Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2016	Feb. 24, 2017	Jun. 30, 2016
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2016
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	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		34,974,985
Entity Public Float			$ 936

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 84,098	$ 196,172
Marketable securities	192,898	142,877
Accounts receivable	2,764	1,224
Prepaid expenses	3,483	1,806
Other current assets	704	305
Total current assets	283,947	342,384
Property and equipment, net	17,961	14,841
Marketable securities, non-current	7,986	0
Other assets	1,369	2,044
Total assets	311,263	359,269
Current liabilities:
Accounts payable	3,995	2,967
Accrued expenses	16,134	11,708
Deferred revenue	4,261	5,866
Deferred rent	1,319	914
Lease exit liability	1,593	2,020
Other current liabilities	0	727
Total current liabilities	27,302	24,202
Deferred revenue, net of current portion	10,045	12,631
Deferred rent, net of current portion	4,867	6,406
Lease exit liability, net of current portion	298	2,693
Total liabilities	42,512	45,932
Stockholders' equity:
Common stock, $0.01 par value – 125,000,000 shares authorized, 34,870,607 and 34,345,754 shares outstanding at December 31, 2016 and 2015, respectively	349	343
Additional paid-in capital	561,198	547,185
Accumulated other comprehensive loss	(82)	(5)
Accumulated deficit	(292,714)	(234,186)
Total stockholders' equity	268,751	313,337
Total liabilities and stockholders' equity	$ 311,263	$ 359,269

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [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)	34,870,607	34,345,754

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues:
Revenue from collaborative agreements	$ 86,582	$ 99,368	$ 47,264
Revenue from government agreements	5,298	1,486	533
Total revenues	91,880	100,854	47,797
Costs and expenses:
Research and development	122,091	98,271	70,186
General and administrative	29,831	22,765	15,926
Total costs and expenses	151,922	121,036	86,112
Loss from operations	(60,042)	(20,182)	(38,315)
Other income	1,514	42	2
Net loss	(58,528)	(20,140)	(38,313)
Other comprehensive loss:
Unrealized loss on investments	(77)	(5)	0
Comprehensive loss	$ (58,605)	$ (20,145)	$ (38,313)
Basic and diluted net loss per common share (in dollars per share)	$ (1.69)	$ (0.63)	$ (1.40)
Basic and diluted weighted average number of common shares (in shares)	34,685,274	31,801,645	27,384,990

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($)	Total	Common Stock	Treasury Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income
Balance at Dec. 31, 2013	$ 78,914,000	$ 252,000	$ (58,000)	$ 254,453,000	$ (175,733,000)	$ 0
Balance (in shares) at Dec. 31, 2013		25,177,597	14,381
Share-based compensation	3,244,000			3,244,000
Issuance of common stock, net of offering costs	76,716,000	$ 22,000		76,694,000
Issuance of common stock, net of offering costs (in shares)		2,250,000
Stock plan related activity	725,000	$ 6,000	$ (19,000)	738,000
Stock plan related activity (in shares)		568,041	865
Retirement of treasury stock	0		$ 58,000	(58,000)
Retirement of treasury stock (in shares)			(14,381)
Unrealized loss on investments	0
Net loss	(38,313,000)				(38,313,000)
Balance at Dec. 31, 2014	121,286,000	$ 280,000	$ (19,000)	335,071,000	(214,046,000)	0
Balance (in shares) at Dec. 31, 2014		27,995,638	865
Share-based compensation	7,847,000			7,847,000
Issuance of common stock, net of offering costs	203,467,000	$ 60,000		203,407,000
Issuance of common stock, net of offering costs (in shares)		5,976,827
Stock plan related activity	882,000	$ 3,000	$ (29,000)	908,000
Stock plan related activity (in shares)		373,289	925
Retirement of treasury stock	0		$ 48,000	(48,000)
Retirement of treasury stock (in shares)			(1,790)
Unrealized loss on investments	(5,000)					(5,000)
Net loss	(20,140,000)				(20,140,000)
Balance at Dec. 31, 2015	313,337,000	$ 343,000	$ 0	547,185,000	(234,186,000)	(5,000)
Balance (in shares) at Dec. 31, 2015		34,345,754	0
Share-based compensation	12,165,000			12,165,000
Stock plan related activity	1,854,000	$ 6,000	$ (39,000)	1,887,000
Stock plan related activity (in shares)		524,853	1,862
Retirement of treasury stock	0		$ 39,000	(39,000)
Retirement of treasury stock (in shares)			(1,862)
Unrealized loss on investments	(77,000)					(77,000)
Net loss	(58,528,000)				(58,528,000)
Balance at Dec. 31, 2016	$ 268,751,000	$ 349,000	$ 0	$ 561,198,000	$ (292,714,000)	$ (82,000)
Balance (in shares) at Dec. 31, 2016		34,870,607	0

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities
Net loss	$ (58,528)	$ (20,140)	$ (38,313)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	7,608	2,863	1,822
Share-based compensation	12,165	7,847	3,244
Changes in operating assets and liabilities:
Accounts receivable	(1,540)	1,711	(931)
Prepaid expenses	(1,677)	2,405	(3,239)
Restricted cash	0	300	105
Other assets	276	(285)	(1,179)
Accounts payable	2,232	(163)	(1,500)
Accrued expenses	4,659	3,545	4,346
Lease exit liability	(2,822)	(3,293)	(1,439)
Deferred revenue	(4,191)	(12,223)	3,317
Deferred rent	(1,134)	4,650	(234)
Other liabilities	(727)	(878)	1,242
Net cash used in operating activities	(43,679)	(13,661)	(32,759)
Cash flows from investing activities
Purchases of marketable securities	(347,762)	(142,910)	0
Proceeds from sales and maturities of marketable securities	288,894	0	0
Purchases of property and equipment	(11,381)	(9,197)	(3,572)
Net cash used in investing activities	(70,249)	(152,107)	(3,572)
Cash flows from financing activities
Proceeds from issuance of common stock, net of offering costs	0	203,467	76,716
Proceeds from stock option exercises	1,893	911	744
Purchase of treasury stock	(39)	(29)	(19)
Net cash provided by financing activities	1,854	204,349	77,441
Net change in cash and cash equivalents	(112,074)	38,581	41,110
Cash and cash equivalents at beginning of period	196,172	157,591	116,481
Cash and cash equivalents at end of period	$ 84,098	$ 196,172	$ 157,591

Organization and Nature of Operations	12 Months Ended
Organization and Nature of Operations	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Nature of Operations	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, 2016

Accounting Policies [Abstract]

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, preclinical 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, 2016 or 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, 2016 or 2015, as the Company has a history of collecting on all outstanding accounts.

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 Measurement at December 31, 2016
			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	$	46,781	$	46,781	$	—	$	—
U.S Treasury securities	8,826		—		8,826		—
Government-sponsored enterprises	29,759		—		29,759		—
Corporate debt securities	166,300		—		166,300		—
Total assets measured at fair value ^(a)	$	251,666	$	46,781	$	204,885	$	—

(a) Total assets measured at fair value at December 31, 2016 includes approximately $50.8 million reported in cash and cash equivalents on the balance sheet.



	Fair Value Measurement 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	$	—

(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. There were no transfers between Level 1 and Level 2 investments during the periods presented.

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.

The Company's revenue relates to agreements with various collaborators and contracts and research grants received from 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,
	2016		2015		2014
Janssen Biotech, Inc. (Janssen)	85	%	72	%	*
Les Laboratoires Servier and Institut de Reserches Servier (collectively, Servier)	*		*		36	%
Boehringer Ingelheim GmbH (Boehringer)	*		12	%	29	%
Takeda Pharmaceutical Company Limited (Takeda)	*		*		17	%
Gilead Sciences, Inc. (Gilead)	*		*		11	%

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



	December 31,
	2016		2015
Janssen	40	%	39	%
U.S. government	19	%	20	%
Servier	31	%	14	%
Takeda	*		14	%
Eli Lilly	*		13	%

* 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, 2016 and 2015, 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 preclinical 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 preclinical 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 FASB ASC Topic 605-25, Revenue Recognition – Multiple-Element Arrangements, and FASB 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 preclinical 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 preclinical 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 preclinical 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 preclinical 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 preclinical and clinical materials.

The Company recognizes revenue related to research and preclinical 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 preclinical development services, including generating and engineering product candidates, on behalf of its licensees during the early evaluation and preclinical 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 their achievement are generally 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 preclinical 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 year ended December 31, 2014 as there were no unrealized gains or losses in that period.

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 Loss Per Share

Basic loss per common share is determined by dividing loss attributable to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration of common stock equivalents. Diluted loss per share is computed by dividing the 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,
	2016			2015			2014
Numerator:
Net loss used for calculation of basic and diluted EPS	$	(58,528	)	$	(20,140	)	$	(38,313	)

Denominator:
Weighted average shares outstanding, basic	34,685,274			31,801,645			27,384,990
Effect of dilutive securities:
Stock options and restricted stock units	—			—			—

Weighted average shares outstanding, diluted	34,685,274			31,801,645			27,384,990
Net loss per share, basic and diluted	$	(1.69	)	$	(0.63	)	$	(1.40	)

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,
	2016	2015	2014
Stock options	1,394,608	1,955,398	2,094,904

Recently Issued Accounting Standards

In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) (ASU 2014-09). 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, with early adoption permitted for interim and annual reporting periods beginning after December 15, 2016. ASU 2014-09 may be adopted either retrospectively or on a modified retrospective basis whereby ASU 2014-09 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. In 2016, the FASB issued ASU 2016-08, Revenue from Contracts with Customers: Principal versus Agent Considerations, ASU 2016-10, Revenue from Contracts with Customers: Identifying Performance Obligations and Licensing, and ASU 2016-12, Revenue from Contracts with Customers: Narrow-Scope Improvements and Practical Expedients to provide supplemental adoption guidance and clarification to ASU 2014-09. The effective date for these new standards is the same as the effective date and transition requirements for ASU 2014-09. Management has begun an initial review of each of the Company's collaboration and license agreements and is performing an assessment of the potential effects of the standard on the Company's consolidated financial statements, accounting policies, and internal controls over financial reporting. The Company anticipates that the adoption of the new revenue recognition standard will have primarily two impacts on its contract revenues generated by its collaborative research and license agreements:

(i) Changes in the model for distinct licenses of functional intellectual property which may result in a timing difference of revenue recognition. Whereas revenue from these arrangements was previously recognized over a period of time pursuant to revenue recognition guidance that was in place for the arrangements at the time such arrangements commenced, revenue from these arrangements may now be recognized at point in time under the new guidance.

(ii) Assessments of milestone payments, which are linked to events that are in the Company’s control, will result in variable consideration that may be recognized at an earlier point in time under the new guidance, when it is probable that the milestone will be achieved without a significant future reversal of cumulative revenue expected.

The Company has not yet completed its final review of the impact of this guidance. The Company has also not concluded on the implementation approach to be used. Management plans to adopt the new standard effective January 1, 2018. The Company continues to monitor additional changes, modifications, clarifications or interpretations being undertaken by the FASB, which may impact the implementation approach management decides to use.

In August 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements - Going Concern, which requires management of an entity to evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the entity’s ability to continue as a going concern within one year after the date that the financial statements are issued or available to be issued. ASU 2014-15 is effective for annual periods ending after December 15, 2016, and interim periods within annual periods beginning after December 15, 2016. The Company’s adoption of this new standard for the year ended December 31, 2016 had no impact on the Company’s consolidated financial statements and related disclosures.

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 adopted ASU 2015-17 on a prospective basis in the first quarter of 2016. The prior reporting period was not retrospectively adjusted. The adoption of this guidance had no impact on the Company's results of operations or cash flows.

In February 2016, the FASB issued ASU No. 2016-02, Leases (ASU 2016-02) that provides principles for the recognition, measurement, presentation and disclosure of leases for both lessees and lessors. ASU 2016-02 requires a lessee to recognize assets and liabilities on the balance sheet for operating leases and changes many key definitions, including the definition of a lease. ASU 2016-02 includes a short-term lease exception for leases with a term of 12 months or less, in which a lessee can make an accounting policy election not to recognize lease assets and lease liabilities. Lessees will continue to differentiate between finance leases (previously referred to as capital leases) and operating leases, using classification criteria that are substantially similar to the previous guidance. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years, with earlier application permitted. The Company is currently evaluating the effect of the standard on its consolidated financial statements and related disclosures.

In March 2016, the FASB issued ASU 2016-09, Improvements to Employee Share-Based Payment Accounting (ASU 2016-09). This amendment addresses several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities and classification on the statement of cash flows. ASU 2016-09 is effective for fiscal years beginning after December 15, 2016, including interim periods within that year. Early adoption is permitted. The Company is evaluating the impact of the standard on its consolidated financial statements and related disclosures.

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.

Marketable Securities

12 Months Ended

Dec. 31, 2016

Investments, Debt and Equity Securities [Abstract]

Marketable Securities

Available-for-sale marketable securities as of December 31, 2016 and 2015 were as follows (in thousands):



	December 31, 2016
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury securities	$	4,826	$	—	$	(1	)	$	4,825
Government-sponsored enterprises	29,764		5		(10		)	29,759
Corporate debt securities	166,376		51		(127		)	166,300
Total	$	200,966	$	56	$	(138	)	$	200,884



	December 31, 2015
	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

The contractual maturities of the available-for-sale marketable securities as of December 31, 2016 were as follows (in thousands):



	Amortized Cost		Fair Value
Mature in one year or less	$	192,985	$	192,898
Mature between one and five years	7,981		7,986
Total	200,966		200,884

All of the Company's available-for-sale securities held at December 31, 2015 had maturity dates of less than one year. All available-for-sale securities in an unrealized loss position as of December 31, 2016 and 2015 were in a loss position for less than twelve months. There were no unrealized losses at December 31, 2016 or 2015 that the Company determined to be other-than-temporary.

- Definition

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

+ References + Details

Property and Equipment

12 Months Ended

Dec. 31, 2016

Property, Plant and Equipment [Abstract]

Property and Equipment

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



	December 31,
	2016			2015
Computer equipment	$	2,520		$	3,069
Software	2,352			1,801
Furniture and office equipment	897			919
Lab equipment	20,208			17,306
Leasehold improvements	17,807			11,936
Property and equipment	43,784			35,031
Less accumulated depreciation	(25,823		)	(20,190		)
Property and equipment, net	$	17,961		$	14,841

Property and equipment balance at December 31, 2016 includes approximately $0.3 million in assets that were purchased in 2016 but were not paid for by year end. Depreciation expense for the years ended December 31, 2016, 2015 and 2014 was $6.8 million, $3.2 million and $1.8 million, respectively.

Stockholders' Equity	12 Months Ended
Stockholders' Equity	Dec. 31, 2016
Equity [Abstract]
Stockholders' Equity	Stockholders' Equity The Company's amended and restated certificate of incorporation authorizes 125,000,000 shares of common stock, and 5,000,000 shares of undesignated preferred stock, both with a par value of $0.01 per share. There were no shares of undesignated preferred stock issued or outstanding as of December 31, 2016 or 2015. In February 2014, the Company completed an 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 an 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
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21484-112644

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

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

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

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

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

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

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

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

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-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
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21564-112644

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name 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, 2016

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-based Compensation

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.

In 2013, 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, 2016, under the 2003 Plan, there were options to purchase an aggregate of 1,193,941 shares of common stock outstanding at a weighted average exercise price of $1.81 per share.

In October 2013, the Company implemented the 2013 Stock Incentive Plan (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, 2016, the maximum number of shares of common stock authorized to be issued by the Company under the 2013 Plan was increased to 5,375,064. 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, 2016, under the 2013 Plan, there were options to purchase an aggregate of 2,644,119 shares of common stock outstanding at a weighted average exercise price of $26.66 per share.

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



	Year Ended December 31,
	2016		2015		2014

Research and development	$	5,778	$	3,623	$	1,562
General and administrative	6,387		4,224		1,682
Total stock-based compensation expense	$	12,165	$	7,847	$	3,244

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,
	2016	2015	2014
Expected dividend yield	0%	0%	0%
Expected volatility	64% - 69%	73% - 75%	67%
Risk-free interest rate	1.2% - 2.4%	1.6% - 2.1%	1.8% - 2.3%
Expected term	6.25 years	6.25 years	6.25 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 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 2016:



	Shares		Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value (in thousands)
Outstanding, December 31, 2015	4,146,064		$	16.90	7.4
Granted	399,949		23.20
Options exercised or RSUs vested	(526,715	)	3.59
Forfeited or expired	(181,238	)	26.53
Outstanding, December 31, 2016	3,838,060		18.93		7.0	$	24,862

December 31, 2016:
Exercisable	2,292,923		13.71		6.1	22,458
Vested and expected to vest	3,651,523		18.57		7.0	24,496

During 2016, 2015 and 2014 the Company issued 526,715, 374,214 and 568,906 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 $1.9 million, $0.9 million and $0.7 million during 2016, 2015 and 2014, respectively.

The weighted-average grant-date fair value of options granted during 2016, 2015 and 2014 was $15.17, $20.90 and $17.41 per share, respectively. The total intrinsic value of options exercised during 2016, 2015 and 2014 was approximately $10.8 million, $10.9 million and $14.5 million, respectively. The total fair value of stock options which vested during 2016, 2015 and 2014 was $11.6 million, $7.3 million and $3.0 million, respectively. As of December 31, 2016, the total unrecognized compensation expense related to non-vested stock options and RSUs, net of related forfeiture estimates, was $22.2 million, which the Company expects to recognize over a weighted-average period of approximately 2.5 years.

Income Taxes

12 Months Ended

Dec. 31, 2016

Income Tax Disclosure [Abstract]

Income Taxes

For the years ended December 31, 2016, 2015 and 2014 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,
	2016			2015
Deferred income tax assets:
Federal U.S. net operating loss carryforward	$	75,377		$	57,949
State net operating loss carryforward	6,583			3,907
Research and development credit, net	12,829			10,278
Orphan drug credit, net	19,855			19,284
Deferred rent	2,497			2,947
Deferred revenue	5,098			6,632
Depreciation	2,926			1,597
Other	5,085			2,532
Gross deferred income tax assets	130,250			105,126
Valuation allowance	(128,844		)	(104,399		)
Net deferred income tax assets	1,406			727

Deferred income tax liabilities:
Prepaid expenditures	(1,406		)	(727		)
Gross deferred income tax liabilities	(1,406		)	(727		)
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 2016 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, 2016, the Company has U.S. federal and state NOL carryforwards of approximately $215.4 million that will expire in various years beginning in 2020 through 2036. In addition, the Company has U.S. federal tax credits of $32.5 million which will expire in various years beginning in 2020 through 2036.

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, 2016, $13.5 million of the Company's US Federal NOLs are limited for use over the years 2017 – 2029 in which a range of such amounts could be utilized on an annual basis of $0.2 million to $1.4 million. The remaining $201.9 million of NOLs is not limited and can be offset against future taxable income. Additionally, approximately $18.6 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,
	2016			2015			2014

United States federal tax at statutory rate	$	(20,489	)	$	(7,049	)	$	(13,410	)
State taxes (net of federal benefit)	(3,116		)	(897		)	(1,608		)
Deferred income tax adjustments	173			661			—
Deferred state blended rate adjustments	(32		)	(493		)	3,034
Research credit, net	(2,551		)	(3,296		)	(2,228		)
Transaction cost deduction	—			—			(379		)
Transaction cost deduction - prior year adjustment	—			—			(564		)
Orphan drug credit, net	(571		)	(106		)	(139		)
Other permanent items	145			(25		)	(382		)
Equity-based compensation	1,997			1,102			756
Change in valuation allowance	24,444			10,103			14,920
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,
	2016			2015		2014
Beginning balance	$	2,425		$	2,047	$	1,708
Increases/(decreases) for current year tax positions	308			357		242
Increases/(decreases) for prior year tax positions	(268		)	21		97
Ending balance	$	2,465		$	2,425	$	2,047

As of December 31, 2016 and 2015, of the total gross unrecognized tax benefits, approximately $2.5 million and $2.4 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, 2016, 2015 and 2014, 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, 2016

Restructuring and Related Activities [Abstract]

Lease Exit Liability

In 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. The Company undertook restructuring activities related to the acquisition of Raven. 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. During the year ended December 31, 2016, the Company entered into an agreement to sublease a portion of the space subject to this operating lease. The Company will receive approximately $1.3 million in sublease payments over its term, which ends at the same time as the original lease in February 2018. No sublease income was contemplated when the restructuring liability was recorded in 2008; therefore, the Company adjusted the liability to reflect the future sublease income during the year ended December 31, 2016 and recorded an offset to research and development expenses of approximately $1.3 million in the same period.

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



Accrual balance at December 31, 2014	$	8,006
Principal payments and other adjustments	(3,293		)
Accrual balance at December 31, 2015	4,713
Principal payments and other adjustments (net of sublease receipts)	(2,822		)
Accrual balance at December 31, 2016	$	1,891

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, 2016, net of the sublease amounts, are as follows (in thousands):



2017	$	1,593
2018	298
Total	$	1,891

Collaboration and Other Agreements	12 Months Ended
Collaboration and Other Agreements	Dec. 31, 2016
Collaboration and License Agreements [Abstract]
Collaboration and Other Agreements	Collaboration and Other Agreements Janssen 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 or duvortuxizumab), 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 (MGD011 Agreement). 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 MGD011 Agreement, the Company granted an exclusive license to Janssen to develop and commercialize duvortuxizumab. Following the Company's submission of the Investigational New Drug (IND) application, Janssen became fully responsible for the development and commercialization of duvortuxizumab. Assuming successful development and commercialization, the agreement entitles the Company to receive up to $205.0 million in development 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 with Janssen 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 MGD011 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 preclinical research period (through the filing of the IND for duvortuxizumab). The Company evaluated the MGD011 Agreement and determined that the license and preclinical research and development activities each represented separate deliverables and were accounted for as separate units of accounting. The Company concluded that the license had standalone value to Janssen and was separable from the research and development services because the license was sublicensable, there were no restrictions as to Janssen's use of the license and Janssen or other third parties have significant research capabilities in this field. Thus, the total arrangement consideration for these two deliverables was allocated using the relative best estimate of selling price method to each deliverable. 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 allocated to the license and preclinical research and development activities. 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 preclinical research and development activities, and a de minimis amount to the ongoing research and development activities. The Company submitted the IND application 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 duvortuxizumab which triggered a $10.0 million milestone to the Company. During the years ended December 31, 2016 and 2015, the Company recognized revenue of approximately $2.0 million and $72.3 million, respectively, under the MGD011 agreement. In May 2016, the Company entered into a separate collaboration and license agreement with Janssen, a related party through ownership of the Company's common stock, for the development and commercialization of MGD015, a product candidate that incorporates the Company's proprietary DART technology to simultaneously target CD3 and an undisclosed tumor target for the potential treatment of various hematological malignancies and solid tumors (MGD015 Agreement). The transaction closed in June 2016, and the Company received the $75.0 million upfront payment from Janssen in July 2016. Under the MGD015 Agreement, the Company granted an exclusive license to Janssen to develop and commercialize MGD015. Janssen will complete the IND-enabling activities and will be fully responsible for the future clinical development and commercialization of MGD015. Assuming successful development and commercialization, the agreement entitles the Company to receive up to $100.0 million in development milestone payments, $265.0 million in regulatory milestone payments and $300.0 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 with Janssen 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 MGD015 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 MGD015 Agreement include the delivery of an exclusive license and research and development services during the preclinical research period. The Company evaluated the MGD015 Agreement with Janssen and determined that the license and preclinical research and development activities each represented separate deliverables and were accounted for as two separate units of accounting. The Company concluded that the license had standalone value to Janssen and was separable from the research and development services because the license was sublicensable, there were no restrictions as to Janssen's use of the license and Janssen or other third parties have significant research capabilities in this field. Thus, the total arrangement consideration for these two deliverables was allocated using the best estimate of relative selling price method to each deliverable. The best estimate of selling price for the exclusive license was determined using information from the previous collaboration and license agreement with Janssen as well as other third party collaboration and license agreements, which are Level 2 fair value measurements. The best estimate of selling price for the research and development services was determined using other similar research and development arrangements, which are also Level 2 fair value measurements. During the year ended December 31, 2016, the Company recognized revenue of $75.8 million, including the $75.0 million upfront fee for the exclusive license under the MGD015 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 had an option to obtain an exclusive worldwide license for MGD010 following the completion of a pre-defined Phase 1a study. Following the announcement of its therapeutic area re-prioritization, Takeda gave formal notification in September 2016 that it did not intend to exercise this option. As a result of Takeda not exercising the option, the Company regained worldwide development and commercialization rights to MGD010. At the inception of the license and option agreement with Takeda, the Company evaluated it and determined that it was a revenue arrangement with multiple deliverables, or performance obligations. The Company's substantive performance obligations under the license and option agreement included 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 was substantive and that the license fee payable upon exercise of the option was not a deliverable at the inception of the arrangement as there was considerable uncertainty that the option would be exercised. The Company determined that each potential future clinical and regulatory milestone was 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., discounted 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 was being recognized over an initial 24-month period, which represented the expected period of development through the completion of a pre-defined Phase 1a study. During the first quarter of 2016, the Company determined that the development period would be extended by eight months, and prospectively adjusted the MGD010 option fee recognition period. 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 in September 2014. Upon the notification that Takeda would not exercise the option to obtain an exclusive worldwide license for MGD010 during the three months ended September 30, 2016, the Company's performance obligation to Takeda ceased, and the remaining deferred revenue under the MGD010 agreement was recognized in full. The Company recognized revenue of approximately $2.1 million, $8.0 million and $3.0 million under the MGD010 agreement during the years ended December 31, 2016, 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, 2016, no revenue was deferred under this agreement. At December 31, 2015, $2.1 million of revenue was deferred under this agreement, all of which was 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 nominate up to three additional compounds on or before September 25, 2017, 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. Servier In September 2012, the Company entered into a 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 (or flotetuzumab) (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. During 2014, Servier exercised its exclusive option to develop and commercialize flotetuzumab, and during 2016 Servier notified the Company that it did not intend to exercise the option for the third DART molecule. Servier retains the option to obtain a license for MGD007. 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 $40.0 million in license fees, $63.0 million in clinical milestone payments, $188.0 million in regulatory milestone payments and $420.0 million in sales milestone payments if Servier exercises the remaining available 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 preclinical 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. As a result of Servier exercising its option in 2014, the Company received a $15.0 million payment from Servier for its license to develop and commercialize flotetuzumab in its territories. Upon exercise of the option, the Company evaluated its performance obligations with respect to the license for flotetuzumab. 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 flotetuzumab. In accordance with the agreement, the Company and Servier will share costs incurred to develop flotetuzumab. 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, 2016, 2015 and 2014 the Company recorded approximately $2.6 million, $0.5 million and $1.0 million as an offset to research and development costs under this collaboration arrangement, respectively. During the years ended December 31, 2016, 2015 and 2014 the Company recognized revenue of $3.3 million, $3.5 million, and $16.7 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 flotetuzumab 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, 2016 or 2015. At December 31, 2016, $11.1 million of revenue was deferred under this agreement, $3.3 million of which was current and $7.8 million of which was non-current. 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. 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 preclinical 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 preclinical, 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 did not have value on a standalone basis (e.g. absent the provision of the research and development services) and therefore did not represent a separate unit of accounting. The Company concluded that because the drug candidate had not yet been developed, the license was 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 no revenue under this agreement during the year ended December 31, 2016. The Company recognized revenue of approximately $12.5 million and $13.7 million during the years ended December 31, 2015 and 2014, respectively, under this agreement. Revenue recognized during the years ended December 31, 2015 and 2014 included milestone payments of $5.0 million and $2.0 million, respectively, for the achievement of clinical milestones. No revenue was deferred under this agreement at December 31, 2016 or 2015. Green Cross In June 2010, the Company entered into a collaboration agreement with Green Cross Corp. (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 separate units 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 has received a total of $5.5 million through December 31, 2016 for reimbursement of research and development services, which is also being recognized over the remaining term of the agreement. The Company recognized revenues of approximately $0.8 million, $0.5 million and $1.7 million under this agreement during the years ended December 31, 2016, 2015 and 2014, respectively. No milestones were achieved under this agreement during the years ended December 31, 2016, 2015 and 2014. At December 31, 2016, $3.2 million of revenue was deferred under this agreement, $0.9 million of which was current and $2.3 million of which was non-current. 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. 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 $5.1 million and $0.2 million in revenue under this contract during the years ended December 31, 2016 and 2015, respectively.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2016

Commitments and Contingencies Disclosure [Abstract]

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. During the year ended December 31, 2016, the Company entered into a sublease agreement for a portion of the South San Francisco space (see Note 8). Future payments to be received by the Company under this sublease total approximately $0.9 million.

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, 2016 and 2015, the Company had recorded a deferred rent liability of $6.2 million and $7.3 million, respectively. Rent expense for the years ended December 31, 2016, 2015 and 2014 was $3.0 million, $0.9 million and $2.0 million, respectively.

Future minimum lease payments under noncancelable operating leases as of December 31, 2016 are as follows (in thousands):



2017	$	6,314
2018	4,210
2019	3,803
2020	2,142
2021	2,574
Thereafter	2,636
	$	21,679

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, 2016
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plan	Employee Benefit Plan In 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 $1.0 million, $0.4 million and $0.3 million for the years ended December 31, 2016, 2015 and 2014, respectively.

Quarterly Financial Information (Unaudited)

12 Months Ended

Dec. 31, 2016

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Information (Unaudited)

Quarterly Financial Information (unaudited)



	1st Quarter			2nd Quarter			3rd Quarter			4th Quarter
	(in thousands, except per share data)
2016
Revenue	$	2,846		$	80,673		$	3,255		$	5,106
Net income (loss)	(30,363		)	40,464			(33,846		)	(34,783		)
Net income (loss) per share, basic	$	(0.88	)	$	1.17		$	(0.97	)	$	(1.00	)
Net income (loss) per share, diluted	$	(0.88	)	$	1.12		$	(0.97	)	$	(1.00	)

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	)

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2016

Accounting Policies [Abstract]

Basis of Presentation and Principles of Consolidation

Use of Estimates

Cash, Cash Equivalents and Marketable Securities

Accounts Receivable

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.

•


•	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.

Concentration of Credit Risk

Property and Equipment

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

Right-to-Develop Agreements

Research and Development Costs

Comprehensive Loss

Stock-based Compensation

Net Loss Per Share

Recently Issued Accounting Standards

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2016

Summary of Fair Value Measurement Financial Assets

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



	Fair Value Measurement at December 31, 2016
			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	$	46,781	$	46,781	$	—	$	—
U.S Treasury securities	8,826		—		8,826		—
Government-sponsored enterprises	29,759		—		29,759		—
Corporate debt securities	166,300		—		166,300		—
Total assets measured at fair value ^(a)	$	251,666	$	46,781	$	204,885	$	—

(a) Total assets measured at fair value at December 31, 2016 includes approximately $50.8 million reported in cash and cash equivalents on the balance sheet.



	Fair Value Measurement 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	$	—

(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

Depreciation is computed using the straight-line method over the following estimated useful lives:



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

Computation of Basic and Diluted 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,
	2016			2015			2014
Numerator:
Net loss used for calculation of basic and diluted EPS	$	(58,528	)	$	(20,140	)	$	(38,313	)

Denominator:
Weighted average shares outstanding, basic	34,685,274			31,801,645			27,384,990
Effect of dilutive securities:
Stock options and restricted stock units	—			—			—

Weighted average shares outstanding, diluted	34,685,274			31,801,645			27,384,990
Net loss per share, basic and diluted	$	(1.69	)	$	(0.63	)	$	(1.40	)

Schedule of Antidilutive Securities Excluded from the Calculation of Diluted 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,
	2016	2015	2014
Stock options	1,394,608	1,955,398	2,094,904

Customer Concentration Risk

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,
	2016		2015		2014
Janssen Biotech, Inc. (Janssen)	85	%	72	%	*
Les Laboratoires Servier and Institut de Reserches Servier (collectively, Servier)	*		*		36	%
Boehringer Ingelheim GmbH (Boehringer)	*		12	%	29	%
Takeda Pharmaceutical Company Limited (Takeda)	*		*		17	%
Gilead Sciences, Inc. (Gilead)	*		*		11	%

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



	December 31,
	2016		2015
Janssen	40	%	39	%
U.S. government	19	%	20	%
Servier	31	%	14	%
Takeda	*		14	%
Eli Lilly	*		13	%

* Balance is less than 10%

Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2016

Investments, Debt and Equity Securities [Abstract]

Available-for-sale Securities

Available-for-sale marketable securities as of December 31, 2016 and 2015 were as follows (in thousands):



	December 31, 2016
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury securities	$	4,826	$	—	$	(1	)	$	4,825
Government-sponsored enterprises	29,764		5		(10		)	29,759
Corporate debt securities	166,376		51		(127		)	166,300
Total	$	200,966	$	56	$	(138	)	$	200,884



	December 31, 2015
	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

The contractual maturities of the available-for-sale marketable securities as of December 31, 2016 were as follows (in thousands):



	Amortized Cost		Fair Value
Mature in one year or less	$	192,985	$	192,898
Mature between one and five years	7,981		7,986
Total	200,966		200,884

- 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, 2016

Property, Plant and Equipment [Abstract]

Schedule of Property and Equipment

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



	December 31,
	2016			2015
Computer equipment	$	2,520		$	3,069
Software	2,352			1,801
Furniture and office equipment	897			919
Lab equipment	20,208			17,306
Leasehold improvements	17,807			11,936
Property and equipment	43,784			35,031
Less accumulated depreciation	(25,823		)	(20,190		)
Property and equipment, net	$	17,961		$	14,841

Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2016

Disclosure of Compensation Related Costs, Share-based Payments [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,
	2016		2015		2014

Research and development	$	5,778	$	3,623	$	1,562
General and administrative	6,387		4,224		1,682
Total stock-based compensation expense	$	12,165	$	7,847	$	3,244

Schedule of Employee Stock Options Award 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,
	2016	2015	2014
Expected dividend yield	0%	0%	0%
Expected volatility	64% - 69%	73% - 75%	67%
Risk-free interest rate	1.2% - 2.4%	1.6% - 2.1%	1.8% - 2.3%
Expected term	6.25 years	6.25 years	6.25 years

Schedule of Stock Option and Restricted Stock Unit Activity

The following table summarizes stock option and restricted stock unit (RSU) activity for 2016:



	Shares		Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value (in thousands)
Outstanding, December 31, 2015	4,146,064		$	16.90	7.4
Granted	399,949		23.20
Options exercised or RSUs vested	(526,715	)	3.59
Forfeited or expired	(181,238	)	26.53
Outstanding, December 31, 2016	3,838,060		18.93		7.0	$	24,862

December 31, 2016:
Exercisable	2,292,923		13.71		6.1	22,458
Vested and expected to vest	3,651,523		18.57		7.0	24,496

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2016

Income Tax Disclosure [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,
	2016			2015
Deferred income tax assets:
Federal U.S. net operating loss carryforward	$	75,377		$	57,949
State net operating loss carryforward	6,583			3,907
Research and development credit, net	12,829			10,278
Orphan drug credit, net	19,855			19,284
Deferred rent	2,497			2,947
Deferred revenue	5,098			6,632
Depreciation	2,926			1,597
Other	5,085			2,532
Gross deferred income tax assets	130,250			105,126
Valuation allowance	(128,844		)	(104,399		)
Net deferred income tax assets	1,406			727

Deferred income tax liabilities:
Prepaid expenditures	(1,406		)	(727		)
Gross deferred income tax liabilities	(1,406		)	(727		)
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,
	2016			2015			2014

United States federal tax at statutory rate	$	(20,489	)	$	(7,049	)	$	(13,410	)
State taxes (net of federal benefit)	(3,116		)	(897		)	(1,608		)
Deferred income tax adjustments	173			661			—
Deferred state blended rate adjustments	(32		)	(493		)	3,034
Research credit, net	(2,551		)	(3,296		)	(2,228		)
Transaction cost deduction	—			—			(379		)
Transaction cost deduction - prior year adjustment	—			—			(564		)
Orphan drug credit, net	(571		)	(106		)	(139		)
Other permanent items	145			(25		)	(382		)
Equity-based compensation	1,997			1,102			756
Change in valuation allowance	24,444			10,103			14,920
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,
	2016			2015		2014
Beginning balance	$	2,425		$	2,047	$	1,708
Increases/(decreases) for current year tax positions	308			357		242
Increases/(decreases) for prior year tax positions	(268		)	21		97
Ending balance	$	2,465		$	2,425	$	2,047

Lease Exit Liability (Tables)

12 Months Ended

Dec. 31, 2016

Restructuring and Related Activities [Abstract]

Changes in Lease Exit Liability

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



Accrual balance at December 31, 2014	$	8,006
Principal payments and other adjustments	(3,293		)
Accrual balance at December 31, 2015	4,713
Principal payments and other adjustments (net of sublease receipts)	(2,822		)
Accrual balance at December 31, 2016	$	1,891

Future Principal Payments Under Lease Agreement

Future principal payments to be made under the lease agreement as of December 31, 2016, net of the sublease amounts, are as follows (in thousands):



2017	$	1,593
2018	298
Total	$	1,891

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2016

Commitments and Contingencies Disclosure [Abstract]

Schedule of Minimum Future Lease Payments

Future minimum lease payments under noncancelable operating leases as of December 31, 2016 are as follows (in thousands):



2017	$	6,314
2018	4,210
2019	3,803
2020	2,142
2021	2,574
Thereafter	2,636
	$	21,679

- 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, 2016

Quarterly Financial Information Disclosure [Abstract]

Company's Consolidated Quarterly Results of Operations



	1st Quarter			2nd Quarter			3rd Quarter			4th Quarter
	(in thousands, except per share data)
2016
Revenue	$	2,846		$	80,673		$	3,255		$	5,106
Net income (loss)	(30,363		)	40,464			(33,846		)	(34,783		)
Net income (loss) per share, basic	$	(0.88	)	$	1.17		$	(0.97	)	$	(1.00	)
Net income (loss) per share, diluted	$	(0.88	)	$	1.12		$	(0.97	)	$	(1.00	)

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	)

Summary of Significant Accounting Policies (Details)	12 Months Ended
Summary of Significant Accounting Policies (Details)	Dec. 31, 2016 USD ($) Segment	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Accounting Policies [Abstract]
Number of operating segments \| Segment	1
Available-for-sale securities, other than temporary impairment losses	$ 0	$ 0
Allowance recorded	0	0
Impaired assets	0	0
Assets held-for-sale	0	0
Unrealized loss on investments	$ (77,000)	$ (5,000)	$ 0

Summary of Significant Accounting Policies - Summary of Fair Value Measurement Financial Asset and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Assets [Abstract]
Cash and cash equivalents	$ 50,800	$ 108,000
Total assets measured at fair value	251,666	250,831
Money market funds
Assets [Abstract]
Cash and cash equivalents	46,781	62,353
U.S Treasury securities
Assets [Abstract]
Marketable securities	8,826	9,348
Government-sponsored enterprises
Assets [Abstract]
Marketable securities	29,759	41,202
Corporate debt securities
Assets [Abstract]
Marketable securities	166,300	137,928
Quoted Prices in Active Markets for Identical Assets, Level 1
Assets [Abstract]
Total assets measured at fair value	46,781	62,353
Quoted Prices in Active Markets for Identical Assets, Level 1 \| Money market funds
Assets [Abstract]
Cash and cash equivalents	46,781	62,353
Quoted Prices in Active Markets for Identical Assets, Level 1 \| U.S Treasury securities
Assets [Abstract]
Marketable securities	0	0
Quoted Prices in Active Markets for Identical Assets, Level 1 \| Government-sponsored enterprises
Assets [Abstract]
Marketable securities	0	0
Quoted Prices in Active Markets for Identical Assets, Level 1 \| Corporate debt securities
Assets [Abstract]
Marketable securities	0	0
Significant Other Observable Inputs, Level 2
Assets [Abstract]
Total assets measured at fair value	204,885	188,478
Significant Other Observable Inputs, Level 2 \| Money market funds
Assets [Abstract]
Cash and cash equivalents	0	0
Significant Other Observable Inputs, Level 2 \| U.S Treasury securities
Assets [Abstract]
Marketable securities	8,826	9,348
Significant Other Observable Inputs, Level 2 \| Government-sponsored enterprises
Assets [Abstract]
Marketable securities	29,759	41,202
Significant Other Observable Inputs, Level 2 \| Corporate debt securities
Assets [Abstract]
Marketable securities	166,300	137,928
Significant Unobservable Inputs, Level 3
Assets [Abstract]
Total assets measured at fair value	0	0
Significant Unobservable Inputs, Level 3 \| Money market funds
Assets [Abstract]
Cash and cash equivalents	0	0
Significant Unobservable Inputs, Level 3 \| U.S Treasury securities
Assets [Abstract]
Marketable securities	0	0
Significant Unobservable Inputs, Level 3 \| Government-sponsored enterprises
Assets [Abstract]
Marketable securities	0	0
Significant Unobservable Inputs, Level 3 \| Corporate debt securities
Assets [Abstract]
Marketable securities	$ 0	$ 0

Summary of Significant Accounting Policies - Summary of Collaborators that Represent More Than 10% of Total Revenue Earned (Details) - Sales revenue, net - Customer Concentration Risk	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Janssen Biotech, Inc. (Janssen)
Concentration Risk [Line Items]
Percentage of all significant revenue earned	85.00%	72.00%
Les Laboratoires Servier and Institut de Reserches Servier (collectively, Servier)
Concentration Risk [Line Items]
Percentage of all significant revenue earned			36.00%
Boehringer Ingelheim GmbH (Boehringer)
Concentration Risk [Line Items]
Percentage of all significant revenue earned		12.00%	29.00%
Takeda Pharmaceutical Company Limited (Takeda)
Concentration Risk [Line Items]
Percentage of all significant revenue earned			17.00%
Gilead Sciences, Inc. (Gilead)
Concentration Risk [Line Items]
Percentage of all significant revenue earned			11.00%

Summary of Significant Accounting Policies - Summary of Collaborators that Represent More Than 10% of Accounts Receivable (Details) - Customer Concentration Risk - Accounts receivable	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Janssen Biotech, Inc. (Janssen)
Concentration Risk [Line Items]
Percentage of significant accounts receivable	40.00%	39.00%
U.S. government
Concentration Risk [Line Items]
Percentage of significant accounts receivable	19.00%	20.00%
Les Laboratoires Servier and Institut de Reserches Servier (collectively, Servier)
Concentration Risk [Line Items]
Percentage of significant accounts receivable	31.00%	14.00%
Takeda
Concentration Risk [Line Items]
Percentage of significant accounts receivable		14.00%
Eli Lilly
Concentration Risk [Line Items]
Percentage of significant accounts receivable		13.00%

Summary of Significant Accounting Policies - Estimated Useful Lives (Details)	12 Months Ended
	Dec. 31, 2016
Computer equipment
Property, Plant and Equipment [Line Items]
Estimated useful lives	3 years
Software
Property, Plant and Equipment [Line Items]
Estimated useful lives	3 years
Furniture
Property, Plant and Equipment [Line Items]
Estimated useful lives	10 years
Laboratory and office equipment
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years
Leasehold improvements
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, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator:
Net loss used for calculation of basic and diluted EPS	$ (34,783)	$ (33,846)	$ 40,464	$ (30,363)	$ (28,451)	$ (15,442)	$ (21,376)	$ 45,129	$ (58,528)	$ (20,140)	$ (38,313)
Denominator:
Weighted average shares outstanding, basic (in shares)									34,685,274	31,801,645	27,384,990
Effect of dilutive securities:
Stock options and restricted stock units (in shares)									0	0	0
Weighted average shares outstanding, diluted (in shares)									34,685,274	31,801,645	27,384,990
Net loss per share, basic and diluted (in dollars per share)									$ (1.69)	$ (0.63)	$ (1.40)

- 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, 2016	Dec. 31, 2015	Dec. 31, 2014
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, (in shares)	1,394,608	1,955,398	2,094,904

Marketable Securities (Details) - USD ($)	12 Months Ended
Marketable Securities (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 200,966,000	$ 142,882,000
Gross Unrealized Gains	56,000	44,000
Gross Unrealized Losses	(138,000)	(49,000)
Fair Value	200,884,000	142,877,000
Available-for-sale securities, mature in one year or less, amortized cost basis	192,985,000
Available-for-sale securities, mature in one year or less, fair value	192,898,000
Available-for-sale securities, maturing between one and five years, amortized cost basis	7,981,000
Available-for-sale securities, maturing between one and five years, fair value	7,986,000
Available-for-sale securities, other than temporary impairment losses	0	0
U.S. Treasury securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	4,826,000	9,354,000
Gross Unrealized Gains	0	1,000
Gross Unrealized Losses	(1,000)	(6,000)
Fair Value	4,825,000	9,349,000
Government-sponsored enterprises
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	29,764,000	22,055,000
Gross Unrealized Gains	5,000	1,000
Gross Unrealized Losses	(10,000)	(9,000)
Fair Value	29,759,000	22,047,000
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	166,376,000	111,473,000
Gross Unrealized Gains	51,000	42,000
Gross Unrealized Losses	(127,000)	(34,000)
Fair Value	$ 166,300,000	$ 111,481,000

Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property and equipment	$ 43,784	$ 35,031
Less accumulated depreciation	(25,823)	(20,190)
Property and equipment, net	17,961	14,841
Property and equipment purchased but not yet paid	300
Depreciation expense	6,800	3,200	$ 1,800
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment	2,520	3,069
Software
Property, Plant and Equipment [Line Items]
Property and equipment	2,352	1,801
Furniture and office equipment
Property, Plant and Equipment [Line Items]
Property and equipment	897	919
Lab equipment
Property, Plant and Equipment [Line Items]
Property and equipment	20,208	17,306
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment	$ 17,807	$ 11,936

Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended
	Jul. 31, 2015	Jan. 31, 2015	Feb. 28, 2014	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Common stock, shares authorized (in shares)				125,000,000	125,000,000
Common stock, par value (in dollars per share)				$ 0.01	$ 0.01
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
Additional shares sold under over-allotments option to underwriter (in shares)	528,750		450,000
Proceeds from sale of shares	$ 141.0		$ 76.7
Johnson & Johnson Innovation JJDC, Inc,
Class of Stock [Line Items]
Sale of common stock (in shares)		1,923,077
Sale of common stock (in dollars per share)		$ 39
Proceeds of stock sale		$ 75.0
Undesignated Preferred Stock
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

Stock- based Compensation - Stock-Based Compensation Expense (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended			84 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	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)	3,838,060	4,146,064
Weighted average exercise price (in dollars per share)	$ 18.93	$ 16.90
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 12,165	$ 7,847	$ 3,244
Equity Incentive Plan 2003
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)	1,193,941
Weighted average exercise price (in dollars per share)	$ 1.81
Stock Incentive Plan 2013
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)	5,375,064
Share-based compensation arrangement by share-based payment award, options, outstanding, number (in shares)	2,644,119
Weighted average exercise price (in dollars per share)	$ 26.66
Stock reserved for future issuance (in shares)	1,960,168
Percentage of common stock share outstanding	4.00%
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 5,778	3,623	1,562
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 6,387	$ 4,224	$ 1,682

Stock- based Compensation - Option Pricing Assumptions (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
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	6 years 3 months
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	64.00%	73.00%
Risk-free interest rate	1.20%	1.60%	1.80%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	69.00%	75.00%
Risk-free interest rate	2.40%	2.10%	2.30%
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, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares, Outstanding, Beginning balance (in shares)	4,146,064
Shares, Granted (in shares)	399,949
Shares, Exercised or RSUs vested (in shares)	(526,715)	(374,214)	(568,906)
Shares, Forfeited or expired (in shares)	(181,238)
Shares, Outstanding, Ending balance (in shares)	3,838,060	4,146,064
Shares, Exercisable (in shares)	2,292,923
Shares, Vested and expected to vest (in shares)	3,651,523
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price [Abstract]
Weighted-average exercise price, Outstanding, Beginning balance (in dollars per share)	$ 16.90
Weighted-average exercise price, Granted (in dollars per share)	23.20
Weighted-average exercise price, Exercised or RSUs vested(in dollars per share)	3.59
Weighted-average exercise price, Forfeited or expired (in dollars per share)	26.53
Weighted-average exercise price, Outstanding, Ending balance (in dollars per share)	18.93	$ 16.90
Weighted-average exercise price, Exercisable (in dollars per share)	13.71
Weighted-average exercise price, Vested and expected to vest (in dollars per share)	$ 18.57
Weighted-average remaining contractual term, Outstanding	7 years	7 years 4 months 24 days
Weighted-average remaining contractual term, Exercisable	6 years 1 month 6 days
Weighted-average remaining contractual term, Vested and expected to vest	7 years
Aggregate intrinsic value, Outstanding, Ending balance	$ 24,862
Aggregate intrinsic value, Exercisable	22,458
Aggregate intrinsic value, Vested and expected to vest	$ 24,496
Common stock, shares issued (in shares)	526,715	374,214	568,906
Cash proceeds from exercise of stock options	$ 1,893	$ 911	$ 744
Weighted-average grant-date fair value of options granted (in dollars per share)	$ 15.17	$ 20.90	$ 17.41
Share-based compensation arrangement by share-based payment award, options, exercises in period, intrinsic value	$ 10,800	$ 10,900	$ 14,500
Fair value of shares vested	11,600	$ 7,300	$ 3,000
Unrecognized compensation cost related to non-vested stock-based compensation arrangements	$ 22,200
Unrecognized compensation expense recognition period	2 years 6 months

Income Taxes - Components of the Company's Deferred Tax Assets (Liabilities) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Provision for federal or state income taxes	$ 0	$ 0	$ 0
Deferred income tax assets:
Federal U.S. net operating loss carryforward	75,377,000	57,949,000
State net operating loss carryforward	6,583,000	3,907,000
Research and development credit, net	12,829,000	10,278,000
Orphan drug credit, net	19,855,000	19,284,000
Deferred rent	2,497,000	2,947,000
Deferred revenue	5,098,000	6,632,000
Depreciation	2,926,000	1,597,000
Other	5,085,000	2,532,000
Gross deferred income tax assets	130,250,000	105,126,000
Valuation allowance	(128,844,000)	(104,399,000)
Net deferred income tax assets	1,406,000	727,000
Deferred income tax liabilities:
Prepaid expenditures	(1,406,000)	(727,000)
Gross deferred income tax liabilities	(1,406,000)	(727,000)
Net deferred income tax asset/(liability)	0	$ 0
Operating Loss Carryforwards [Line Items]
Remaining portion of net operating losses	201,900,000
Net operating losses, recognized as a benefit through additional-paid-in-capital	18,600,000
U.S. Federal and State
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	215,400,000
U.S. Federal Government
Operating Loss Carryforwards [Line Items]
US Federal tax credits carry forward	32,500,000
Net operating loss for limited use	13,500,000
U.S. Federal Government \| Minimum
Operating Loss Carryforwards [Line Items]
Net operating losses limited for use utilized on an annual basis	200,000
U.S. Federal Government \| Maximum
Operating Loss Carryforwards [Line Items]
Net operating losses limited for use utilized on an annual basis	$ 1,400,000

Income Taxes - Reconciliation of Reported Estimated Income Tax Benefit (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
United States federal tax at statutory rate	$ (20,489)	$ (7,049)	$ (13,410)
State taxes (net of federal benefit)	(3,116)	(897)	(1,608)
Deferred income tax adjustments	173	661	0
Deferred state blended rate adjustments	(32)	(493)	3,034
Research credit, net	(2,551)	(3,296)	(2,228)
Transaction cost deduction	0	0	(379)
Transaction cost deduction - prior year adjustment	0	0	(564)
Orphan drug credit, net	(571)	(106)	(139)
Other permanent items	145	(25)	(382)
Equity-based compensation	1,997	1,102	756
Change in valuation allowance	24,444	10,103	14,920
Income tax expense/(benefit)	$ 0	$ 0	$ 0

Income Taxes - Reconciliation of the Beginning and Ending Amount of Gross Unrecognized Tax Benefits (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$ 2,425,000	$ 2,047,000	$ 1,708,000
Increases/(decreases) for current year tax positions	308,000	357,000	242,000
Increases/(decreases) for prior year tax positions	(268,000)	21,000	97,000
Ending balance	2,465,000	2,425,000	2,047,000
Gross unrecognized tax benefits	2,500,000	2,400,000
Unrecognized interest or penalties	$ 0	$ 0	$ 0

Lease Exit Liability Lease Exit Liability - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	May 31, 2016
Restructuring Cost and Reserve [Line Items]
Future sublease payments to be received	$ 0.9
Reduction in research and development expense	$ 1.3
Raven Biotechnologies Inc.
Restructuring Cost and Reserve [Line Items]
Future sublease payments to be received		$ 1.3

Lease Exit Liability - Changes in Lease Exit Liability (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Restructuring Reserve [Roll Forward]
Reduction of research and development expense	$ 1,900
Contract termination
Restructuring Reserve [Roll Forward]
Accrual beginning balance	4,713	$ 8,006
Principal payments and other adjustments (net of sublease receipts)	(2,822)	(3,293)
Accrual ending balance	$ 1,891	$ 4,713

Lease Exit Liability - Future Principal Payments Under Lease Agreement (Details) $ in Thousands	Dec. 31, 2016 USD ($)
Operating Leased Assets [Line Items]
2017	$ 6,314
2018	4,210
Total	21,679
Raven Biotechnologies Inc.
Operating Leased Assets [Line Items]
2017	1,593
2018	298
Total	$ 1,891

Collaboration and Other Agreements, Janssen Biotech, Inc. (Details) - Janssen Biotech Inc. - USD ($)	1 Months Ended			12 Months Ended
	Jul. 31, 2016	Jan. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	May 31, 2016	Jul. 31, 2015
Janssen MGD011 Agreement
Collaboration and Other Agreements [Line Items]
Sale of common stock (in shares)			1,923,077
Proceeds of stock sale		$ 75,000,000	$ 75,000,000
Nonrefundable upfront payment					$ 50,000,000
Sale of common stock (in dollars per share)		$ 39.00
Premium received on stock purchase		$ 12,300,000
Total consideration		125,000,000
Amount allocated to equity		62,700,000
Amount allocated to license and R&D		62,300,000
Clinical milestone earned during period							$ 10,000,000
Recognized revenue under agreement				$ 2,000,000	$ 72,300,000
Janssen MGD011 Agreement \| Maximum
Collaboration and Other Agreements [Line Items]
Potential clinical milestone payments under agreement		205,000,000.0
Potential regulatory milestone payments under agreement		220,000,000.0
Potential sales milestone payments under agreement		$ 150,000,000.0
Janssen MGD015 Agreement
Collaboration and Other Agreements [Line Items]
Nonrefundable upfront payment	$ 75,000,000			75,000,000
Potential clinical milestone payments under agreement						$ 100,000,000.0
Potential regulatory milestone payments under agreement						265,000,000
Potential sales milestone payments under agreement						$ 300,000,000
Recognized revenue under agreement				$ 75,800,000

Collaboration and Other Agreements, Takeda (Details) - USD ($)	1 Months Ended	12 Months Ended
	May 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Collaboration and Other Agreements [Line Items]
Deferred revenue included in current liabilities		$ 4,261,000	$ 5,866,000
Takeda Pharmaceutical Company Limited (Takeda) \| Takeda MGD010 Agreement
Collaboration and Other Agreements [Line Items]
Nonrefundable upfront payment	$ 15,000,000
Amount allocated to agreement	$ 10,000,000
Deferred revenue included in current liabilities			2,100,000
Expected period of development	24 months
Recognized revenue under agreement		2,100,000	8,000,000	$ 3,000,000
Milestone received			3,000,000
Deferred revenue		$ 0	2,100,000
Takeda Pharmaceutical Company Limited (Takeda) \| Research Collaboration and License Option Agreement
Collaboration and Other Agreements [Line Items]
Amount allocated to agreement	$ 5,000,000
Recognized revenue under agreement			$ 1,300,000	$ 5,000,000

Collaboration and Other Agreements, Servier (Details)	1 Months Ended	12 Months Ended
Collaboration and Other Agreements, Servier (Details)	Sep. 30, 2012 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($) Milestone
Collaboration and Other Agreements [Line Items]
Deferred revenue included in current liabilities		$ 4,261,000	$ 5,866,000
Deferred revenue included in long-term liabilities		10,045,000	12,631,000
Servier \| Servier DART
Collaboration and Other Agreements [Line Items]
Nonrefundable upfront payment	$ 20,000,000
Original period of development	29 months
Expected period of development	75 months
Change in accounting estimate, current year impact				$ 3,700,000
Option exercise fee				$ 15,000,000
Option exercise fee recognition period				82 months
Offset to research and development costs under collaboration arrangement		2,600,000	500,000	$ 1,000,000
Recognized revenue under agreement		3,300,000	3,500,000	$ 16,700,000
Number of milestones achieved \| Milestone				2
Milestone payment		0	0	$ 5,000,000
Review period				30 days
Deferred revenue		11,100,000	14,400,000
Deferred revenue included in current liabilities		3,300,000	3,300,000
Deferred revenue included in long-term liabilities		$ 7,800,000	$ 11,100,000
Servier \| Maximum \| Servier DART
Collaboration and Other Agreements [Line Items]
Potential License Fee	$ 40,000,000
Potential clinical milestone payments under agreement	63,000,000
Potential regulatory milestone payments under agreement	188,000,000
Potential sales milestone payments under agreement	$ 420,000,000

Collaboration and Other Agreements, Boehringer (Details) - Boehringer Ingelheim GmbH (Boehringer)	1 Months Ended	12 Months Ended
	Oct. 31, 2010 USD ($) Payment	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Collaboration and Other Agreements [Line Items]
Nonrefundable upfront payment	$ 15,000,000
Number of annual maintenance payments received \| Payment	3
Clinical milestone payments	$ 34,000,000
Additional potential regulatory milestone payments under agreement	88,500,000
Additional potential sales milestone payments under agreement	$ 82,500,000
Recognized revenue under agreement		$ 0	$ 12,500,000	$ 13,700,000
Milestone payment			5,000,000	$ 2,000,000
Deferred revenue		$ 0	$ 0

Collaboration and Other Agreements, Green Cross (Details) - USD ($)	1 Months Ended	12 Months Ended
	Jun. 30, 2010	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Collaboration and Other Agreements [Line Items]
Deferred revenue included in current liabilities		$ 4,261,000	$ 5,866,000
Deferred revenue included in long-term liabilities		10,045,000	12,631,000
Green Cross
Collaboration and Other Agreements [Line Items]
Nonrefundable upfront payment	$ 1,000,000
Adjustment to revenue from contract material modification				$ 1,300,000
Proceeds from research and development services		5,500,000
Recognized revenue under agreement		800,000	500,000	1,700,000
Milestone achieved		0	0	$ 0
Deferred revenue		3,200,000	2,000,000
Deferred revenue included in current liabilities		900,000	400,000
Deferred revenue included in long-term liabilities		$ 2,300,000	$ 1,600,000
Green Cross \| Maximum
Collaboration and Other Agreements [Line Items]
Aggregate potential future cost reimbursement	5,500,000.0
Clinical and commercial milestone payments	$ 2,500,000.0

Collaboration and Other Agreements, NIAID Contract (Details) - NIAID		12 Months Ended
	Sep. 15, 2015 USD ($) Molecule	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Collaboration And Other Agreements [Line Items]
Commercialization of molecules \| Molecule	2
Base period value	$ 7,500,000
Recognized revenue under agreement		$ 5,100,000	$ 200,000
Maximum
Collaboration And Other Agreements [Line Items]
Additional development funding options	17,000,000.0
Total potential value	$ 24,500,000.0

Commitments and Contingencies (Details) $ in Thousands	12 Months Ended
Commitments and Contingencies (Details) $ in Thousands	Dec. 31, 2016 USD ($) Lease	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Operating Leased Assets [Line Items]
Number of leases \| Lease	5
Lease incentives	$ 5,100
Future sublease payments to be received	900
Deferred rent liability	6,200	$ 7,300
Rent expense	3,000	$ 900	$ 2,000
Future minimum rental payments required under all non-cancelable operating leases [Abstract]
2017	6,314
2018	4,210
2019	3,803
2019	2,142
2020	2,574
Thereafter	2,636
Total	$ 21,679
Office, laboratory and manufacturing space
Operating Leased Assets [Line Items]
Lessee leasing arrangements, term of operating leases	7 years

Employee Benefit Plan (Details) - USD ($) $ in Millions	12 Months Ended
Employee Benefit Plan (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2012
Compensation and Retirement Disclosure [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	$ 1.0	$ 0.4	$ 0.3

Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 5,106	$ 3,255	$ 80,673	$ 2,846	$ 8,178	$ 14,681	$ 6,716	$ 71,279	$ 91,880	$ 100,854	$ 47,797
Net loss	$ (34,783)	$ (33,846)	$ 40,464	$ (30,363)	$ (28,451)	$ (15,442)	$ (21,376)	$ 45,129	$ (58,528)	$ (20,140)	$ (38,313)
Net income (loss) per share, basic (in dollars per share)	$ (1.00)	$ (0.97)	$ 1.17	$ (0.88)	$ (0.83)	$ (0.46)	$ (0.71)	$ 1.53
Net income (loss) per share, diluted (in dollars per share)	$ (1.00)	$ (0.97)	$ 1.12	$ (0.88)	$ (0.83)	$ (0.46)	$ (0.71)	$ 1.42

- 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