,000

22,500,000

5,000,000

77,000,000

77,000,000

100,000,000

100,000,000

'

Number of development and commercialization licenses taken

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3

'

'

'

'

2

Number of pre-defined and related undisclosed targets

'

'

'

'

'

'

'

'

'

'

'

'

2

'

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2

License exercise fee, for the fourth license

'

'

'

'

'

'

'

'

'

'

'

1,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Agreed upon fee receivable on conversion of non-exclusive target to an exclusive target

'

'

'

'

'

'

'

'

'

'

'

'

'

5,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Payments received under collaboration agreement in connection with amended agreement

'

'

'

'

'

'

'

'

'

3,500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Potential milestone payments under second option

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

238,000,000

'

22,500,000

'

'

115,500,000

'

100,000,000

'

'

Amount of arrangement consideration included in license and milestone fees

305,000

22,010,000

39,150,000

23,372,000

'

'

'

'

'

'

'

'

'

'

'

17,200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cumulative catch-up amount included in license and milestone fees

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$1,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Estimated utilization period after commercialization

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'10 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Discount rate (as a percent)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

16.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Estimated term of development and commercialization license

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'25 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Collaborative_Agreements_Detai4

Collaborative Agreements (Details 5) (USD $)

3 Months Ended

9 Months Ended

28 Months Ended

1 Months Ended

9 Months Ended

28 Months Ended

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2011

Mar. 31, 2014

Mar. 31, 2014

Dec. 31, 2011

Dec. 31, 2011

Dec. 31, 2011

Dec. 31, 2011

Dec. 31, 2011

Dec. 31, 2011

Mar. 31, 2014

Dec. 31, 2011

Dec. 31, 2011

Lilly

Lilly

Lilly

Lilly

Lilly

Lilly

Lilly

Lilly

Lilly

Lilly

Lilly

Lilly

Lilly

Lilly

Lilly

Lilly

Lilly

Lilly

Sales milestones

Future Technological Improvements

Research Services

Right-to-test agreement

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

item

No exercise fee

No exercise fee

Exercise fee of $2 million

Exercise fee of $2 million

Development milestones

Development milestones

Development milestones

Regulatory milestones

Sales milestones

Maximum

Maximum

No exercise fee

Exercise fee of $2 million

Phase I clinical trial

Collaborative Agreements disclosures

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Term of agreement

'

'

'

'

'

'

'

'

'3 years

'

'

'

'

'

'

'

'

'

'

'

'

'

Payments received under collaboration agreement

'

'

'

'

$28,200,000

$800,000

$600,000

$3,300,000

$20,000,000

$2,000,000

'

'

$23,500,000

'

'

'

'

'

'

'

'

'

Potential milestone payments for each subsequent license

'

'

'

'

'

'

'

'

'

'

'

2,000,000

2,000,000

'

200,500,000

'

199,000,000

30,500,000

29,000,000

5,000,000

70,000,000

100,000,000

Number of development and commercialization licenses taken

'

'

'

'

'

'

'

'

'

'

2

'

'

'

'

'

'

'

'

'

'

'

License exercise fee, per subsequent license

'

'

'

'

'

'

'

'

'

'

2,000,000

'

'

0

'

2,000,000

'

'

'

'

'

'

Estimated utilization period after commercialization

'

'

'

'

'

'

'

'

'

'

'

'10 years

'

'

'

'

'

'

'

'

'

'

Discount rate (as a percent)

'

'

'

'

'

'

'

'

'

'

'

16.00%

'

'

'

'

'

'

'

'

'

'

Amount of arrangement consideration included in license and milestone fees

305,000

22,010,000

39,150,000

23,372,000

'

'

'

'

'

'

'

7,800,000

'

'

'

'

'

'

'

'

'

'

Estimated term of development and commercialization license

'

'

'

'

'

'

'

'

'

'

'

'25 years

'

'

'

'

'

'

'

'

'

'

Remaining arrangement consideration to be recognized as license revenue

'

'

'

'

'

'

'

'

'

'

'

$15,700,000

$15,700,000

'

'

'

'

'

'

'

'

'

Collaborative_Agreements_Detai5

Collaborative Agreements (Details 6) (USD $)

3 Months Ended

9 Months Ended

1 Months Ended

9 Months Ended

1 Months Ended

9 Months Ended

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Mar. 31, 2013

Jun. 30, 2013

Jan. 31, 2014

Mar. 31, 2014

Jan. 31, 2014

Jan. 31, 2014

Jan. 31, 2014

Jan. 31, 2014

Mar. 31, 2014

Jan. 31, 2014

Jan. 31, 2014

Jan. 31, 2014

Jan. 31, 2014

Jan. 31, 2014

CytomX

CytomX

CytomX

CytomX

CytomX

CytomX

CytomX

CytomX

CytomX

CytomX

CytomX

CytomX

Future Technological Improvements

Research Services

Right-to-test agreement

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Development and Commercialization License

Maximum

Development milestones

Development milestones

Regulatory milestones

Sales milestones

Phase I clinical trial

Collaborative Agreements disclosures

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Upfront payments received under collaboration agreement

'

'

'

'

'

'

'

'

'

$0

'

'

'

'

'

'

'

Potential milestone payments to be received

'

'

'

'

'

'

'

'

'

'

'

'

160,000,000

10,000,000

1,000,000

50,000,000

100,000,000

Potential milestone payments to be paid

'

'

'

'

'

'

'

'

'

'

'

'

80,000,000

7,000,000

1,000,000

23,000,000

50,000,000

Discount rate (as a percent)

'

'

'

'

'

'

'

'

'

'

'

13.00%

'

'

'

'

'

Estimated utilization period after commercialization

'

'

'

'

'

'

'

'

'

'

'

'10 years

'

'

'

'

'

Fair value of consideration for services provided

'

'

'

'

'

13,100,000

'

350,000

140,000

13,000,000

12,700,000

'

'

'

'

'

'

Estimated term of development and commercialization license

'

'

'

'

'

'

'

'

'

'

'

'25 years

'

'

'

'

'

License fee revenue

305,000

22,010,000

39,150,000

23,372,000

'

'

0

'

'

'

'

'

'

'

'

'

'

Arrangement consideration included in long-term deferred revenue

59,348,000

'

59,348,000

'

63,384,000

'

13,000,000

'

'

'

'

'

'

'

'

'

'

Fair value of consideration for services received

'

'

'

'

'

'

'

$310,000

$12,800,000

'

'

'

'

'

'

'

'

Capital_Stock_Details

Capital Stock (Details) (USD $)

3 Months Ended

9 Months Ended

107 Months Ended

9 Months Ended

12 Months Ended

3 Months Ended

9 Months Ended

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Mar. 31, 2014

Jun. 30, 2013

Jun. 30, 2012

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Mar. 31, 2013

Nov. 30, 2013

2001 Director Plan

2001 Director Plan

2001 Director Plan

2001 Director Plan

2001 Director Plan

Compensation Policy for Non-Employee Directors

Compensation Policy for Non-Employee Directors

Compensation Policy for Non-Employee Directors

Compensation Policy for Non-Employee Directors

Compensation Policy for Non-Employee Directors

Compensation Policy for Non-Employee Directors

Compensation Policy for Non-Employee Directors

Compensation Policy for Non-Employee Directors

Stock options

Stock options

Stock options

Stock options

Stock options

Stock options

Stock options

Stock options

Deferred share units

Deferred share units

Deferred share units

Deferred share units

Deferred share units

Stock-Based Compensation

'

'

'

'

'

'

'

'

'

'

'

'

'

Expense and (expense reduction)

$2,000

$21,000

($11,000)

($4,000)

'

'

'

'

$118,000

$98,000

$315,000

$253,000

'

Stock units issued (in shares)

'

'

'

'

0

'

'

'

'

'

'

'

'

Vesting period

'

'

'

'

'

'1 year

'

'

'

'

'1 year

'

'

Common stock issued to settle retiring director's share units (in shares)

'

'

'

'

'

'

'

'

'

'

'

'

43,615

Stock options granted to directors (in shares)

'

'

'

'

'

80,000

41,805

33,187

'

'

'

'

'

Cash_and_Cash_Equivalents_Deta

Cash and Cash Equivalents (Details) (USD $)	Mar. 31, 2014	Jun. 30, 2013	Mar. 31, 2013	Jun. 30, 2012
In Thousands, unless otherwise specified
Cash and Cash Equivalents	'	'	'	'
Cash and cash equivalents	$164,076	$194,960	$206,103	$160,938

Commitments_and_Contingencies_1

Commitments and Contingencies (Details) (USD $)	Mar. 31, 2014	Apr. 30, 2012	Dec. 31, 2009	Dec. 31, 2013	Jul. 27, 2007	Apr. 30, 2014	Mar. 31, 2014	Aug. 31, 2013	Apr. 30, 2013
		830 Winter Street, Waltham, MA	830 Winter Street, Waltham, MA	830 Winter Street, Waltham, MA	830 Winter Street, Waltham, MA	830 Winter Street, Waltham, MA	Norwood, MA	100 River Ridge Drive, Norwood, MA	100 River Ridge Drive, Norwood, MA
		sqft	sqft	sqft	sqft	Subsequent event	sqft		sqft
						item
Operating leases	'	'	'	'	'	'	'	'	'
Area of space leased (in square feet)	'	'	'	'	89,000	'	43,850	'	7,507
Initial lease term period	'	'3 years	'	'	'	'	'	'5 years 2 months	'
Additional area of space leased (in square feet)	'	'	'	19,000	'	'	'	'	'
Construction allowance receivable	'	'	'	$746,000	'	$1,100,000	'	'	'
Number of additional terms for which lease agreement can be extended	'	'	'	'	'	2	'	'	'
Additional term period for which lease agreement can be extended	'	'	'	'	'	'5 years	'5 years	'5 years	'
Area of property covered under sublease agreement (in square feet)	'	7,310	14,100	'	'	'	'	'	'
Additional period for which sublease agreement can be extended	'	'	'2 years	'	'	'	'	'	'
Minimum rental commitments under the non-cancelable operating lease agreements	'	'	'	'	'	'	'	'	'
2014 (three months remaining)	1,537,000	'	'	'	'	'	'	'	'
2015	7,053,000	'	'	'	'	'	'	'	'
2016	6,831,000	'	'	'	'	'	'	'	'
2017	6,848,000	'	'	'	'	'	'	'	'
2018	6,954,000	'	'	'	'	'	'	'	'
Thereafter	12,267,000	'	'	'	'	'	'	'	'
Total minimum lease payments	41,490,000	'	'	'	'	'	'	'	'
Total minimum rental payments from subleases	-573,000	'	'	'	'	'	'	'	'
Total minimum lease payments, net	40,917,000	'	'	'	'	'	'	'	'
Collaborations	'	'	'	'	'	'	'	'	'
Potential milestone payments receivable	162,000,000	'	'	'	'	'	'	'	'
Amount reimbursable by a third party	$1,400,000	'	'	'	'	'	'	'	'