Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2015	Feb. 22, 2016	Jun. 30, 2015
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2015
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	Yes
Entity Current Reporting Status	No
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		34,526,106
Entity Public Float			$ 1,050

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 196,172	$ 157,591
Marketable securities	142,877	0
Accounts receivable	1,224	2,935
Prepaid expenses	1,806	4,211
Other current assets	305	0
Total current assets	342,384	164,737
Restricted cash	0	300
Property and equipment, net	14,841	6,785
Other assets	2,044	2,064
Total assets	359,269	173,886
Current liabilities:
Accounts payable	2,967	1,669
Accrued expenses	11,708	7,930
Lease exit liability	2,020	1,642
Deferred revenue	5,866	14,248
Other liabilities	727	1,605
Total current liabilities	23,288	27,094
Lease exit liability, net of current portion	2,693	6,364
Deferred rent liability	7,320	2,670
Deferred revenue, net of current portion	12,631	16,472
Total liabilities	45,932	52,600
Stockholders' equity:
Common stock, $0.01 par value - 125,000,000 shares authorized, 34,345,754 and 27,995,638 shares outstanding at December 31, 2015 and 2014, respectively	343	280
Treasury stock, at cost; no shares at December 31, 2015 and 865 shares at December 31, 2014	0	(19)
Additional paid-in capital	547,185	335,071
Accumulated other comprehensive loss	(5)	0
Accumulated deficit	(234,186)	(214,046)
Total stockholders' equity	313,337	121,286
Total liabilities and stockholders' equity	$ 359,269	$ 173,886

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2015	Dec. 31, 2014
CONSOLIDATED BALANCE SHEETS [Abstract]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	125,000,000	125,000,000
Common stock, shares outstanding (in shares)	34,345,754	27,995,638
Treasury stock, shares (in shares)	0	865

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues:
Revenue from collaborative agreements	$ 99,368	$ 47,264	$ 56,753
Revenue from government agreements	1,486	533	1,282
Total revenues	100,854	47,797	58,035
Costs and expenses:
Research and development	98,271	70,186	46,582
General and administrative	22,765	15,926	11,087
Total costs and expenses	121,036	86,112	57,669
Income (loss) from operations	(20,182)	(38,315)	366
Other income (expense)	42	2	(627)
Net loss	(20,140)	(38,313)	(261)
Other comprehensive loss:
Unrealized loss on investments, net	(5)	0	0
Comprehensive loss	$ (20,145)	$ (38,313)	$ (261)
Basic and diluted net loss per common share (in dollars per share)	$ (0.63)	$ (1.40)	$ (0.04)
Basic and diluted weighted average number of common shares (in shares)	31,801,645	27,384,990	6,847,697

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income [Member]
Balance at Dec. 31, 2012	$ (8,238)	$ 2,948	$ 10	$ (58)	$ 164,334	$ (175,472)	$ 0
Balance (in shares) at Dec. 31, 2012		294,720,231	1,098,914	14,381
Share-based compensation	862	$ 0	$ 0	$ 0	862	0	0
Issuance of common stock, net of offering costs	83,623	$ 0	$ 58	$ 0	83,565	0	0
Issuance of common stock, net of offering costs (in shares)		0	5,750,000	0
Conversion of preferred stock to common stock	1,860	$ (2,948)	$ 171	$ 0	4,637	0	0
Conversion of preferred stock to common stock (in shares)		(294,720,231)	17,060,634	0
Stock option exercises	$ 1,068	$ 0	$ 13	$ 0	1,055	0	0
Stock option exercises (in shares)	1,268,049	0	1,268,049	0
Net loss	$ (261)	$ 0	$ 0	$ 0	0	(261)	0
Balance at Dec. 31, 2013	78,914	$ 0	$ 252	$ (58)	254,453	(175,733)	0
Balance (in shares) at Dec. 31, 2013		0	25,177,597	14,381
Share-based compensation	3,244	$ 0	$ 0	$ 0	3,244	0	0
Issuance of common stock, net of offering costs	$ 76,716	$ 0	$ 22	$ 0	76,694	0	0
Issuance of common stock, net of offering costs (in shares)		0	2,250,000	0
Stock option exercises (in shares)	568,906
Stock plan related activity	$ 725	$ 0	$ 6	$ (19)	738	0	0
Stock plan related activity (in shares)		0	568,041	865
Retirement of treasury stock	0	$ 0	$ 0	$ 58	(58)	0	0
Retirement of treasury stock (in shares)		0	0	(14,381)
Net loss	(38,313)	$ 0	$ 0	$ 0	0	(38,313)	0
Balance at Dec. 31, 2014	121,286	$ 0	$ 280	$ (19)	335,071	(214,046)	0
Balance (in shares) at Dec. 31, 2014		0	27,995,638	865
Share-based compensation	7,847	$ 0	$ 0	$ 0	7,847	0	0
Issuance of common stock, net of offering costs	$ 203,467	$ 0	$ 60	$ 0	203,407	0	0
Issuance of common stock, net of offering costs (in shares)		0	5,976,827	0
Stock option exercises (in shares)	374,214
Stock plan related activity	$ 882	$ 0	$ 3	$ (29)	908	0	0
Stock plan related activity (in shares)		0	373,289	925
Retirement of treasury stock	0	$ 0	$ 0	$ 48	(48)	0	0
Retirement of treasury stock (in shares)		0	0	(1,790)
Unrealized loss on investments	(5)	$ 0	$ 0	$ 0	0	0	(5)
Net loss	(20,140)	0	0	0	0	(20,140)	0
Balance at Dec. 31, 2015	$ 313,337	$ 0	$ 343	$ 0	$ 547,185	$ (234,186)	$ (5)
Balance (in shares) at Dec. 31, 2015		0	34,345,754	0

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating activities
Net loss	$ (20,140)	$ (38,313)	$ (261)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	2,863	1,822	1,193
Share-based compensation	7,847	3,244	862
Fair value adjustment of warrant liability	0	0	626
Changes in operating assets and liabilities:
Accounts receivable	1,711	(931)	42
Prepaid expenses	2,405	(3,239)	(834)
Restricted cash	300	105	0
Other assets	(285)	(1,179)	(375)
Accounts payable	(163)	(1,500)	(570)
Accrued expenses	3,545	4,346	2,347
Lease exit liability	(3,293)	(1,439)	(629)
Deferred revenue	(12,223)	3,317	(16,676)
Deferred rent	4,650	(234)	103
Other liabilities	(878)	1,242	0
Net cash used in operating activities	(13,661)	(32,759)	(14,172)
Cash flows from investing activities
Purchases of marketable securities	(142,910)	0	0
Purchases of property and equipment	(9,197)	(3,572)	(2,961)
Net cash used in investing activities	(152,107)	(3,572)	(2,961)
Cash flows from financing activities
Proceeds from issuance of common stock, net of offering costs	203,467	76,716	84,771
Proceeds from stock option exercises	911	744	1,100
Purchase of treasury stock	(29)	(19)	0
Net cash provided by financing activities	204,349	77,441	85,871
Net change in cash and cash equivalents	38,581	41,110	68,738
Cash and cash equivalents at beginning of period	157,591	116,481	47,743
Cash and cash equivalents at end of period	196,172	157,591	116,481
Noncash financing activities:
Conversion of preferred stock	$ 0	$ 0	$ 2,947

Organization and Nature of Operations	12 Months Ended
Organization and Nature of Operations	Dec. 31, 2015
Organization and Nature of Operations [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, as well as various autoimmune disorders and infectious 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.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2015

Summary of Significant 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 UK Limited. 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, stock-based compensation, 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.

Cash, Cash Equivalents and Marketable Securities

The Company considers all investments in highly liquid financial instruments with a maturity of 90 days or less at the date of purchase to be cash equivalents. Cash and cash equivalents includes investments in money market funds with commercial banks and financial institutions, securities issued by the U.S. government and its agencies, Government Sponsored Enterprise agency debt obligations and corporate debt obligations. Cash equivalents are stated at amortized cost, plus accrued interest, which approximates fair value.

The Company carries marketable securities classified as available-for-sale at fair value as determined by prices for identical or similar securities at the balance sheet date. Marketable securities consist of Level 2 financial instruments in the fair-value hierarchy. The Company records unrealized gains and losses as a component of other comprehensive loss within the statements of operations and comprehensive loss and as a separate component of stockholders' equity. Realized gains or losses on available-for-sale securities are determined using the specific identification method and the Company includes net realized gains and losses in other income (expense).

At each balance sheet date, the Company assesses available-for-sale securities in an unrealized loss position to determine whether the unrealized loss is other-than-temporary. The Company considers factors including: the significance of the decline in value compared to the cost basis, underlying factors contributing to a decline in the prices of securities in a single asset class, the length of time the market value of the security has been less than its cost basis, the security's relative performance versus its peers, sector or asset class, expected market volatility and the market and economy in general. The Company also evaluates whether it is more likely than not that it will be required to sell a security prior to recovery of its fair value. An impairment loss is recognized at the time the Company determines that a decline in the fair value below its cost basis is other-than-temporary. There were no unrealized losses at December 31, 2015 that the Company determined to be other-than-temporary.

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, 2015 or 2014, as the Company has a history of collecting on all outstanding accounts.

Restricted Cash

The Company was required to maintain certificates of deposit that served as collateral for corporate credit card accounts. $300,000 was classified as restricted cash on the consolidated balance sheet at December 31, 2014. The restriction was released during the year ended December 31, 2015.

Fair Value of Financial Instruments

The Company's financial instruments consist of cash and cash equivalents, marketable securities, accounts receivable, accounts payable and accrued expenses. The carrying amount of accounts receivable, accounts payable and accrued expenses are generally considered to be representative of their respective fair values because of their short-term nature. 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 measured at fair value on a recurring basis were as follows (in thousands):

	Fair Value Measurements at December 31, 2015
				Quoted Prices in Active Markets for Identical Assets			Significant Other Observable Inputs			Significant Unobservable Inputs
	Total			Level 1			Level 2			Level 3
Assets:
Money market funds		$	62,353		$	62,353		$	-		$	-
U.S Treasury securities			9,348			-			9,348			-
Government-sponsored enterprises			41,202			-			41,202			-
Corporate debt securities			137,928			-			137,928			-
Total assets measured at fair value (a)		$	250,831		$	62,353		$	188,478		$	-

	Fair Value Measurements at December 31, 2014
				Quoted Prices in Active Markets for Identical Assets			Significant Other Observable Inputs			Significant Unobservable Inputs
	Total			Level 1			Level 2			Level 3
Assets:
Money market funds			26,046			26,046			—			—
Restricted cash			300			300			—			—
Total assets measured at fair value		$	26,346		$	26,346		$	—		$	—

(a) Total assets measured at fair value at December 31, 2015 includes approximately $108.0 million reported in cash and cash equivalents on the balance sheet.

The fair value of Level 2 securities is determined from market pricing and other observable market inputs for similar securities obtained from various third-party data providers. These inputs either represent quoted prices for similar assets in active markets or have been derived from observable market data.

Concentration of Credit Risk

Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash, cash equivalents, marketable securities and accounts receivable. We maintain our cash and money market funds with financial institutions that are federally insured. While balances deposited in these institutions often exceed Federal Deposit Insurance Corporation limits, we have not experienced any losses on related accounts to date. Our investment policy limits investments to certain types of debt securities issued by the U.S. government, its agencies and institutions with investment-grade credit ratings and places restrictions on maturities and concentration by type and issuer. The counterparties are various corporations, financial institutions and government agencies of high credit standing.

For the years ended December 31, 2015, 2014 and 2013, the Company's collaboration revenue relates to agreements with Janssen Biotech, Inc. (Janssen), Takeda Pharmaceutical Company Limited (Takeda), Les Laboratoires Servier and Institut de Recherches Servier (collectively, Servier), Gilead Sciences, Inc. (Gilead), Boehringer Ingelheim GmbH (Boehringer), and Green Cross Corp. (Green Cross). Other revenue is related to contracts and research grants received from U.S. government agencies. The majority of the outstanding receivables are due from the Company's collaborators and U.S. government agencies.

The following table includes those collaborators that represent more than 10% of total revenue earned in the periods indicated:

	Year Ended December 31,
	2015		2014		2013
Janssen		71.7%		*		*
Servier		*		36.4%		51.6%
Boehringer		12.4%		28.6%		24.8%
Takeda		*		16.8%		*
Gilead		*		11.4%		13.8%

The following table includes those collaborators that represent more than 10% of accounts receivable at the date indicated:

	December 31,
	2015		2014
Janssen		39.0%		*
U.S. government		20.0 %		*
Servier		14.0 %		33.3%
Takeda		14.0%		*
Eli Lilly		13.0%		*
Boehringer		*		21.2 %
Green Cross		*		17.9 %

* Balance is less than 10%

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, 2015 and 2014, 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 likely than not 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: 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 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 does not directly control when any collaborator will achieve milestones or become liable for royalty payments.

When entering into a new collaboration arrangement or materially modifying an existing arrangement, 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 selling prices of deliverables under an arrangement may be derived using third-party evidence (TPE), or a best estimate of selling price (BESP), if vendor specific objective evidence (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, company-specific factors, and 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 evaluates whether the exclusive license has standalone value to the collaborator based on consideration of the relevant facts and circumstances for each arrangement. Factors considered in this determination include the research and development capabilities of the collaborator and the availability of relevant research expertise in the marketplace. In addition, the Company considers 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. 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. Total arrangement consideration is then allocated to each of the units of accounting using the relative-selling-price method. If facts and circumstances dictate that the exclusive license does not have stand-alone value, then the related payments are deferred and revenue is recognized throughout the period of performance.

Management reassesses the period of performance over which the Company recognizes deferred upfront license fees and makes adjustments as appropriate in the period in which a change in the estimated period of performance is identified. 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 is reasonably assured. 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 agreements.

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 (i) the consideration is commensurate with either (a) the entity's performance to achieve the milestone, or (b) 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, (ii) the consideration relates solely to past performance and (iii) 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, and therefore defers any 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. For right-to-develop agreements that include multiple deliverables, the Company determines the selling prices of deliverables under the arrangement 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 using the process for an exclusive license as described above.

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.

Right-to-develop agreements may contain cost-sharing provisions whereby the Company and the collaborator share the cost of research and development activities. Reimbursement of research and development expenses received in connection with these agreements is recorded as a reduction of such expenses.

Comprehensive Loss

Comprehensive loss represents net loss adjusted for the change during the periods attributed to unrealized gains and losses on available-for-sale securities. Comprehensive loss equals net loss for the years ended December 31, 2014 and 2013 as there were no unrealized gains or losses in those years.

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.

Basic and diluted loss per common share is computed as follows (in thousands except share and per share data):

	Year Ended December 31,
	2015			2014			2013
Numerator:
Net loss used for calculation of basic and diluted EPS	$	(20,140	)	$	(38,313	)	$	(261	)

Denominator:
Weighted average shares outstanding, basic		31,801,645			27,384,990			6,847,697
Effect of dilutive securities:
Stock options and restricted stock units		-			-			-
Weighted average shares outstanding, diluted		31,801,645			27,384,990			6,847,697

Net loss per share, basic and diluted	$	(0.63	)	$	(1.40	)	$	(0.04	)

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

	Year Ended December 31,
	2015		2014		2013
Effect of converted preferred stock		—		—		13,189,920
Stock options		1,955,398		2,094,904		2,313,970

Recently Issued Accounting Standards

In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (ASU 2014-09) as modified by ASU No. 2015-14, Revenue from Contracts with Customers: Deferral of the Effective Date (ASU 2014-14). ASU 2014-09 will eliminate transaction- and industry-specific revenue recognition guidance under current GAAP and replace it with a principle-based approach for determining revenue recognition. ASU 2014-09 will require that companies recognize revenue based on the value of transferred goods or services as they occur in the contract. The ASU also will require additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. ASU 2014-09 is effective for annual reporting periods beginning after December 15, 2017 and interim periods therein. Early adoption at the original effective date, for interim and annual reporting periods beginning after December 15, 2016, will be permitted. The new standard may be adopted either retrospectively or on a modified retrospective basis whereby the new standard would be applied to new contracts and existing contracts with remaining performance obligations as of the effective date, with a cumulative catch-up adjustment recorded to beginning retained earnings at the effective date for existing contracts with remaining performance obligations. Management is currently assessing what effect the adoption of ASU 2014-09 will have on the Company's consolidated financial statements and accompanying notes.

In November 2015, the FASB issued ASU No. 2015-17, Income Taxes, Balance Sheet Classification of Deferred Taxes (ASU 2015-17). ASU 2015-17 requires entities to present deferred tax assets and deferred tax liabilities as noncurrent on a classified balance sheet. ASU 2015-17 is effective for annual and interim reporting periods after December 15, 2016 and companies are permitted to apply ASU 2015-17 either prospectively or retrospectively. Early adoption of ASU 2015-17 is permitted. The Company has elected to early adopt ASU 2015-17 on a prospective basis in the first quarter of 2016. The adoption will have no effect on the Company's consolidated financial statements due to the full valuation allowance recognized against deferred tax assets.

The Company has evaluated all other ASUs issued 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.

Investments

12 Months Ended

Dec. 31, 2015

Investments [Abstract]

Investments

3. Investments

Available-for-sale investments as of December 31, 2015 were as follows (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury securities	$	9,354	$	1	$	(6	)	$	9,349
Government-sponsored enterprises		22,055		1		(9	)		22,047
Corporate debt securities		111,473		42		(34	)		111,481
Total	$	142,882	$	44	$	(49	)	$	142,877

All of the Company's available-for-sale investments held at December 31, 2015 had maturity dates of less than one year, and all available-for-sale investments in an unrealized loss position as of December 31, 2015 were in a loss position for less than twelve months.

- Definition

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

+ References + Details

Property and Equipment

12 Months Ended

Dec. 31, 2015

Property and Equipment [Abstract]

Property and Equipment

4. Property and Equipment

Property and equipment consists of the following (in thousands):

	December 31,
	2015			2014
Computer equipment	$	3,069		$	2,596
Software		1,801			1,683
Furniture and office equipment		919			751
Lab equipment		17,306			13,917
Leasehold improvements		11,936			5,193
Property and equipment		35,031			24,140
Less accumulated depreciation		(20,190	)		(17,355	)
Property and equipment, net	$	14,841		$	6,785

Property and equipment balance at December 31, 2015 includes approximately $1.7 million in assets that were purchased in 2015 but were not paid for by year end. Depreciation expense for the years ended December 31, 2015, 2014 and 2013 was $3.2 million, $1.8 million and $1.2 million, respectively.

Stockholders' Equity	12 Months Ended
Stockholders' Equity	Dec. 31, 2015
Stockholders' Equity [Abstract]
Stockholders' Equity	5. Stockholders' Equity 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. In October 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. In May 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. In July 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. In September 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. 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, 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. 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, 2015 or 2014. 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 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 February 2014, the Company completed a follow-on equity offering, in which the Company sold 1,800,000 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 proceeds of $76.7 million from this offering, net of underwriting discounts and commissions and other offering expenses. In January 2015, the Company's stock purchase agreement and investor agreement, each with Johnson & Johnson Innovation – JJDC, Inc. (JJDC) became effective (See Note 9 for additional information). Under these agreements, JJDC purchased 1,923,077 new shares of the Company's common stock at a price of $39.00 per share, representing proceeds of $75.0 million. In July 2015, the Company completed a follow-on equity offering, in which the Company sold 3,525,000 shares of its common stock at a price of $37.00 per share. Additionally, the underwriters of the offering exercised the full amount of their over-allotment option resulting in the sale of an additional 528,750 shares of the Company's common stock at a price of $37.00 per share. The Company received net proceeds of $141.0 million from this offering, net of underwriting discounts and commissions and other estimated offering expenses.

- Definition

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

+ References

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

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

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

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

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

Reference 6: http://www.xbrl.org/2003/role/presentationRef
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-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770

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

Reference 8: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 505
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-Subparagraph (SX 210.3-04)
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Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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-URI http://asc.fasb.org/extlink&oid=6405834&loc=d3e23285-112656

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

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

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

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

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section E

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section C

+ Details

Stock-based Compensation

12 Months Ended

Dec. 31, 2015

Stock-based Compensation [Abstract]

Stock-based Compensation

6. Stock-based Compensation

The Company's 2000 Stock Option and Incentive Plan (2000 Plan) allowed for the grant of awards in respect of an aggregate of 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. 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. As of December 31, 2015, under the 2000 Plan, there were options to purchase an aggregate of 19,571 shares of common stock outstanding at a weighted average exercise price of $0.81 per share.

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 2012, the maximum number of shares of common stock authorized to be issued by the Company under the 2003 Plan was increased 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.

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. As of December 31, 2015, under the 2003 Plan, there were options to purchase an aggregate of 1,649,193 shares of common stock outstanding at a weighted average exercise price of $1.72 per share.

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 was 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. During the year ended December 31, 2015, the maximum number of shares of common stock authorized to be issued by the Company under the 2013 Plan was increased to 4,087,098. 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, 2015, under the 2013 Plan, there were options to purchase an aggregate of 2,477,300 shares of common stock outstanding at a weighted average exercise price of $27.13 per share.

The following stock-based compensation amounts were recognized for the periods indicated (in thousands):

	Year Ended December 31,
	2015			2014			2013

Research and development		$	3,623		$	1,562		$	507
General and administrative			4,224			1,682			355
Total stock-based compensation expense		$	7,847		$	3,244		$	862

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,
	2015		2014		2013

Expected dividend yield		0%		0%		0%
Expected volatility		73% - 75%		67%		53% - 67%
Risk-free interest rate		1.6% - 2.1%		1.8% - 2.3%		1.2% - 2.2%
Expected term	6.25 years		6.25 years		7 years

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 estimates volatility based on 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 6.25 years. The Company uses a simplified method to calculate the average expected term.

In addition to the assumptions above, 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. 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 following table summarizes stock option and restricted stock unit (RSU) activity for 2015:

	Shares			Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value (in thousands)
Outstanding, December 31, 2014		3,572,116		$	11.40		7.3
Granted		987,680			31.59
Exercised		(374,214	)		2.45
Forfeited or expired		(39,518	)		23.44
Outstanding, December 31, 2015		4,146,064			16.90		7.4		$	59,344

December 31, 2015:
Exercisable		1,992,951			7.94		5.7			46,012
Vested and expected to vest		3,894,148			16.50		7.3			57,267

During 2015, 2014 and 2013 the Company issued 374,214, 568,906 and 1,268,049 net shares of common stock, respectively, in conjunction with stock option exercises and RSU lapses. The Company received cash proceeds from the exercise of stock options of approximately $0.9 million, $0.7 million and $1.1 million during 2015, 2014 and 2013, respectively.

The weighted-average grant-date fair value of options granted during 2015, 2014 and 2013 was $20.90, $17.41 and $6.91 per share, respectively. The total intrinsic value of options exercised during 2015, 2014 and 2013 was approximately $10.9 million, $14.5 million and $5.4 million, respectively. The total fair value of stock options which vested during 2015, 2014 and 2013 was $7.3 million, $3.0 million and $0.5 million, respectively. As of December 31, 2015, the total unrecognized compensation expense related to non-vested stock options and RSUs, net of related forfeiture estimates, was $30.5 million, which the Company expects to recognize over a weighted-average period of approximately four years.

Income Taxes

12 Months Ended

Dec. 31, 2015

Income Taxes [Abstract]

Income Taxes

7. Income Taxes

For the years ended December 31, 2015, 2014 and 2013 there was no provision for income taxes due to taxable losses generated, fully offset by a valuation allowance.

The significant components of the Company's deferred income tax assets (liabilities) were as follows (in thousands):

	December 31,
	2015			2014
Deferred income tax assets:
Federal U.S. net operating loss carryforward	$	57,949		$	55,358
State net operating loss carryforward		3,907			3,723
Research and development credit, net		10,278			7,177
Orphan drug credit, net		19,284			19,287
Deferred rent		2,947			4,069
Deferred revenue		6,632			3,989
Depreciation		1,597			1,337
Other		2,532			962
Gross deferred income tax assets		105,126			95,902
Valuation allowance		(104,399	)		(94,297	)
Net deferred income tax assets		727			1,605

Deferred income tax liabilities:
Prepaid expenditures		(727	)		(1,605	)
Gross deferred income tax liabilities		(727	)		(1,605	)
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 2015 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.

As of December 31, 2015, the Company has U.S. federal and state NOL carryforwards of approximately $165.6 million that will expire in various years beginning in 2020 through 2035. In addition, the Company has U.S. federal tax credits of $29.3 million which will expire in various years beginning in 2020 through 2035.

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 through the Company's acquisitions. As of December 31, 2015, $13.5 million of the Company's US Federal NOLs are limited for use over the years 2016 – 2028 in which a range of such amounts could be utilized on an annual basis of $0.2 million to $1.4 million. The remaining $152.1 million of NOLs is not limited and can be offset against future taxable income. Additionally, approximately $14.7 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 (in thousands):

	Year Ended December 31,
	2015			2014			2013

United States federal tax at statutory rate	$	(7,049	)	$	(13,410	)	$	(91	)
State taxes (net of federal benefit)		(897	)		(1,608	)		609
Deferred income tax adjustments		661			—			(855	)
Deferred state blended rate adjustments		(493	)		3,034			(344	)
Research credit, net		(3,296	)		(2,228	)		(226	)
Transaction cost deduction		—			(379	)		—
Transaction cost deduction - prior year adjustment		—			(564	)		—
Orphan drug credit, net		(106	)		(139	)		(843	)
Other permanent items		(25	)		(382	)		3
Equity-based compensation		1,102			756			241
Fair value adjustment of preferred stock warrant liability		—			—			219
Change in valuation allowance		10,103			14,920			1,287
Income tax expense/(benefit)	$	—		$	—		$	—

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

	Year Ended December 31,
	2015			2014			2013

Beginning balance		$	2,047		$	1,708		$	1,592
Increases/(decreases) for current year tax positions			357			242			116
Increases/(decreases) for prior year tax positions			21			97			—
Decreases as a result of expiration of statute of limitations			—			—			—
Ending balance		$	2,425		$	2,047		$	1,708

As of December 31, 2015 and 2014, of the total gross unrecognized tax benefits, approximately $2.0 million and $1.7 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, 2015, 2014 and 2013, 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 forward remain open to examination due to the carryover of unused net operating losses and tax credits.

Lease Exit Liability

12 Months Ended

Dec. 31, 2015

Lease Exit Liability [Abstract]

Lease Exit Liability

8. 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 into 2018.

Changes in the lease exit liability are as follows (in thousands):

Accrual balance at December 31, 2013	$	$9,445
Principal payments		(1,439	)
Accrual balance at December 31, 2014		8,006
Principal payments and other adjustments		(3,293	)
Accrual balance at December 31, 2015	$	$4,713

During 2015, the Company corrected an immaterial error attributed to the estimated lease term that resulted in a reduction of research and development expense of $1.9 million.

Future principal payments to be made under the lease agreement as of December 31, 2015 are as follows (in thousands):

2016	$	2,020
2017		2,281
2018		412
Total	$	4,713

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, 2015, 2014, and 2013.

Collaboration and Other Agreements	12 Months Ended
Collaboration and Other Agreements	Dec. 31, 2015
Collaboration and License Agreements [Abstract]
Collaboration and License Agreements	9. Collaboration and Other Agreements Janssen Biotech, Inc. In December 2014, the Company entered into a collaboration and license agreement with Janssen for the development and commercialization of MGD011 (also known as JNJ-64052781), a product candidate that incorporates the Company's proprietary DART technology to simultaneously target CD19 and CD3 for the potential treatment of B-cell hematological malignancies. The Company contemporaneously entered into an agreement with JJDC under which JJDC agreed to purchase 1,923,077 new shares of the Company's common stock for proceeds of $75.0 million. Upon closing the transaction in January 2015, the Company received a $50.0 million upfront payment from Janssen as well as the $75.0 million investment in the Company's common stock. Under the collaboration and license agreement, the Company granted an exclusive license to Janssen to develop and commercialize MGD011. Following the Company's submission of the Investigational New Drug (IND) application, Janssen became fully responsible for the development and commercialization of MGD011. Assuming successful development and commercialization, the Company could receive up to $205.0 million in clinical milestone payments, $220.0 million in regulatory milestone payments and $150.0 million in sales milestone payments. The Company determined that each potential future clinical and regulatory milestone is substantive. Although the sales milestones are not considered substantive, they will be 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. The Company may elect to fund a portion of late-stage clinical development in exchange for a profit share in the U.S. and Canada. If commercialized, the Company would be eligible to receive low double-digit royalties on any global net sales and has the option to co-promote the molecule with Janssen in the United States. The Company evaluated the collaboration and license agreement with Janssen and determined that it is a revenue arrangement with multiple deliverables, or performance obligations. The Company's substantive performance obligations under the collaboration and license agreement include the delivery of an exclusive license and research and development services during the pre-clinical research period (through the filing of the IND for MGD011). The Company evaluated the collaboration and license agreement with Janssen and determined that the license and pre-clinical research and development activities represented one unit of accounting, and thus the total arrangement consideration was allocated using the relative selling price method to the deliverables. After identifying the deliverables included within the arrangement, the Company determined its best estimate of selling price for each of the deliverables. The best estimate of selling price for the exclusive license was determined using a discounted cash flow model that includes level 3 fair value measurements. The best estimate of selling price for the research and development services was determined using third party evidence of other similar research and development arrangements, which are level 2 fair value measurements. The Company evaluated the stock purchase agreement and the collaboration and license agreement as one arrangement and determined that the stock purchase price of $39.00 per share exceeded the fair value of the common stock by $12.3 million. This excess was recognized in the same manner as the upfront payment. Of the total arrangement consideration of $125.0 million, the Company allocated $62.7 million to equity (representing the fair value of common stock purchased), $62.3 million to the license and pre-clinical research and development activities, and a de minimis amount to the ongoing research and development activities. The Company submitted the IND and therefore met its performance obligation during the year ended December 31, 2015. In July 2015, Janssen dosed the first patient in an open-label Phase 1 study of MGD011 which triggered a $10.0 million milestone to the Company. During the year ended December 31, 2015, the Company recognized revenues of approximately $72.3 million under the agreement. Takeda In May 2014, the Company entered into a license and option agreement with Takeda for the development and commercialization of MGD010, a product candidate that incorporates the Company's proprietary DART technology to simultaneously engage CD32B and CD79B, which are two B-cell surface proteins. MGD010 is being developed for the treatment of autoimmune disorders. Upon execution of the agreement, Takeda made a non-refundable payment of $15.0 million to the Company. Takeda has an option to obtain an exclusive worldwide license for MGD010 following the completion of a pre-defined Phase 1a study. The Company will lead all product development activities until that time. If Takeda exercises its option, it will assume responsibility for future development and pay the Company a license fee of $15.0 million. Assuming successful development and commercialization of MGD010, the Company is eligible to receive up to $93.0 million in clinical and regulatory milestone payments and $375.5 million in sales milestone payments. If commercialized, the Company would receive low double-digit to high-teen royalties on any global net sales and has the option to co-promote MGD010 with Takeda in the United States. Finally, the Company may elect to fund a portion of Phase 3 clinical development in exchange for a North American profit share. The Company evaluated the license and option agreement with Takeda and has determined that it is a revenue arrangement with multiple deliverables, or performance obligations. The Company's substantive performance obligations under the license and option agreement include exclusivity, research and development services through the Phase 1a study and delivery of a future license for an initial research compound. The Company concluded that the MGD010 option is substantive and that the license fee payable upon exercise of the option is not a deliverable at the inception of the arrangement as there is considerable uncertainty that the option would be exercised. The Company determined that each potential future clinical 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. The Company determined that these performance obligations represent a single unit of accounting, because the exclusivity clause does not have stand-alone value to Takeda without the Company's technical expertise and development through the pre-defined Phase 1a study. After identifying the deliverables included within the arrangement, the Company determined its best estimate of selling price. The Company allocated $10.0 million to the exclusivity clause to its technology and the research and development services and $5.0 million to the exclusive license for the initial research compound. The Company's determination of best estimate of selling price for the research and development services relied upon other similar transactions. The Company relied upon the income approach (e.g., future cash flows) to determine the value of the license of the to-be-delivered compound along with other similar license transactions with differing indications but similar stage of development. The portion of the up-front fee allocated to the MGD010 option is being recognized over an initial 24-month period, which represents the expected period of development through the completion of a pre-defined Phase 1a study. The portion of the up-front fee allocated to the license for the initial research compound was deferred until the research collaboration and license option agreement was executed and the license delivered. The Company recognized revenue of approximately $8.0 million and $3.0 million under the MGD010 agreement during the years ended December 31, 2015 and 2014, respectively. Revenue recognized during the year ended December 31, 2015 included a $3.0 million milestone payment received upon initiation of a Phase 1a trial of MGD010. At December 31, 2015, $2.1 million of revenue was deferred under this agreement, all of which was current. At December 31, 2014, $7.1 million of revenue was deferred under this agreement, $5.0 million of which was current and $2.1 million of which was non-current. In September 2014, the Company and Takeda executed a research collaboration and license option agreement, which formalized the license for the initial research compound contemplated in the May 2014 arrangement. Under the terms of the agreement, Takeda may identify up to three additional compounds, which will be subject to separate research and development plans. The Company determined that it could recognize the entire license fee allocated to this agreement as (1) the executed contract constituted persuasive evidence of an arrangement, (2) the delivery of the license occurred and the Company had no current or future performance obligations, (3) the total consideration for the license was fixed and known at the time of its execution and there were not any extended payment terms or rights of return, and (4) the cash was received. The Company is also entitled to receive reimbursements for research and development services provided to Takeda with respect to the initial research compound under a separate research plan. The Company recognized revenue of approximately $1.3 million and $5.0 million under this agreement during the years ended December 31, 2015 and 2014, respectively. Revenue during the year ended December 31, 2014 includes the $5.0 million license fee. Takeda terminated its option to license the first program under this research collaboration agreement in 2015 and retains an option for three others. Gilead In January 2013, the Company entered into an agreement with Gilead for the research, development and commercialization of up to four DART molecules. The time period for Gilead's exercise of three of the four options has expired. The Company received an initial $7.5 million license fee for the first DART molecule, and is eligible to receive an additional license fee of $7.5 million for the one remaining DART molecule if it is selected by Gilead. The Company is further entitled to receive up to an additional $20.0 million in pre-clinical milestones and up to $247.5 million in additional clinical, regulatory and sales milestones if Gilead exercises its remaining option and achieves all of the requisite milestones. The Company determined that any remaining licenses are conditional deliverables, which are substantive options that were not granted with a substantial discount. The Company 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 royalties on product sales. The Company evaluated the research collaboration agreement with Gilead and 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 stand-alone value for the license and research and development services, the combined unit of accounting (the upfront payment and the expected research and development reimbursements) was recognized ratably over a period of 21 months, which represented 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 did not recognize any revenue under this agreement for the year ended December 31, 2015. The Company recognized revenues of approximately $5.5 million and $8.0 million under this agreement for the years ended December 31, 2014 and 2013, respectively. There was no deferred revenue under this agreement at December 31, 2015 or 2014. No milestones have been achieved under this agreement. Servier In November 2011, the Company entered into a right-to-develop collaboration agreement with Servier under which the Company granted Servier an option to obtain an exclusive license to develop and commercialize enoblituzumab. In October 2015, Servier notified the Company that they would not exercise this option and this agreement terminated. Upon execution of the agreement, Servier made a nonrefundable payment of $20.0 million to the Company. 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 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 was being recognized ratably over the initial 27-month period, which represented the expected period of development and the Company's participation on the research and development committee. During 2014, the Company determined that the development period will last longer than originally estimated, and prospectively adjusted its period of recognition of the upfront payment to a 42-month period. During the years ended December 31, 2015, 2014 and 2013 the Company recognized revenue of $0.1 million, $0.7 million and $21.3 million, respectively, under this agreement. Revenue recognized during 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 enoblituzumab. At December 31, 2014, $0.1 million of revenue remained deferred under this agreement, all of which was current. There was no deferred revenue under this agreement at December 31, 2015. 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 molecules, consisting of those designated by the Company as MGD006 (also known as S80880) 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 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 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 from low double-digit to mid-teen royalties on net product sales in its territories. The Company evaluated the research collaboration agreement with Servier and 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 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 upfront license payment was deferred and initially recognized ratably over a 29-month period, which represented the expected development period. During 2014, the Company and Servier further refined the research plan related to the three DART molecules and as such, the development period was extended. Based on this revised development period, the Company prospectively adjusted its period of recognition of the upfront payment to a 75-month period. The impact of this change in accounting estimate reduced revenue that would have been recognized in 2014 by $3.7 million. During 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. Upon exercise of the option, the Company evaluated its performance obligations with respect to the license for MGD006. The Company's substantive performance obligations under this research collaboration include an exclusive license to its technology, technical, scientific and intellectual property support to the research plan and participation on an executive committee and a research and development committee. The Company determined that the performance obligations with respect to the 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 $15.0 million license fee was deferred and is being recognized ratably over a period of 82 months, which represents the expected development period for MGD006. In accordance with the agreement, the Company and Servier will share costs incurred to develop MGD006. Reimbursement of research and development expenses received in connection with this collaborative cost-sharing agreement is recorded as a reduction to research and development expense. During the years ended December 31, 2015 and 2014 the Company recorded approximately $0.5 million and $1.0 million as an offset to research and development costs under this collaboration arrangement, respectively. No such offset was recorded in 2013. During the years ended December 31, 2015, 2014 and 2013 the Company recognized revenue of $3.5 million, $16.7 million, and $8.6 million, respectively, under this agreement. Revenue during the year ended December 31, 2014 includes two $5.0 million milestone payments from Servier upon the achievement of clinical milestones related to the IND applications for MGD006 and MGD007 clearing the 30-day review period by the U.S. FDA. No milestones were recognized under this agreement during the years ended December 31, 2015 or 2013. At December 31, 2015, $14.4 million of revenue was deferred under this agreement, $3.3 million of which was current and $11.1 million of which was non-current. At December 31, 2014, $17.7 million of revenue was deferred under this agreement, $3.3 million of which was current and $14.4 million of which was non-current. Boehringer In October 2010 the Company entered into a collaboration and license agreement with Boehringer to discover, develop and commercialize multiple DART molecules that were to be evaluated during a five-year period that ended in October 2015. 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 DART molecules generated under the agreement. Upon execution of the agreement, the Company received an upfront payment of $15.0 million. The Company subsequently received three annual maintenance payments. These maintenance payments were being recognized over the estimated period of development. The Company has the potential to earn additional milestone payments of approximately $34.0 million related to pre-clinical and clinical development, $88.5 million related to regulatory milestones and $82.5 million related to sales milestones for each of the two ongoing programs under this agreement. The Company determined that each potential future pre-clinical, clinical 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 would be required to pay the Company mid-single digit royalties on product sales. 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 accounting and recognized over the expected obligation period associated with the research and development services through October 2015, which represented the estimated period of development. The Company and Boehringer 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. The Company recognized revenues of approximately $12.5 million, $13.7 million and $14.4 million during the years ended December 31, 2015, 2014 and 2013, respectively, under this agreement. Revenue recognized in the years ended December 31, 2015, 2014 and 2013 included milestone payments of $5.0 million, $2.0 million and $5.0 million, respectively, for the achievement of clinical milestones. At December 31, 2015, no revenue was deferred under this agreement. At December 31, 2014, $5.8 million of revenue was deferred under this agreement, all of which was current. Pfizer In October 2010, the Company entered into a three year agreement with Pfizer, Inc. (Pfizer) to discover, develop and commercialize up to two DART 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 the DART program licensed 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 evaluated the research collaboration agreement with Pfizer and 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 represented 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 recognized 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 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. The Company recognized revenues of approximately $0.5 million, $0.1 million and $3.5 million during the years ended December 31, 2015, 2014 and 2013, respectively. Included in the 2015 revenues are milestone payments totaling $0.5 million. As of December 31, 2015 and December 31, 2014, there was no remaining deferred revenue under this agreement. 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 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. In March 2014, the Company and Green Cross entered into an amendment to the original agreement, causing the terms of the original agreement to be materially modified. Upon execution of the amendment, the Company became eligible to receive reimbursement for costs incurred for Phase 2 and Phase 3 clinical trials up to $5.5 million as well as clinical development and commercial milestone payments of up to $2.5 million. The Company 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 evaluated the collaboration agreement with Green Cross and determined that it is a revenue arrangement with multiple deliverables or performance obligations. As a result of the material modification to the arrangement in March 2014, the Company reassessed the entire arrangement in accordance with the guidance provided by ASC 605-25, Multiple Element Arrangements (Revenue Recognition) as the original agreement was accounted for prior to adopting ASU 2009-13. The Company's substantive performance obligations under this agreement include an exclusive license to its technologies, research and development services, and participation in a joint steering committee. The Company concluded that the license and the reimbursements for research and development services do not have value on a standalone basis and therefore do not represent a separate unit of accounting. The initial $1.0 million upfront payment received by the Company upon execution of the original agreement 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. Further, due to the fact the research and development services are not deemed to have stand-alone value, revenue for those services will be recognized over the entire term of the agreement (through June 2020). As a result of reassessing the arrangement in accordance with ASC 605-25, the Company was required to record an adjustment on the date of the material modification to reflect the revenue that would have resulted had the entity applied the requirements of ASC 605-25 from the inception of the agreement. As a result, the Company recorded an additional $1.3 million of revenue during 2014. The Company recognized revenues of approximately $0.5 million, $1.7 million and $0.1 million under this agreement during the years ended December 31, 2015, 2014 and 2013, respectively. No milestones were achieved under this agreement during the years ended December 31, 2015, 2014 and 2013. At December 31, 2015, $2.0 million of revenue was deferred under this agreement, $0.4 million of which was current and $1.6 million of which was non-current. At December 31, 2014, there was a $0.5 million unbilled receivable balance under this agreement, which is included in other assets on the consolidated balance sheet. NIAID Contract The Company entered into a contract with the National Institute of Allergy and Infectious Diseases (NIAID), effective as of September 15, 2015, to perform product development and to advance up to two DART molecules, including MGD014. Under this contract, the Company will develop these product candidates for Phase 1/2 clinical trials as therapeutic agents, in combination with latency reversing treatments, to deplete cells infected with human immunodeficiency virus (HIV) infection. This contract includes a base period of $7.5 million to support development of MGD014 through IND application submission with the FDA, as well as up to $17.0 million in additional development funding via NIAID options. Should NIAID fully exercise such options, the Company could receive total payments of up to $24.5 million. The total potential period of performance under the award is from September 15, 2015 through September 14, 2022. The Company recognized $0.2 million in revenue under this contract during the year ended December 31, 2015.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2015

Commitments and Contingencies [Abstract]

Commitments and Contingencies

10. Commitments and Contingencies

Operating Leases

The Company leases manufacturing, office and laboratory space in Rockville, Maryland under five leases that have terms that expire between 2018 and 2022 unless renewed. This includes a seven-year lease executed in July 2015 for additional space that the Company intends to use as mixed-use office, laboratory and manufacturing space. Under the terms of the lease, which commenced on January 1, 2016, the Company received an assignment fee from the former tenant and a tenant improvement allowance from the landlord totaling $5.1 million, which has been recorded as deferred rent and will be recognized over the lease term. The Company also leases office and laboratory space in South San Francisco under a lease that expires on February 28, 2018.

All of the leases contain rent escalation clauses and certain leases contain rent abatements. 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, 2015 and 2014, the Company had recorded a deferred rent liability of $7.3 million and $2.7 million, respectively. Rent expense for the years ended December 31, 2015, 2014 and 2013 was $0.9 million, $2.0 million and $2.7 million, respectively.

Future minimum lease payments under noncancelable operating leases as of December 31, 2015 are as follows (in thousands):

2016	$	6,130
2017		6,314
2018		4,210
2019		3,803
2020		2,142
Thereafter		5,210
	$	27,809

Contingencies

From time to time, the Company may be subject to various litigation and related matters arising in the ordinary course of business. The Company does not believe it is currently subject to any material matters where there is at least a reasonable possibility that a material loss may be incurred.

Employee Benefit Plan	12 Months Ended
Employee Benefit Plan	Dec. 31, 2015
Employee Benefit Plan [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 $0.4 million, $0.3 million and $0.3 million for the years ended December 31, 2015, 2014 and 2013, respectively.

Quarterly Financial Information (Unaudited)

12 Months Ended

Dec. 31, 2015

Quarterly Financial Information (Unaudited) [Abstract]

Quarterly Financial Information (Unaudited)

12. Quarterly Financial Information (unaudited)

	1st Quarter			2nd Quarter			3rd Quarter			4th Quarter
	(in thousands, except per share data)
2015
Revenue	$	71,279		$	6,716		$	14,681		$	8,178
Net income (loss)		45,129			(21,376	)		(15,442	)		(28,451	)
Net income (loss) per share, basic	$	1.53		$	(0.71	)	$	(0.46	)	$	(0.83	)
Net income (loss) per share, diluted	$	1.42		$	(0.71	)	$	(0.46	)	$	(0.83	)

2014
Revenue	$	14,719		$	9,220		$	18,382		$	5,476
Net loss		(3,108	)		(12,259	)		(3,928	)		(19,018	)
Net loss per share, basic and diluted	$	(0.12	)	$	(0.44	)	$	(0.14	)	$	(0.68	)

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2015

Summary of Significant Accounting Policies [Abstract]

Basis of Presentation and Principles of Consolidation

Use of Estimates

Cash and Cash Equivalents

Cash, Cash Equivalents and Marketable Securities

Accounts Receivable

Restricted Cash

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 measured at fair value on a recurring basis were as follows (in thousands):

	Fair Value Measurements at December 31, 2015
				Quoted Prices in Active Markets for Identical Assets			Significant Other Observable Inputs			Significant Unobservable Inputs
	Total			Level 1			Level 2			Level 3
Assets:
Money market funds		$	62,353		$	62,353		$	-		$	-
U.S Treasury securities			9,348			-			9,348			-
Government-sponsored enterprises			41,202			-			41,202			-
Corporate debt securities			137,928			-			137,928			-
Total assets measured at fair value (a)		$	250,831		$	62,353		$	188,478		$	-

	Fair Value Measurements at December 31, 2014
				Quoted Prices in Active Markets for Identical Assets			Significant Other Observable Inputs			Significant Unobservable Inputs
	Total			Level 1			Level 2			Level 3
Assets:
Money market funds			26,046			26,046			—			—
Restricted cash			300			300			—			—
Total assets measured at fair value		$	26,346		$	26,346		$	—		$	—

(a) Total assets measured at fair value at December 31, 2015 includes approximately $108.0 million reported in cash and cash equivalents on the balance sheet.

Concentration of Credit Risk

The following table includes those collaborators that represent more than 10% of total revenue earned in the periods indicated:

	Year Ended December 31,
	2015		2014		2013
Janssen		71.7%		*		*
Servier		*		36.4%		51.6%
Boehringer		12.4%		28.6%		24.8%
Takeda		*		16.8%		*
Gilead		*		11.4%		13.8%

The following table includes those collaborators that represent more than 10% of accounts receivable at the date indicated:

	December 31,
	2015		2014
Janssen		39.0%		*
U.S. government		20.0 %		*
Servier		14.0 %		33.3%
Takeda		14.0%		*
Eli Lilly		13.0%		*
Boehringer		*		21.2 %
Green Cross		*		17.9 %

* Balance is less than 10%

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

Income Taxes

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

Comprehensive Income (Loss)

Comprehensive Loss

Stock-based Compensation

Net Income (Loss) Per Share

Basic and diluted loss per common share is computed as follows (in thousands except share and per share data):

	Year Ended December 31,
	2015			2014			2013
Numerator:
Net loss used for calculation of basic and diluted EPS	$	(20,140	)	$	(38,313	)	$	(261	)

Denominator:
Weighted average shares outstanding, basic		31,801,645			27,384,990			6,847,697
Effect of dilutive securities:
Stock options and restricted stock units		-			-			-
Weighted average shares outstanding, diluted		31,801,645			27,384,990			6,847,697

Net loss per share, basic and diluted	$	(0.63	)	$	(1.40	)	$	(0.04	)

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

	Year Ended December 31,
	2015		2014		2013
Effect of converted preferred stock		—		—		13,189,920
Stock options		1,955,398		2,094,904		2,313,970

Recently Issued Accounting Standards

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2015

Summary of Fair Value Measurement Financial Asset and Liabilities

Financial assets measured at fair value on a recurring basis were as follows (in thousands):

	Fair Value Measurements at December 31, 2015
				Quoted Prices in Active Markets for Identical Assets			Significant Other Observable Inputs			Significant Unobservable Inputs
	Total			Level 1			Level 2			Level 3
Assets:
Money market funds		$	62,353		$	62,353		$	-		$	-
U.S Treasury securities			9,348			-			9,348			-
Government-sponsored enterprises			41,202			-			41,202			-
Corporate debt securities			137,928			-			137,928			-
Total assets measured at fair value (a)		$	250,831		$	62,353		$	188,478		$	-

	Fair Value Measurements at December 31, 2014
				Quoted Prices in Active Markets for Identical Assets			Significant Other Observable Inputs			Significant Unobservable Inputs
	Total			Level 1			Level 2			Level 3
Assets:
Money market funds			26,046			26,046			—			—
Restricted cash			300			300			—			—
Total assets measured at fair value		$	26,346		$	26,346		$	—		$	—

(a) Total assets measured at fair value at December 31, 2015 includes approximately $108.0 million reported in cash and cash equivalents on the balance sheet.

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 loss per common share is computed as follows (in thousands except share and per share data):

	Year Ended December 31,
	2015			2014			2013
Numerator:
Net loss used for calculation of basic and diluted EPS	$	(20,140	)	$	(38,313	)	$	(261	)

Denominator:
Weighted average shares outstanding, basic		31,801,645			27,384,990			6,847,697
Effect of dilutive securities:
Stock options and restricted stock units		-			-			-
Weighted average shares outstanding, diluted		31,801,645			27,384,990			6,847,697

Net loss per share, basic and diluted	$	(0.63	)	$	(1.40	)	$	(0.04	)

Schedule of Antidilutive Securities Excluded from the Calculation of Diluted Income (Loss) Per Share

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

	Year Ended December 31,
	2015		2014		2013
Effect of converted preferred stock		—		—		13,189,920
Stock options		1,955,398		2,094,904		2,313,970

Summary of Significant Revenue [Member]

Summary of Percentage of Customer Concentration

The following table includes those collaborators that represent more than 10% of total revenue earned in the periods indicated:

	Year Ended December 31,
	2015		2014		2013
Janssen		71.7%		*		*
Servier		*		36.4%		51.6%
Boehringer		12.4%		28.6%		24.8%
Takeda		*		16.8%		*
Gilead		*		11.4%		13.8%

Summary of Significant Accounts Receivable[Member]

Summary of Percentage of Customer Concentration

The following table includes those collaborators that represent more than 10% of accounts receivable at the date indicated:

	December 31,
	2015		2014
Janssen		39.0%		*
U.S. government		20.0 %		*
Servier		14.0 %		33.3%
Takeda		14.0%		*
Eli Lilly		13.0%		*
Boehringer		*		21.2 %
Green Cross		*		17.9 %

* Balance is less than 10%

Investments (Tables)

12 Months Ended

Dec. 31, 2015

Investments [Abstract]

Available-for-sale Securities

Available-for-sale investments as of December 31, 2015 were as follows (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury securities	$	9,354	$	1	$	(6	)	$	9,349
Government-sponsored enterprises		22,055		1		(9	)		22,047
Corporate debt securities		111,473		42		(34	)		111,481
Total	$	142,882	$	44	$	(49	)	$	142,877

- Definition

Tabular disclosure of available-for-sale securities which includes, but is not limited to, changes in the cost basis and fair value, fair value and gross unrealized gain (loss), fair values by type of security, contractual maturity and classification, amortized cost basis, contracts to acquire securities to be accounted for as available-for-sale, debt maturities, transfers to trading, change in net unrealized holding gain (loss) net of tax, continuous unrealized loss position fair value, aggregate losses qualitative disclosures, other than temporary impairment (OTTI) losses or other disclosures related to available for sale securities.

+ References + Details

Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2015

Property and Equipment [Abstract]

Schedule of Property and Equipment

Property and equipment consists of the following (in thousands):

	December 31,
	2015			2014
Computer equipment	$	3,069		$	2,596
Software		1,801			1,683
Furniture and office equipment		919			751
Lab equipment		17,306			13,917
Leasehold improvements		11,936			5,193
Property and equipment		35,031			24,140
Less accumulated depreciation		(20,190	)		(17,355	)
Property and equipment, net	$	14,841		$	6,785

Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2015

Stock-based Compensation [Abstract]

Schedule of Stock-Based Compensation Expense

The following stock-based compensation amounts were recognized for the periods indicated (in thousands):

	Year Ended December 31,
	2015			2014			2013

Research and development		$	3,623		$	1,562		$	507
General and administrative			4,224			1,682			355
Total stock-based compensation expense		$	7,847		$	3,244		$	862

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

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,
	2015		2014		2013

Expected dividend yield		0%		0%		0%
Expected volatility		73% - 75%		67%		53% - 67%
Risk-free interest rate		1.6% - 2.1%		1.8% - 2.3%		1.2% - 2.2%
Expected term	6.25 years		6.25 years		7 years

Schedule of Stock Option and Restricted Stock Unit Activity

The following table summarizes stock option and restricted stock unit (RSU) activity for 2015:

	Shares			Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value (in thousands)
Outstanding, December 31, 2014		3,572,116		$	11.40		7.3
Granted		987,680			31.59
Exercised		(374,214	)		2.45
Forfeited or expired		(39,518	)		23.44
Outstanding, December 31, 2015		4,146,064			16.90		7.4		$	59,344

December 31, 2015:
Exercisable		1,992,951			7.94		5.7			46,012
Vested and expected to vest		3,894,148			16.50		7.3			57,267

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2015

Income Taxes [Abstract]

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

The significant components of the Company's deferred income tax assets (liabilities) were as follows (in thousands):

	December 31,
	2015			2014
Deferred income tax assets:
Federal U.S. net operating loss carryforward	$	57,949		$	55,358
State net operating loss carryforward		3,907			3,723
Research and development credit, net		10,278			7,177
Orphan drug credit, net		19,284			19,287
Deferred rent		2,947			4,069
Deferred revenue		6,632			3,989
Depreciation		1,597			1,337
Other		2,532			962
Gross deferred income tax assets		105,126			95,902
Valuation allowance		(104,399	)		(94,297	)
Net deferred income tax assets		727			1,605

Deferred income tax liabilities:
Prepaid expenditures		(727	)		(1,605	)
Gross deferred income tax liabilities		(727	)		(1,605	)
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 (in thousands):

	Year Ended December 31,
	2015			2014			2013

United States federal tax at statutory rate	$	(7,049	)	$	(13,410	)	$	(91	)
State taxes (net of federal benefit)		(897	)		(1,608	)		609
Deferred income tax adjustments		661			—			(855	)
Deferred state blended rate adjustments		(493	)		3,034			(344	)
Research credit, net		(3,296	)		(2,228	)		(226	)
Transaction cost deduction		—			(379	)		—
Transaction cost deduction - prior year adjustment		—			(564	)		—
Orphan drug credit, net		(106	)		(139	)		(843	)
Other permanent items		(25	)		(382	)		3
Equity-based compensation		1,102			756			241
Fair value adjustment of preferred stock warrant liability		—			—			219
Change in valuation allowance		10,103			14,920			1,287
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 (in thousands):

	Year Ended December 31,
	2015			2014			2013

Beginning balance		$	2,047		$	1,708		$	1,592
Increases/(decreases) for current year tax positions			357			242			116
Increases/(decreases) for prior year tax positions			21			97			—
Decreases as a result of expiration of statute of limitations			—			—			—
Ending balance		$	2,425		$	2,047		$	1,708

Lease Exit Liability (Tables)

12 Months Ended

Dec. 31, 2015

Lease Exit Liability [Abstract]

Changes in Lease Exit Liability

Changes in the lease exit liability are as follows (in thousands):

Accrual balance at December 31, 2013	$	$9,445
Principal payments		(1,439	)
Accrual balance at December 31, 2014		8,006
Principal payments and other adjustments		(3,293	)
Accrual balance at December 31, 2015	$	$4,713

During 2015, the Company corrected an immaterial error attributed to the estimated lease term that resulted in a reduction of research and development expense of $1.9 million.

Future Principal Payments Under Lease Agreement

Future principal payments to be made under the lease agreement as of December 31, 2015 are as follows (in thousands):

2016	$	2,020
2017		2,281
2018		412
Total	$	4,713

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2015

Commitments and Contingencies [Abstract]

Schedule of Minimum Future Lease Payments

Future minimum lease payments under noncancelable operating leases as of December 31, 2015 are as follows (in thousands):

2016	$	6,130
2017		6,314
2018		4,210
2019		3,803
2020		2,142
Thereafter		5,210
	$	27,809

- 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 (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2015

Quarterly Financial Information (Unaudited) [Abstract]

Company's Consolidated Quarterly Results of Operations

12. Quarterly Financial Information (unaudited)

	1st Quarter			2nd Quarter			3rd Quarter			4th Quarter
	(in thousands, except per share data)
2015
Revenue	$	71,279		$	6,716		$	14,681		$	8,178
Net income (loss)		45,129			(21,376	)		(15,442	)		(28,451	)
Net income (loss) per share, basic	$	1.53		$	(0.71	)	$	(0.46	)	$	(0.83	)
Net income (loss) per share, diluted	$	1.42		$	(0.71	)	$	(0.46	)	$	(0.83	)

2014
Revenue	$	14,719		$	9,220		$	18,382		$	5,476
Net loss		(3,108	)		(12,259	)		(3,928	)		(19,018	)
Net loss per share, basic and diluted	$	(0.12	)	$	(0.44	)	$	(0.14	)	$	(0.68	)

Summary of Significant Accounting Policies (Details)	12 Months Ended
Summary of Significant Accounting Policies (Details)	Dec. 31, 2015 USD ($) Segment	Dec. 31, 2014 USD ($)
Summary of Significant Accounting Policies [Abstract]
Number of operating segments \| Segment	1
Allowance recorded	$ 0	$ 0
Amounts classified as restricted cash	0	300,000
Impaired assets	0	0
Assets held-for-sale	0	$ 0
Cash and cash equivalents	$ 108,000,000

Summary of Significant Accounting Policies - Summary of Fair Value Measurement Financial Asset and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Assets [Abstract]
Cash and cash equivalents	$ 108,000
Restricted cash	0	$ 300
Total Assets	250,831	26,346
Money Market Funds [Member]
Assets [Abstract]
Cash and cash equivalents	62,353	26,046
U.S. Treasury Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Current	9,348
Government-sponsored Enterprises [Member]
Assets [Abstract]
Available-for-sale Securities, Current	41,202
Corporate Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Current	137,928
Quoted Prices in Active Markets for Identical Assets Level 1 [Member]
Assets [Abstract]
Restricted cash		300
Total Assets	62,353	26,346
Quoted Prices in Active Markets for Identical Assets Level 1 [Member] \| Money Market Funds [Member]
Assets [Abstract]
Cash and cash equivalents	62,353	26,046
Quoted Prices in Active Markets for Identical Assets Level 1 [Member] \| U.S. Treasury Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Current	0
Quoted Prices in Active Markets for Identical Assets Level 1 [Member] \| Government-sponsored Enterprises [Member]
Assets [Abstract]
Available-for-sale Securities, Current	0
Quoted Prices in Active Markets for Identical Assets Level 1 [Member] \| Corporate Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Current	0
Significant Other Observable Inputs, Level 2 [Member]
Assets [Abstract]
Restricted cash		0
Total Assets	188,478	0
Significant Other Observable Inputs, Level 2 [Member] \| Money Market Funds [Member]
Assets [Abstract]
Cash and cash equivalents	0	0
Significant Other Observable Inputs, Level 2 [Member] \| U.S. Treasury Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Current	9,348
Significant Other Observable Inputs, Level 2 [Member] \| Government-sponsored Enterprises [Member]
Assets [Abstract]
Available-for-sale Securities, Current	41,202
Significant Other Observable Inputs, Level 2 [Member] \| Corporate Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Current	137,928
Significant Unobservable Inputs, Level 3 [Member]
Assets [Abstract]
Restricted cash		0
Total Assets	0	0
Significant Unobservable Inputs, Level 3 [Member] \| Money Market Funds [Member]
Assets [Abstract]
Cash and cash equivalents	0	$ 0
Significant Unobservable Inputs, Level 3 [Member] \| U.S. Treasury Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Current	0
Significant Unobservable Inputs, Level 3 [Member] \| Government-sponsored Enterprises [Member]
Assets [Abstract]
Available-for-sale Securities, Current	0
Significant Unobservable Inputs, Level 3 [Member] \| Corporate Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Current	$ 0

Summary of Significant Accounting Policies - Summary of Collaborators that Represent More Than 10% of Total Revenue Earned (Details) - Sales Revenue, Net [Member]	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Servier [Member]
Concentration Risk [Line Items]
Percentage of all significant revenue earned		36.40%	51.60%
Boehringer [Member]
Concentration Risk [Line Items]
Percentage of all significant revenue earned	12.40%	28.60%	24.80%
Takeda [Member]
Concentration Risk [Line Items]
Percentage of all significant revenue earned		16.80%
Gilead [Member]
Concentration Risk [Line Items]
Percentage of all significant revenue earned		11.40%	13.80%
Janssen [Member]
Concentration Risk [Line Items]
Percentage of all significant revenue earned	71.70%

Summary of Significant Accounting Policies - Summary of Collaborators that Represent More Than 10% of Accounts Receivable (Details) - Accounts Receivable [Member]	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Servier [Member]
Concentration Risk [Line Items]
Significant Accounts Receivable	14.00%	33.30%
Boehringer [Member]
Concentration Risk [Line Items]
Significant Accounts Receivable		21.20%
Green Cross [Member]
Concentration Risk [Line Items]
Significant Accounts Receivable		17.90%
Janssen [Member]
Concentration Risk [Line Items]
Significant Accounts Receivable	39.00%
U.S Government [Member]
Concentration Risk [Line Items]
Significant Accounts Receivable	20.00%
Takeda [Member]
Concentration Risk [Line Items]
Significant Accounts Receivable	14.00%
Eli Lilly [Member]
Concentration Risk [Line Items]
Significant Accounts Receivable	13.00%

Summary of Significant Accounting Policies - Estimated Useful Lives (Details)	12 Months Ended
	Dec. 31, 2015
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 (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Numerator:
Net loss used for calculation of basic and diluted EPS	$ (28,451)	$ (15,442)	$ (21,376)	$ 45,129	$ (19,018)	$ (3,928)	$ (12,259)	$ (3,108)	$ (20,140)	$ (38,313)	$ (261)
Denominator:
Weighted average shares outstanding, basic (in shares)									31,801,645	27,384,990	6,847,697
Effect of dilutive securities:
Stock options and restricted stock units									0	0	0
Weighted average shares outstanding, diluted (in shares)									31,801,645	27,384,990	6,847,697
Net loss per share, basic and diluted (in dollars per share)									$ (0.63)	$ (1.40)	$ (0.04)

- Definition

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

+ References + Details

Summary of Significant Accounting Policies - Schedule of Antidilutive Securities Excluded from the Calculation of Diluted Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Effect of Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, (in shares)	0	0	13,189,920
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, (in shares)	1,955,398	2,094,904	2,313,970

Investments (Details) $ in Thousands	Dec. 31, 2015 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	$ 142,882
Gross unrealized gains	44
Gross unrealized losses	(49)
Fair value	142,877
Government-sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	22,055
Gross unrealized gains	1
Gross unrealized losses	(9)
Fair value	22,047
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	111,473
Gross unrealized gains	42
Gross unrealized losses	(34)
Fair value	111,481
U.S. Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	9,354
Gross unrealized gains	1
Gross unrealized losses	(6)
Fair value	$ 9,349

Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property and equipment	$ 35,031	$ 24,140
Less accumulated depreciation	(20,190)	(17,355)
Property and equipment, net	14,841	6,785
Depreciation expense	3,200	1,800	$ 1,200
Property, Plant and Equipment, Non-cash Additions	1,700
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	3,069	2,596
Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	1,801	1,683
Furniture and Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	919	751
Lab Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	17,306	13,917
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	$ 11,936	$ 5,193

Stockholders' Equity (Details) - USD ($)				1 Months Ended							12 Months Ended		24 Months Ended
Stockholders' Equity (Details) - USD ($)	Oct. 16, 2013	Jan. 11, 2011	May. 16, 2010	Jul. 31, 2015	Feb. 28, 2014	Mar. 31, 2011	Sep. 30, 2008	Jul. 31, 2008	May. 31, 2006	Oct. 31, 2004	Dec. 31, 2015	Dec. 31, 2013	Dec. 31, 2003	Dec. 31, 2014
Class of Stock [Line Items]
Number of shares issued or sold (in shares)				3,525,000	1,800,000
Price per share (in dollars per share)				$ 37.00	$ 36.50
Proceeds from sale of shares				$ 141,000,000	$ 76,700,000
Reverse stock split												1-for-18.7739
Common stock, shares authorized (in shares)											125,000,000	425,000,000		125,000,000
Additional shares sold under over-allotments option to underwriter (in shares)				528,750	450,000
Johnson & Johnson Innovation JJDC, Inc, [Member]
Class of Stock [Line Items]
Sale of common stock (in shares)											1,923,077
Sale of common stock (in dollars per share)											$ 39.00
Proceeds of stock sale											$ 75,000,000
IPO [Member]
Class of Stock [Line Items]
Number of shares issued or sold (in shares)	5,000,000
Price per share (in dollars per share)	$ 16.00
Proceeds from initial public offering net of expenses	$ 83,800,000
Over-Allotment Option [Member]
Class of Stock [Line Items]
Number of shares issued or sold (in shares)	750,000
Price per share (in dollars per share)	$ 16.00
Series A Preferred Stock [Member]
Class of Stock [Line Items]
Number of shares issued or sold (in shares)													34,239,374
Proceeds from issuance of convertible preferred stock													$ 34,000,000
Price per share (in dollars per share)													$ 1.00
Accrued noncumulative dividends on preferred stock (in dollars per share)											$ 0.08
Series A-1 Preferred Stock [Member]
Class of Stock [Line Items]
Convertible preferred stock series (in shares)											1.506
Conversion price of preferred stock (in dollars per share)											$ 12.39
Series A-2 Preferred Stock [Member]
Class of Stock [Line Items]
Convertible preferred stock series (in shares)											1.00
Conversion price of preferred stock (in dollars per share)											$ 18.77
Series B Preferred Stock [Member]
Class of Stock [Line Items]
Number of shares issued or sold (in shares)										71,401,237
Proceeds from issuance of convertible preferred stock										$ 30,300,000
Related offering costs										$ 238,000
Shares of common stock allocated (in shares)									10,003,300
Accrued noncumulative dividends on preferred stock (in dollars per share)											$ 0.0341
Convertible preferred stock series (in shares)											1.14
Conversion price of preferred stock (in dollars per share)											$ 6.95
Series C Preferred Stock [Member]
Class of Stock [Line Items]
Number of shares issued or sold (in shares)									110,952,217
Proceeds from issuance of convertible preferred stock									$ 44,900,000
Related offering costs									$ 101,246
Accrued noncumulative dividends on preferred stock (in dollars per share)											$ 0.0324
Convertible preferred stock series (in shares)											1.00
Conversion price of preferred stock (in dollars per share)											$ 7.70
Series D Preferred Stock [Member]
Class of Stock [Line Items]
Accrued noncumulative dividends on preferred stock (in dollars per share)											$ 0.0522
Convertible preferred stock series (in shares)											1.00
Conversion price of preferred stock (in dollars per share)											$ 12.20
Series D Preferred Stock [Member] \| Raven Biotechnologies Inc. [Member]
Class of Stock [Line Items]
Shares issued to acquire entity (in shares)						14,446,227		12,466,039
Series D-2 Preferred Stock [Member]
Class of Stock [Line Items]
Number of shares issued or sold (in shares)		18,427,388	6,916,110				38,337,678
Proceeds from issuance of convertible preferred stock							$ 24,800,000
Related offering costs							$ 156,788
Exercise price (in dollars per share)											0.65
Proceeds from sale of shares		$ 12,000,000
Accrued noncumulative dividends on preferred stock (in dollars per share)											$ 0.0522
Convertible preferred stock series (in shares)											1.00
Conversion price of preferred stock (in dollars per share)											$ 12.20
Undesignated Preferred Stock [Member]
Class of Stock [Line Items]
Undesignated preferred stock, shares authorized (in shares)											5,000,000
Undesignated preferred stock, par value (in dollars per share)											$ 0.01
Undesignated preferred stock, shares issued (in shares)											0			0
Undesignated preferred stock, shares outstanding (in shares)											0			0
Series A-1 Preferred Stock [Member]
Class of Stock [Line Items]
Shares of common stock allocated (in shares)										13,604,016
Warrant [Member]
Class of Stock [Line Items]
Warrants to purchase shares (in shares)			518,708				2,875,327

Stock- based Compensation - Stock-Based Compensation Expense (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Oct. 31, 2013	Feb. 28, 2003
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, options, outstanding, number (in shares)	4,146,064	3,572,116
Weighted average exercise price (in dollars per share)	$ 16.90	$ 11.40
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 7,847	$ 3,244	$ 862
Stock Option Plan 2000 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, number of shares authorized (in shares)	150,297
Share-based compensation arrangement by share-based payment award, options, outstanding, number (in shares)	19,571
Weighted average exercise price (in dollars per share)	$ 0.81
Equity Incentive Plan 2003 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, number of shares authorized (in shares)						2,051,644
Increased number of shares authorized (in shares)				4,336,730
Share-based compensation arrangement by share-based payment award, options, outstanding, number (in shares)	1,649,193
Weighted average exercise price (in dollars per share)	$ 1.72
Stock Incentive Plan 2013 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, number of shares authorized (in shares)					1,960,168
Increased number of shares authorized (in shares)	4,087,098
Share-based compensation arrangement by share-based payment award, options, outstanding, number (in shares)	2,477,300
Weighted average exercise price (in dollars per share)	$ 27.13
Stock reserved for future issuance (in shares)	1,960,168
Percentage of common stock share outstanding	4.00%
Research and Development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 3,623	1,562	507
General and Administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 4,224	$ 1,682	$ 355

Stock- based Compensation - Option Pricing Assumptions (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	0.00%	0.00%	0.00%
Expected volatility		67.00%
Expected term	6 years 3 months	6 years 3 months	7 years
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	73.00%		53.00%
Risk-free interest rate	1.60%	1.80%	1.20%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	75.00%		67.00%
Risk-free interest rate	2.10%	2.30%	2.20%
Options granted, maximum term	10 years

Stock- based Compensation - Stock Option and Restricted Stock Unit Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stock-based Compensation [Abstract]
Shares, Outstanding, Beginning Balance (in shares)	3,572,116
Shares, Granted (in shares)	987,680
Shares, Exercised (in shares)	(374,214)	(568,906)	(1,268,049)
Shares, Forfeited or expired (in shares)	(39,518)
Shares, Outstanding, Ending Balance (in shares)	4,146,064	3,572,116
Shares, Exercisable (in shares)	1,992,951
Shares, Vested and expected to vest (in shares)	3,894,148
Weighted-Average Exercise Price, Outstanding, Beginning Balance (in dollars per share)	$ 11.40
Weighted-Average Exercise Price, Granted (in dollars per share)	31.59
Weighted-Average Exercise Price, Exercised (in dollars per share)	2.45
Weighted-Average Exercise Price, Forfeited or expired (in dollars per share)	23.44
Weighted-Average Exercise Price, Outstanding, Ending Balance (in dollars per share)	16.90	$ 11.40
Weighted-Average Exercise Price, Exercisable (in dollars per share)	7.94
Weighted-Average Exercise Price, Vested and expected to vest (in dollars per share)	$ 16.50
Weighted-Average Remaining Contractual Term, Outstanding	7 years 4 months 24 days	7 years 3 months 18 days
Weighted-Average Remaining Contractual Term, Exercisable	5 years 8 months 12 days
Weighted-Average Remaining Contractual Term, Vested and expected to vest	7 years 3 months 18 days
Aggregate Intrinsic Value, Outstanding, Ending Balance	$ 59,344
Aggregate Intrinsic Value, Exercisable	46,012
Aggregate Intrinsic Value, Vested and expected to vest	$ 57,267
Common stock, shares issued (in shares)	374,214	568,906	1,268,049
Cash proceeds from exercise of stock options	$ 911	$ 744	$ 1,100
Weighted-average grant-date fair value of options granted (in dollars per share)	$ 20.90	$ 17.41	$ 6.91
Share-based compensation arrangement by share-based payment award, options, exercises in period, intrinsic value	$ 10,900	$ 14,500	$ 5,400
Fair value of shares vested	7,300	$ 3,000	$ 500
Unrecognized compensation cost related to non-vested stock-based compensation arrangements	$ 30,500
Unrecognized compensation expense recognition period	4 years

Income Taxes - Components of the Company's Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Taxes [Abstract]
Provision for federal or state income taxes	$ 0	$ 0	$ 0
Deferred income tax assets [Abstract]
Federal U.S. net operating loss carryforward	57,949	55,358
State net operating loss carryforward	3,907	3,723
Research and development credit, net	10,278	7,177
Orphan drug credit, net	19,284	19,287
Deferred rent	2,947	4,069
Deferred revenue	6,632	3,989
Depreciation	1,597	1,337
Other	2,532	962
Gross deferred income tax assets	105,126	95,902
Valuation allowance	(104,399)	(94,297)
Net deferred income tax assets	727	1,605
Deferred income tax liabilities [Abstract]
Prepaid expenditures	(727)	(1,605)
Gross deferred income tax liabilities	(727)	(1,605)
Net deferred income tax asset/(liability)	$ 0	$ 0
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards expiration start year	2020
Net operating loss carryforward expiration ending year	2035
Remaining portion of net operating losses	$ 152,100
Net operating losses, recognized as a benefit through additional-paid-in-capital	14,700
U.S. Federal Government [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	165,600
US Federal Tax credits carry forward	$ 29,300
Federal tax credit expiration start year	2020
Federal tax credit expiration ending year	2035
Net operating loss for limited use	$ 13,500
U.S. Federal Government [Member] \| Minimum [Member]
Operating Loss Carryforwards [Line Items]
Net operating losses limited for year	2016
Net operating losses limited for use utilized on an annual basis	$ 200
U.S. Federal Government [Member] \| Maximum [Member]
Operating Loss Carryforwards [Line Items]
Net operating losses limited for year	2028
Net operating losses limited for use utilized on an annual basis	$ 1,400
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 165,600

Income Taxes - Reconciliation of Reported Estimated Income Tax Benefit (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Taxes [Abstract]
United States federal tax at statutory rate	$ (7,049)	$ (13,410)	$ (91)
State taxes (net of federal benefit)	(897)	(1,608)	609
Deferred income tax adjustments	661	0	(855)
Deferred state blended rate adjustments	(493)	3,034	(344)
Research credit, net	(3,296)	(2,228)	(226)
Transaction cost deduction	0	(379)	0
Transaction cost deduction - prior year adjustment	0	(564)	0
Orphan drug credit, net	(106)	(139)	(843)
Other permanent items	(25)	(382)	3
Equity-based compensation	1,102	756	241
Fair value adjustment of preferred stock warrant liability	0	0	219
Change in valuation allowance	10,103	14,920	1,287
Income tax expense/(benefit)	$ 0	$ 0	$ 0

Income Taxes - Reconciliation of the Beginning and Ending Amount of Gross Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Taxes [Abstract]
Beginning balance	$ 2,047	$ 1,708	$ 1,592
Increases/(decreases) for current year tax positions	357	242	116
Increases/(decreases) for prior year tax positions	21	97	0
Decreases as a result of expiration of statute of limitations	0	0	0
Ending balance	2,425	2,047	1,708
Gross unrecognized tax benefits	2,000	1,700
Unrecognized interest or penalties	$ 0	$ 0	$ 0
Minimum [Member]
Income Tax Examination [Line Items]
Open Tax Year	2001

Lease Exit Liability - Changes in Lease Exit Liability (Details) - USD ($) $ in Thousands		12 Months Ended
	Jul. 16, 2008	Dec. 31, 2015	Dec. 31, 2014
Restructuring Cost and Reserve [Line Items]
Amount of immaterial error correction		$ 1,900
Series D Convertible Preferred Stock [Member]
Restructuring Cost and Reserve [Line Items]
Shares issued in connection with acquisition	12,466,039
Contract Termination [Member]
Restructuring Cost and Reserve [Line Items]
Accrual Beginning Balance		8,006	$ 9,445
Principal payments		(3,293)	(1,439)
Accrual Ending Balance		$ 4,713	$ 8,006

Lease Exit Liability - Future Principal Payments Under Lease Agreement (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Jul. 16, 2008
Operating Leased Assets [Line Items]
2016	$ 6,130,000
2017	6,314,000
2018	4,210,000
Total	$ 27,809,000
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
Raven Biotechnologies Inc. [Member]
Operating Leased Assets [Line Items]
2016	2,020,000
2017	2,281,000
2018	412,000
Total	$ 4,713,000

Collaboration and Other Agreements, Janssen Biotech, Inc. (Details) - Janssen Biotech Inc. [Member] $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) $ / shares shares
Collaboration and Other Agreements [Line Items]
Collaboration agreement date	December 2014
Sale of common stock (in shares) \| shares	1,923,077
Sale of common stock (in dollars per share) \| $ / shares	$ 39.00
Proceeds of stock sale	$ 75.0
Premium received on stock purchase	12.3
Non-refundable upfront payment receivable	50.0
Total consideration	125.0
Amount allocated to equity	62.7
Amount allocated to license and R&D	62.3
Clinical milestone earned during period	10.0
Recognized revenue under agreement	72.3
Maximum [Member]
Collaboration and Other Agreements [Line Items]
Potential Clinical Milestone Payments Under Agreement	205.0
Potential Sales Milestone Payments Under Agreement	150.0
Potential Regulatory Milestone Payments Under Agreement	$ 220.0

Collaboration and Other Agreements, Takeda (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	May. 31, 2014	Dec. 31, 2015	Dec. 31, 2014
Collaboration and Other Agreements [Line Items]
Deferred revenue included in current liabilities		$ 5,866	$ 14,248
Deferred revenue included in long-term liabilities		$ 12,631	16,472
Takeda [Member]
Collaboration and Other Agreements [Line Items]
Nonrefundable upfront payment	$ 15,000
Takeda [Member] \| Research Collaboration and License Option Agreement [Member]
Collaboration and Other Agreements [Line Items]
Collaboration agreement date		September 2014
Recognized revenue under agreement		$ 1,300	5,000
Amount allocated to agreement		$ 5,000
Takeda [Member] \| Takeda MGD010 Agreement [Member]
Collaboration and Other Agreements [Line Items]
Collaboration agreement date		May 2014
Recognized revenue under agreement		$ 8,000	3,000
Milestone received		3,000
Deferred revenue		2,100	7,100
License option fee		15,000
Amount allocated to agreement		$ 10,000
Deferred revenue included in current liabilities			5,000
Expected period of development		24 months
Deferred revenue included in long-term liabilities		$ 2,100	$ 2,100
Takeda [Member] \| Takeda MGD010 Agreement [Member] \| Maximum [Member]
Collaboration and Other Agreements [Line Items]
Potential Clinical And Regulatory Milestone Payments Under Agreement		93,000
Potential Sales Milestone Payments Under Agreement		$ 375,500

Collaboration and Other Agreements, Gilead (Details) - Gilead [Member] $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2013 Molecule	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Collaboration and Other Agreements [Line Items]
Collaboration agreement date		January 2013
Recognized revenue under agreement		$ 0.0	$ 5.5	$ 8.0
Deferred revenue		$ 0.0	0.0
Expected period of development		21 months
Commercialization of molecules \| Molecule	4
License grant fees		$ 7.5
Milestone achieved		0.0	$ 0.0
Maximum [Member]
Collaboration and Other Agreements [Line Items]
Additional Potential Pre-Clinical Milestone Payments Under Agreement		20.0
Additional Potential Clinical, Regulatory And Sales Milestone Payments Under Agreement		$ 247.5

Collaboration and Other Agreements, Servier (Details) $ in Thousands	1 Months Ended		12 Months Ended
	Sep. 30, 2012 USD ($)	Nov. 30, 2011 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($) Milestone	Dec. 31, 2013 USD ($)
Collaboration and Other Agreements [Line Items]
Deferred revenue included in current liabilities			$ 5,866	$ 14,248
Deferred revenue included in long-term liabilities			$ 12,631	16,472
Servier [Member] \| Servier DART [Member]
Collaboration and Other Agreements [Line Items]
Collaboration agreement date			September 2012
Nonrefundable upfront payment	$ 20,000
Original period of development			29 months
Expected period of development			75 months
Recognized revenue under agreement			$ 3,500	16,700	$ 8,600
Milestone payment			0	5,000	0
Deferred revenue included in current liabilities			3,300	3,300
Change in accounting estimate, current year impact			3,700
Option exercise fee				15,000
Offset to research and development costs under collaboration arrangement			$ 500	$ 1,000	0
Option exercise fee recognition period			82 months
Number of milestones achieved \| Milestone				2
Review period				30 days
Deferred revenue			$ 14,400	$ 17,700
Deferred revenue included in long-term liabilities			$ 11,100	14,400
Servier [Member] \| Servier MGA271 [Member]
Collaboration and Other Agreements [Line Items]
Collaboration agreement date			November 2011
Nonrefundable upfront payment		$ 20,000
Original period of development			27 months
Expected period of development			42 months
Recognized revenue under agreement			$ 100	700	21,300
Milestone payment					$ 10,000
Deferred revenue included in current liabilities			0	$ 100
Servier [Member] \| Maximum [Member] \| Servier DART [Member]
Collaboration and Other Agreements [Line Items]
Clinical milestone payments under agreement			5,000
Potential License Fee			65,000
Potential Clinical Milestone Payments Under Agreement			98,000
Potential Regulatory Milestone Payments Under Agreement			300,000
Potential Sales Milestone Payments Under Agreement			$ 630,000

Collaboration and Other Agreements, Boehringer (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Oct. 31, 2010 USD ($)	Dec. 31, 2015 USD ($) Payment	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Collaboration and Other Agreements [Line Items]
Deferred revenue included in current liabilities		$ 5,866	$ 14,248
Boehringer [Member]
Collaboration and Other Agreements [Line Items]
Collaboration agreement date		October 2010
Nonrefundable upfront payment	$ 15,000
Number of annual maintenance payments received \| Payment		3
Clinical milestone payments		$ 34,000
Additional potential regulatory milestone payments under agreement		88,500
Additional potential sales milestone payments under agreement		$ 82,500
Research obligation completion date		October 2015
Recognized revenue under agreement		$ 12,500	13,700	$ 14,400
Deferred revenue		0	5,800
Deferred revenue included in current liabilities			5,800
Milestone payment		$ 5,000	$ 2,000	$ 5,000

Collaboration and Other Agreements, Pfizer (Details)	1 Months Ended	12 Months Ended
Collaboration and Other Agreements, Pfizer (Details)	Oct. 31, 2010 USD ($)	Dec. 31, 2015 USD ($) Molecule Program	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Collaboration and Other Agreements [Line Items]
Deferred revenue included in current liabilities		$ 5,866,000	$ 14,248,000
Pfizer [Member]
Collaboration and Other Agreements [Line Items]
Collaboration agreement date		October 2010
Period of agreement		3 years
Commercialization of molecules \| Molecule		2
Nonrefundable upfront payment	$ 5,000,000
DART program \| Program		1
Research obligation completion date		January 2014
Term of the agreement		January 2014
Recognized revenue under agreement		$ 500,000	100,000	$ 3,500,000
Milestone achieved		500,000
Deferred revenue included in current liabilities		0	$ 0
Potential Pre-clinical and Clinical Milestone Payments Under Agreement		17,000,000
Potential Sales Milestone Payments Under Agreement		$ 195,000,000

Collaboration and Other Agreements, Green Cross (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Jun. 30, 2010	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Collaboration and Other Agreements [Line Items]
Deferred revenue included in current liabilities		$ 5,866	$ 14,248
Deferred revenue included in long-term liabilities		$ 12,631	16,472
Green Cross [Member]
Collaboration and Other Agreements [Line Items]
Collaboration agreement date		June 2010
Term of the agreement		June 2020
Nonrefundable upfront payment	$ 1,000
Adjustment to revenue from contract material modification			1,300
Recognized revenue under agreement		$ 500	1,700	$ 100
Milestone achieved		0	0	$ 0
Deferred revenue		2,000
Unbilled receivable balance			$ 500
Deferred revenue included in current liabilities		400
Deferred revenue included in long-term liabilities		1,600
Green Cross [Member] \| Maximum [Member]
Collaboration and Other Agreements [Line Items]
Aggregate potential future cost reimbursement		5,500
Clinical and commercial milestone payments		$ 2,500

Collaboration and Other Agreements, NIAID Contract (Details) - NIAID [Member] $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) Molecule
Collaboration And Other Agreements [Line Items]
Agreement beginning date	September 15, 2015
Commercialization of molecules \| Molecule	2
Base period value	$ 7.5
Recognized revenue under agreement	$ 0.2
Agreement end date	September 14, 2022
Maximum [Member]
Collaboration And Other Agreements [Line Items]
Additional development funding options	$ 17.0
Total potential value	$ 24.5

Commitments and Contingencies (Details) $ in Thousands	12 Months Ended
Commitments and Contingencies (Details) $ in Thousands	Dec. 31, 2015 USD ($) Lease	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Minimum [Member]
Operating Leased Assets [Line Items]
Lease expiration date	Apr. 30, 2018
Maximum [Member]
Operating Leased Assets [Line Items]
Lease expiration date	Dec. 31, 2022
Number of leases \| Lease	5
Deferred rent liability	$ 7,300	$ 2,700
Rent expense	900	$ 2,000	$ 2,700
Lease incentives	5,100
Future minimum rental payments required under all non-cancelable operating leases [Abstract]
2016	6,130
2017	6,314
2018	4,210
2019	3,803
2020	2,142
Thereafter	5,210
Total	$ 27,809
Office and Laboratory Space [Member] \| South San Francisco [Member]
Operating Leased Assets [Line Items]
Lease expiration date	Feb. 28, 2018
Office, Laboratory and Manufacturing Space [Member]
Operating Leased Assets [Line Items]
Lessee leasing arrangements, term of operating leases	7 years
Lessee leasing arrangements, origination date	Jul. 31, 2015
Lease Commencement Date	Jan. 01, 2016

Employee Benefit Plan (Details) - USD ($) $ in Millions		12 Months Ended
Employee Benefit Plan (Details) - USD ($) $ in Millions	Sep. 25, 2002	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Employee Benefit Plan [Abstract]
Eligible age to participate in plan	21 years
Percentage of employee contribution to salary	100.00%
Percentage of employee vested contribution		100.00%
Defined contribution plan, employer discretionary contribution amount		$ 0.4	$ 0.3	$ 0.3

Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Information (Unaudited) [Abstract]
Revenue	$ 8,178	$ 14,681	$ 6,716	$ 71,279	$ 5,476	$ 18,382	$ 9,220	$ 14,719	$ 100,854	$ 47,797	$ 58,035
Net loss	$ (28,451)	$ (15,442)	$ (21,376)	$ 45,129	$ (19,018)	$ (3,928)	$ (12,259)	$ (3,108)	$ (20,140)	$ (38,313)	$ (261)
Net income (loss) per share, basic (in dollars per share)	$ (0.83)	$ (0.46)	$ (0.71)	$ 1.53
Net income (loss) per share, diluted (in dollars per share)	$ (0.83)	$ (0.46)	$ (0.71)	$ 1.42
Net loss per share, basic and diluted (in dollars per share)					$ (0.68)	$ (0.14)	$ (0.44)	$ (0.12)	$ (0.63)	$ (1.40)	$ (0.04)

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

+ References + Details