Document and Entity Information (USD $)	12 Months Ended
Document and Entity Information (USD $)	Dec. 31, 2013	Feb. 28, 2014
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2013
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	FY
Entity Registrant Name	MACROGENICS INC
Entity Central Index Key	0001125345
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		27,471,329
Entity Public Float		$ 698,022,185

Consolidated Balance Sheets (USD $)	Dec. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 116,481,409	$ 47,743,155
Accounts receivable	2,004,019	2,046,219
Prepaid expenses	971,705	137,634
Total current assets	119,457,133	49,927,008
Restricted cash	404,850	404,850
Property and equipment, net	5,035,232	3,267,796
Other assets	885,166	147,246
Total assets	125,782,381	53,746,900
Current liabilities:
Accounts payable	3,169,034	3,739,125
Accrued expenses	3,583,552	1,237,025
Lease exit liability-current	1,438,742	628,768
Deferred revenue-current	20,267,323	24,123,176
Other liabilities-current	362,920
Total current liabilities	28,821,571	29,728,094
Lease exit liability, net of current portion	8,006,428	9,445,171
Deferred rent liability	2,904,227	2,801,653
Preferred stock warrant liability		52,947
Deferred revenue, net of current portion	7,135,687	19,956,343
Total liabilities	46,867,913	61,984,208
Stockholders' equity (deficit):
Common stock, $0.01 par value-125,000,000 shares authorized and 25,177,597 shares outstanding at December 31, 2013; 425,000,000 shares authorized and 1,098,914 shares outstanding at December 31, 2012	251,775	10,989
Treasury stock, at cost; 14,381 shares at December 31, 2013 and December 31, 2012	(57,742)	(57,742)
Additional paid-in capital	254,453,673	164,334,646
Accumulated deficit	(175,733,238)	(175,472,403)
Total stockholders' equity (deficit)	78,914,468	(8,237,308)
Total liabilities and stockholders' equity (deficit)	125,782,381	53,746,900
Series A-1 Convertible Preferred Stock [Member]
Stockholders' equity (deficit):
Convertible preferred stock		268,748
Series A-2 Convertible Preferred Stock [Member]
Stockholders' equity (deficit):
Convertible preferred stock		73,646
Series B Convertible Preferred Stock [Member]
Stockholders' equity (deficit):
Convertible preferred stock		714,012
Series C Convertible Preferred Stock [Member]
Stockholders' equity (deficit):
Convertible preferred stock		1,109,522
Series D-1 Convertible Preferred Stock [Member]
Stockholders' equity (deficit):
Convertible preferred stock		144,462
Series D-2 Convertible Preferred Stock [Member]
Stockholders' equity (deficit):
Convertible preferred stock		$ 636,812

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	125,000,000	425,000,000
Common stock, shares outstanding	25,177,597	1,098,914
Treasury stock, shares	14,381	14,381
Series A-1 Convertible Preferred Stock [Member]
Convertible preferred stock, par value		$ 0.01
Convertible preferred stock, shares authorized		26,874,792
Convertible preferred stock, shares issued		26,874,792
Convertible preferred stock, shares outstanding		26,874,792
Aggregate liquidation preference		$ 27,000,000
Series A-2 Convertible Preferred Stock [Member]
Convertible preferred stock, par value		$ 0.01
Convertible preferred stock, shares authorized		7,364,582
Convertible preferred stock, shares issued		7,364,582
Convertible preferred stock, shares outstanding		7,364,582
Aggregate liquidation preference		7,000,000
Series B Convertible Preferred Stock [Member]
Convertible preferred stock, par value		$ 0.01
Convertible preferred stock, shares authorized		71,401,237
Convertible preferred stock, shares issued		71,401,237
Convertible preferred stock, shares outstanding		71,401,237
Aggregate liquidation preference		31,000,000
Series C Convertible Preferred Stock [Member]
Convertible preferred stock, par value		$ 0.01
Convertible preferred stock, shares authorized		110,952,217
Convertible preferred stock, shares issued		110,952,217
Convertible preferred stock, shares outstanding		110,952,217
Aggregate liquidation preference		45,000,000
Series D-1 Convertible Preferred Stock [Member]
Convertible preferred stock, par value		$ 0.01
Convertible preferred stock, shares authorized		30,000,000
Convertible preferred stock, shares issued		14,446,227
Convertible preferred stock, shares outstanding		14,446,227
Aggregate liquidation preference		9,400,000
Series D-2 Convertible Preferred Stock [Member]
Convertible preferred stock, par value		$ 0.01
Convertible preferred stock, shares authorized		75,000,000
Convertible preferred stock, shares issued		63,681,176
Convertible preferred stock, shares outstanding		63,681,176
Aggregate liquidation preference		$ 41,500,000

Consolidated Statements of Operations and Comprehensive Income (Loss) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues:
Revenue from collaborative research	$ 56,753,123	$ 59,645,819	$ 47,054,397
Grant revenue	1,281,545	4,180,279	10,152,969
Total revenues	58,034,668	63,826,098	57,207,366
Costs and expenses:
Research and development	46,581,930	45,432,894	41,088,899
General and administrative	11,086,759	10,187,894	10,868,791
Total costs and expenses	57,668,689	55,620,788	51,957,690
Income (loss) from operations	365,979	8,205,310	5,249,676
Other income (expense)	(626,814)	156,445	1,467,444
Net comprehensive income (loss)	$ (260,835)	$ 8,361,755	$ 6,717,120
Basic net income (loss) per common share	$ (0.04)	$ 0.00	$ 0.00
Diluted net income (loss) per common share	$ (0.04)	$ 0.00	$ 0.00
Basic weighted average number of common shares	6,847,697	1,083,276	1,025,602
Diluted weighted average number of common shares	6,847,697	1,083,276	1,025,602

Consolidated Statements of Stockholders' Equity (USD $)	Total	Series A-1 Convertible Preferred Stock [Member]	Series A-2 Convertible Preferred Stock [Member]	Series B Convertible Preferred Stock [Member]	Series C Convertible Preferred Stock [Member]	Series D-1 Convertible Preferred Stock [Member]	Series D-2 Convertible Preferred Stock [Member]	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]
Beginning Balance at Dec. 31, 2010	$ (38,634,058)	$ 268,748	$ 73,646	$ 714,012	$ 1,109,522	$ 144,462	$ 452,538	$ 10,007	$ (57,742)	$ 149,202,027	$ (190,551,278)
Beginning Balance, Shares at Dec. 31, 2010		26,874,792	7,364,582	71,401,237	110,952,217	14,446,227	45,253,788	1,000,681	14,381
Share-based compensation	2,347,439									2,347,439
Issuance of common stock/convertible Series D-2 stock, net of offering costs	12,014,815						184,274			11,830,541
Issuance of common stock/convertible Series D-2 stock, net of offering costs, Shares							18,427,388
Stock option exercises	70,400							483		69,917
Stock option exercises, Shares	49,883							48,349
Net income (loss)	6,717,120										6,717,120
Ending Balance at Dec. 31, 2011	(17,484,284)	268,748	73,646	714,012	1,109,522	144,462	636,812	10,490	(57,742)	163,449,924	(183,834,158)
Ending Balance, Shares at Dec. 31, 2011		26,874,792	7,364,582	71,401,237	110,952,217	14,446,227	63,681,176	1,049,030	14,381
Share-based compensation	838,395									838,395
Stock option exercises	46,826							499		46,327
Stock option exercises, Shares	863,176							49,884
Net income (loss)	8,361,755										8,361,755
Ending Balance at Dec. 31, 2012	(8,237,308)	268,748	73,646	714,012	1,109,522	144,462	636,812	10,989	(57,742)	164,334,646	(175,472,403)
Ending Balance, Shares at Dec. 31, 2012		26,874,792	7,364,582	71,401,237	110,952,217	14,446,227	63,681,176	1,098,914	14,381
Share-based compensation	862,162									862,162
Issuance of common stock/convertible Series D-2 stock, net of offering costs	83,622,358							57,500		83,564,858
Issuance of common stock/convertible Series D-2 stock, net of offering costs, Shares								5,750,000
Conversion of preferred stock to common stock	1,860,591	(268,748)	(73,646)	(714,012)	(1,109,522)	(144,462)	(636,812)	170,606		4,637,187
Conversion of preferred stock to common stock, Shares		(26,874,792)	(7,364,582)	(71,401,237)	(110,952,217)	(14,446,227)	(63,681,176)	17,060,634
Stock option exercises	1,067,500							12,680		1,054,820
Stock option exercises, Shares	1,268,049							1,268,049
Net income (loss)	(260,835)										(260,835)
Ending Balance at Dec. 31, 2013	$ 78,914,468							$ 251,775	$ (57,742)	$ 254,453,673	$ (175,733,238)
Ending Balance, Shares at Dec. 31, 2013								25,177,597	14,381

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
Consolidated Statements of Cash Flows (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating activities
Net income (loss)	$ (260,835)	$ 8,361,755	$ 6,717,120
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation expense	1,193,340	959,930	1,147,300
Share-based compensation	862,162	838,395	2,347,439
Fair value adjustment of warrant liability	626,349	(150,695)	(1,459,435)
Changes in operating assets and liabilities:
Accounts receivable	42,200	1,351,650	12,551,066
Prepaid expenses	(834,071)	(91,160)	76,876
Restricted cash		177,321	(513)
Other assets	(375,000)	780	(133,782)
Accounts payable	(570,091)	(7,312,331)	(10,271,048)
Accrued expenses	2,346,527	185,200	272,988
Lease exit liability	(628,769)	(533,560)	(447,019)
Deferred revenue	(16,676,509)	(10,810,089)	(4,275,976)
Deferred rent	102,574	440,815	232,324
Net cash (used in) provided by operating activities	(14,172,123)	(6,581,989)	6,757,340
Cash flows from investing activities
Purchases of property and equipment	(2,960,776)	(940,043)	(500,213)
Net cash used in investing activities	(2,960,776)	(940,043)	(500,213)
Cash flows from financing activities
Proceeds from issuance of preferred stock			12,014,816
Proceeds from issuance of common stock, net of offering costs	85,871,153	46,826	70,400
Net cash provided by financing activities	85,871,153	46,826	12,085,216
Net change in cash and cash equivalents	68,738,254	(7,475,206)	18,342,343
Cash and cash equivalents at beginning of period	47,743,155	55,218,361	36,876,018
Cash and cash equivalents at end of period	116,481,409	47,743,155	55,218,361
Noncash financing activities:
Conversion of preferred stock	$ 2,947,202

Organization and Nature of Operations	12 Months Ended
Organization and Nature of Operations	Dec. 31, 2013
Accounting Policies [Abstract]
Organization and Nature of Operations	1. Organization and Nature of Operations MacroGenics, Inc. (the “Company”) was incorporated in Delaware on August 14, 2000. The Company is a clinical-stage biopharmaceutical company focused on discovering and developing innovative monoclonal antibody-based therapeutics for the treatment of cancer and autoimmune diseases. The Company generates its pipeline of product candidates from its proprietary suite of next-generation antibody technology platforms which it believes improve the performance of monoclonal antibodies and antibody-derived molecules. These product candidates, which the Company has identified through its understanding of disease biology and immune-mediated mechanisms, may address disease-specific challenges which are not currently being met by existing therapies. The Company creates both differentiated molecules that are directed to novel cancer targets, as well as “bio-betters” which are drugs designed to improve upon marketed medicines. On October 16, 2013, the Company completed an initial public offering (“IPO”) of its common stock, which resulted in the sale of 5,750,000 shares, including all additional shares available to cover over-allotments, at a price of $16.00 per share. The Company received net proceeds before expenses from the IPO of $85.6 million after deducting underwriting discounts and commissions paid by the Company.

- Definition

The entire disclosure for organization, consolidation and basis of presentation of financial statements disclosure.

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+ Details

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2013

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Basis of Presentation and Principles of Consolidation

The consolidated financial statements include the accounts of MacroGenics, Inc. and its wholly owned subsidiary, MacroGenics West, Inc. All intercompany accounts and transactions have been eliminated in consolidation. The Company currently operates in one operating segment. Operating segments are defined as components of an enterprise about which separate discrete information is available for the chief operating decision maker, or decision making group, in deciding how to allocate resources and assessing performance. The Company views its operations and manages its business in one segment, which is developing monoclonal antibody-based therapeutics for cancer, autoimmune and infectious diseases.

Use of Estimates

The preparation of the financial statements in accordance with generally accepted accounting principles (“GAAP”) requires the Company to make estimates and judgments in certain circumstances that affect the reported amounts of assets, liabilities, revenues and expenses, and related disclosure of contingent assets and liabilities. In preparing these consolidated financial statements, management has made its best estimates and judgments of certain amounts included in the financial statements, giving due consideration to materiality. On an ongoing basis, the Company evaluates its estimates, including those related to revenue recognition, fair values of assets, convertible preferred stock and common stock, preferred stock warrant liability, income taxes, pre-clinical study and clinical trial accruals and other contingencies. Management bases its estimates on historical experience or on various other assumptions that it believes to be reasonable under the circumstances. Actual results could differ from these estimates.

In addition, prior to the Company’s IPO in October 2013, the Company utilized estimates and assumptions in determining the fair value of its common stock. The Company granted stock options at exercise prices not less than the fair value of its common stock as determined by the Board of Directors, with input from management. Management used contemporaneous valuations in estimating the fair value of its common stock. The board of directors determined the estimated fair value of the common stock based on a number of objective and subjective factors, including external market considerations affecting the biotechnology industry and the historic prices at which the Company sold shares of its preferred stock.

Cash and Cash Equivalents

The Company considers all investments in highly liquid financial instruments with an original maturity of three months or less at the date of purchase to be cash equivalents. Cash and cash equivalents consist of certificates of deposit and investments in money market funds with commercial banks and financial institutions. Cash equivalents are stated at amortized cost, plus accrued interest, which approximates fair value.

Accounts Receivable

Accounts receivable that management has the intent and ability to collect are reported in the consolidated balance sheets at outstanding amounts, less an allowance for doubtful accounts. The Company writes off uncollectible receivables when the likelihood of collection is remote.

The Company evaluates the collectability of accounts receivable on a regular basis. The allowance, if any, is based upon various factors including the financial condition and payment history of customers, an overall review of collections experience on other accounts and economic factors or events expected to affect future collections experience. No allowance was recorded as of December 31, 2013 or 2012, as the Company has a history of collecting on all outstanding accounts.

Restricted Cash

The Company is required to maintain certificates of deposit that serve as collateral for various operating leases and corporate credit card accounts. Amounts classified as restricted cash on the consolidated balance sheets are $404,850 at December 31, 2013 and 2012.

Fair Value of Financial Instruments

The fair market values of the financial instruments included in the financial statements, which include cash equivalents and money market accounts, approximate their carrying values at December 31, 2013 and 2012, due to their short-term maturities. The Company accounts for recurring and non-recurring fair value measurements in accordance with the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 820, Fair Value Measurements and Disclosures (“ASC 820”). ASC 820 defines fair value, establishes a fair value hierarchy for assets and liabilities measured at fair value, and requires expanded disclosures about fair value measurements. The ASC 820 hierarchy ranks the quality of reliability of inputs, or assumptions, used in the determination of fair value and requires assets and liabilities carried at fair value to be classified and disclosed in one of the following three categories:

•

Level 1—Fair value is determined by using unadjusted quoted prices that are available in active markets for identical assets and liabilities.

•

Level 2—Fair value is determined by using inputs other than Level 1 quoted prices that are directly or indirectly observable. Inputs can include quoted prices for similar assets and liabilities in active markets or quoted prices for identical assets and liabilities in inactive markets. Related inputs can also include those used in valuation or other pricing models, such as interest rates and yield curves that can be corroborated by observable market data.

•

Level 3—Fair value is determined by inputs that are unobservable and not corroborated by market data. Use of these inputs involves significant and subjective judgments to be made by a reporting entity – e.g., determining an appropriate adjustment to a discount factor for illiquidity associated with a given security.

The Company evaluates financial assets and liabilities subject to fair value measurements on a recurring basis to determine the appropriate level at which to classify them each reporting period. This determination requires the Company to make subjective judgments as to the significance of inputs used in determining fair value and where such inputs lie within the ASC 820 hierarchy.

Financial assets and liabilities subject to fair value measurements were as follows:


	Fair Value Measurements at December 31, 2013
				Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	Total			Level 1		Level 2		Level 3
Assets:
Cash and cash equivalents	$	90,434,435		$	90,434,435	$	—	$	—
Money market funds		26,046,974			26,046,974		—		—
Restricted cash		404,850			404,850		—		—

Total Assets	$	116,886,259		$	116,886,259	$	—	$	—


	Fair Value Measurements at December 31, 2012
				Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	Total			Level 1		Level 2		Level 3
Assets:
Cash and cash equivalents	$	18,695,197		$	18,695,197	$	—	$	—
Money market funds		29,047,958			29,047,958		—		—
Restricted cash		404,850			404,850		—		—

Total Assets	$	48,148,005		$	48,148,005	$	—	$	—

Liabilities:
Preferred stock warrant liability	$	(52,947	)	$	—	$	—	$	(52,947	)

As of December 31, 2012, the Company transferred its money market funds from Level 2 to Level 1 because the inputs are now based upon a quoted market price.

The Company’s Level 1 securities primarily consist of restricted cash, cash equivalents and money market funds. The Company determines the estimated fair value for its Level 1 securities using quoted (unadjusted) prices for identical assets or liabilities in active markets.

The Company determines the estimated fair value for its Level 2 securities using the following methods: quoted prices for similar assets/liabilities in active markets, inputs other than quoted prices that are observable for the asset/liability (e.g., interest rates, yield curves volatilities, default rates, etc.) and inputs that are derived principally from or corroborated by other observable market data.

The following table provides a rollforward of the Company’s preferred stock warrant liability, which was the only financial instrument measured at fair value on a recurring basis using significant unobservable inputs (Level 3) as defined in ASC 820:


Balance at December 31, 2012	$	(52,947	)
Total unrealized gains (losses) included in earnings		(626,349	)
Settlement of preferred stock warrants		679,296

Balance at December 31, 2013	$	—

In order to estimate the fair value of the preferred stock purchase warrants, the business enterprise value was established based on a discounted cash flow model (income approach). The Company utilized an option pricing method to value the shares using a contingent claims analysis, which applies a series of call options whose inputs reflect the liquidation preferences and conversion behavior of the different classes of equity. After the equity value of the business enterprise was determined, the total equity value is allocated to the various equity instruments such as preferred stock, stock options and preferred stock purchase warrants. Key management estimates relate to the time period to liquidation and conversion behavior of a particular class of stockholders. The business enterprise value includes assumptions related to product approval, market penetration and costs to develop the product. Significant changes to these assumptions would result in increases/decreases to the fair value of the outstanding warrants.

The total unrealized gains (losses) on the preferred stock warrants included in earnings is included as a component of other income (expense) in the consolidated statement of operations and comprehensive income. Immediately prior to the Company’s IPO in October 2013, all the preferred stock warrants were exercised and converted into shares of Series D-2 preferred stock, which were subsequently converted to common stock.

Concentration of Credit Risk

Substantially all of the Company’s cash and cash equivalents are maintained with major financial institutions in the United States. Deposits held with banks may exceed the amount of insurance provided on such deposits. Generally, these deposits may be redeemed upon demand and, therefore, bear minimal risk.

Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash and cash equivalents, and accounts receivable. The counterparties are various corporations, financial institutions and government agencies of high credit standing.

For the years ended December 31, 2013, 2012 and 2011, all of the Company’s grant revenue was related to contracts and research grants received from U.S. government agencies. Collaborations with Les Laboratoires Servier and Institut de Recherches Servier (collectively, “Servier”), Boehringer Ingelheim GmbH (“Boehringer”), Gilead Sciences, Inc. (“Gilead”), Pfizer, Inc. (“Pfizer”) and Eli Lilly & Co. (“Eli Lilly”) account for all other revenue. All outstanding receivables are due from the Company’s collaborators and U.S. government agencies.

The following table represents the percentage of all significant revenue earned in the periods indicated:


	Year Ended December 31,
	2013			2012			2011
Servier		51.6	%		17.3	%		—
Boehringer		24.8	%		18.4	%		15.6	%
Gilead		13.8	%		—			—
Pfizer		6.0	%		8.7	%		10.8	%
Government Agencies		2.2	%		6.5	%		17.7	%
Eli Lilly		1.4	%		48.9	%		54.0	%

The following table represents the percentage of all significant accounts receivable:


	December 31,
	2013			2012
Gilead		53.4	%		—
Pfizer.		12.3	%		45.4	%
Boehringer		12.2	%		18.0	%
Eli Lilly		7.0	%		28.2	%
Servier		6.4	%		—
Government Agencies		4.6	%		8.4	%

Property and Equipment

Property and equipment are stated at cost. Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is credited or charged to operations. Repairs and maintenance costs are expensed as incurred. Depreciation is computed using the straight-line method over the following estimated useful lives:


Computer equipment		3 years
Software		3 years
Furniture		10 years
Laboratory and office equipment		5 years
Leasehold improvements		Shorter of lease term or useful life

Impairment of Long-Lived Assets

The Company assesses the recoverability of its long-lived assets in accordance with the provisions of ASC 360, Property, Plant and Equipment. ASC 360 requires that long-lived assets be reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of the long-lived asset is measured by a comparison of the carrying amount of the asset to future undiscounted net cash flows expected to be generated by the asset or asset group. If carrying value exceeds the sum of undiscounted cash flows, the Company then determines the fair value of the underlying asset group. Any impairment to be recognized is measured by the amount by which the carrying amount of the asset group exceeds the estimated fair value of the asset group. Assets to be disposed of are reported at the lower of the carrying amount or fair value, less costs to sell. As of December 31, 2013 and 2012, the Company determined that there were no impaired assets and had no assets held-for-sale.

Income Taxes

Deferred tax assets and liabilities are determined based on differences between the financial reporting and tax basis of assets and liabilities and are measured using the enacted tax rates and laws that are expected to be in effect when the differences are expected to reverse. The effect on deferred tax assets and liabilities of a change in tax rates is recognized as income in the period that such tax rate changes are enacted. The measurement of a deferred tax asset is reduced, if necessary, by a valuation allowance if it is more likely than not that some portion or all of the deferred tax asset will not be realized. Financial statement recognition of a tax position taken or expected to be taken in a tax return is determined based on a more-likely-than-not threshold of that position being sustained. If the tax position meets this threshold, the benefit to be recognized is measured as the largest amount that is more than 50% likely to be realized upon ultimate settlement. The Company’s policy is to record interest and penalties related to uncertain tax positions as a component of income tax expense.

Revenues

Revenue Recognition

The Company enters into collaboration and license agreements with collaborators for the development of monoclonal antibody-based therapeutics to treat cancer and other complex diseases. The terms of these agreements contain multiple deliverables which may include (i) licenses, or options to obtain licenses, to the Company’s technological platforms, such as its Fc Optimization and Dual-Affinity Re-Targeting (“DART”) technologies, (ii) rights to future technological improvements, (iii) research and development activities to be performed on behalf of the collaborator or as part of the collaboration, and (iv) the manufacture of pre-clinical or clinical materials for the collaborator. Payments to the Company under these agreements may include nonrefundable license fees, option fees, exercise fees, payments for research and development activities, payments for the manufacture of pre-clinical or clinical materials, license maintenance payments, payments based upon the achievement of certain milestones and royalties on product sales. Other benefits to the Company of these agreements include the right to sell products resulting from the collaborative efforts of the parties in specific geographic territories. The Company follows the provisions of the FASB 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 the achievement of certain criteria, 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.

For the periods presented, the Company had the following two types of agreements with the parties identified below: 1) exclusive development and commercialization licenses to use the Company’s technology and/or certain other intellectual property to develop compounds against specified targets (referred to herein as exclusive licenses); and 2) Option/research agreements to secure on established terms, development and commercialization licenses to anticancer and other therapeutic product candidates to collaborator selected targets developed by the Company during an option period (referred to herein as right-to-develop agreements).

There are no performance, cancellation, termination or refund provisions in any of the arrangements that contain material financial consequences to the Company.

Exclusive Licenses

The deliverables under an exclusive license agreement generally include the exclusive license to the Company’s DART technology with respect to a specified antigen target, and may also include deliverables related to rights to future technological improvements, research and pre-clinical development activities to be performed on behalf of the collaborator. In some cases the Company may have an option to participate in the co-development of product candidates that result from such agreements.

Generally, exclusive license agreements contain nonrefundable terms for payments and, depending on the terms of the agreement, provide that the Company will (i) at the collaborator’s request, provide research and pre-clinical development services at negotiated prices which are generally consistent with what other third parties would charge, (ii) earn payments upon the achievement of certain milestones, (iii) earn royalty payments, and (iv) in some cases grant the Company an option to participate in the development and commercialization of products that result from such agreements. Royalty rates may vary over the royalty term depending on the Company’s intellectual property rights and whether the Company exercises any co-development and co-commercialization 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 any collaborator will achieve milestones or become liable for royalty payments.

In determining the units of accounting, management evaluates whether the exclusive license has stand-alone value from the undelivered elements to the collaborator based on the consideration of the relevant facts and circumstances for each arrangement. Factors considered in this determination include the research and development capabilities of the partner and the availability of technology platform and product 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 collaboration agreements, recent pre-clinical and clinical testing results of therapeutic product candidates that use the Company’s technology platforms, 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 exclusive 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 January 1, 2011, the Company determined that its licenses lacked stand-alone value because it did not have vendor-specific objective evidence of selling price (“VSOE”), 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. In making the determination of the length of the period over which to defer revenue for contracts entered into prior to the adoption of ASU No. 2009-13, significant judgment and estimation is used by the Company 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. 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 the Company’s substantial involvement. ASU No. 2009-13 amends the criteria for separating and allocating consideration in a multiple element arrangement by modifying the fair value requirements for revenue recognition and eliminating the use of the residual value method. The selling prices of deliverables under an arrangement may be derived using third-party evidence (“TPE”), or a best estimate of selling price (“BESP”), if VSOE is not available. The objective of BESP is to determine the price at which the Company would transact a sale if the element within the license agreement was sold on a standalone basis. Establishing BESP involves management’s judgment and considers multiple factors, including market conditions and company-specific factors, including those factors contemplated in negotiating the agreements, as well as internally developed models that include assumptions related to market opportunity, discounted cash flows, estimated development costs, probability of success and the time needed to commercialize a product candidate pursuant to the license. In validating the BESP, management considers whether changes in key assumptions used to determine the BESP will have a significant effect on the allocation of the arrangement consideration between the multiple deliverables. Deliverables under the arrangement are separate units of accounting if (i) the delivered item has value to the customer on a standalone basis and (ii) if the arrangement includes a general right of return relative to the delivered item, delivery or performance of the undelivered item is considered probable and substantially within the Company’s control. The arrangement consideration that is fixed or determinable at the inception of the arrangement is allocated to the separate units of accounting based on their relative selling prices. The appropriate revenue recognition model is applied to each element and revenue is accordingly recognized as each element is delivered. Management exercises significant judgment in determining whether a deliverable is a separate unit of accounting.

In determining the separate units of accounting, the Company evaluated whether the exclusive license had standalone value to the collaborator based on consideration of the relevant facts and circumstances for each arrangement. Factors considered in this determination included the research and development capabilities of the collaborator and the availability of relevant research expertise in the marketplace. In addition, the Company considered whether or not (i) the collaborator could use the license for its intended purpose without the receipt of the remaining deliverables, (ii) the value of the license was dependent on the undelivered items and (iii) the collaborator or other vendors could provide the undelivered items.

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 single target 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 pre-clinical activity on another product candidate and its remaining period of substantial involvement can be estimated. In the event that a single target 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 or through the remaining substantial involvement in the wind down of the agreement.

Upfront payments on exclusive 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 and the manufacture of pre-clinical and clinical materials.

The Company recognizes revenue related to research and pre-clinical development 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 typically performs research activities and pre-clinical development services, including generating and engineering product candidates, on behalf of its licensees during the early evaluation and pre-clinical testing stages of drug development under its exclusive licenses. The Company records amounts received for research materials produced or services performed as revenue from collaborative research.

The Company’s 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 initiates 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 (“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 the Company does 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.

Right-to-Develop Agreements

The Company’s right-to-develop agreements provide collaborators with an exclusive option to obtain licenses to develop and commercialize in specified geographic territories product candidates developed by the Company under agreed upon research and pre-clinical development product programs. The product candidates resulting from each program are all directed to a specific target selected by the collaborator. 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) the selection of a target for a program, (iii) upon the exercise of an option to acquire a development and commercialization license (referred to as exercise fees or payments earned) for a program, or (iv) some combination of all of these fees.

The accounting for right-to-develop agreements is dependent on the nature of the options granted to the collaborator. Options are considered substantive if, at the inception of a right-to-develop agreement, the Company is at risk as to whether the collaborator 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 imposed on the collaborator as a result of exercising the options.

For right-to-develop agreements where the options to secure development and commercialization licenses to a product program 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-develop 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 exercise options for development and commercialization licenses. These periods are specific to each collaboration agreement. If a collaborator selects a target for a product program, any substantive option fee is deferred and recognized over the life of the option, generally 12 months. Subsequent to the adoption of ASU No. 2009-13, the Company’s evaluation of whether the option is substantive is consistent with pre-adoption of ASU No. 2009-13. How the Company determines the selling price of the option is the only difference between pre and post adoption of ASU No. 2009-13. Post adoption of ASU No. 2009-13, the selling prices of deliverables under an arrangement may be derived using TPE or a BESP, if VSOE is not available. The objective of BESP is to determine the price at which the Company would transact a sale if the element within the right-to-develop agreement was sold on a standalone basis. Establishing BESP involves management’s judgment and considers multiple factors, including market conditions and company-specific factors, including those factors contemplated in negotiating the agreements, as well as internally developed models that include assumptions related to market opportunity, discounted cash flows, estimated development costs, probability of success and the time needed to commercialize a product candidate pursuant to the right-to-develop agreement. In validating the BESP, management considers whether changes in key assumptions used to determine the BESP will have a significant effect on the allocation of the arrangement consideration between the multiple deliverables. Deliverables under the arrangement are separate units of accounting if (i) the delivered item has value to the customer on a standalone basis and (ii) if the arrangement includes a general right of return relative to the delivered item, delivery or performance of the undelivered item is considered probable and substantially within the Company’s control. The arrangement consideration that is fixed or determinable at the inception of the arrangement is allocated to the separate units of accounting based on their relative selling prices. The appropriate revenue recognition model is applied to each element and revenue is accordingly recognized as each element is delivered. Management exercises significant judgment in determining whether a deliverable is a separate unit of accounting.

If a collaborator exercises an option and acquires a development and commercialization license to a product program, the Company attributes the exercise fee to the development and commercialization license. The Company determines the selling price of the option license, upon exercise, through management’s best estimate. Management’s determination of selling price includes such factors as stage of development, market potential and cash flow models used during the negotiation with the collaborator. Through December 31, 2013, none of our collaboration partners had exercised an option. However, one of our collaboration partners did elect to exercise an option in February 2014. See Note 13 for additional information.

Upon exercise of an option to acquire a development and commercialization license, the Company would also attribute any remaining deferred option fee, in addition to the consideration received for the license upon exercise of the option, to the development and commercialization license. The Company then applies the multiple-element revenue recognition criteria to the development and commercialization license and other deliverables, if any, to determine the appropriate revenue recognition method. This model is consistent with the Company’s accounting policy for upfront payments on exclusive licenses (discussed above). In the event a right-to-develop 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. The Company’s right-to-develop agreements have been determined to contain substantive options.

For right-to-develop agreements where the options to secure development and commercialization licenses to product programs 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. The Company does not directly control when any collaborator will exercise its options for development and commercialization licenses.

Research and Development Costs

Research and development expenditures are expensed as incurred. Research and development costs primarily consist of employee related expenses, including salaries and benefits, expenses incurred under agreements with contract research organizations, investigative sites and consultants that conduct the Company’s clinical trials, the cost of acquiring and manufacturing clinical trial materials and other allocated expenses, license fees for and milestone payments related to in-licensed products and technologies, stock-based compensation expense, and costs associated with non-clinical activities and regulatory approvals.

Comprehensive Income (Loss)

Effective January 1, 2012, the Company adopted ASU 2011-05, Presentation of Comprehensive Income, which amended ASC Topic 220, Comprehensive Income (“ASU 2011-05”). The amendments in ASU 2011-05 require the presentation of the comprehensive income (loss) and its components as part of the consolidated financial statements. Comprehensive income (loss) is comprised of the net income (loss) and other changes in equity that are excluded from net income (loss). Comprehensive income (loss) equals net income (loss) for the years ended December 31, 2013, 2012 and 2011.

Stock-based Compensation

Stock-based payments are accounted for in accordance with the provisions of ASC 718, Compensation – Stock Compensation. The fair value of stock-based payments is estimated, on the date of grant, using the Black-Scholes model. The resulting fair value is recognized ratably over the requisite service period, which is generally the vesting period of the option.

For all time-vesting awards granted, expense is amortized using the straight-line attribution method. For awards that contain a performance condition, expense is amortized using the accelerated attribution method. Recognition of stock-based compensation expense is based on the value of the portion of stock-based awards that is ultimately expected to vest during the period.

The Company utilizes the Black-Scholes model for estimating fair value of its stock options granted. Option valuation models, including the Black-Scholes model, require the input of highly subjective assumptions, and changes in the assumptions used can materially affect the grant-date fair value of an award. These assumptions include the risk-free rate of interest, expected dividend yield, expected volatility and the expected life of the award.

Net Income (Loss) Per Share

Basic income (loss) per common share is determined by dividing income (loss) attributable to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration of common stock equivalents. Diluted income (loss) per share is computed by dividing the earnings (loss) attributable to common stockholders by the weighted-average number of common share equivalents outstanding for the period. The treasury stock method is used to determine the dilutive effect of the Company’s stock option grants, potential Employee Stock Purchase Plan awards and warrants and the if-converted method is used to determine the dilutive effect of the Company’s preferred stock.

Prior to the Company’s initial public offering, net income (loss) per share was calculated under the two-class method under which all earnings (distributed and undistributed) are allocated to each class of common stock and participating securities based on their respective rights to receive dividends. In the event that the Board of Directors declared a dividend payable in cash or other property on the then-outstanding shares of common stock, the holders of the Series A-1, A-2, B, C, D, and D-2 convertible preferred stock would be entitled to receive the amount of dividends per share of preferred stock that would be payable on the largest number of whole shares of common stock into which each share of preferred stock could then be converted. Therefore, the Series A-1, A-2, B, C, D and D-2 are participating securities. All of the outstanding shares of Series A-1, A-2, B, C, D, and D-2 convertible preferred stock converted to common stock upon the consummation of the Company’s IPO.

Basic and diluted income (loss) per common share is computed as follows:


	Year Ended December 31,
	2013			2012			2011
Net income (loss)	$	(260,835	)	$	8,361,755		$	6,717,120
Less: undistributed earnings allocated to participating securities		—			(8,361,755	)		(6,717,120	)

Net income (loss) allocable to common shares	$	(260,835	)	$	—		$	—

Basic weighted average common shares outstanding		6,847,697			1,083,276			1,025,602
Basic income (loss) per common share	$	(0.04	)	$	0.00		$	0.00
Net income (loss)	$	(260,835	)	$	8,361,755		$	6,717,120
Less: undistributed earnings allocated to participating securities and other add-backs to net income (loss)		—			(8,361,755	)		(6,717,120	)

Net income (loss) allocable to common shares	$	(260,835	)	$	—		$	—

Basic weighted average common shares outstanding		6,847,697			1,083,276			1,025,602
Effect of dilutive securities		—			—			—

Diluted weighted average common shares outstanding		6,847,697			1,083,276			1,025,602

Diluted income (loss) per common share	$	(0.04	)	$	0.00		$	0.00

The following common stock equivalents were excluded from the calculation of diluted net income (loss) per share because their effect would be anti-dilutive:


	Year Ended December 31,
	2013		2012		2011
Series A-1 Preferred Stock		—		2,156,114		2,156,114
Series A-2 Preferred Stock		—		392,274		392,274
Series B Preferred Stock		—		4,336,037		4,336,037
Series C Preferred Stock		—		5,909,906		5,909,906
Series D Preferred Stock		—		769,468		769,468
Series D-2 Preferred Stock		—		3,391,991		3,391,991
Effect of Converted Preferred Stock		13,189,920		—		—
Warrants to purchase Series D-2 Preferred Stock		—		180,784		180,784
Stock Options		2,313,970		3,249,702		2,885,417

Recently Issued Accounting Standards Adopted

In July 2013, the FASB issued ASU No. 2013-11, which amended ASC Topic 740 regarding presentation of an unrecognized tax benefit when a net operating loss (“NOL”) carryforward, a similar tax loss, or a tax credit carryforward exists. The amendments in ASU No. 2013-11 require an entity to present an unrecognized tax benefit as a reduction of a deferred tax asset for an NOL carryforward, or similar tax loss or tax credit carryforward, rather than as a liability when (1) the uncertain tax position would reduce the NOL or other carryforward under the tax law of the applicable jurisdiction and (2) the entity intends to use the deferred tax asset for that purpose. The ASU does not require new recurring disclosures. This amendment is effective prospectively for fiscal years beginning after December 15, 2013. The Company does not believe this amendment will have a material impact on its financial statements.

The Company has evaluated all ASUs through the date the consolidated financials were issued and believes that the adoption of these will not have a material impact on the Company’s consolidated financial statements.

- Definition

The entire disclosure for all significant accounting policies of the reporting entity.

+ References+ Details

Property and Equipment

12 Months Ended

Dec. 31, 2013

Property Plant And Equipment [Abstract]

Property and Equipment

3. Property and Equipment

Property and equipment consists of the following:


	December 31,
	2013			2012
Computer equipment	$	2,379,254		$	2,003,706
Software		1,477,416			1,323,081
Furniture		599,650			599,650
Lab equipment		11,166,619			8,747,790
Office equipment		51,360			51,360
Leasehold improvements		4,893,770			4,881,706

Property and equipment		20,568,069			17,607,293
Less accumulated depreciation		(15,532,837	)		(14,339,497	)

Property and equipment, net	$	5,035,232		$	3,267,796

Depreciation expense for the years ended December 31, 2013, 2012 and 2011 was $1.2 million, $1.0 million and $1.1 million, respectively.

- Definition

The entire disclosure for long-lived, physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, accounting policies and methodology, roll forwards, depreciation, depletion and amortization expense, including composite depreciation, accumulated depreciation, depletion and amortization expense, useful lives and method used, income statement disclosures, assets held for sale and public utility disclosures.

+ References+ Details

Stockholders' Equity (Deficit)	12 Months Ended
Stockholders' Equity (Deficit)	Dec. 31, 2013
Equity [Abstract]
Stockholders' Equity (Deficit)	4. Stockholders’ Equity (Deficit) During 2002 and 2003, the Company issued a total of 34,239,374 shares of Series A-1 and Series A-2 convertible preferred stock (“Series A preferred stock”) for $1.00 per share resulting in net proceeds of approximately $34.0 million. On October 12, 2004, the Company entered into a series of transactions raising $30.3 million, net of related offering costs of approximately $238,000, from the sale of 71,401,237 shares of its Series B convertible preferred stock (“Series B preferred stock”). In connection with the Series B preferred stock offering, 13,604,016 shares of common stock were allocated to holders of Series A-1 preferred stock as an anti-dilution measure. On May 16, 2006, the Company raised $44.9 million, net of related offering costs of $101,246, from the sale of 110,952,217 shares of its Series C convertible preferred stock (“Series C preferred stock”). In connection with the Series C preferred stock offering, 10,003,300 shares of common stock were allocated to holders of Series B preferred stock as an anti-dilution measure. On July 16, 2008, the Company issued 12,466,039 shares of its Series D convertible preferred stock (“Series D preferred stock”) in exchange for all of the outstanding capital stock and convertible notes payable of Raven Biotechnologies, Inc. (“Raven”). Subsequently, in March 2011 a settlement was reached with the former Raven stockholders bringing the total Series D preferred stock issued in connection with the Raven acquisition to 14,446,227 shares. On September 19, 2008, the Company raised $24.8 million, net of related offering costs of $156,788, from the sale of 38,337,678 shares of its Series D-2 convertible preferred stock (“Series D-2 preferred stock”). The Company also issued preferred stock warrants for the purchase of 2,875,327 shares of Series D-2 preferred stock. The preferred stock warrants were exercisable at any time prior to September 2018, but expired upon an IPO, and had a stated exercise price of $0.65 per warrant. On May 16, 2010, the Company exercised a put notice to Eli Lilly in accordance with the Series D-2 preferred stock purchase agreement, resulting in the issuance of 6,916,110 shares of Series D-2 preferred stock and a warrant to purchase 518,708 additional shares of Series D-2 preferred stock. On January 11, 2011, the Company raised gross proceeds of $12.0 million from the sale of 18,427,388 shares of its Series D-2 preferred stock. Issuance costs associated with the sale were not material. Due to certain provisions in the Series D-2 convertible preferred stock warrant agreement, these warrants were required to be classified as a liability. Management believed that the circumstances requiring cash settlement of the award were remote. The Series D-2 preferred stock warrant liability was recorded at fair value and has been adjusted to fair value at the end of each reporting period using the Option-Pricing Method, with changes in value recorded as “Other income (expense)” in the accompanying consolidated statements of operations and comprehensive income (loss). Prior to the Company’s IPO in October 2013, all the preferred stock warrants were exercised and subsequently were converted into shares of common stock in connection with the IPO. Dividends were noncumulative and accrued on the Series A-1, Series A-2, Series B, Series C, Series D and Series D-2 preferred stock at a rate of $0.08, $0.0341, $0.0324 and $0.0522 per annum, respectively, and were payable when and as declared by the Board of Directors. Dividends had to be declared so that the Series A, Series B, Series C and Series D preferred stock were paid in like-kind and participated equally to those of the Series D-2 preferred and common stock. No dividends had been declared prior to the conversion of the preferred stock to common stock in connection with the IPO. The Company’s Series A-1, Series A-2, Series B, Series C, Series D and Series D-2 preferred stock were initially convertible into 1.506, 1.00, 1.14, 1.00, 1.00 and 1.00 shares, respectively, of common stock at the option of the holder. The conversion ratio of certain series of preferred stock was subject to change in the event specified dilutive transactions occurred, which included the Company’s IPO. There were no anti-dilution protections for the Series A-2 preferred stock and no adjustment to the Series A-1 preferred stock conversion price was to be made if a common stock issuance was at a price per share greater than the conversion price of the Series C preferred stock. Upon consummation of the Company’s IPO in October 2013, all outstanding shares of preferred stock automatically converted to shares of the Company’s common stock at the applicable conversion ratios then in effect. The conversion price was $12.39, $18.77, $6.95, $7.70, $12.20 and $12.20 for each share of Series A-1, A-2, Series B, Series C, Series D and Series D-2 convertible preferred stock, respectively. On October 16, 2013, the Company completed its IPO, in which 5,000,000 shares of the Company’s common stock were sold at a price of $16.00 per share. Additionally, the underwriters of the Company’s IPO exercised the full amount of their over-allotment option resulting in the sale of an additional 750,000 shares of the Company’s common stock at a price of $16.00 per share. The Company received net proceeds of $83.8 million from the IPO, net of underwriting discounts and commissions and other offering expenses. Upon consummation of the IPO, all outstanding shares of preferred stock automatically converted to common stock at the applicable conversion ratios then in effect. In connection with preparing for its IPO in October 2013, the Company’s Board of Directors and stockholders approved a 1-for-18.7739 reverse stock split of the Company’s common stock. The reverse stock split became effective on September 26, 2013. All share and per share amounts in the consolidated financial statements and notes thereto have been retroactively adjusted for all periods presented to give effect to this reverse stock split, including reclassifying an amount equal to the reduction in par value of common stock to additional paid-in capital. In addition, in September 2013, the Company’s Board of Directors and stockholders approved an amendment of the Company’s certificate of incorporation to, among other things, change the definition of a designated public offering to remove the per share price requirement. The amended and restated certificate of incorporation also changed the authorized number of shares of common stock from 425,000,000 to 125,000,000, and authorized 5,000,000 shares of undesignated preferred stock with a par value of $0.01 per share. There were no shares of undesignated preferred stock issued or outstanding as of December 31, 2013.

- 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 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.29-31)

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+ Details

Shared-Based Payments

12 Months Ended

Dec. 31, 2013

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Shared-Based Payments

5. Shared-Based Payments

Stock Option Plan

The Company’s 2000 Stock Option and Incentive Plan (“2000 Plan”) allowed for the grant of awards in respect of an aggregate of 130,725 shares, which was increased to 150,297 shares, of the Company’s common stock in the form of incentive stock options, non-qualified stock options, stock appreciation rights, restricted stock and restricted stock units and other performance awards. As of December 31, 2013, under the 2000 Plan, there were options to purchase an aggregate of 23,657 shares of common stock outstanding at a weighted average exercise price of $0.83 per share. The 2000 Plan has expired, and no further awards may be issued under the plan. Any shares of common stock subject to awards under the 2000 Plan that expire, terminate, or are otherwise surrendered, canceled, forfeited or repurchased without having been fully exercised, or resulting in any common stock being issued, will become available for issuance under the 2013 Stock Incentive Plan (“2013 Plan”) up to a specified number of shares.

Effective February 2003, the Company implemented the 2003 Equity Incentive Plan (“2003 Plan”), and it was amended and approved by the Company’s stockholders in 2005. The 2003 Plan originally allowed for the grant of awards in respect of an aggregate of 2,051,644 shares of the Company’s common stock. Between 2006 and 2010 the maximum number of shares of common stock authorized to be issued by the Company under the 2003 Plan was increased by 1,739,116 shares to 3,790,760. During the year ended December 31, 2012, the maximum number of shares of common stock authorized to be issued by the Company under the 2003 Plan was increased by 545,970 shares to 4,336,730. Stock options granted under the 2003 Plan may be either incentive stock options as defined by the Internal Revenue Code (“IRC”), or non-qualified stock options.

As of December 31, 2013, under the 2003 Plan, there were options to purchase an aggregate of 2,559,011 shares of common stock outstanding at a weighted average exercise price of $1.52 per share. Upon the completion of the IPO, the 2003 Plan was terminated, and no further awards may be issued under the plan. Any shares of common stock subject to awards under the 2003 Plan that expire, terminate, or are otherwise surrendered, canceled, forfeited or repurchased without having been fully exercised, or resulting in any common stock being issued, will become available for issuance under the 2013 Plan, up to a specified number of shares.

In October 2013, the Company implemented the 2013 Plan. The 2013 Plan provides for the grant of stock options and other stock-based awards, as well as cash-based performance awards. The aggregate number of shares of common stock initially available for issuance pursuant to awards under the 2013 Plan is 1,960,168 shares. The number of shares of common stock reserved for issuance will automatically increase on January 1 of each year from January 1, 2014 through and including January 1, 2023, by the lesser of (a) 1,960,168 shares, (b) 4.0% of the total number of shares of common stock outstanding on December 31 of the preceding calendar year, or (c) the number of shares of common stock determined by the Board of Directors. All of the shares available for issuance under the 2013 Plan are eligible for issuance pursuant to the exercise of incentive stock options. If an option expires or terminates for any reason without having been fully exercised, if any shares of restricted stock are forfeited, or if any award terminates, expires or is settled without all or a portion of the shares of common stock covered by the award being issued, such shares are available for the grant of additional awards. However, any shares that are withheld (or delivered) to pay withholding taxes or to pay the exercise price of an option are not available for the grant of additional awards. As of December 31, 2013, under the 2013 Plan, there were options to purchase an aggregate of 618,290 shares of common stock outstanding at a weighted average exercise price of $19.06 per share.

Stock Option Exchange

On March 16, 2011 (“Exchange Date”), the Company modified certain outstanding options with exercise prices of $1.88 and $4.69 (“Original Options”). These Original Options were canceled and replaced with options having an exercise price of $0.94 (“Replacement Options”), reflecting the current fair market value of the Company’s common stock on the Exchange Date. Original Options submitted for exchange were replaced on a one-for-one basis with Replacement Options. Additionally, the Replacement Options retain all terms and conditions of the Original Options except for the reduction to the exercise price as described above.

Total compensation associated with the Replacement Options consisted of the grant-date fair value of the Original Options for which the requisite service period is expected to be rendered (or has already been rendered) at the Exchange Date, plus the incremental cost associated with the modification of terms. The incremental compensation expense was measured as the excess of the fair value of the Replacement Options over the fair value of the Original Options re-measured as of the Exchange Date. A total of 1,921,894 Original Options were exchanged for Replacement Options.

The following stock-based compensation amounts were recognized for the periods indicated:


	Year Ended December 31,
	2013		2012		2011
Research and development	$	507,142	$	471,809	$	1,018,935
General and administrative		355,020		366,586		1,328,504

Total stock-based compensation expense	$	862,162	$	838,395	$	2,347,439

Employee Stock Options

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


	Year Ended December 31,
	2013	2012	2011
Expected dividend yield..	0%	0%	0%
Expected volatility	53% - 67%	51%	62%
Risk-free interest rate	1.24% - 2.19%	1.18%	1.35%
Expected term.	7 years	7 years	7 years
Expected forfeiture rate..	5.06% - 5.57%	5.57%	5.58%

Expected Dividend Yield—The Company has never declared or paid dividends and has no plans to do so in the foreseeable future.

Expected Volatility—Volatility is a measure of the amount by which a financial variable such as a share price has fluctuated (historical volatility) or is expected to fluctuate (expected volatility) during a period. As the Company does not yet have sufficient history of its own volatility, the Company has identified several public entities of similar size, complexity and stage of development and calculates historical volatility using the volatility of these companies.

Risk-Free Interest Rate—This is the U.S. Treasury rate for the week of each option grant during the year, having a term that most closely resembles the expected life of the option.

Expected Term—This is the period of time that the options granted are expected to remain unexercised. Options granted have a maximum term of ten years. The Company estimates the expected life of the option term to be seven years. The Company uses a simplified method to calculate the average expected term.

Expected Forfeiture Rate—The forfeiture rate is the estimated percentage of options granted that is expected to be forfeited or canceled on an annual basis before becoming fully vested. The Company estimates the forfeiture rate based on turnover data with further consideration given to the class of the employees to whom the options were granted.

Equity instruments issued to non-employees are accounted for under the provisions of ASC 505-50, Equity Based Payments to Non-Employees. Accordingly, the estimated fair value of the equity instrument is recorded on the earlier of the performance commitment date or the date the services required are completed.

The following table summarizes stock option activity for 2013:


	Shares			Weighted- Average Exercise Price		Weighted-Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value (in thousands)
Outstanding, December 31, 2012		3,249,541		$	0.94		7.3
Granted		1,307,101			10.70
Exercised		(1,268,049	)		0.85
Forfeited or expired		(87,635	)		1.11

Outstanding, December 31, 2013		3,200,958			4.90		6.9	$	67,532

December 31, 2013:
Exercisable		1,688,251			0.94		4.8		42,311
Vested and expected to vest		3,022,948			4.64		6.8		64,574

During 2013, 2012 and 2011 the Company issued 1,268,049, 863,176 and 49,883 shares of common stock, respectively, in conjunction with stock option exercises. The Company received cash proceeds from the exercise of these stock options of approximately $1.1 million, $46,826 and $53,225 during 2013, 2012 and 2011, respectively.

The weighted-average grant-date fair value of options granted during 2013, 2012 and 2011 was $6.91, $0.94 and $0.94 per share, respectively. The total intrinsic value of options exercised during 2013, 2012 and 2011 was approximately $5.4 million, $271,929 and $102,418, respectively. The total fair value of stock options which vested during 2013, 2012 and 2011 was $487,603, $879,024 and $1,108,107, respectively. As of December 31, 2013, the total unrecognized compensation expense related to non-vested stock options, net of related forfeiture estimates, was $7.6 million, which the Company expects to recognize over a weighted-average period of approximately four years.

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References+ Details

Income Taxes

12 Months Ended

Dec. 31, 2013

Income Tax Disclosure [Abstract]

Income Taxes

6. Income Taxes

For the years ended December 31, 2013, 2012 and 2011 there was no current provision for federal or state income taxes due to the taxable losses which resulted or use of legacy NOL carryforwards.

The significant components of the Company’s deferred tax assets (liabilities) were as follows:


	December 31,
	2013			2012
Deferred income tax assets:
Federal U.S. net operating loss carryforward	$	36,561,195		$	35,330,167
State net operating loss carryforward		3,315,514			3,521,722
Research and development credit, net		3,785,612			2,777,899
Orphan drug credit, net		19,883,076			19,039,613
Deferred rent		5,132,458			5,218,002
Deferred revenue		8,216,695			9,379,064
Depreciation		1,438,477			1,247,772
Other		1,438,870			1,575,782

Gross deferred income tax assets		79,771,897			78,090,021
Valuation allowance		(79,376,945	)		(78,090,021	)

Net deferred income tax assets		394,952			—
Deferred income tax liabilities:
Other		(394,952	)		—

Gross deferred income tax liabilities		(394,952	)		—
Net deferred income tax asset/(liability)	$	—		$	—

The Company recognizes valuation allowances to reduce deferred tax assets to the amount that is more likely than not to be realized. In assessing the likelihood of realization, management considers (i) future reversals of existing taxable temporary differences; (ii) future taxable income exclusive of reversing temporary difference and carryforwards; (iii) taxable income in prior carryback years if carryback is permitted under applicable tax law; and (iv) tax planning strategies. The Company’s net deferred income tax asset is not more likely than not to be utilized due to the lack of sufficient sources of future taxable income and cumulative book losses which have resulted over the years. The net increase in the valuation allowance in 2013 is due to the fact the Company generated research and development and orphan drug credits and NOL carryforwards which increased the net deferred tax asset. The increase in the credits and NOL carryforwards were offset by the decrease in deferred revenue and resulted in a net current year increase to the valuation allowance.

The Company has reported book losses from inception through December 31, 2010. The NOL carryforwards of approximately $104.8 million for U.S. federal and approximately $60.3 million for state will expire in various years beginning in 2023 through 2033. In addition, the Company has U.S. federal tax credits of $23.7 million which will expire in various years beginning in 2020 through 2033.

The use of the Company’s U.S. federal NOL and tax credit carryforwards in future years are restricted due to changes in the Company’s ownership and tax attributes acquired by the Company in a purchase. As of December 31, 2013, $8.5 million of the Company’s NOLs are limited for use over the years 2014 – 2027 in which a range of such amounts could be utilized on an annual basis of $0.2 million to $1.4 million. The remaining $96.3 million of NOLs is not limited and can be offset against future taxable income. Additionally, approximately $1.8 million of NOLs will be recognized as a benefit through additional-paid-in-capital when realized. Further, despite the NOL and credit carryforwards, the Company may have a future tax liability due to an alternative minimum tax or state tax requirements in which net operating losses do not exist.

The reconciliation of the reported estimated income tax benefit to the amount that would result by applying the U.S. federal statutory tax rate to the net income is as follows:


	Year Ended December 31,
	2013			2012			2011
United States federal tax at statutory rate	$	(91,293	)	$	2,926,615		$	2,350,992
State taxes (net of federal benefit)		609,476			1,460,289			1,480,185
Deferred income tax adjustments		(855,130	)		(512,375	)		—
Deferred state blended rate adjustments		(344,178	)		—			—
Research credit, net		(225,605	)		—			—
Orphan drug credit, net		(843,463	)		(4,895,671	)		(7,056,607	)
Other permanent items		2,931			7,627			4,696
Equity-based compensation		241,467			279,165			725,811
Fair value adjustment of preferred stock warrant liability		218,872			(52,743	)		(496,208	)
Change in valuation allowance		1,286,923			787,093			2,991,131

Income tax expense/(benefit)	$	—		$	—		$	—

A reconciliation of the beginning and ending amount of gross unrecognized tax benefits is as follows:


	Year Ended December 31,
	2013		2012		2011
Beginning balance	$	1,592,357	$	1,533,986	$	1,246,025
Increases/(decreases) for current year tax positions		115,502		58,371		287,961
Increases/(decreases) for prior year tax positions		—		—		—
Decreases as a result of expiration of statute of limitations		—		—		—

Ending balance	$	1,707,859	$	1,592,357	$	1,533,986

As of December 31, 2013 and 2012, of the total gross unrecognized tax benefits, approximately $1.2 million and $1.1 million would favorably impact the Company’s effective income tax rate, respectively. Although, due to the Company’s determination that the deferred income tax asset would not more likely than not be realized, a valuation allowance would be recorded, therefore, zero net impact would result within the Company’s effective income tax rate. The Company’s uncertain income tax position liability has been recorded to deferred income taxes to offset the tax attribute carryforward amounts.

For the years ended December 31, 2013, 2012 and 2011, the Company has not recognized any interest or penalties related to the uncertain income tax positions due to the fact such position is related to tax attribute carryforwards which have not yet been utilized. The Company does not expect its unrecognized income tax position to significantly decrease within the next twelve months.

The Company’s U.S. Federal and state income tax returns from 2001 to 2012 remain subject to examination by the tax authorities. The Company’s 2001 through 2009 years remain open for examination, even though the statute of limitations has expired, due to the net operating losses and credits carried forward for use in prospective years.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References+ Details

Lease Exit Liability

12 Months Ended

Dec. 31, 2013

Restructuring And Related Activities [Abstract]

Lease Exit Liability

7. Lease Exit Liability

On July 16, 2008, the Company acquired Raven Biotechnologies, Inc. (“Raven”), a private South San Francisco-based company focused on the development of monoclonal antibody therapeutics for treating cancer. Raven was considered a development-stage enterprise as defined in ASC 915, Development Stage Entities. In connection with the acquisition, the Company issued 12,466,039 shares of its Series D convertible preferred stock in exchange for all of the outstanding capital stock and convertible notes payable of Raven.

The Company undertook restructuring activities related to the acquisition of Raven. These restructuring activities included reductions in staffing levels and the intended exit of leased facilities. All severance-related payments were completed in the year ended December 31, 2009.

In connection with these restructuring activities, as part of the cost of acquisition, the Company established a restructuring liability attributed to an existing operating lease. The terms of the operating lease extend through 2018.

Changes in the lease exit liability are as follows:


Accrual balance at December 31, 2011	$10,607,499
Principal payments	(533,560	)

Accrual balance at December 31, 2012	10,073,939
Principal payments	(628,769	)

Accrual balance at December 31, 2013	$9,445,170

Future principal payments to be made under the lease agreement for the next five years and thereafter as of December 31, 2013 are as follows:


2014	$	1,438,742
2015		1,641,905
2016		1,866,031
2017		2,113,118
2018		2,385,374
Thereafter		—

	$	9,445,170

The purchase agreement provides for a specified total of certain contingent milestones that are based on the achievement of certain product sales derived from the acquired Raven technology. Also, a onetime payment of $5.0 million will be made to the Raven stockholders upon the initiation of patient dosing in the first Phase 2 clinical trial of any product derived from the Raven “Cancer Stem Cell Program.” No payment shall be made if the Phase 2 trial start date has not occurred on or before July 15, 2018. Other consideration includes a percentage of revenue (excluding consideration for research and development and equity) received by the Company for license of a product derived from the Raven “Cancer Stem Cell Program” and a onetime payment ranging from $8.0 million to $12.0 million dependent upon a specified level of sales of products derived from the Raven “Cancer Stem Cell Program.”

The contingent consideration will be accounted for as additional purchase price and recorded as incremental in-process research and development expense when it is deemed probable that the contingencies will be attained. No additional amounts have been recorded during the years ended December 31, 2013, 2012 and 2011.

- Definition

The entire disclosure for restructuring and related activities. Description of restructuring activities such as exit and disposal activities, include facts and circumstances leading to the plan, the expected plan completion date, the major types of costs associated with the plan activities, total expected costs, the accrual balance at the end of the period, and the periods over which the remaining accrual will be settled.

+ References+ Details

Collaboration and License Agreements	12 Months Ended
Collaboration and License Agreements	Dec. 31, 2013
Text Block [Abstract]
Collaboration and License Agreements	8. Collaboration and License Agreements *Servier* In November 2011, the Company entered into a right-to-develop collaboration agreement with Servier for the development and commercialization of MGA271 in all countries other than the United States, Canada, Mexico, Japan, South Korea and India. Upon execution of the agreement, Servier made a nonrefundable payment of $20.0 million to the Company. The Company is eligible to receive up to $30.0 million in license grant fees, $47.0 million in clinical milestone payments, $140.0 million in regulatory milestone payments and $208.0 million in sales milestone payments if Servier exercises the option, obtains regulatory approval for and successfully commercializes MGA271. The Company concluded that the license grant fees are not deliverables at the inception of the arrangement. The Company has determined that each potential future clinical, development and regulatory milestone is substantive. Although sales milestones are not considered substantive, they are still recognized upon achievement of the milestone (assuming all other revenue recognition criteria have been met) because there are no undelivered elements that would preclude revenue recognition at that time. In the event Servier exercises its option to continue development of MGA271, Servier must pay a license grant fee. Under this agreement, Servier would be obligated to pay the Company from low double digit to mid-teen royalties on product sales in its territories. The Company has evaluated the research collaboration agreement with Servier and has determined that it is a revenue arrangement with multiple deliverables, or performance obligations. The Company concluded that the option is substantive and that the license fees for this option is not a deliverable at the inception of the arrangement as there is considerable uncertainty that the option would be exercised and the additional fee to be paid upon exercise of the option represents its estimated selling price (i.e. no substantial discount was given). The Company’s substantive performance obligations under this research collaboration include an exclusivity clause to its technology, technical, scientific and intellectual property support to the research plan during the first year of the agreement and participation on an executive committee and a research and development committee. The Company determined that these performance obligations represent a single unit of accounting, since the license does not have stand-alone value to Servier without the Company’s technical expertise and committee participation. As such, the initial upfront payment was deferred and is being recognized ratably over the initial 27-month period, which represents the expected period of development and the Company’s participation on the research and development committee. The Company further concluded that each potential future clinical, development and regulatory milestone is substantive. During the years ended December 31, 2013, 2012 and 2011 the Company recognized revenue of $21.3 million, $9.1 million and 0.9 million, respectively, under this agreement. Revenue recognized in the year ended December 31, 2013 included a $10.0 million substantive milestone payment received upon dosing the first patient in a Phase 1 dose expansion cohort trial of MGA271. At December 31, 2013, $0.9 million of revenue remained deferred under this agreement, all of which was included in current liabilities. At December 31, 2012, $10.0 million of revenue was deferred under this agreement, $9.1 million of which was included in current liabilities and $0.9 million of which was included in long-term liabilities. In September 2012, the Company entered into a second right-to-develop collaboration agreement with Servier and granted it options to obtain three separate exclusive licenses to develop and commercialize DART-based molecules, consisting of those designated by the Company as MGD006 and MGD007, as well as a third DART molecule, in all countries other than the United States, Canada, Mexico, Japan, South Korea and India. Upon execution of the agreement, Servier made a nonrefundable payment of $20.0 million to the Company. In addition, the Company will be eligible to receive up to $65.0 million in license grant fees, $98.0 million in clinical milestone payments, including $5.0 million upon IND acceptance for each of MGD006, MGD007 and a third DART molecule, $300.0 million in regulatory milestone payments and $630.0 million in sales milestone payments if Servier exercises all of the options and successfully develops, obtains regulatory approval for, and commercializes a product under each license. In addition to these milestones, the Company and Servier will share Phase 2 and Phase 3 development costs. The Company has determined that each potential future clinical, development and regulatory milestone is substantive. Although sales milestones are not considered substantive, they are still recognized upon achievement of the milestone (assuming all other revenue recognition criteria have been met) because there are no undelivered elements that would preclude revenue recognition at that time. Under this agreement, Servier would be obligated to pay the Company between high-single digit and mid-teen royalties on net product sales in its territories. The Company has evaluated the research collaboration agreement with Servier and has determined that it is a revenue arrangement with multiple deliverables, or performance obligations. The Company concluded that each option is substantive and that the license fees for each option are not deliverables at the inception of the arrangement and were not issued with a substantial discount. The Company’s substantive performance obligations under this research collaboration include an exclusivity clause to its technology, technical, scientific and intellectual property support to the research plan during the first year of the agreement and participation on an executive committee and a research and development committee. The Company determined that the performance obligations with respect to the pre-clinical development represent a single unit of accounting, since the license does not have stand-alone value to Servier without the Company’s technical expertise and committee participation. As such, the initial up front license payment was deferred and is being recognized ratably over the initial 29-month period, which represents the expected development period. The Company further concluded that each potential future clinical, development and regulatory milestone is substantive. During the years ended December 31, 2013 and 2012 the Company recognized revenue of $8.6 million, and $2.0 million, respectively. No milestones have been recognized under this agreement during the years ended December 31, 2013 and 2012. At December 31, 2013, $9.4 million of revenue was deferred under this agreement, $8.6 million of which was included in current liabilities and $0.8 million of which was included in long-term liabilities. At December 31, 2012, $18.0 million of revenue was deferred under this agreement, $8.6 million of which was included in current liabilities and $9.4 million of which was included in long-term liabilities. In February 2014, Servier exercised its exclusive option to develop and commercialize MGD006. As a result of the exercise, the Company received a $15.0 million payment from Servier for its license to develop and commercialize MGD006 in its territories. In addition, the Company received a $5.0 million payment from Servier upon the achievement of a clinical milestone related to the IND application for MGD006 clearing the 30-day review period by the FDA. *Gilead* In January 2013, the Company entered into an agreement with Gilead for the research, development and commercialization of up to four DART-based molecules. The time period for Gilead’s exercise of one option has expired. At present, Gilead retains a license to one and options to two of the original four programs. Gilead has exclusive worldwide rights for each of these remaining programs. The Company received an initial $7.5 million license grant fee for the first DART-based molecule, and is eligible to receive additional license grant fees of $7.5 million on each of the remaining two DART-based molecules if they are selected by Gilead. The Company is further eligible to receive up to an additional $20 to $25 million in pre-clinical milestones across each of the three remaining DART programs and up to approximately $240 to $250 million per remaining program in additional clinical, regulatory and sales milestones if Gilead exercises both remaining options and achieves all of the requisite milestones under each option and license. The Company has determined that the other licenses are conditional deliverables, which are substantive options that were not granted with a substantial discount. The Company has determined that each potential future clinical, development and regulatory milestone is substantive. Although sales milestones are not considered substantive, they are still recognized upon achievement of the milestone (assuming all other revenue recognition criteria have been met) because there are no undelivered elements that would preclude revenue recognition at that time. Gilead also provides funding for the Company’s internal and external research costs under the agreement. Additionally, Gilead would be obligated to pay the Company high single digit to low double digit, but less than teen royalties on product sales. The Company has evaluated the research collaboration agreement with Gilead and has determined that it is a revenue arrangement with multiple deliverables, or performance obligations. The Company’s substantive performance obligations under this research collaboration include a license to its technology and research and development services. The Company concluded that the deliverables do not have stand alone value and therefore, represent a combined single unit of accounting. Due to the lack of standalone value for the license and research and development services, the combined unit of accounting (the upfront payment and the expected research and development reimbursements) is being recognized ratably over a period of 21 months, which represents the expected development period. The Company and Gilead have also agreed to establish a joint research committee to facilitate the governance and oversight of the parties’ activities under the agreements. Management considered whether participation on the joint committee may be a deliverable and determined that it was not a deliverable. Had management considered participation on the joint committee as a deliverable, it would not have had a material impact on the accounting for the arrangement. The Company recognized revenues of approximately $8.0 million under this agreement for the year ended December 31, 2013. No milestones have been achieved under this agreement. At December 31, 2013, $3.6 million of revenue was deferred under this agreement, all of which was included in current liabilities. *Boehringer* In October 2010 the Company entered into a collaboration and license agreement with Boehringer to discover, develop and commercialize up to ten DART-based molecules which span multiple therapeutic areas. Under the terms of the agreement, the Company granted Boehringer an exclusive, worldwide, royalty-bearing, license under its intellectual property to research, develop, and market DARTs generated under the agreement throughout the world. Upon execution of the agreement, the Company received an upfront payment of $15.0 million. The Company subsequently received three annual maintenance payments including one in the fourth quarter of 2013. These maintenance payments are being recognized over the estimated period of development. The Company has the potential to earn milestone payments of approximately $41.0 million related to pre-clinical and clinical development, $89.0 million related to regulatory milestones and $83.0 million related to sales milestones for each of the DART programs under this agreement in the case of full commercial success of multiple DART products. The Company has determined that each potential future clinical, development and regulatory milestone is substantive. Although sales milestones are not considered substantive, they are still recognized upon achievement of the milestone (assuming all other revenue recognition criteria have been met) because there are no undelivered elements that would preclude revenue recognition at that time. Boehringer also provides funding for the Company’s internal and external research costs and is required to pay the Company mid-single digit royalties on product sales. In November 2013, Boehringer nominated a bi-specific antibody therapeutic candidate generated by the Company’s DART technology for pre-clinical development. This formal selection of a development candidate triggered a $5.0 million milestone payment to the Company. From the commencement of the collaboration through December 31, 2013, the Company has received $48.8 million under this agreement, including upfront, annual maintenance and milestone payments as well as research funding. In addition, Boehringer purchased $10.0 million of the Company’s Series D-2 Preferred Stock in January 2011. This preferred stock was converted to common stock upon the Company’s IPO in October 2013. The Company determined that the deliverables under the Boehringer agreement include the license, the research and development services to be performed by the Company, and the co-promotion/manufacturing services. The Company concluded that the co-promotional activities were optional and were subject to further negotiation upon reaching regulatory approval. As such, the co-promotional period is not included in the expected obligation period to perform services. The Company concluded that the undelivered element of research and development services had fair value. The Company concluded that the license does not have value on a standalone basis (e.g. absent the provision of the research and development services) and therefore does not represent a separate unit of accounting. The Company concluded that because the drug candidate has not yet been developed, the license is of no value to Boehringer without the ensuing research and development activities using the DART technology, which is proprietary to the Company. Likewise, Boehringer could not sell the license to another party (without the Company agreeing to provide the research and development activities for the other party). Therefore, the upfront license fee and research and development services were treated as a combined unit of account and recognized over the expected obligation period associated with the research and development services through September 2015, which represents the estimated period of development. The Company and Boehringer have also agreed to establish a joint research committee to facilitate the governance and oversight of the parties’ activities under the agreements. Management considered whether participation on the joint committee may be a deliverable and determined that it was not a deliverable. However, had management considered participation on the joint committee as a deliverable, it would not have had a material impact on the accounting for the arrangement as the period of participation in this committee matched the obligation period for the research and development services. There have been no material modifications to this agreement since the adoption of ASU 2009-13 on January 1, 2011. The Company recognized revenues of approximately $14.4 million, $11.7 million and $8.9 million during the years ended December 31, 2013, 2012 and 2011, respectively. Revenue recognized in the years ended December 31, 2013 and 2012 included milestone payments of $5.0 million and $2.0 million, respectively, for the achievement of clinical milestones. No milestones were achieved in the year ended December 31, 2011. At December 31, 2013, $12.8 million of revenue was deferred under this agreement, $7.0 million of which was included in current liabilities and $5.8 million of which was included in long-term liabilities. At December 31, 2012, $14.0 million of revenue was deferred under this agreement, $5.0 million of which was included in current liabilities and $9.0 million of which was included in long-term liabilities. *Pfizer* In October 2010, the Company entered into a three year agreement with Pfizer to discover, develop and commercialize up to two DART-based molecules. The Company granted Pfizer a non-exclusive worldwide, royalty-bearing license and received an upfront payment of $5.0 million and has received milestone payments and funding for the Company’s internal and external research costs under the agreement. The Company is eligible to receive milestone payments of approximately $17.0 million related to pre-clinical and clinical development and $195.0 million related to commercialization and sales milestones for each DART program under this agreement. The Company has determined that each potential future technical and development milestone is substantive. Although sales milestones are not considered substantive, they are still recognized upon achievement of the milestone (assuming all other revenue recognition criteria have been met) because there are no undelivered elements that would preclude revenue recognition at that time. Pfizer is responsible for all pre-clinical and clinical development costs for the program. In addition, Pfizer is required to pay the Company mid-single digit to low-teen royalties on product sales. Under this collaboration, one DART program is currently being pursued and the Company completed its research obligations under this program in January 2014. The Company has evaluated the research collaboration agreement with Pfizer and has determined that it is a revenue arrangement with multiple deliverables, or performance obligations. The Company’s substantive performance obligations under this research collaboration include an exclusive license to its technology, research and development services and manufacturing services. The Company concluded that the manufacturing services were optional and were subject to further negotiation upon reaching regulatory approval. As such, the manufacturing services are not included in the expected obligation period to perform services. The Company determined that it had fair value of the undelivered element of the research and development services. However, the Company concluded that the license does not have value on a standalone basis (e.g. absent the provision of the research and development services) and therefore does not represent a separate unit of accounting. Facts that were considered included the development of the candidate noting that because the drug candidate has not yet been developed, the license is of no value to Pfizer without the ensuing research and development activities using the DART technology, which is proprietary to the Company. Likewise, Pfizer could not sell the license to another party (without the Company agreeing to provide the research and development activities for the other party). Therefore, the upfront license fee and research and development services were treated as a combined unit of accounting and recognized over the expected obligation period associated with the research and development services through January 2014, which represents the estimated period of development. The $5.0 million upfront payment received by the Company is non-refundable; therefore, there is no right of return for the license. The Company recognizes revenue associated with this non-refundable up-front license fee through the expected obligation period associated with the research and development services, which ended in January 2014. The Company and Pfizer have also agreed to establish a joint research committee to facilitate the governance and oversight of the parties’ activities under the agreements. Management considered whether participation on the joint committee may be a deliverable and determined that it was not a deliverable because it is a participating right and not an obligation of the Company. However, had management considered participation on the joint committee as a deliverable, it would not have had a material impact on the accounting for the arrangement. There have been no material modifications to this agreement since the adoption of ASU 2009-13 on January 1, 2011. The Company recognized revenues of approximately $3.5 million, $5.5 million and $5.2 million during the years ended December 31, 2013, 2012 and 2011, respectively. Included in the 2012 revenues are milestone payments totaling $500,000. No additional milestones have been achieved under this agreement through December 31, 2013. At December 31, 2013 and 2012, $7,291 and $1.3 million of revenue was deferred under this agreement, respectively, all of which was included in current liabilities. *Green Cross* In June 2010, the Company entered into a collaboration agreement with Green Cross for the development of the Company’s anti-HER2 antibody known as MGAH22, or margetuximab. This arrangement grants Green Cross an exclusive license to conduct specified Phase 1 and Phase 2 clinical trials and commercialize margetuximab in South Korea. Upon execution of the agreement, Green Cross made a nonrefundable payment of $1.0 million to the Company. The Company is eligible to receive clinical development and commercial milestone payments of up to $4.5 million. The Company has determined that each potential clinical development and commercial milestone is substantive. The Company is also entitled to receive royalties on net sales of margetuximab in South Korea. The Company and Green Cross have formed a joint steering committee to coordinate and oversee activities on which the companies collaborate under the agreement. The Company has evaluated the collaboration agreement with Green Cross and has determined that it is a revenue arrangement with multiple deliverables or performance obligations. The Company’s substantive performance obligations under this agreement include an exclusive license to its technologies and participation in a joint steering committee. The Company concluded that the license does not have value on a standalone basis and therefore does not represent a separate unit of accounting. Likewise, Green Cross could not sell the license to another party. The $1.0 million upfront payment received by the Company is non-refundable; as such, there is no right of return for the license. Therefore, the upfront license fee and participation on the joint steering committee were treated as a combined unit of accounting and will be recognized over the term of the agreement through June 2020. There have been no material modifications to this agreement since the adoption of ASU 2009-13 on January 1, 2011. The Company recognized revenues of approximately $100,000 under this agreement during each of the three years ended December 31, 2013. No milestones were achieved under this agreement during the three years ended December 31, 2013. At December 31, 2013, $650,000 of revenue was deferred under this agreement, $100,000 of which was included in current liabilities and $550,000 of which was included in long-term liabilities. At December 31, 2012, $750,000 of revenue was deferred under this agreement, $100,000 of which was included in current liabilities and $650,000 of which was included in long-term liabilities. *Eli Lilly* In October 2007, the Company entered into an exclusive license and collaboration agreement (together, the Agreements) with Eli Lilly to jointly develop and commercialize teplizumab, a humanized anti-CD3 monoclonal antibody. As part of the Agreements, Eli Lilly acquired the exclusive rights to the molecule. Upon execution of the Agreements, Eli Lilly made a nonrefundable payment of $41.0 million to the Company. In May 2008, Eli Lilly paid the Company a milestone payment of $50.0 million and in May 2010, Eli Lilly paid an additional milestone of $5.0 million. On October 28, 2010, Lilly notified the Company of its decision to terminate the agreement after review of one year of clinical data from the Protégé trial in Type 1 diabetes patients treated with teplizumab. Such data failed to support the primary efficacy end point in the study. In February 2011, the Company reacquired the commercial rights to the molecule from Eli Lilly. During the year ended December 31, 2012, Eli Lilly satisfied its obligation related to the cost of monitoring patients under the Protégé and Encore trials. The Company’s obligations continued through September 2012, which represented the follow up period for enrolled patients and the Company’s final reporting of the trial’s results. There is no additional clinical trial activity under the Eli Lilly Agreements as it relates to such trials. However, Eli Lily continues to reimburse the Company for monitoring patients in one currently active trial. During the years ended December 2013, 2012 and 2011, the Company recognized revenue of $0.8 million, $31.2 million and $30.9 million, respectively, under this agreement. No milestones were achieved under this agreement during the three years ended December 31, 2013.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2013

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

9. Commitments and Contingencies

Operating Leases

The Company leases office and laboratory space in Rockville, Maryland under a lease that expires on March 31, 2018, and leases a manufacturing facility in Rockville under a lease that expires on December 31, 2014. The Company has an option under each lease to continue the respective lease for five years under the same terms. The Company also subleases office and laboratory space in South San Francisco under a lease that expires on December 31, 2018. All of the leases contain rent escalation clauses. For financial reporting purposes, rent expense is charged to operations on a straight-line basis over the term of the lease. As of December 31, 2013 and 2012, the Company had recorded a deferred rent liability of $2.9 million and $2.8 million, respectively. Rent expense for the years ended December 31, 2013, 2012 and 2011 was $2.7 million, $2.7 million and $2.9 million, respectively.

Future minimum lease payments under noncancelable operating leases at December 31, 2013 are as follows:


2014	$	3,651,421
2015		3,310,884
2016		3,410,210
2017		3,512,517
2018		2,780,398
Thereafter		—

	$	16,665,430

- Definition

The entire disclosure for commitments and contingencies.

+ References+ Details

Product Milestone Payments and Royalty Agreements	12 Months Ended
Product Milestone Payments and Royalty Agreements	Dec. 31, 2013
Text Block [Abstract]
Product Milestone Payments and Royalty Agreements	10. Product Milestone Payments and Royalty Agreements In connection with an Asset Purchase Agreement with Tolerance Therapeutics, Inc. (“Tolerance”) entered into during June 2005, the Company may be required to issue Tolerance additional consideration as follows: (i) $10,950,000 if certain milestones are met, including the initiation of Phase 3 trials and filing of various regulatory product license applications; (ii) 36,135 shares of common stock; and (iii) royalty payments between 1.75% and 4.0% of net sales of products acquired from or patented by Tolerance or other product fees earned by the Company. Any additional consideration required to be paid under the Asset Purchase Agreement will be recorded as research and development expense when incurred. No payments related to the additional consideration have occurred during the three years ended December 31, 2013. Additionally, certain agreements require the Company to pay royalties. Currently, the Company is not obligated to pay royalties, as no revenue from product sales is being generated by the Company.

Quarterly Financial Information

12 Months Ended

Dec. 31, 2013

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Information

12. Quarterly Financial Information (unaudited)


	1^st Quarter			2^nd Quarter			3^rd Quarter		4^th Quarter
	(in thousands, except per share data)
2013
Revenue	$	10,598		$	12,299		$	20,232	$	14,906
Net income (loss)		(3,366	)		(294	)		6,604		(3,205	)
Net income (loss) per share, basic	$	(2.93	)	$	(0.24	)	$	0.14	$	(0.14	)
Net income (loss) per share, diluted	$	(2.93	)	$	(0.24	)	$	0.01	$	(0.14	)
2012
Revenue	$	20,510		$	17,435		$	16,082	$	9,799
Net income (loss)		4,320			3,546			2,601		(2,105	)
Net income (loss) per share, basic	$	0.00		$	0.00		$	0.00	$	(1.92	)
Net income (loss) per share, diluted	$	0.00		$	0.00		$	0.00	$	(1.92	)

Annual net income (loss) per share includes the effects of income allocated to participating securities.

- Definition

The entire disclosure for the quarterly financial data in the annual financial statements. The disclosure may include a tabular presentation of financial information for each fiscal quarter for the current and previous year, including revenues, gross profit, income or loss before extraordinary items and earnings per share data. It also includes an indication if the information in the note is unaudited, comments on the aggregate effect of year-end adjustments, and an explanation of matters or transactions that affect comparability or are pertinent to an understanding of the information furnished.

+ References+ Details

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2013
Subsequent Events [Abstract]
Subsequent Events	13. Subsequent Events In February 2014, Servier exercised its exclusive option to develop and commercialize MGD006. Servier will gain exclusive development and commercial rights in all countries outside of the U.S., Canada, Mexico, Japan, South Korea and India. In those countries, the Company will retain development and commercialization rights. As a result of the exercise, the Company received a $15.0 million payment from Servier. In addition, the IND application for MGD006 has cleared the 30-day review period by the FDA, triggering an additional $5.0 million payment to the Company by Servier. In February 2014, the Company completed a follow-on equity offering, in which the Company sold 1.8 million shares of its common stock at a price of $36.50 per share. Additionally, the underwriters of the offering exercised the full amount of their over-allotment option resulting in the sale of an additional 450,000 shares of the Company’s common stock at a price of $36.50 per share. The Company received net proceeds of $76.7 million from this offering, net of underwriting discounts and commissions and other estimated offering expenses.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2013

Accounting Policies [Abstract]

Basis of Presentation and Principles of Consolidation

Basis of Presentation and Principles of Consolidation

Use of Estimates

Use of Estimates

Cash and Cash Equivalents

Cash and Cash Equivalents

Accounts Receivable

Accounts Receivable

Restricted Cash

Restricted Cash

Fair Value of Financial Instruments

Fair Value of Financial Instruments

•

Level 1—Fair value is determined by using unadjusted quoted prices that are available in active markets for identical assets and liabilities.

•

Financial assets and liabilities subject to fair value measurements were as follows:


	Fair Value Measurements at December 31, 2013
				Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	Total			Level 1		Level 2		Level 3
Assets:
Cash and cash equivalents	$	90,434,435		$	90,434,435	$	—	$	—
Money market funds		26,046,974			26,046,974		—		—
Restricted cash		404,850			404,850		—		—

Total Assets	$	116,886,259		$	116,886,259	$	—	$	—


	Fair Value Measurements at December 31, 2012
				Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	Total			Level 1		Level 2		Level 3
Assets:
Cash and cash equivalents	$	18,695,197		$	18,695,197	$	—	$	—
Money market funds		29,047,958			29,047,958		—		—
Restricted cash		404,850			404,850		—		—

Total Assets	$	48,148,005		$	48,148,005	$	—	$	—

Liabilities:
Preferred stock warrant liability	$	(52,947	)	$	—	$	—	$	(52,947	)

As of December 31, 2012, the Company transferred its money market funds from Level 2 to Level 1 because the inputs are now based upon a quoted market price.


Balance at December 31, 2012	$	(52,947	)
Total unrealized gains (losses) included in earnings		(626,349	)
Settlement of preferred stock warrants		679,296

Balance at December 31, 2013	$	—

Concentration of Credit Risk

Concentration of Credit Risk

The following table represents the percentage of all significant revenue earned in the periods indicated:


	Year Ended December 31,
	2013			2012			2011
Servier		51.6	%		17.3	%		—
Boehringer		24.8	%		18.4	%		15.6	%
Gilead		13.8	%		—			—
Pfizer		6.0	%		8.7	%		10.8	%
Government Agencies		2.2	%		6.5	%		17.7	%
Eli Lilly		1.4	%		48.9	%		54.0	%

The following table represents the percentage of all significant accounts receivable:


	December 31,
	2013			2012
Gilead		53.4	%		—
Pfizer.		12.3	%		45.4	%
Boehringer		12.2	%		18.0	%
Eli Lilly		7.0	%		28.2	%
Servier		6.4	%		—
Government Agencies		4.6	%		8.4	%

Property and Equipment

Property and Equipment


Computer equipment		3 years
Software		3 years
Furniture		10 years
Laboratory and office equipment		5 years
Leasehold improvements		Shorter of lease term or useful life

Impairment of Long-Lived Assets

Impairment of Long-Lived Assets

Income Taxes

Income Taxes

Revenues

Revenues

Revenue Recognition

There are no performance, cancellation, termination or refund provisions in any of the arrangements that contain material financial consequences to the Company.

Exclusive Licenses

The Company does not directly control when any collaborator will achieve milestones or become liable for royalty payments.

Right-to-Develop Agreements

Research and Development Costs

Research and Development Costs

Comprehensive Income (Loss)

Comprehensive Income (Loss)

Stock-based Compensation

Stock-based Compensation

Net Income (Loss) Per Share

Net Income (Loss) Per Share

Basic and diluted income (loss) per common share is computed as follows:


	Year Ended December 31,
	2013			2012			2011
Net income (loss)	$	(260,835	)	$	8,361,755		$	6,717,120
Less: undistributed earnings allocated to participating securities		—			(8,361,755	)		(6,717,120	)

Net income (loss) allocable to common shares	$	(260,835	)	$	—		$	—

Basic weighted average common shares outstanding		6,847,697			1,083,276			1,025,602
Basic income (loss) per common share	$	(0.04	)	$	0.00		$	0.00
Net income (loss)	$	(260,835	)	$	8,361,755		$	6,717,120
Less: undistributed earnings allocated to participating securities and other add-backs to net income (loss)		—			(8,361,755	)		(6,717,120	)

Net income (loss) allocable to common shares	$	(260,835	)	$	—		$	—

Basic weighted average common shares outstanding		6,847,697			1,083,276			1,025,602
Effect of dilutive securities		—			—			—

Diluted weighted average common shares outstanding		6,847,697			1,083,276			1,025,602

Diluted income (loss) per common share	$	(0.04	)	$	0.00		$	0.00

The following common stock equivalents were excluded from the calculation of diluted net income (loss) per share because their effect would be anti-dilutive:


	Year Ended December 31,
	2013		2012		2011
Series A-1 Preferred Stock		—		2,156,114		2,156,114
Series A-2 Preferred Stock		—		392,274		392,274
Series B Preferred Stock		—		4,336,037		4,336,037
Series C Preferred Stock		—		5,909,906		5,909,906
Series D Preferred Stock		—		769,468		769,468
Series D-2 Preferred Stock		—		3,391,991		3,391,991
Effect of Converted Preferred Stock		13,189,920		—		—
Warrants to purchase Series D-2 Preferred Stock		—		180,784		180,784
Stock Options		2,313,970		3,249,702		2,885,417

Recently Issued Accounting Standards Adopted

Recently Issued Accounting Standards Adopted

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2013

Summary of Fair Value Measurement Financial Asset and Liabilities

Financial assets and liabilities subject to fair value measurements were as follows:


	Fair Value Measurements at December 31, 2013
				Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	Total			Level 1		Level 2		Level 3
Assets:
Cash and cash equivalents	$	90,434,435		$	90,434,435	$	—	$	—
Money market funds		26,046,974			26,046,974		—		—
Restricted cash		404,850			404,850		—		—

Total Assets	$	116,886,259		$	116,886,259	$	—	$	—


	Fair Value Measurements at December 31, 2012
				Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	Total			Level 1		Level 2		Level 3
Assets:
Cash and cash equivalents	$	18,695,197		$	18,695,197	$	—	$	—
Money market funds		29,047,958			29,047,958		—		—
Restricted cash		404,850			404,850		—		—

Total Assets	$	48,148,005		$	48,148,005	$	—	$	—

Liabilities:
Preferred stock warrant liability	$	(52,947	)	$	—	$	—	$	(52,947	)

Summary of Preferred Stock Warrant Liability


Balance at December 31, 2012	$	(52,947	)
Total unrealized gains (losses) included in earnings		(626,349	)
Settlement of preferred stock warrants		679,296

Balance at December 31, 2013	$	—

Estimated Useful Lives

Repairs and maintenance costs are expensed as incurred. Depreciation is computed using the straight-line method over the following estimated useful lives:


Computer equipment		3 years
Software		3 years
Furniture		10 years
Laboratory and office equipment		5 years
Leasehold improvements		Shorter of lease term or useful life

Computation of Basic and Diluted Income (Loss) Per Common Share

Basic and diluted income (loss) per common share is computed as follows:


	Year Ended December 31,
	2013			2012			2011
Net income (loss)	$	(260,835	)	$	8,361,755		$	6,717,120
Less: undistributed earnings allocated to participating securities		—			(8,361,755	)		(6,717,120	)

Net income (loss) allocable to common shares	$	(260,835	)	$	—		$	—

Basic weighted average common shares outstanding		6,847,697			1,083,276			1,025,602
Basic income (loss) per common share	$	(0.04	)	$	0.00		$	0.00
Net income (loss)	$	(260,835	)	$	8,361,755		$	6,717,120
Less: undistributed earnings allocated to participating securities and other add-backs to net income (loss)		—			(8,361,755	)		(6,717,120	)

Net income (loss) allocable to common shares	$	(260,835	)	$	—		$	—

Basic weighted average common shares outstanding		6,847,697			1,083,276			1,025,602
Effect of dilutive securities		—			—			—

Diluted weighted average common shares outstanding		6,847,697			1,083,276			1,025,602

Diluted income (loss) per common share	$	(0.04	)	$	0.00		$	0.00

Schedule of Dilutive Securities Used In Calculation of Diluted Earnings Per Share

The following common stock equivalents were excluded from the calculation of diluted net income (loss) per share because their effect would be anti-dilutive:


	Year Ended December 31,
	2013		2012		2011
Series A-1 Preferred Stock		—		2,156,114		2,156,114
Series A-2 Preferred Stock		—		392,274		392,274
Series B Preferred Stock		—		4,336,037		4,336,037
Series C Preferred Stock		—		5,909,906		5,909,906
Series D Preferred Stock		—		769,468		769,468
Series D-2 Preferred Stock		—		3,391,991		3,391,991
Effect of Converted Preferred Stock		13,189,920		—		—
Warrants to purchase Series D-2 Preferred Stock		—		180,784		180,784
Stock Options		2,313,970		3,249,702		2,885,417

Summary of Significant Revenue [Member]

Summary of Percentage of Customer Concentration

The following table represents the percentage of all significant revenue earned in the periods indicated:


	Year Ended December 31,
	2013			2012			2011
Servier		51.6	%		17.3	%		—
Boehringer		24.8	%		18.4	%		15.6	%
Gilead		13.8	%		—			—
Pfizer		6.0	%		8.7	%		10.8	%
Government Agencies		2.2	%		6.5	%		17.7	%
Eli Lilly		1.4	%		48.9	%		54.0	%

Summary of Significant Accounts Receivable[Member]

Summary of Percentage of Customer Concentration

The following table represents the percentage of all significant accounts receivable:


	December 31,
	2013			2012
Gilead		53.4	%		—
Pfizer.		12.3	%		45.4	%
Boehringer		12.2	%		18.0	%
Eli Lilly		7.0	%		28.2	%
Servier		6.4	%		—
Government Agencies		4.6	%		8.4	%

- Definition

Tabular disclosure of financial instruments measured at fair value, including those classified in shareholders' equity measured on a recurring or nonrecurring basis. Disclosures include, but are not limited to, fair value measurements recorded and the reasons for the measurements, level within the fair value hierarchy in which the fair value measurements are categorized and transfers between levels 1 and 2. Nonrecurring fair value measurements are those that are required or permitted in the statement of financial position in particular circumstances.

+ References+ Details

- Definition

Tabular disclosure of the fair value measurement of liabilities using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets), and gains or losses recognized in other comprehensive income (loss) and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issues, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs) by class of liability.

+ References+ Details

- Definition

Tabular disclosure of the nature of a concentration, a benchmark to which it is compared, and the percentage that the risk is to the benchmark.

+ References+ Details

Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2013

Property Plant And Equipment [Abstract]

Schedule of Property and Equipment

Property and equipment consists of the following:


	December 31,
	2013			2012
Computer equipment	$	2,379,254		$	2,003,706
Software		1,477,416			1,323,081
Furniture		599,650			599,650
Lab equipment		11,166,619			8,747,790
Office equipment		51,360			51,360
Leasehold improvements		4,893,770			4,881,706

Property and equipment		20,568,069			17,607,293
Less accumulated depreciation		(15,532,837	)		(14,339,497	)

Property and equipment, net	$	5,035,232		$	3,267,796

Shared-Based Payments (Tables)

12 Months Ended

Dec. 31, 2013

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Stock-Based Compensation Expense

The following stock-based compensation amounts were recognized for the periods indicated:


	Year Ended December 31,
	2013		2012		2011
Research and development	$	507,142	$	471,809	$	1,018,935
General and administrative		355,020		366,586		1,328,504

Total stock-based compensation expense	$	862,162	$	838,395	$	2,347,439

Schedule of Fair Value Option Award Estimated on the Date of Grant Using the Black-Scholes Option-Pricing Model

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


	Year Ended December 31,
	2013	2012	2011
Expected dividend yield..	0%	0%	0%
Expected volatility	53% - 67%	51%	62%
Risk-free interest rate	1.24% - 2.19%	1.18%	1.35%
Expected term.	7 years	7 years	7 years
Expected forfeiture rate..	5.06% - 5.57%	5.57%	5.58%

Schedule of Stock Option Activity

The following table summarizes stock option activity for 2013:


	Shares			Weighted- Average Exercise Price		Weighted-Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value (in thousands)
Outstanding, December 31, 2012		3,249,541		$	0.94		7.3
Granted		1,307,101			10.70
Exercised		(1,268,049	)		0.85
Forfeited or expired		(87,635	)		1.11

Outstanding, December 31, 2013		3,200,958			4.90		6.9	$	67,532

December 31, 2013:
Exercisable		1,688,251			0.94		4.8		42,311
Vested and expected to vest		3,022,948			4.64		6.8		64,574

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2013

Income Tax Disclosure [Abstract]

Components of the Company's Deferred Tax Assets (Liabilities)

The significant components of the Company’s deferred tax assets (liabilities) were as follows:


	December 31,
	2013			2012
Deferred income tax assets:
Federal U.S. net operating loss carryforward	$	36,561,195		$	35,330,167
State net operating loss carryforward		3,315,514			3,521,722
Research and development credit, net		3,785,612			2,777,899
Orphan drug credit, net		19,883,076			19,039,613
Deferred rent		5,132,458			5,218,002
Deferred revenue		8,216,695			9,379,064
Depreciation		1,438,477			1,247,772
Other		1,438,870			1,575,782

Gross deferred income tax assets		79,771,897			78,090,021
Valuation allowance		(79,376,945	)		(78,090,021	)

Net deferred income tax assets		394,952			—
Deferred income tax liabilities:
Other		(394,952	)		—

Gross deferred income tax liabilities		(394,952	)		—
Net deferred income tax asset/(liability)	$	—		$	—

Reconciliation of Reported Estimated Income Tax Benefit

The reconciliation of the reported estimated income tax benefit to the amount that would result by applying the U.S. federal statutory tax rate to the net income is as follows:


	Year Ended December 31,
	2013			2012			2011
United States federal tax at statutory rate	$	(91,293	)	$	2,926,615		$	2,350,992
State taxes (net of federal benefit)		609,476			1,460,289			1,480,185
Deferred income tax adjustments		(855,130	)		(512,375	)		—
Deferred state blended rate adjustments		(344,178	)		—			—
Research credit, net		(225,605	)		—			—
Orphan drug credit, net		(843,463	)		(4,895,671	)		(7,056,607	)
Other permanent items		2,931			7,627			4,696
Equity-based compensation		241,467			279,165			725,811
Fair value adjustment of preferred stock warrant liability		218,872			(52,743	)		(496,208	)
Change in valuation allowance		1,286,923			787,093			2,991,131

Income tax expense/(benefit)	$	—		$	—		$	—

Reconciliation of the Beginning and Ending Amount of Gross Unrecognized Tax Benefits

A reconciliation of the beginning and ending amount of gross unrecognized tax benefits is as follows:


	Year Ended December 31,
	2013		2012		2011
Beginning balance	$	1,592,357	$	1,533,986	$	1,246,025
Increases/(decreases) for current year tax positions		115,502		58,371		287,961
Increases/(decreases) for prior year tax positions		—		—		—
Decreases as a result of expiration of statute of limitations		—		—		—

Ending balance	$	1,707,859	$	1,592,357	$	1,533,986

Lease Exit Liability (Tables)

12 Months Ended

Dec. 31, 2013

Restructuring And Related Activities [Abstract]

Changes in Lease Exit Liability

Changes in the lease exit liability are as follows:


Accrual balance at December 31, 2011	$10,607,499
Principal payments	(533,560	)

Accrual balance at December 31, 2012	10,073,939
Principal payments	(628,769	)

Accrual balance at December 31, 2013	$9,445,170

Future Principal Payments Under Lease Agreement

Future principal payments to be made under the lease agreement for the next five years and thereafter as of December 31, 2013 are as follows:


2014	$	1,438,742
2015		1,641,905
2016		1,866,031
2017		2,113,118
2018		2,385,374
Thereafter		—

	$	9,445,170

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2013

Commitments And Contingencies Disclosure [Abstract]

Schedule of Minimum Future Lease Payments Payables

Future minimum lease payments under noncancelable operating leases at December 31, 2013 are as follows:


2014	$	3,651,421
2015		3,310,884
2016		3,410,210
2017		3,512,517
2018		2,780,398
Thereafter		—

	$	16,665,430

- Definition

Tabular disclosure of a lessee's leasing arrangements including: (1) the basis on which contingent rental payments are determined, (2) the existence and terms of renewal or purchase options and escalation clauses, (3) restrictions imposed by lease arrangements, such as those concerning dividends, additional debt, and further leasing, (4) rent holidays, rent concessions, or leasehold improvement incentives and unusual provisions or conditions. Disclosure may also include the specific period used to amortize material leasehold improvements made at the inception of the lease or during the lease term. Additionally, for operating leases having initial or remaining noncancelable lease terms in excess of one year: (a) future minimum rental payments required as of the date of the latest balance sheet presented, in the aggregate and for each of the five succeeding fiscal years, (b) the total of minimum rentals to be received in the future under noncancelable subleases as of the date of the latest balance sheet presented, and (c) for all operating leases, rental expense for each period for which an income statement is presented, with separate amounts for minimum rentals, contingent rentals, and sublease rentals. Rental payments under leases with terms of a month or less that were not renewed need not be included.

+ References+ Details

Quarterly Financial Information (Tables)

12 Months Ended

Dec. 31, 2013

Quarterly Financial Information Disclosure [Abstract]

Company's Consolidated Quarterly Results of Operations


	1^st Quarter			2^nd Quarter			3^rd Quarter		4^th Quarter
	(in thousands, except per share data)
2013
Revenue	$	10,598		$	12,299		$	20,232	$	14,906
Net income (loss)		(3,366	)		(294	)		6,604		(3,205	)
Net income (loss) per share, basic	$	(2.93	)	$	(0.24	)	$	0.14	$	(0.14	)
Net income (loss) per share, diluted	$	(2.93	)	$	(0.24	)	$	0.01	$	(0.14	)
2012
Revenue	$	20,510		$	17,435		$	16,082	$	9,799
Net income (loss)		4,320			3,546			2,601		(2,105	)
Net income (loss) per share, basic	$	0.00		$	0.00		$	0.00	$	(1.92	)
Net income (loss) per share, diluted	$	0.00		$	0.00		$	0.00	$	(1.92	)

Organization and Nature of Operations - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended	0 Months Ended
	Dec. 31, 2013	Oct. 16, 2013 IPO [Member]
Organization And Nature Of Business [Line Items]
MacroGenics incorporated date	Aug. 14, 2000
Initial public offering number of share sold		5,750,000
Initial public offering price per share		$ 16.00
Proceeds from initial public offering before offering expenses		$ 85.6

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013 Segment	Dec. 31, 2012
Accounting Policies [Abstract]
Number of operating segments	1
Original maturity of financial instruments	3 months	3 months
Allowance recorded	$ 0	$ 0
Amounts classified as restricted cash	$ 404,850	$ 404,850
Percentage of largest amount likely to be realized upon ultimate settlement	50.00%

Summary of Significant Accounting Policies - Summary of Fair Value Measurement Financial Asset and Liabilities (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Assets:
Cash and cash equivalents	$ 90,434,435	$ 18,695,197
Money market funds	26,046,974	29,047,958
Restricted cash	404,850	404,850
Total Assets	116,886,259	48,148,005
Liabilities:
Preferred stock warrant liability		(52,947)
Quoted Prices in Active Markets for Identical Assets Level 1 [Member]
Assets:
Cash and cash equivalents	90,434,435	18,695,197
Money market funds	26,046,974	29,047,958
Restricted cash	404,850	404,850
Total Assets	116,886,259	48,148,005
Liabilities:
Preferred stock warrant liability
Significant Other Observable Inputs Level 2 [Member]
Assets:
Cash and cash equivalents
Money market funds
Restricted cash
Total Assets
Liabilities:
Preferred stock warrant liability
Significant Unobservable Inputs Level 3 [Member]
Assets:
Cash and cash equivalents
Money market funds
Restricted cash
Total Assets
Liabilities:
Preferred stock warrant liability		$ (52,947)

Summary of Significant Accounting Policies - Summary of Preferred Stock Warrant Liability (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Settlement of preferred stock warrants	$ 1,860,591
Warrant [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance beginning of year	(52,947)
Total unrealized gains (losses) included in earnings	(626,349)
Settlement of preferred stock warrants	679,296
Balance end of year

Summary of Significant Accounting Policies - Summary of Percentage of Significant Revenue (Detail) (Sales [Member])	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Servier [Member]
Concentration Risk [Line Items]
Percentage of all significant revenue earned	51.60%	17.30%
Boehringer [Member]
Concentration Risk [Line Items]
Percentage of all significant revenue earned	24.80%	18.40%	15.60%
Gilead [Member]
Concentration Risk [Line Items]
Percentage of all significant revenue earned	13.80%
Pfizer [Member]
Concentration Risk [Line Items]
Percentage of all significant revenue earned	6.00%	8.70%	10.80%
Government Agencies [Member]
Concentration Risk [Line Items]
Percentage of all significant revenue earned	2.20%	6.50%	17.70%
Eli Lilly [Member]
Concentration Risk [Line Items]
Percentage of all significant revenue earned	1.40%	48.90%	54.00%

Summary of Significant Accounting Policies - Summary of Significant Accounts Receivable (Detail) (Accounts Receivable [Member])	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Gilead [Member]
Concentration Risk [Line Items]
Significant Accounts Receivable	53.40%
Pfizer [Member]
Concentration Risk [Line Items]
Significant Accounts Receivable	12.30%	45.40%
Boehringer [Member]
Concentration Risk [Line Items]
Significant Accounts Receivable	12.20%	18.00%
Eli Lilly [Member]
Concentration Risk [Line Items]
Significant Accounts Receivable	7.00%	28.20%
Servier [Member]
Concentration Risk [Line Items]
Significant Accounts Receivable	6.40%
Government Agencies [Member]
Concentration Risk [Line Items]
Significant Accounts Receivable	4.60%	8.40%

Summary of Significant Accounting Policies - Estimated Useful Lives (Detail)	12 Months Ended
	Dec. 31, 2013
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	3 years
Software [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	3 years
Furniture [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	10 years
Laboratory and Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	5 years
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Leasehold improvements	Shorter of lease term or useful life

Summary of Significant Accounting Policies - Computation of Basic and Diluted Income (Loss) Per Common Share (Detail) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accounting Policies [Abstract]
Net income (loss)	$ (3,205,000)	$ 6,604,000	$ (294,000)	$ (3,366,000)	$ (2,105,000)	$ 2,601,000	$ 3,546,000	$ 4,320,000	$ (260,835)	$ 8,361,755	$ 6,717,120
Less: undistributed earnings allocated to participating securities										(8,361,755)	(6,717,120)
Net income (loss) allocable to common shares									(260,835)
Basic weighted average common shares outstanding									6,847,697	1,083,276	1,025,602
Basic income (loss) per common share	$ (0.14)	$ 0.14	$ (0.24)	$ (2.93)	$ (1.92)	$ 0.00	$ 0.00	$ 0.00	$ (0.04)	$ 0.00	$ 0.00
Net income (loss)	(3,205,000)	6,604,000	(294,000)	(3,366,000)	(2,105,000)	2,601,000	3,546,000	4,320,000	(260,835)	8,361,755	6,717,120
Less: undistributed earnings allocated to participating securities and other add-backs to net income (loss)										(8,361,755)	(6,717,120)
Net income (loss) allocable to common shares									$ (260,835)
Basic weighted average common shares outstanding									6,847,697	1,083,276	1,025,602
Effect of dilutive securities
Diluted weighted average common shares outstanding									6,847,697	1,083,276	1,025,602
Diluted income (loss) per common share	$ (0.14)	$ 0.01	$ (0.24)	$ (2.93)	$ (1.92)	$ 0.00	$ 0.00	$ 0.00	$ (0.04)	$ 0.00	$ 0.00

Summary of Significant Accounting Policies - Schedule of Dilutive Securities Used In Calculation of Diluted Earnings Per Share (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Series A-1 Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Preferred Stock		2,156,114	2,156,114
Series A-2 Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Preferred Stock		392,274	392,274
Series B Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Preferred Stock		4,336,037	4,336,037
Series C Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Preferred Stock		5,909,906	5,909,906
Series D Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Preferred Stock		769,468	769,468
Series D-2 Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Preferred Stock		3,391,991	3,391,991
Effect of Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Preferred Stock	13,189,920
Warrant [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Preferred Stock		180,784	180,784
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Preferred Stock	2,313,970	3,249,702	2,885,417

- Definition

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

+ References+ Details

Property and Equipment - Schedule of Property and Equipment (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Property and equipment	$ 20,568,069	$ 17,607,293
Less accumulated depreciation	(15,532,837)	(14,339,497)
Property and equipment, net	5,035,232	3,267,796
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	2,379,254	2,003,706
Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	1,477,416	1,323,081
Furniture [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	599,650	599,650
Lab Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	11,166,619	8,747,790
Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	51,360	51,360
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	$ 4,893,770	$ 4,881,706

Stockholders' Equity (Deficit) - Additional Information (Detail) (USD $)	12 Months Ended					0 Months Ended		24 Months Ended	0 Months Ended	12 Months Ended	0 Months Ended	12 Months Ended		0 Months Ended	1 Months Ended	12 Months Ended		0 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2011	Dec. 31, 2012	May 16, 2006	Oct. 12, 2004	Oct. 16, 2013 IPO [Member]	Jan. 11, 2011 Series D-2 Convertible Preferred Stock [Member]	Dec. 31, 2003 Series A Preferred Stock [Member]	Oct. 12, 2004 Series B Preferred Stock [Member]	Dec. 31, 2013 Series B Preferred Stock [Member]	May 16, 2006 Series C Preferred Stock [Member]	Dec. 31, 2013 Series C Preferred Stock [Member]	Dec. 31, 2013 Series D Preferred Stock [Member]	Jul. 16, 2008 Series D Preferred Stock [Member] Raven Biotechnologies Inc [Member]	Mar. 31, 2011 Series D Preferred Stock [Member] Raven Biotechnologies Inc [Member]	Dec. 31, 2013 Series A- One Preferred Stock [Member]	Dec. 31, 2013 Series A- Two Preferred Stock [Member]	May 16, 2010 Series D Two Preferred Stock [Member]	Sep. 19, 2008 Series D Two Preferred Stock [Member]	Dec. 31, 2013 Series D Two Preferred Stock [Member]	Dec. 31, 2013 Undesignated Preferred Stock [Member]
Stockholders Equity [Line Items]
Number of shares issued or sold						5,000,000	18,427,388	34,239,374	71,401,237		110,952,217							6,916,110	38,337,678
Proceeds from issuance of convertible preferred stock		$ 12,014,816						$ 34,000,000	$ 30,300,000		$ 44,900,000								$ 24,800,000
Price per share						$ 16.00		$ 1.00
Related offering costs									238,000		101,246								156,788
Shares of common stock allocated				10,003,300	13,604,016
Shares issued to acquire entity														12,466,039	14,446,227
Purchased shares																		518,708	2,875,327
Exercise price																				0.65
Proceeds from sale of shares							12,000,000
Accrued noncumulative dividends on preferred stock										$ 0.0341		$ 0.0324	$ 0.0522			$ 0.08	$ 0.08			$ 0.0522
Convertible preferred stock series										1.14		1.00	1.00			1.506	1.00			1.00
Conversion price of preferred stock										$ 6.95		$ 7.70	$ 12.20			$ 12.39	$ 18.77			$ 12.20
Additional shares sold under over-allotments Option to underwriter						750,000
Proceeds from initial public offering net of expenses						$ 83,800,000
Reverse stock split	1-for-18.7739
Common stock, shares authorized	125,000,000		425,000,000
Undesignated preferred stock, shares authorized																					5,000,000
Undesignated preferred stock, par value																					$ 0.01
Undesignated preferred stock, shares issued																					0
Undesignated preferred stock, shares outstanding																					0

Shared-Based Payments - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended			60 Months Ended				12 Months Ended		12 Months Ended		12 Months Ended
	Mar. 16, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Feb. 28, 2003	Mar. 16, 2011 Stock Option One [Member] Original Options [Member]	Mar. 16, 2011 Stock Option Two [Member] Original Options [Member]	Dec. 31, 2013 Stock Option Plan 2000 [Member]	Dec. 31, 2013 Two Thousand and Three Stock Option Plan [Member]	Dec. 31, 2013 Two Thousand and Thirteen Stock Incentive Plan [Member]	Oct. 31, 2013 Two Thousand and Thirteen Stock Incentive Plan [Member]	Dec. 31, 2013 Equity Incentive Plan 2003 [Member]	Dec. 31, 2013 Maximum [Member] Equity Incentive Plan 2003 [Member]
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Aggregate of shares						2,051,644			130,725			1,960,168
Increase in aggregate of shares			4,336,730		3,790,760				150,297
Common stock share outstanding		3,200,958	3,249,541						23,657	2,559,011	618,290
weighted average exercise price	$ 0.94	$ 4.90	$ 0.94				$ 1.88	$ 4.69	$ 0.83	$ 1.52	$ 19.06
Common Stock			545,970		1,739,116
Percentage of Common stock share outstanding											4.00%
Description of exchange ratio of original options with replacement options	one-for-one basis
Total original Options exchanged for replacement Options		1,921,894
Options granted, maximum term														10 years
Expected life of option term		7 years	7 years	7 years									7 years
Common stock, shares issued		1,268,049	863,176	49,883
Cash proceeds from exercise of stock options		$ 1,100,000	$ 46,826	$ 53,225
Weighted-average grant-date fair value of options granted		$ 6.91	$ 0.94	$ 0.94
Aggregate intrinsic value of options exercised		5,400,000	271,929	102,418
Fair value of shares vested		487,603	879,024	1,108,107
Unrecognized compensation cost related to non-vested stock-based compensation arrangements		$ 7,600,000
Unrecognized compensation expense recognition period		4 years

Shared-Based Payments - Schedule of Stock-Based Compensation Expense (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 862,162	$ 838,395	$ 2,347,439
Research and Development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	507,142	471,809	1,018,935
General and Administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 355,020	$ 366,586	$ 1,328,504

Shared-Based Payments - Schedule of Fair Value Option Award Estimated on the Date of Grant Using the Black-Scholes Option-Pricing Model (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield		0.00%	0.00%
Expected volatility		51.00%	62.00%
Risk-free interest rate		1.18%	1.35%
Expected term	7 years	7 years	7 years
Expected forfeiture rate		5.57%	5.58%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	0.00%
Expected volatility	53.00%
Risk-free interest rate	1.24%
Expected forfeiture rate	5.06%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	67.00%
Risk-free interest rate	2.19%
Expected forfeiture rate	5.57%

Shared-Based Payments - Schedule of Stock Option Activity (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Mar. 16, 2011
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares, Outstanding, Beginning Balance	3,249,541
Shares, Granted	1,307,101
Shares, Exercised	(1,268,049)	(863,176)	(49,883)
Shares, Forfeited or expired	(87,635)
Shares, Outstanding, Ending Balance	3,200,958	3,249,541
Shares, Exercisable	1,688,251
Shares, Vested and expected to vest	3,022,948
Weighted- Average Exercise Price, Outstanding, Beginning Balance	$ 0.94			$ 0.94
Weighted- Average Exercise Price, Granted	$ 10.70
Weighted- Average Exercise Price, Exercised	$ 0.85
Weighted- Average Exercise Price, Forfeited or expired	$ 1.11
Weighted- Average Exercise Price, Outstanding, Ending Balance	$ 4.90	$ 0.94		$ 0.94
Weighted- Average Exercise Price, Exercisable	$ 0.94
Weighted- Average Exercise Price, Vested and expected to vest	$ 4.64
Weighted- Average Remaining Contractual Term, Outstanding	6 years 10 months 24 days	7 years 3 months 18 days
Weighted- Average Remaining Contractual Term, Exercisable	4 years 9 months 18 days
Weighted- Average Remaining Contractual Term, Vested and expected to vest	6 years 9 months 18 days
Aggregate Intrinsic Value, Outstanding, Ending Balance	$ 67,532
Aggregate Intrinsic Value, Exercisable	42,311
Aggregate Intrinsic Value, Vested and expected to vest	$ 64,574

Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
Income Taxes - Additional Information (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Taxes Disclosure [Line Items]
Provision for federal or state income taxes	$ 0	$ 0	$ 0
Net operating loss carryforwards expiration start year	2023
Net operating loss carryforwards expiration ending year	2033
Federal Tax credit expiration start year	2020
Federal Tax credit expiration ending year	2033
Net operating loss	8,500,000
Net operating losses limited for year minimum	2014
Net operating losses limited for year maximum	2027
Remaining portion of net operating losses	96,300,000
Net operating losses, recognized as a benefit through additional-paid-in-capital	1,800,000
Gross unrecognized tax benefits	0	1,100,000
Unrecognized interest or penalties	0	0	0
Income tax examination year subject to examination, Range start	2001
Income tax examination year subject to examination, Range End	2012
Minimum [Member]
Income Taxes Disclosure [Line Items]
Net operating losses limited for use utilized on an annual basis	200,000
Maximum [Member]
Income Taxes Disclosure [Line Items]
Net operating losses limited for use utilized on an annual basis	1,400,000
U.S. Federal Government [Member]
Income Taxes Disclosure [Line Items]
Net operating loss carryforwards	104,800,000
US Federal Tax credits carry forward	23,700,000
State and Local Jurisdiction [Member]
Income Taxes Disclosure [Line Items]
Net operating loss carryforwards	$ 60,300,000

Income Taxes - Components of the Company's Deferred Tax Assets (Liabilities) (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Deferred income tax assets:
Federal U.S. net operating loss carryforward	$ 36,561,195	$ 35,330,167
State net operating loss carryforward	3,315,514	3,521,722
Research and development credit, net	3,785,612	2,777,899
Orphan drug credit, net	19,883,076	19,039,613
Deferred rent	5,132,458	5,218,002
Deferred revenue	8,216,695	9,379,064
Depreciation	1,438,477	1,247,772
Other	1,438,870	1,575,782
Gross deferred income tax assets	79,771,897	78,090,021
Valuation allowance	(79,376,945)	(78,090,021)
Net deferred income tax assets	394,952
Deferred income tax liabilities:
Other	(394,952)
Gross deferred income tax liabilities	(394,952)
Net deferred income tax asset/(liability)

Income Taxes - Reconciliation of Reported Estimated Income Tax Benefit (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
United States federal tax at statutory rate	$ (91,293)	$ 2,926,615	$ 2,350,992
State taxes (net of federal benefit)	609,476	1,460,289	1,480,185
Deferred income tax adjustments	(855,130)	(512,375)
Deferred state blended rate adjustments	(344,178)
Research credit, net	(225,605)
Orphan drug credit, net	(843,463)	(4,895,671)	(7,056,607)
Other permanent items	2,931	7,627	4,696
Equity- based compensation	241,467	279,165	725,811
Fair value adjustment of preferred stock warrant liability	218,872	(52,743)	(496,208)
Change in valuation allowance	1,286,923	787,093	2,991,131
Income tax expense/(benefit)

Income Taxes - Reconciliation of the Beginning and Ending Amount of Gross Unrecognized Tax Benefits (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
Beginning balance	$ 1,592,357	$ 1,533,986	$ 1,246,025
Increases/(decreases) for current year tax positions	115,502	58,371	287,961
Increases/(decreases) for prior year tax positions
Decreases as a result of expiration of statute of limitations
Ending balance	$ 1,707,859	$ 1,592,357	$ 1,533,986

Lease Exit Liability - Additional Information (Detail) (USD $)	1 Months Ended	12 Months Ended
	Jul. 16, 2008	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Restructuring Cost and Reserve [Line Items]
Operating Lease	2018
Onetime purchase payment under purchase agreement	$ 5,000,000
Additional amounts recorded		0	0	0
Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Onetime payment paid under license of product	8,000,000
Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Onetime payment paid under license of product	$ 12,000,000
Convertible Preferred Stock Series D [Member]
Restructuring Cost and Reserve [Line Items]
Shares issued in connection with acquisition	12,466,039

Lease Exit Liability - Changes in Lease Exit Liability (Detail) (Contract Termination [Member], USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Contract Termination [Member]
Restructuring Cost and Reserve [Line Items]
Accrual Beginning Balance	$ 10,073,939	$ 10,607,499
Principal payments	(628,769)	(533,560)
Accrual Ending Balance	$ 9,445,170	$ 10,073,939

Lease Exit Liability - Future Principal Payments under Lease Agreement (Detail) (USD $)	Dec. 31, 2013
Future Minimum Leases Payments Under Leases (Line Items)
2014	$ 3,651,421
2015	3,310,884
2016	3,410,210
2017	3,512,517
2018	2,780,398
Thereafter
Total	16,665,430
Contract Termination [Member]
Future Minimum Leases Payments Under Leases (Line Items)
2014	1,438,742
2015	1,641,905
2016	1,866,031
2017	2,113,118
2018	2,385,374
Thereafter
Total	$ 9,445,170

Collaboration and License Agreements - Additional Information (Detail) (USD $)	12 Months Ended			1 Months Ended	12 Months Ended								12 Months Ended						1 Months Ended		12 Months Ended						1 Months Ended			12 Months Ended
	Dec. 31, 2013	Dec. 31, 2011	Dec. 31, 2012	Feb. 28, 2014 Subsequent Event [Member]	Dec. 31, 2013 Servier [Member]	Dec. 31, 2012 Servier [Member]	Dec. 31, 2011 Servier [Member]	Dec. 31, 2013 Servier [Member] Second Right to Develop Collaboration [Member]	Dec. 31, 2012 Servier [Member] Second Right to Develop Collaboration [Member]	Dec. 31, 2013 Gilead [Member] Molecule	Dec. 31, 2013 Gilead [Member] Minimum [Member]	Dec. 31, 2013 Gilead [Member] Maximum [Member]	Dec. 31, 2013 Gilead [Member] Expired Option Agreement [Member] Molecule	Dec. 31, 2013 Gilead [Member] License Agreement Terms [Member] Molecule	Dec. 31, 2013 Gilead [Member] Option Agreement [Member] Program	Dec. 31, 2013 Boehringer [Member] Payments Molecule	Dec. 31, 2012 Boehringer [Member]	Dec. 31, 2011 Boehringer [Member]	Jan. 31, 2011 Boehringer [Member] Series D-2 Convertible Preferred Stock [Member]	Oct. 31, 2010 Pfizer [Member] Molecule	Dec. 31, 2013 Pfizer [Member] Program	Dec. 31, 2012 Pfizer [Member]	Dec. 31, 2011 Pfizer [Member]	Dec. 31, 2013 Green Cross [Member]	Dec. 31, 2012 Green Cross [Member]	Dec. 31, 2011 Green Cross [Member]	Oct. 28, 2010 Eli Lilly [Member]	May 31, 2010 Eli Lilly [Member]	May 31, 2008 Eli Lilly [Member]	Dec. 31, 2013 Eli Lilly [Member]	Dec. 31, 2012 Eli Lilly [Member]	Dec. 31, 2011 Eli Lilly [Member]
License And Collaboration Agreements [Line Items]
Collaboration agreement date					November 2011			September 2012		January 2013						October 2010				October 2010				June 2010						October 2007
Non-refundable upfront payment					$ 20,000,000			$ 20,000,000		$ 7,500,000						$ 15,000,000				$ 5,000,000	$ 5,000,000			$ 1,000,000						$ 41,000,000
Additional license grant fees				15,000,000	30,000,000			65,000,000		7,500,000
Clinical milestone payments				5,000,000	47,000,000			98,000,000								41,000,000					17,000,000			4,500,000
Regulatory milestone payments					140,000,000			300,000,000								89,000,000
Sales milestone payments					208,000,000			630,000,000								83,000,000					195,000,000
Expected period of development					27 months			29 months		21 months
Recognized revenue under agreement					21,300,000	9,100,000	900,000	8,600,000	2,000,000	8,000,000						14,400,000	11,700,000	8,900,000			3,500,000	5,500,000	5,200,000	100,000	100,000	100,000				800,000	31,200,000	30,900,000
Milestone payment					10,000,000											5,000,000	2,000,000					500,000						5,000,000	50,000,000
Deferred revenue					900,000	10,000,000		9,400,000	18,000,000							12,800,000	14,000,000							650,000	750,000
Deferred revenue included in current liabilities	20,267,323		24,123,176			9,100,000		8,600,000	8,600,000	3,600,000						7,000,000	5,000,000				7,291	1,300,000		100,000	100,000
Deferred revenue included in long-term liabilities	7,135,687		19,956,343			900,000		800,000	9,400,000							5,800,000	9,000,000							550,000	650,000
Clinical milestone payments under agreement								5,000,000
Review period				30 days
Commercialization of molecules										4			1	1	2	10				2
Clinical milestone payments under agreement											20,000,000	25,000,000
Additional clinical, regulatory and sales milestone payments											240,000,000	250,000,000
Number of annual maintenance payments received																3
Received including upfront, annual maintenance and milestone payment																48,800,000
Preferred Stock purchased	$ 83,622,358	$ 12,014,815																	$ 10,000,000
Research obligation completion date																2015-09					2014-01
Period of agreement																				3 years
DART program																					1
Term of the agreement																								2020-06
Review of clinical data																											1 year

Commitments and Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating Leases [Line Items]
Deferred rent liability	$ 2.9	$ 2.8
Lessee leasing arrangements, operating leases, renewal term	5 years
Rent expense	$ 2.7	$ 2.7	$ 2.9
Lease [Member] \| Office and Laboratory Space [Member]
Operating Leases [Line Items]
Lease expiration date	Mar. 31, 2018
Lease [Member] \| Manufacturing Facilities [Member]
Operating Leases [Line Items]
Lease expiration date	Dec. 31, 2014
Sublease [Member] \| Office and Laboratory Space [Member]
Operating Leases [Line Items]
Lease expiration date	Dec. 31, 2018

Commitments and Contingencies - Schedule of Minimum Future Lease Payments Receivable (Detail) (USD $)	Dec. 31, 2013
Commitments And Contingencies Disclosure [Abstract]
2014	$ 3,651,421
2015	3,310,884
2016	3,410,210
2017	3,512,517
2018	2,780,398
Thereafter
Total	$ 16,665,430

Product Milestone Payments and Royalty Agreements - Additional Information (Detail) (USD $)	36 Months Ended		1 Months Ended
	Dec. 31, 2013	Jun. 30, 2005	Jun. 30, 2005 Minimum [Member]	Jun. 30, 2005 Maximum [Member]
Royalty Agreement [Line Items]
Additional consideration of asset purchase agreement		$ 10,950,000
Common stock shares		36,135
Maximum royalty payments percentage			1.75%	4.00%
Payments related to the additional considerations	$ 0

Employee Benefit Plan - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended
	Sep. 25, 2002 Age	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Contribution Pension And Other Postretirement Plans Disclosure [Abstract]
Eligibility of employee participation plan	21
Percentage of employee contribution to salary	100.00%
Percentage of employee vested contribution		100.00%
Company's contribution to plan total		$ 252,930	$ 225,195	$ 217,097

Quarterly Financial Information - Company's Consolidated Quarterly Results of Operations (Detail) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 14,906,000	$ 20,232,000	$ 12,299,000	$ 10,598,000	$ 9,799,000	$ 16,082,000	$ 17,435,000	$ 20,510,000	$ 58,034,668	$ 63,826,098	$ 57,207,366
Net income (loss)	$ (3,205,000)	$ 6,604,000	$ (294,000)	$ (3,366,000)	$ (2,105,000)	$ 2,601,000	$ 3,546,000	$ 4,320,000	$ (260,835)	$ 8,361,755	$ 6,717,120
Net income (loss) per share, basic	$ (0.14)	$ 0.14	$ (0.24)	$ (2.93)	$ (1.92)	$ 0.00	$ 0.00	$ 0.00	$ (0.04)	$ 0.00	$ 0.00
Net income (loss) per share, diluted	$ (0.14)	$ 0.01	$ (0.24)	$ (2.93)	$ (1.92)	$ 0.00	$ 0.00	$ 0.00	$ (0.04)	$ 0.00	$ 0.00

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References+ Details

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References+ Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 20

-Article 9

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Other Comprehensive Income

-URI http://asc.fasb.org/extlink&oid=6519514

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Net Income

-URI http://asc.fasb.org/extlink&oid=6518256

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 260

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 6: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.19)

-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 10

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-Subparagraph (SX 210.5-03.18)

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Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-Section S99

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-Subparagraph (SX 210.7-04.22)

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Reference 9: http://www.xbrl.org/2003/role/presentationRef

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-URI http://asc.fasb.org/extlink&oid=28358780&loc=d3e565-108580

Reference 10: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 19

-Article 5

+ Details

Subsequent Events - Additional Information (Detail) (Subsequent Event [Member], USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended
	Feb. 28, 2014
Subsequent Event [Line Items]
Clinical milestone payments	$ 5.0
Additional license grant fees	15.0
Review period	30 days
Common stock number of shares sold	1,800,000
Common stock, price per share	$ 36.50
Additional shares sold under over-allotments Option to underwriter	450,000
Additional shares sold under over-allotments option to underwriter, price per share	$ 36.50
Proceeds from sale of shares	76.7
Servier [Member]
Subsequent Event [Line Items]
Clinical milestone payments	5.0
Additional license grant fees	$ 15.0
Review period	30 days

Employee Benefit Plan	12 Months Ended
Employee Benefit Plan	Dec. 31, 2013
Compensation And Retirement Disclosure [Abstract]
Employee Benefit Plan	11. Employee Benefit Plan On September 25, 2002, the Company established the MacroGenics 401(k) Plan (the “Plan”) for its employees under Section 401(k) of the IRC. Under this Plan, all employees at least 21 years of age are eligible to participate in the Plan, starting on the first day of each month. Employees may contribute up to 100% of their salary, subject to government maximums. Employees are 100% vested in their contributions to the Plan. The Company’s contribution to the Plan, as determined by the Board of Directors, is discretionary. The Company’s contributions to the Plan totaled $252,930, $225,195 and $217,097 for the years ended December 31, 2013, 2012 and 2011, respectively.