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Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2014	Oct. 31, 2014
Document and Entity Information
Entity Registrant Name	Celldex Therapeutics, Inc.
Entity Central Index Key	0000744218
Document Type	10-Q
Document Period End Date	Sep. 30, 2014
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		89,589,105
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	Q3

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2014	Dec. 31, 2013
Current Assets:
Cash and Cash Equivalents	$ 32,525	$ 169,402
Marketable Securities	191,553	133,581
Accounts and Other Receivables	2,905	489
Prepaid and Other Current Assets	2,842	1,717
Total Current Assets	229,825	305,189
Property and Equipment, Net	10,716	9,973
Intangible Assets, Net	22,060	22,820
Other Assets	99	148
Goodwill	8,965	8,965
Total Assets	271,665	347,095
Current Liabilities:
Accounts Payable	1,720	2,243
Accrued Expenses	17,703	17,179
Current Portion of Long-Term Liabilities	2,191	928
Total Current Liabilities	21,614	20,350
Other Long-Term Liabilities	10,679	6,950
Total Liabilities	32,293	27,300
Commitments and Contingent Liabilities
Stockholders' Equity:
Convertible Preferred Stock, $.01 Par Value; 3,000,000 Shares Authorized; No Shares Issued and Outstanding at September 30, 2014 and December 31, 2013
Common Stock, $.001 Par Value; 297,000,000 Shares Authorized; 89,436,933 and 89,246,832 Shares Issued and Outstanding at September 30, 2014 and December 31, 2013, respectively	89	89
Additional Paid-In Capital	668,596	662,717
Accumulated Other Comprehensive Income	2,624	2,668
Accumulated Deficit	(431,937)	(345,679)
Total Stockholders' Equity	239,372	319,795
Total Liabilities and Stockholders' Equity	$ 271,665	$ 347,095

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2014	Dec. 31, 2013
CONDENSED CONSOLIDATED BALANCE SHEETS
Convertible Preferred Stock, Par Value (in dollars per share)	$ 0.01	$ 0.01
Convertible Preferred Stock, Shares Authorized	3,000,000	3,000,000
Convertible Preferred Stock, Shares Issued	0	0
Convertible Preferred Stock, Shares Outstanding	0	0
Common Stock, Par Value (in dollars per share)	$ 0.001	$ 0.001
Common Stock, Shares Authorized	297,000,000	297,000,000
Common Stock, Shares Issued	89,436,933	89,246,832
Common Stock, Shares Outstanding	89,436,933	89,246,832

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
REVENUE:
Product Development and Licensing Agreements	$ 284	$ 40	$ 518	$ 117
Contracts and Grants	817	940	1,591	1,040
Product Royalties				2,334
Total Revenue	1,101	980	2,109	3,491
OPERATING EXPENSE:
Research and Development	26,185	20,417	77,355	49,597
Royalty				2,334
General and Administrative	5,004	3,578	14,373	10,128
Amortization of Acquired Intangible Assets	254	254	760	760
Total Operating Expense	31,443	24,249	92,488	62,819
Operating Loss	(30,342)	(23,269)	(90,379)	(59,328)
Investment and Other Income, Net	2,260	142	4,121	682
Interest Expense		(13)		(842)
Net Loss	$ (28,082)	$ (23,140)	$ (86,258)	$ (59,488)
Basic and Diluted Net Loss Per Common Share (Note 3) (in dollars per share)	$ (0.31)	$ (0.29)	$ (0.97)	$ (0.76)
Shares Used in Calculating Basic and Diluted Net Loss per Share (Note 3) (in shares)	89,404	81,015	89,346	78,676
COMPREHENSIVE LOSS:
Net Loss	$ (28,082)	$ (23,140)	$ (86,258)	$ (59,488)
Other Comprehensive (Loss) Income:
Foreign Currency Translation Adjustments	(3)		(4)	(3)
Unrealized Gain (Loss) on Marketable Securities	(121)	138	(40)	(56)
Comprehensive Loss	$ (28,206)	$ (23,002)	$ (86,302)	$ (59,547)

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Cash Flows from Operating Activities:
Net Loss	$ (86,258)	$ (59,488)
Adjustments to Reconcile Net Loss to Net Cash Used in Operating Activities:
Depreciation and Amortization	1,764	1,422
Amortization of Intangible Assets	760	760
Amortization and Premium of Marketable Securities	(754)	(1,232)
Realized Gain on Sales and Maturities of Marketable Securities	(11)
Gain (Loss) on Sales or Disposal of Assets		(21)
Stock-Based Compensation Expense	4,719	3,400
Non-Cash Interest Expense		97
Changes in Operating Assets and Liabilities:
Accounts and Other Receivables	(2,416)	(846)
Prepaid and Other Current Assets	(1,428)	(1,457)
Other Assets	49	267
Accounts Payable and Accrued Expenses	(740)	2,954
Other Liabilities	4,992	1,432
Net Cash Used in Operating Activities	(79,323)	(52,712)
Cash Flows from Investing Activities:
Sales and Maturities of Marketable Securities	89,215	30,679
Purchases of Marketable Securities	(146,159)	(92,400)
Acquisition of Property and Equipment	(1,766)	(1,901)
Proceeds from Sales or Disposal of Assets		21
Net Cash Used in Investing Activities	(58,710)	(63,601)
Cash Flows from Financing Activities:
Net Proceeds from Stock Issuances		114,187
Proceeds from Issuance of Stock from Employee Benefit Plans	1,160	2,931
Payments of Term Loan		(11,029)
Payments of Other Liabilities		(44)
Net Cash Provided by Financing Activities	1,160	106,045
Effect of Exchange Rate Changes on Cash and Cash Equivalents	(4)	(3)
Net Decrease in Cash and Cash Equivalents	(136,877)	(10,271)
Cash and Cash Equivalents at Beginning of Period	169,402	24,897
Cash and Cash Equivalents at End of Period	$ 32,525	$ 14,626

Basis of Presentation	9 Months Ended
Basis of Presentation	Sep. 30, 2014
Basis of Presentation
Basis of Presentation	(1) Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared by Celldex Therapeutics, Inc. (the “Company” or “Celldex”) in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and reflect the operations of the Company and its wholly-owned subsidiary. All intercompany transactions have been eliminated in consolidation. These interim financial statements do not include all the information and footnotes required by U.S. GAAP for annual financial statements and should be read in conjunction with the audited financial statements for the year ended December 31, 2013, which are included in the Company’s Annual Report on Form 10-K filed with the Securities and Exchange Commission (“SEC”) on March 3, 2014. In the opinion of management, the interim financial statements reflect all normal recurring adjustments necessary to fairly state the Company’s financial position and results of operations for the interim periods presented. The year-end condensed consolidated balance sheet data presented for comparative purposes was derived from audited financial statements, but does not include all disclosures required by U.S. GAAP. The results of operations for the interim periods are not necessarily indicative of the results of operations to be expected for any future interim period or the fiscal year ending December 31, 2014. At September 30, 2014, the Company had cash, cash equivalents and marketable securities of $224.1 million. The Company incurred a loss of $86.3 million for the nine months ended September 30, 2014. Net cash used in operations for the nine months ended September 30, 2014 was $79.3 million. The Company believes that the cash, cash equivalents and marketable securities at September 30, 2014 will be sufficient to meet estimated working capital requirements and fund planned operations for at least the next twelve months. During the next twelve months, the Company may take further steps to raise additional capital to meet its long-term liquidity needs. These capital raising activities may include, but may not be limited to, one or more of the following: the licensing of technology programs with existing or new collaborative partners, possible business combinations, issuance of debt, or the issuance of common stock or other securities via private placements or public offerings. While the Company continues to seek capital through a number of means, there can be no assurance that additional financing will be available on acceptable terms, if at all, and the Company’s negotiating position in capital-raising efforts may worsen as existing resources are used. There is also no assurance that the Company will be able to enter into further collaborative relationships. Additional equity financing may be dilutive to the Company’s stockholders; debt financing, if available, may involve significant cash payment obligations and covenants that restrict the Company’s ability to operate as a business; and licensing or strategic collaborations may result in royalties or other terms which reduce the Company’s economic potential from products under development.

Significant Accounting Policies	9 Months Ended
Significant Accounting Policies	Sep. 30, 2014
Significant Accounting Policies
Significant Accounting Policies	(2) Significant Accounting Policies The significant accounting policies used in preparation of these condensed consolidated financial statements for the nine months ended September 30, 2014 are consistent with those discussed in Note 2 to the consolidated financial statements in our Annual Report on Form 10-K for the year ended December 31, 2013. Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”) or other standard setting bodies that are adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on the Company’s financial position or results of operations upon adoption. In May 2014, the FASB issued a new U.S. GAAP accounting standard that creates modifications to various other revenue accounting standards for specialized transactions and industries. The new U.S. GAAP accounting standard is intended to conform revenue accounting principles with a concurrently issued new standard under International Financial Reporting Standards, as well as, to enhance disclosures related to disaggregated revenue information. The updated guidance is effective for annual reporting periods beginning on or after December 15, 2016, and interim periods within those annual periods. Early adoption is not permitted. The Company will further study the implications of this standard in order to evaluate the expected impact on the consolidated financial statements. In August 2014, the FASB issued a new U.S. GAAP accounting standard that provides guidance about management’s responsibility to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern and to provide related footnote disclosures. The new accounting standard requires management to assess an entity’s ability to continue as a going concern by incorporating and expanding upon certain principles that are currently in U.S. auditing standards. The new accounting standard is effective for the annual period ending after December 15, 2016, and for annual periods and interim periods thereafter. Early application is permitted. The Company does not expect the adoption of this standard to have a material impact on the consolidated financial statements.

Net Loss Per Share

9 Months Ended

Sep. 30, 2014

Net Loss Per Share

Net Loss Per Share

(3) Net Loss Per Share

Basic net loss per common share is based upon the weighted-average number of common shares outstanding during the period, excluding restricted stock that has been issued but is not yet vested. Diluted net loss per common share is based upon the weighted-average number of common shares outstanding during the period plus additional weighted-average potentially dilutive common shares outstanding during the period when the effect is dilutive. The potentially dilutive common shares that have not been included in the net loss per common share calculations because the effect would have been anti-dilutive are as follows:

	Three and Nine Months Ended September 30,
	2014	2013

Stock options	6,999,421	6,077,377
Restricted stock	9,000	9,000
	7,008,421	6,086,377

Comprehensive Loss

9 Months Ended

Sep. 30, 2014

Comprehensive Loss

Comprehensive Loss

(4) Comprehensive Loss

The changes in Accumulated Other Comprehensive Income by component for the three and nine months ended September 30, 2014 are summarized below. No amounts were reclassified out of accumulated other comprehensive income during the three or nine months ended September 30, 2014.

	Unrealized Gain (Loss) on Marketable Securities, net of tax			Foreign Currency Items			Total
	(In thousands)
Balance at June 30, 2014	$	163		$	2,585		$	2,748
Other comprehensive income (loss) before reclassifications	(121		)	(3		)	(124		)
Amounts reclassified from other comprehensive income	—			—			—
Net current-period other comprehensive income	(121		)	(3		)	(124		)
Balance at September 30, 2014	$	42		$	2,582		$	2,624

Balance at December 31, 2013	$	82		$	2,586		$	2,668
Other comprehensive income (loss) before reclassifications	(40		)	(4		)	(44		)
Amounts reclassified from other comprehensive income	—			—			—
Net current-period other comprehensive income	(40		)	(4		)	(44		)
Balance at September 30, 2014	$	42		$	2,582		$	2,624

- Definition

The entire disclosure for comprehensive income, which includes, but is not limited to, 1) the amount of income tax expense or benefit allocated to each component of other comprehensive income, including reclassification adjustments, 2) the reclassification adjustments for each classification of other comprehensive income and 3) the ending accumulated balances for each component of comprehensive income.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-Topic 220
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-Section 45
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-Name Accounting Standards Codification
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-Name Accounting Standards Codification
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Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Reclassification Adjustments
-URI http://asc.fasb.org/extlink&oid=6522872

+ Details

Fair Value Measurements

9 Months Ended

Sep. 30, 2014

Fair Value Measurements

Fair Value Measurements

(5) Fair Value Measurements

The following tables set forth the Company’s financial assets subject to fair value measurements:

	As of September 30, 2014		Level 1		Level 2		Level 3
	(In thousands)
Money market funds and cash equivalents	$	27,995	$	—	$	27,995	$	—
Marketable securities	191,553		—		191,553		—
	$	219,548	$	—	$	219,548	$	—

	As of December 31, 2013		Level 1		Level 2		Level 3
	(In thousands)
Money market funds and cash equivalents	$	148,549	$	—	$	148,549	$	—
Marketable securities	133,581		—		133,581		—
	$	282,130	$	—	$	282,130	$	—

There have been no transfers of assets or liabilities between the fair value measurement classifications. The Company’s financial instruments consist mainly of cash and cash equivalents, marketable securities, short-term accounts receivable and accounts payable. The Company values its marketable securities utilizing independent pricing services which normally derive security prices from recently reported trades for identical or similar securities, making adjustments based on significant observable transactions. At each balance sheet date, observable market inputs may include trade information, broker or dealer quotes, bids, offers or a combination of these data sources. Short-term accounts receivable and accounts payable are reflected in the accompanying consolidated financial statements at cost, which approximates fair value due to the short-term nature of these instruments.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Marketable Securities

9 Months Ended

Sep. 30, 2014

Marketable Securities

Marketable Securities

(6) Marketable Securities

A summary of marketable securities is shown below:

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(In thousands)
September 30, 2014
Marketable securities
U.S. government and municipal obligations
Maturing in one year or less	$	40,198	$	43	$	(5	)	$	40,236
Maturing after one year through three years	30,293		67		(9		)	30,351
Total U.S. government and municipal obligations	$	70,491	$	110	$	(14	)	$	70,587
Corporate debt securities
Maturing in one year or less	$	92,510	$	20	$	(34	)	$	92,496
Maturing after one year through three years	28,510		2		(42		)	28,470
Total corporate debt securities	$	121,020	$	22	$	(76	)	$	120,966
Total marketable securities	$	191,511	$	132	$	(90	)	$	191,553

December 31, 2013
Marketable securities
U.S. government and municipal obligations
Maturing in one year or less	$	55,531	$	27	$	(4	)	$	55,554
Maturing after one year through three years	18,234		56		(4		)	18,286
Total U.S. government and municipal obligations	$	73,765	$	83	$	(8	)	$	73,840
Corporate debt securities
Maturing in one year or less	$	38,973	$	9	$	(9	)	$	38,973
Maturing after one year through three years	20,761		12		(5		)	20,768
Total corporate debt securities	$	59,734	$	21	$	(14	)	$	59,741
Total marketable securities	$	133,499	$	104	$	(22	)	$	133,581

The marketable securities held by the Company were high investment grade and there were no marketable securities that the Company considered to be other-than-temporarily impaired as of September 30, 2014. Marketable securities include $1.2 million and $0.9 million in accrued interest at September 30, 2014 and December 31, 2013, respectively.

- Definition

The entire disclosure for investments in certain debt and equity securities.

+ References + Details

Intangible Assets and Goodwill

9 Months Ended

Sep. 30, 2014

Intangible Assets and Goodwill

Intangible Assets and Goodwill

(7) Intangible Assets and Goodwill

Intangible assets, net of accumulated amortization, and goodwill are as follows:

		September 30, 2014							December 31, 2013
	Estimated Life	Cost		Accumulated Amortization			Net		Cost		Accumulated Amortization			Net
	(In thousands)
Intangible Assets:
IPR&D	Indefinite	$	11,800	—			$	11,800	$	11,800	—			$	11,800
Amgen Amendment	16 years	14,500		$	(4,484	)	10,016		14,500		$	(3,812	)	10,688
Core Technology	11 years	1,296		(1,052		)	244		1,296		(964		)	332
Total Intangible Assets		$	27,596	$	(5,536	)	$	22,060	$	27,596	$	(4,776	)	$	22,820
Goodwill	Indefinite	$	8,965	—			$	8,965	$	8,965	—			$	8,965

The IPR&D intangible asset was recorded in connection with the acquisition of CuraGen and relates to the development of glembatumumab vedotin. At the date of acquisition and at September 30, 2014, glembatumumab vedotin had not yet reached technological feasibility nor did it have any alternative future use. Glembatumumab vedotin is in a randomized study for the treatment of triple negative breast cancer.

The Company performed an annual impairment test of the IPR&D and goodwill assets as of July 1, 2014 and concluded that the IPR&D and goodwill assets were not impaired.

- Definition

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

+ References + Details

Other Long-TermLiabilities

9 Months Ended

Sep. 30, 2014

Other Long-Term Liabilities

Other Long-Term Liabilities

(8) Other Long-Term Liabilities

Other long-term liabilities include the following:

	September 30, 2014			December 31, 2013
	(In thousands)
Deferred Rent	$	499		$	419
Net Deferred Tax Liability related to IPR&D	4,661			4,661
Deferred Income from Sale of Tax Benefits	2,253			1,630
Deferred Revenue	5,457			1,168
Total	12,870			7,878
Less Current Portion	(2,191		)	(928		)
Long-Term Portion	$	10,679		$	6,950

In January 2014, 2013, 2012 and 2011, the Company received approval from the New Jersey Economic Development Authority and agreed to sell New Jersey tax benefits worth $1.1 million, $0.8 million, $0.8 million and $0.6 million to an independent third party for $1.0 million, $0.8 million, $0.7 million and $0.5 million, respectively. Under the agreement, the Company must maintain a base of operations in New Jersey for five years or the tax benefits must be paid back on a pro-rata basis based on the number of years completed. During the nine months ended September 30, 2014 and 2013, the Company recorded $0.4 million and $0.2 million to other income related to the sale of these tax benefits, respectively.

In September 2013, the Company entered into an agreement with Rockefeller University pursuant to which the Company will perform research and development services for Rockefeller. The agreement includes an approved project plan for the development services of $4.8 million and a term of three years. The agreement included an upfront payment of $1.3 million which is being recognized as revenue over the term of the agreement. The Company will bill Rockefeller quarterly for actual time and direct costs incurred and record those amounts to revenue in the quarter the services are performed. The Company recorded revenue related to the Rockefeller agreement of $0.8 million and $0.9 million during the three months ended September 30, 2014 and 2013 and $1.5 million and $0.9 million during the nine months ended September 30, 2014 and 2013, respectively.

In May 2014, the Company entered into a clinical trial collaboration with Bristol-Myers Squibb Company (“BMS”) to evaluate the safety, tolerability and preliminary efficacy of varlilumab and nivolumab, BMS’s PD-1 immune checkpoint inhibitor, in a Phase 1/2 study. Under the terms of this clinical trial collaboration, BMS made a one-time payment to the Company of $5.0 million and the companies amended the terms of the Company’s existing license agreement with Medarex (a subsidiary of BMS) related to the Company’s CD27 program whereby certain future milestone payments were waived and future royalty rates were reduced that may have been due from the Company to Medarex. In return, BMS was granted a time-limited right of first negotiation if the Company wishes to out-license varlilumab. The companies also agreed to work exclusively with each other to explore anti-PD-1 antagonist antibody and anti-CD27 agonist antibody combination regimens. The clinical trial collaboration provides that the companies will share development costs and that the Company will be responsible for conducting the Phase 1/2 study, which is expected to begin in the fourth quarter of 2014.

The Company has determined that its performance obligations under the BMS agreement, which primarily include performing research and development, supplying varlilumab and participating in the joint development committee, should be accounted for as a single unit of accounting and estimated that its performance period under the BMS agreement would be 5 years. Accordingly, the $5 million up-front payment was initially recorded as deferred revenue and is being recognized as revenue on a straight-line basis over the estimated 5-year performance period using the Contingency Adjusted Performance Model (“CAPM”). The BMS agreement also provides for BMS to reimburse the Company for 50% of the external costs incurred by the Company in connection with the clinical trial. These BMS payments will be recognized as revenue under the CAPM. The Company recorded $0.3 million and $0.4 million in revenue related to the BMS agreement during the three and nine months ended September 30, 2014, respectively.

Stockholders' Equity	9 Months Ended
Stockholders' Equity	Sep. 30, 2014
Stockholders' Equity
Stockholders' Equity	(9) Stockholders’ Equity During the nine months ended September 30, 2013, the Company issued 2,433,608 shares of its common stock under its controlled equity offering sales agreement with Cantor Fitzgerald & Co., as amended, resulting in net proceeds to the Company of $17.1 million, after deducting commission and offering expenses. During the nine months ended September 30, 2013, the Company issued 13,800,000 shares of its common stock in an underwritten public offering resulting in net proceeds to the Company of $97.0 million, after deducting underwriting fees and offering expenses. In October 2014, the Company entered into an amended and restated supply agreement with Biosyn Corporation. Under the supply agreement, Biosyn will manufacture and supply keyhole limpet hemocyanin (KLH) to the Company for use in connection with the development, manufacture or commercial sale of rindopepimut. In connection with the supply agreement, the Company issued to Biosyn 152,172 shares of its common stock having a value of $2.0 million.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(d),(e))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21484-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB TOPIC 4.E)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74512-122707

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21488-112644

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29-31)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
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-Paragraph 4
-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
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-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6405834&loc=d3e23285-112656

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
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-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Preferred Stock
-URI http://asc.fasb.org/extlink&oid=6521494

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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-Section 50
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-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21564-112644

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph d
-Article 4

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 29, 30, 31
-Article 5

Reference 16: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section E

Reference 17: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Article 4

Reference 18: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section C

Reference 19: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

+ Details

Stock-Based Compensation

9 Months Ended

Sep. 30, 2014

Stock-Based Compensation

Stock-Based Compensation

(10) Stock-Based Compensation

A summary of stock option activity for the nine months ended September 30, 2014 is as follows:

	Shares		Weighted Average Exercise Price Per Share		Weighted Average Remaining Contractual Term (In Years)
Options Outstanding at December 31, 2013	5,770,544		$	8.17	7.0
Granted	1,405,350		$	13.65
Exercised	(167,303	)	$	6.04
Canceled	(9,170	)	$	10.70
Options Outstanding at September 30, 2014	6,999,421		$	9.32	7.0
Options Vested and Expected to Vest at September 30, 2014	6,937,665		$	9.28	7.0
Options Exercisable at September 30, 2014	3,878,159		$	6.92	5.4
Shares Available for Grant under the 2008 Plan	694,762

The weighted average grant-date fair value of stock options granted during the nine months ended September 30, 2014 was $8.81 per share. Stock-based compensation expense for the three and nine months ended September 30, 2014 and 2013 was recorded as follows:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2014		2013		2014		2013
	(In thousands)
Research and development	$	977	$	1,326	$	2,315	$	2,190
General and administrative	981		690		2,404		1,210
Total stock-based compensation expense	$	1,958	$	2,016	$	4,719	$	3,400

The fair values of employee and director stock options granted during the three and nine months ended September 30, 2014 and 2013 were valued using the Black-Scholes option-pricing model with the following assumptions:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2014		2013		2014		2013
Expected stock price volatility	72	%	72	%	71 - 72	%	72	%
Expected option term	6.0 years		6.0 years		6.0 years		6.0 years
Risk-free interest rate	2.1 - 2.2	%	1.9 - 2.0	%	2.1 - 2.2	%	1.2 - 2.0	%
Expected dividend yield	None		None		None		None

Income Taxes	9 Months Ended
Income Taxes	Sep. 30, 2014
Income Taxes
Income Taxes	(11) Income Taxes Massachusetts, New Jersey and Connecticut are the three states in which the Company primarily operates or has operated and has income tax nexus. The Company is not currently under examination by any jurisdictions for any tax year. The Company has evaluated the positive and negative evidence bearing upon the realizability of its net deferred tax assets, which are comprised principally of net operating loss carryforwards, capitalized R&D expenditures and R&D tax credit carryforwards. The Company has determined that it is more likely than not that it will not recognize the benefits of federal and state deferred tax assets and, as a result, a full valuation allowance was maintained at September 30, 2014 and December 31, 2013 against the Company’s net deferred tax assets.

Significant Accounting Policies (Policies)	9 Months Ended
Significant Accounting Policies (Policies)	Sep. 30, 2014
Significant Accounting Policies
Recent Accounting Pronouncements	Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”) or other standard setting bodies that are adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on the Company’s financial position or results of operations upon adoption. In May 2014, the FASB issued a new U.S. GAAP accounting standard that creates modifications to various other revenue accounting standards for specialized transactions and industries. The new U.S. GAAP accounting standard is intended to conform revenue accounting principles with a concurrently issued new standard under International Financial Reporting Standards, as well as, to enhance disclosures related to disaggregated revenue information. The updated guidance is effective for annual reporting periods beginning on or after December 15, 2016, and interim periods within those annual periods. Early adoption is not permitted. The Company will further study the implications of this standard in order to evaluate the expected impact on the consolidated financial statements. In August 2014, the FASB issued a new U.S. GAAP accounting standard that provides guidance about management’s responsibility to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern and to provide related footnote disclosures. The new accounting standard requires management to assess an entity’s ability to continue as a going concern by incorporating and expanding upon certain principles that are currently in U.S. auditing standards. The new accounting standard is effective for the annual period ending after December 15, 2016, and for annual periods and interim periods thereafter. Early application is permitted. The Company does not expect the adoption of this standard to have a material impact on the consolidated financial statements.

Net Loss Per Share (Tables)

9 Months Ended

Sep. 30, 2014

Net Loss Per Share

Schedule of potentially dilutive common shares that have not been included in the net loss per common share calculations because the effect would have been anti-dilutive

	Three and Nine Months Ended September 30,
	2014	2013

Stock options	6,999,421	6,077,377
Restricted stock	9,000	9,000
	7,008,421	6,086,377

Comprehensive Loss (Tables)

9 Months Ended

Sep. 30, 2014

Comprehensive Loss

Summary of changes in accumulated other comprehensive income by component

	Unrealized Gain (Loss) on Marketable Securities, net of tax			Foreign Currency Items			Total
	(In thousands)
Balance at June 30, 2014	$	163		$	2,585		$	2,748
Other comprehensive income (loss) before reclassifications	(121		)	(3		)	(124		)
Amounts reclassified from other comprehensive income	—			—			—
Net current-period other comprehensive income	(121		)	(3		)	(124		)
Balance at September 30, 2014	$	42		$	2,582		$	2,624

Balance at December 31, 2013	$	82		$	2,586		$	2,668
Other comprehensive income (loss) before reclassifications	(40		)	(4		)	(44		)
Amounts reclassified from other comprehensive income	—			—			—
Net current-period other comprehensive income	(40		)	(4		)	(44		)
Balance at September 30, 2014	$	42		$	2,582		$	2,624

Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2014

Fair Value Measurements

Schedule of financial assets subject to fair value measurements

	As of September 30, 2014		Level 1		Level 2		Level 3
	(In thousands)
Money market funds and cash equivalents	$	27,995	$	—	$	27,995	$	—
Marketable securities	191,553		—		191,553		—
	$	219,548	$	—	$	219,548	$	—

	As of December 31, 2013		Level 1		Level 2		Level 3
	(In thousands)
Money market funds and cash equivalents	$	148,549	$	—	$	148,549	$	—
Marketable securities	133,581		—		133,581		—
	$	282,130	$	—	$	282,130	$	—

Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2014

Marketable Securities

Summary of marketable securities

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(In thousands)
September 30, 2014
Marketable securities
U.S. government and municipal obligations
Maturing in one year or less	$	40,198	$	43	$	(5	)	$	40,236
Maturing after one year through three years	30,293		67		(9		)	30,351
Total U.S. government and municipal obligations	$	70,491	$	110	$	(14	)	$	70,587
Corporate debt securities
Maturing in one year or less	$	92,510	$	20	$	(34	)	$	92,496
Maturing after one year through three years	28,510		2		(42		)	28,470
Total corporate debt securities	$	121,020	$	22	$	(76	)	$	120,966
Total marketable securities	$	191,511	$	132	$	(90	)	$	191,553

December 31, 2013
Marketable securities
U.S. government and municipal obligations
Maturing in one year or less	$	55,531	$	27	$	(4	)	$	55,554
Maturing after one year through three years	18,234		56		(4		)	18,286
Total U.S. government and municipal obligations	$	73,765	$	83	$	(8	)	$	73,840
Corporate debt securities
Maturing in one year or less	$	38,973	$	9	$	(9	)	$	38,973
Maturing after one year through three years	20,761		12		(5		)	20,768
Total corporate debt securities	$	59,734	$	21	$	(14	)	$	59,741
Total marketable securities	$	133,499	$	104	$	(22	)	$	133,581

Intangible Assets and Goodwill (Tables)

9 Months Ended

Sep. 30, 2014

Intangible Assets and Goodwill

Schedule of intangible assets, net of accumulated amortization, and goodwill

		September 30, 2014							December 31, 2013
	Estimated Life	Cost		Accumulated Amortization			Net		Cost		Accumulated Amortization			Net
	(In thousands)
Intangible Assets:
IPR&D	Indefinite	$	11,800	—			$	11,800	$	11,800	—			$	11,800
Amgen Amendment	16 years	14,500		$	(4,484	)	10,016		14,500		$	(3,812	)	10,688
Core Technology	11 years	1,296		(1,052		)	244		1,296		(964		)	332
Total Intangible Assets		$	27,596	$	(5,536	)	$	22,060	$	27,596	$	(4,776	)	$	22,820
Goodwill	Indefinite	$	8,965	—			$	8,965	$	8,965	—			$	8,965

Other Long-Term Liabilities (Tables)

9 Months Ended

Sep. 30, 2014

Other Long-Term Liabilities

Schedule of Other long-term liabilities

	September 30, 2014			December 31, 2013
	(In thousands)
Deferred Rent	$	499		$	419
Net Deferred Tax Liability related to IPR&D	4,661			4,661
Deferred Income from Sale of Tax Benefits	2,253			1,630
Deferred Revenue	5,457			1,168
Total	12,870			7,878
Less Current Portion	(2,191		)	(928		)
Long-Term Portion	$	10,679		$	6,950

Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2014

Stock-Based Compensation

Summary of stock option activity

	Shares		Weighted Average Exercise Price Per Share		Weighted Average Remaining Contractual Term (In Years)
Options Outstanding at December 31, 2013	5,770,544		$	8.17	7.0
Granted	1,405,350		$	13.65
Exercised	(167,303	)	$	6.04
Canceled	(9,170	)	$	10.70
Options Outstanding at September 30, 2014	6,999,421		$	9.32	7.0
Options Vested and Expected to Vest at September 30, 2014	6,937,665		$	9.28	7.0
Options Exercisable at September 30, 2014	3,878,159		$	6.92	5.4
Shares Available for Grant under the 2008 Plan	694,762

Schedule of stock-based compensation expense

	Three Months Ended September 30,				Nine Months Ended September 30,
	2014		2013		2014		2013
	(In thousands)
Research and development	$	977	$	1,326	$	2,315	$	2,190
General and administrative	981		690		2,404		1,210
Total stock-based compensation expense	$	1,958	$	2,016	$	4,719	$	3,400

Schedule of assumptions used for the fair values of employee stock options granted

	Three Months Ended September 30,				Nine Months Ended September 30,
	2014		2013		2014		2013
Expected stock price volatility	72	%	72	%	71 - 72	%	72	%
Expected option term	6.0 years		6.0 years		6.0 years		6.0 years
Risk-free interest rate	2.1 - 2.2	%	1.9 - 2.0	%	2.1 - 2.2	%	1.2 - 2.0	%
Expected dividend yield	None		None		None		None

Basis of Presentation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Basis of Presentation (Details) - USD ($) $ in Thousands	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Basis of Presentation
Cash, cash equivalents and marketable securities	$ 224,100		$ 224,100
Net Loss	$ (28,082)	$ (23,140)	(86,258)	$ (59,488)
Net cash used in operations			$ (79,323)	$ (52,712)

Net Loss Per Share (Details) - shares	3 Months Ended	9 Months Ended
Net Loss Per Share (Details) - shares	Sep. 30, 2014	Sep. 30, 2014
Anti-dilutive securities
Potentially dilutive common shares that have not been included in the net loss per common share calculations because the effect would have been anti-dilutive	7,008,421	6,086,377
Stock options
Anti-dilutive securities
Potentially dilutive common shares that have not been included in the net loss per common share calculations because the effect would have been anti-dilutive	6,999,421	6,077,377
Restricted stock
Anti-dilutive securities
Potentially dilutive common shares that have not been included in the net loss per common share calculations because the effect would have been anti-dilutive	9,000	9,000

Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Comprehensive Loss (Details) - USD ($) $ in Thousands	Sep. 30, 2014	Sep. 30, 2014
Changes in accumulated other comprehensive income (loss) by component
Amounts reclassified from other comprehensive income	$ 0	$ 0
Balance at the beginning of the period	2,748	2,668
Other comprehensive income (loss) before reclassifications	(124)	(44)
Net current-period other comprehensive income	(124)	(44)
Balance at the end of the period	2,624	2,624
Unrealized Gain (Loss) on Marketable Securities, net of tax
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	163	82
Other comprehensive income (loss) before reclassifications	(121)	(40)
Net current-period other comprehensive income	(121)	(40)
Balance at the end of the period	42	42
Foreign Currency Items
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	2,585	2,586
Other comprehensive income (loss) before reclassifications	(3)	(4)
Net current-period other comprehensive income	(3)	(4)
Balance at the end of the period	$ 2,582	$ 2,582

- Definition

Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

+ References + Details

Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2014	Dec. 31, 2013
Fair value measurements
Assets transferred between the fair value measurement classifications	$ 0
Liabilities transferred between the fair value measurement classifications	0
Fair Value Measurements. \| Fair value
Fair value measurements
Money market funds and cash equivalents	27,995	$ 148,549
Marketable securities	191,553	133,581
Total financial assets at fair value	219,548	282,130
Fair Value Measurements. \| Level 2
Fair value measurements
Money market funds and cash equivalents	27,995	148,549
Marketable securities	191,553	133,581
Total financial assets at fair value	$ 219,548	$ 282,130

Marketable Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2014	Dec. 31, 2013
Amortized Cost
Amortized cost	$ 191,511	$ 133,499
Gross Unrealized Gains
Gross Unrealized Gains	132	104
Gross Unrealized Losses
Gross Unrealized Losses	(90)	(22)
Fair Value
Fair Value	191,553	133,581
Marketable securities considered to be other-than-temporarily impaired	0
Accrued interest included in marketable securities	1,200	900
U.S. government and municipal obligations
Amortized Cost
Maturing in one year or less	40,198	55,531
Maturing after one year through three years	30,293	18,234
Amortized cost	70,491	73,765
Gross Unrealized Gains
Maturing in one year or less	43	27
Maturing after one year through three years	67	56
Gross Unrealized Gains	110	83
Gross Unrealized Losses
Maturing in one year or less	(5)	(4)
Maturing after one year through three years	(9)	(4)
Gross Unrealized Losses	(14)	(8)
Fair Value
Maturing in one year or less	40,236	55,554
Maturing after one year through three years	30,351	18,286
Fair Value	70,587	73,840
Corporate debt securities
Amortized Cost
Maturing in one year or less	92,510	38,973
Maturing after one year through three years	28,510	20,761
Amortized cost	121,020	59,734
Gross Unrealized Gains
Maturing in one year or less	20	9
Maturing after one year through three years	2	12
Gross Unrealized Gains	22	21
Gross Unrealized Losses
Maturing in one year or less	(34)	(9)
Maturing after one year through three years	(42)	(5)
Gross Unrealized Losses	(76)	(14)
Fair Value
Maturing in one year or less	92,496	38,973
Maturing after one year through three years	28,470	20,768
Fair Value	$ 120,966	$ 59,741

Intangible Assets and Goodwill (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Intangible Assets and Goodwill
Goodwill	$ 8,965	$ 8,965
Finite-lived intangible asset
Accumulated Amortization	(5,536)	(4,776)
Total Intangible Assets
Cost of total intangible assets	27,596	27,596
Intangible Assets, Net (Excluding Goodwill)	$ 22,060	22,820
Amgen Amendment
Finite-lived intangible asset
Estimated Life	16 years
Cost	$ 14,500	14,500
Accumulated Amortization	(4,484)	(3,812)
Net	$ 10,016	10,688
Core Technology
Finite-lived intangible asset
Estimated Life	11 years
Cost	$ 1,296	1,296
Accumulated Amortization	(1,052)	(964)
Net	244	332
IPR&D
Indefinite-lived intangible assets:
Indefinite-lived intangible assets	$ 11,800	$ 11,800

Other Long-Term Liabilities (Details) - USD ($) $ in Thousands	1 Months Ended				9 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Other Long-Term Liabilities
Deferred Rent					$ 499		$ 419
Net Deferred Tax Liability related to IPR&D					4,661		4,661
Deferred Income from Sale of Tax Benefits					2,253		1,630
Deferred Revenue					5,457		1,168
Total					12,870		7,878
Less Current Portion					(2,191)		(928)
Long-Term Portion					$ 10,679		$ 6,950
Amount at which New Jersey tax benefit agreed to be sold	$ 1,100	$ 800	$ 800	$ 600
Amount of sale of New Jersey tax benefit	$ 1,000	$ 800	$ 700	$ 500
Period for which base of operations must be maintained					5 years
Other income related to sale of tax benefits					$ 400	$ 200

Other Long-Term Liabilities (Details 2) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended
	May 31, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
REVENUE
Contracts and Grants			$ 817	$ 940	$ 1,591	$ 1,040
Rockefeller Development Services Agreement
REVENUE
Approved project plan for the development services		$ 4,800
Term of the agreement		3 years
Upfront payment recognized as revenue over the term of the agreement		$ 1,300
Contracts and Grants			800	$ 900	1,500	$ 900
Collaborative Arrangement
REVENUE
Term of the agreement	5 years
Upfront payment recognized as revenue over the term of the agreement	$ 5,000
Contracts and Grants			$ 300		$ 400
Reimbursement of external costs incurred by the company (as a percent)	50.00%

Stockholders' Equity (Details) - USD ($) $ in Thousands	1 Months Ended	9 Months Ended
Stockholders' Equity (Details) - USD ($) $ in Thousands	Oct. 31, 2014	Sep. 30, 2013	Sep. 30, 2014	Dec. 31, 2013
Stockholders' Equity
Common stock issued (in shares)		13,800,000
Net proceeds from sale of common stock		$ 114,187
Net proceeds from sale of stock in an underwritten public offering		$ 97,000
Shares common stock issued in connection with supply agreement			89,436,933	89,246,832
Biosyn Corporation \| Subsequent event
Stockholders' Equity
Shares issued for services	$ 2,000
Shares common stock issued in connection with supply agreement	152,172
Cantor Amendment
Stockholders' Equity
Common stock issued (in shares)		2,433,608
Net proceeds from sale of common stock		$ 17,100

Stock-Based Compensation (Details) - Stock options - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Shares
Options Outstanding at beginning of the period (in shares)	5,770,544
Granted (in shares)	1,405,350
Exercised (in shares)	(167,303)
Canceled (in shares)	(9,170)
Options Outstanding at the end of the period (in shares)	6,999,421	5,770,544
Options Vested and Expected to Vest at the end of the period (in shares)	6,937,665
Options Exercisable at the end of the period (in shares)	3,878,159
Shares Available for Grant under the 2008 Plan (in shares)	694,762
Weighted Average Exercise Price Per Share
Options Outstanding at beginning of the period (in dollars per share)	$ 8.17
Granted (in dollars per share)	13.65
Exercised (in dollars per share)	6.04
Canceled (in dollars per share)	10.70
Options Outstanding at the end of the period (in dollars per share)	9.32	$ 8.17
Options Vested and Expected to Vest at the end of the period (in dollars per share)	9.28
Options Exercisable at the end of the period (in dollars per share)	$ 6.92
Weighted Average Remaining Contractual Term
SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	7 years	7 years
SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	7 years	7 years
Options Vested and Expected to Vest at the end of the period	7 years
Options Exercisable at the end of the period	5 years 4 months 24 days
Additional information
Weighted average grant-date fair value (in dollars per share)	$ 8.81

Stock-Based Compensation (Details 2) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Valuation and Expenses Information
Total stock-based compensation expense (in dollars)	$ 1,958	$ 2,016	$ 4,719	$ 3,400
Stock options
Assumptions used for fair values of employee and director stock options granted
Expected stock price volatility (as a percent)	72.00%	72.00%		72.00%
Expected stock price volatility, minimum (as a percent)			71.00%
Expected stock price volatility, maximum (as a percent)			72.00%
Expected option term	6 years	6 years	6 years	6 years
Risk-free interest rate, minimum (as a percent)	2.10%	1.90%	2.10%	1.20%
Risk-free interest rate, maximum (as a percent)	2.20%	2.00%	2.20%	2.00%
Expected dividend yield (as a percent)	0.00%	0.00%	0.00%	0.00%
Research and development
Valuation and Expenses Information
Total stock-based compensation expense (in dollars)	$ 977	$ 1,326	$ 2,315	$ 2,190
General and administrative
Valuation and Expenses Information
Total stock-based compensation expense (in dollars)	$ 981	$ 690	$ 2,404	$ 1,210

Income Taxes (Details)	Sep. 30, 2014 item
Income Taxes
Number of states in which the entity primarily operates or has operated and has income tax nexus	3