Merrimack Pharmaceuticals (MACK) 10-Q 2 May 16 2016 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2016	Apr. 27, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q1
Trading Symbol	MACK
Entity Registrant Name	MERRIMACK PHARMACEUTICALS INC
Entity Central Index Key	1,274,792
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		127,725,130

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 48,237	$ 185,606
Marketable securities	84,153
Restricted cash	101	101
Accounts receivable, net	15,637	6,483
Inventory	8,083	3,717
Prepaid expenses and other current assets	4,470	5,487
Total current assets	160,681	201,394
Restricted cash	584	584
Property and equipment, net	20,824	21,915
Other assets	27	27
Intangible assets, net	7,211	7,355
Goodwill	3,605	3,605
Total assets	192,932	234,880
Current liabilities:
Accounts payable, accrued expenses and other	50,449	52,082
Deferred revenues	45,097	50,137
Deferred rent	1,817	1,527
Total current liabilities	97,363	103,746
Deferred revenues, net of current portion	47,103	51,197
Deferred rent, net of current portion	4,832	4,926
Deferred tax incentives, net of current portion	934	1,045
Long-term debt	259,843	257,655
Total liabilities	$ 410,075	$ 418,569
Commitments and contingencies
Non-controlling interest	$ 54	$ 239
Stockholders' deficit:
Preferred stock, $0.01 par value: 10,000 shares authorized at March 31, 2016 and December 31, 2015; no shares issued or outstanding at March 31, 2016 or December 31, 2015
Common stock, $0.01 par value: 200,000 shares authorized at March 31, 2016 and December 31, 2015, 116,411 and 115,871 shares issued and outstanding at March 31, 2016 and December 31, 2015, respectively	$ 1,164	$ 1,159
Additional paid-in capital	622,358	617,145
Accumulated other comprehensive loss	(14)
Accumulated deficit	(840,705)	(802,232)
Total stockholders' deficit	(217,197)	(183,928)
Total liabilities, non-controlling interest and stockholders' deficit	$ 192,932	$ 234,880

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	116,411,000	115,871,000
Common stock, shares outstanding	116,411,000	115,871,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Revenues:
Product revenues, net	$ 9,968
License and collaboration revenues	11,313	$ 14,842
Total revenues	21,281	14,842
Costs and expenses:
Cost of product revenues	711
Research and development expenses	32,882	35,679
Selling, general and administrative expenses	17,795	9,189
Total costs and expenses	51,388	44,868
Loss from operations	(30,107)	(30,026)
Other income and expenses
Interest income	72	47
Interest expense	(8,580)	(4,566)
Other (expense) income, net	(43)	113
Net loss	(38,658)	(34,432)
Net (loss) income attributable to non-controlling interest	(185)	327
Net loss attributable to Merrimack Pharmaceuticals, Inc.	(38,473)	(34,759)
Other comprehensive (loss) income:
Unrealized (loss) gain on available-for-sale securities	(14)	47
Other comprehensive (loss) income	(14)	47
Comprehensive loss	$ (38,487)	$ (34,712)
Net loss per share available to common stockholders-basic and diluted	$ (0.33)	$ (0.32)
Weighted-average common shares used in computing net loss per share available to common stockholders-basic and diluted	116,064	107,148

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities
Net loss	$ (38,658)	$ (34,432)
Adjustments to reconcile net loss to net cash used in operating activities
Non-cash interest expense	2,190	1,937
Depreciation and amortization	1,537	1,054
Stock-based compensation	3,533	3,370
Changes in operating assets and liabilities:
Accounts receivable	(9,154)	(935)
Inventory	(4,366)
Accounts payable, accrued expenses and other	(1,205)	4,649
Deferred revenues	(9,134)	(12,222)
Other assets and liabilities, net	1,734	1,500
Net cash used in operating activities	(53,523)	(35,079)
Cash flows from investing activities
Purchases of marketable securities	(84,262)
Proceeds from sales and maturities of marketable securities		25,163
Purchases of property and equipment	(1,229)	(1,204)
Net cash (used in) provided by investing activities	(85,491)	23,959
Cash flows from financing activities
Proceeds from exercise of options and warrants to purchase common stock	1,645	3,136
Proceeds from issuance of preferred stock by Silver Creek Pharmaceuticals, Inc.		1,129
Net cash provided by financing activities	1,645	4,265
Net decrease in cash and cash equivalents	(137,369)	(6,855)
Cash and cash equivalents, beginning of period	185,606	35,688
Cash and cash equivalents, end of period	48,237	28,833
Non-cash investing and financing activities
Property and equipment in accounts payable and accrued expenses	388	1,177
Receivables related to stock option exercises in prepaid expenses and other current assets	53	200
Supplemental disclosure of cash flows
Cash paid for interest	$ 2,813	$ 3,868

Nature of the Business

Nature of the Business	3 Months Ended
	Mar. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of the Business	1. Nature of the Business Merrimack Pharmaceuticals, Inc. (the “Company”) is a biopharmaceutical company discovering, developing and commercializing innovative medicines consisting of novel therapeutics paired with diagnostics for the treatment of cancer. The Company has one marketed therapeutic oncology product and multiple targeted therapeutic oncology candidates in clinical development. The Company’s most advanced program is its therapeutic ONIVYDE, which it markets in the United States. In addition to ONIVYDE and its product candidates in clinical development, the Company has multiple product candidates in preclinical development and a discovery effort advancing additional candidate medicines. The Company has tailored ONIVYDE and its other product candidates to target specific disease mechanisms that its research suggests are common across many solid tumor types. The Company believes that ONIVYDE and its other product candidates have the potential to address major unmet medical needs. The Company also has an agreement to utilize its manufacturing expertise to develop, manufacture and exclusively supply bulk drug product to a third party, who will in turn process the drug into finished product and commercialize it globally following regulatory approval. The Company was incorporated in the Commonwealth of Massachusetts in 1993 and reincorporated in the State of Delaware in October 2010. The Company is subject to risks and uncertainties common to companies in the biopharmaceutical industry, including, among other things, its ability to secure additional capital to fund operations, success of clinical trials, development by competitors of new technological innovations, dependence on collaborative arrangements, protection of proprietary technology, compliance with government regulations and dependence on key personnel. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel, infrastructure and extensive compliance reporting capabilities. The Company has incurred significant losses and has not generated significant revenue from commercial sales. The accompanying condensed consolidated financial statements have been prepared on a basis which assumes that the Company will continue as a going concern and which contemplates the realization of assets and satisfaction of liabilities and commitments in the normal course of business. The Company may seek additional funding through public or private debt or equity financings, or through existing or new collaboration arrangements. The Company may not be able to obtain financing on acceptable terms, or at all, and the Company may not be able to enter into additional collaborative arrangements. The terms of any financing may adversely affect the holdings or the rights of the Company’s stockholders. Arrangements with collaborators or others may require the Company to relinquish rights to certain of its technologies or product candidates. If the Company is unable to obtain funding, the Company could be forced to delay, reduce or eliminate its research and development programs or commercialization efforts, which could adversely affect its business prospects.

Basis of Presentation and Conso

Basis of Presentation and Consolidation	3 Months Ended
	Mar. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Consolidation	2. Basis of Presentation and Consolidation The accompanying condensed consolidated financial statements as of March 31, 2016 and December 31, 2015, and for the three months ended March 31, 2016 and 2015, have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the “SEC”) and generally accepted accounting principles in the United States of America (“GAAP”) for condensed consolidated financial information. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, these condensed consolidated financial statements reflect all adjustments which are necessary for a fair statement of the Company’s financial position and results of its operations, as of and for the periods presented. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015 filed with the SEC on February 26, 2016. The information presented in the condensed consolidated financial statements and related notes as of March 31, 2016, and for the three months ended March 31, 2016 and 2015, is unaudited. The December 31, 2015 condensed consolidated balance sheet included herein was derived from the audited financial statements as of that date, but does not include all disclosures, including notes, required by GAAP for complete financial statements. Interim results for the three months ended March 31, 2016 are not necessarily indicative of the results that may be expected for the fiscal year ending December 31, 2016, or any future period. These condensed consolidated financial statements also include the accounts of the Company and its majority owned subsidiary, Silver Creek Pharmaceuticals, Inc. (“Silver Creek”). All intercompany transactions and balances have been eliminated in consolidation. As of March 31, 2016, the Company’s unrestricted cash and cash equivalents includes $0.2 million of cash and cash equivalents held by Silver Creek. This $0.2 million held by Silver Creek is designated for the operations of Silver Creek. During the three months ended March 31, 2015, Silver Creek issued and sold a total of 0.9 million shares of Silver Creek Series B preferred stock at a price per share of $1.35 to investors and received net proceeds of $1.1 million, after deducting issuance costs. No shares of Silver Creek Series B preferred stock were sold during the three months ended March 31, 2016. The Company’s ownership of Silver Creek was 56% as of both March 31, 2016 and December 31, 2015. The change in the non-controlling interest related to Silver Creek was as follows: (in thousands) Non-Controlling Interest Balance at December 31, 2015 $ 239 Net loss attributable to Silver Creek (185 ) Balance at March 31, 2016 $ 54 (in thousands) Non-Controlling Interest Balance at December 31, 2014 $ 69 Net income attributable to Silver Creek 327 Balance at March 31, 2015 $ 396

Net Loss Per Common Share

Net Loss Per Common Share	3 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Net Loss Per Common Share	3. Net Loss Per Common Share Basic net loss per share is calculated by dividing the net loss available to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share is computed by dividing the net loss available to common stockholders by the weighted-average number of common share equivalents outstanding for the period determined using the treasury-stock method. For purposes of this calculation, convertible preferred stock, stock options and warrants are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive. As discussed in Note 10, “Borrowings,” in July 2013, the Company issued $125.0 million aggregate principal amount of 4.50% convertible notes due 2020 (the “Convertible Notes”) in an underwritten public offering. Following the repayment and satisfaction in full of the Company’s obligations to Hercules Technology Growth Capital, Inc. (“Hercules”) under its Loan and Security Agreement with Hercules (the “Loan Agreement”), which occurred in December 2015, upon any conversion of the Convertible Notes, the Convertible Notes may be settled, at the Company’s election, in cash, shares of the Company’s common stock or a combination of cash and shares of the Company’s common stock. For purposes of calculating the maximum dilutive impact, it is presumed that the conversion premium will be settled in common stock, inclusive of a contractual make-whole provision resulting from a fundamental change, and the resulting potential common shares included in diluted earnings per share if the effect is more dilutive. The stock options, warrants and conversion premium on the Convertible Notes are excluded from the calculation of diluted loss per share because the net loss for the three months ended March 31, 2016 and 2015 causes such securities to be anti-dilutive. Securities excluded from the calculation of diluted loss per share are shown in the chart below: Three Months Ended March 31, (in thousands) 2016 2015 Outstanding options to purchase common stock 21,647 20,285 Common stock warrants — 741 Conversion of the Convertible Notes 25,000 25,000

License and Collaboration Agree

License and Collaboration Agreements	3 Months Ended
	Mar. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
License and Collaboration Agreements	4. License and Collaboration Agreements Baxalta On September 23, 2014, the Company and Baxter International Inc., Baxter Healthcare Corporation and Baxter Healthcare SA entered into a license and collaboration agreement (the “Baxalta Agreement”) for the development and commercialization of ONIVYDE outside of the United States and Taiwan (the “Licensed Territory”). In connection with Baxter International Inc.’s separation of the Baxalta business, the Baxalta Agreement was assigned to Baxalta during the second quarter of 2015. As part of the Baxalta Agreement, the Company granted Baxalta an exclusive, royalty-bearing right and license under the Company’s patent rights and know-how to develop and commercialize ONIVYDE in the Licensed Territory. Baxalta is responsible for using commercially reasonable efforts to develop, obtain regulatory approvals for and, following regulatory approval, commercialize ONIVYDE in the Licensed Territory. A joint steering committee comprised of an equal number of representatives from each of Baxalta and the Company is responsible for approving changes to the global development plan for ONIVYDE, including all budgets, and overseeing the parties’ development and commercialization activities with respect to ONIVYDE. Unless otherwise agreed, the Company will be responsible for conducting all clinical trials contemplated by the global development plan for ONIVYDE and manufacturing all clinical material needed for such trials. Under the terms of the Baxalta Agreement, the Company received a $100.0 million upfront, nonrefundable cash payment in September 2014. In addition, the Company is eligible to receive from Baxalta (i) up to an aggregate of $100.0 million upon the achievement of specified research and development milestones, of which the Company has received $62.5 million from Baxalta through March 31, 2016, (ii) up to an aggregate of $520.0 million upon the achievement of specified regulatory milestones, of which the Company has received $20.0 million from Baxalta through March 31, 2016, and (iii) up to an aggregate of $250.0 million upon the achievement of specified sales milestones. Under the terms of the Baxalta Agreement, the Company will bear up to the first $98.8 million of costs related to the development of ONIVYDE for pancreatic cancer patients who have not previously received gemcitabine-based therapy; however, the Company expects most of these costs to be offset by payments received upon the achievement of clinical trial-related milestones. The Company and Baxalta will share equally all other clinical trial costs contemplated by the global development plan. The Company is also entitled to tiered, escalating royalties ranging from sub-teen double digits to low twenties percentages of net sales of ONIVYDE in the Licensed Territory. The Company and Baxalta are parties to a commercial supply agreement pursuant to which the Company will supply ONIVYDE bulk drug substance to Baxalta and, at Baxalta’s option, may manage fill and finish activities to be conducted by a third-party contract manufacturer for Baxalta. Baxalta also has the option to manufacture ONIVYDE itself, in which case the Company will perform a technology transfer of its manufacturing process to Baxalta. If not terminated earlier by either party, the Baxalta Agreement will expire upon expiration of all royalty and other payment obligations of Baxalta under the Baxalta Agreement. Either party may terminate the Baxalta Agreement in the event of an uncured material breach by the other party. Baxalta may also terminate the Baxalta Agreement on a product-by-product, country-by-country or sub-territory-by-sub-territory basis or in its entirety, for its convenience, upon 180 days’ prior written notice. In addition, the Company may terminate the Baxalta Agreement if Baxalta challenges or supports any challenge of the Company’s licensed patent rights. At the inception of the collaboration, the Company identified the following deliverables as part of the Baxalta Agreement: (i) license to develop and commercialize ONIVYDE in Baxalta’s territories, (ii) discovery, research, development and manufacturing services required to complete ongoing clinical trials related to ONIVYDE, (iii) discovery, research, development and manufacturing services needed to complete future clinical trials in further indications related to ONIVYDE, (iv) the option to perform a technology transfer of the Company’s manufacturing process related to the production of ONIVYDE to Baxalta and (v) participation on the joint steering committee. The Company concluded that none of the deliverables identified at the inception of the collaboration has standalone value from the other undelivered elements. As such, all deliverables represent a single unit of accounting. The Company has determined that the collaboration represents a services agreement and as such has estimated the level of effort expected to be completed as a result of providing the identified deliverables. The Company will recognize revenue from the nonrefundable upfront payment, forecasted non-substantive milestone payments and estimated payments related to discovery, research, development and technology transfer services based on proportional performance as effort is completed over the expected services period, which is estimated to be substantially complete by June 30, 2020. The Company will periodically review and, if necessary, revise the estimated service period related to its collaboration with Baxalta. As of March 31, 2016, the Company has achieved $62.5 million of the $90.0 million of forecasted non-substantive milestones that are included in the Company’s proportional performance revenue recognition model and $20.0 million of the $530.0 million of substantive milestones that are included in the Baxalta Agreement. Research, development and regulatory milestones that are considered substantive on the basis of the contingent nature of the milestone will be recognized as revenue in full in the period in which the associated milestone is achieved, assuming all other revenue recognition criteria are met. All sales milestones will be accounted for in the same manner as royalties and recorded as revenue upon achievement of the milestone, assuming all other revenue recognition criteria are met. During the second quarter of 2015, the European Medicines Agency (“EMA”) accepted for review a Marketing Authorization Application (“MAA”) filed by Baxalta for ONIVYDE. As a result of this acceptance, the Company recognized $20.0 million of revenue related to a substantive milestone payment owed from Baxalta. In August 2015, the Company achieved a $15.0 million milestone related to the submission of the protocol for the Company’s Phase 2 clinical trial of ONIVYDE in front-line metastatic pancreatic cancer. This milestone is a non-substantive milestone, and revenue related to the achievement of this milestone will be recognized through the proportional performance revenue recognition model. In October 2015, the Company achieved an additional $47.5 million milestone related to the enrollment of the first patient in a Phase 2 clinical trial of ONIVYDE in front-line pancreatic cancer. This milestone is also a non-substantive milestone, and revenue related to the achievement of this milestone will be recognized through the proportional performance revenue recognition model. During the three months ended March 31, 2016 and 2015, the Company recognized $11.3 million and $14.8 million, respectively, of revenue under the proportional performance revenue recognition model. No substantive milestones were achieved during either of the three months ended March 31, 2016 or 2015. As of March 31, 2016 and December 31, 2015, the Company maintained the following assets and liabilities related to the Baxalta Agreement: (in thousands) March 31, December 31, Accounts receivable, billed $ 1,250 $ 1,336 Accounts receivable, unbilled 914 626 Deferred revenues 88,217 97,365 Of the $88.2 million of deferred revenues related to the Baxalta Agreement as of March 31, 2016, $45.1 million is classified as current in the condensed consolidated balance sheets based upon the Company’s estimate of revenues that will be recognized under the proportional performance revenue recognition model as a result of effort expected to be completed within the next twelve months. PharmaEngine, Inc. On May 5, 2011, the Company and PharmaEngine, Inc. (“PharmaEngine”) entered into an assignment, sublicense and collaboration agreement (the “PharmaEngine Agreement”) under which the Company reacquired rights in Europe and certain countries in Asia to ONIVYDE. In exchange, the Company agreed to pay PharmaEngine a nonrefundable, noncreditable upfront payment of $10.0 million and up to an additional $80.0 million in aggregate development and regulatory milestones and $130.0 million in aggregate sales milestones. PharmaEngine is also entitled to tiered royalties on net sales of ONIVYDE in Europe and certain countries in Asia. PharmaEngine is not responsible for any future development costs of ONIVYDE except those required specifically for regulatory approval in Taiwan. On September 22, 2014, the Company amended the PharmaEngine Agreement to redefine sublicense revenue and reduce the portion of sublicense revenue that the Company is required to pay to PharmaEngine. As a result of this amendment, the Company made a $7.0 million milestone payment to PharmaEngine in September 2014. Additionally, as a result of this amendment, a previously contingent $5.0 million milestone payment was paid to PharmaEngine in the second quarter of 2015. Prior to the amendment of the PharmaEngine Agreement, this milestone payment was contingent upon the award of certain specified regulatory designations. These milestone payments were recognized as research and development expense during the year ended December 31, 2014. The Company also made an $11.0 million milestone payment to PharmaEngine in July 2015 in connection with the EMA’s acceptance for review of an MAA for ONIVYDE, which occurred, and was recognized as research and development expense, in the second quarter of 2015. During the three months ended March 31, 2016 and 2015, the Company recognized research and development expenses of less than $0.1 million and $0.2 million, respectively, related to the PharmaEngine Agreement. Actavis In November 2013, the Company and Watson Laboratories, Inc. (“Actavis”) entered into a development, license and supply agreement (the “Actavis Agreement”) pursuant to which the Company will develop, manufacture and exclusively supply the bulk form of doxorubicin HCl liposome injection (the “Initial Product”) to Actavis. The Actavis Agreement was subsequently amended in January 2015 to transfer certain responsibilities from the Company to Actavis in exchange for reducing the aggregate milestone payments that the Company is eligible to receive by $0.4 million. Under the Actavis Agreement, Actavis is responsible for all costs related to finished product processing and global commercialization. Pursuant to the agreement, additional products may be developed for Actavis in the future, the identities of which will be mutually agreed upon. The Company is eligible to receive up to $15.1 million in milestone and development payments, as well as additional reimbursement for specific activities performed by the Company at the request of Actavis, of which $3.9 million in total has been received through March 31, 2016. The Company will also receive a double digit percentage of net profits on global sales of the Initial Product and any additional products. The Company will manufacture and supply the Initial Product to Actavis in bulk form at an agreed upon unit price. The Actavis Agreement will expire with respect to the Initial Product and any additional products developed in the future ten years after Actavis’ first sale of the applicable product, unless terminated earlier, and will automatically renew for additional two year periods thereafter unless either party provides notice of non-renewal. Either party may terminate the Actavis Agreement in the event of an uncured material breach or bankruptcy filing by the other party. Actavis may also terminate the Actavis Agreement for convenience in specified circumstances upon 90 days’ prior written notice. The Company applied revenue recognition guidance to determine whether the performance obligations under the Actavis Agreement, including the license, participation on steering committees, development services, and manufacturing and supply services could be accounted for separately or as a single unit of accounting. The Company determined that these obligations represent a single unit of accounting and will recognize revenue as product is supplied to Actavis. Therefore, the Company has recorded $4.0 million of billed and billable milestones and development expenses related to the Actavis Agreement as deferred revenue as of both March 31, 2016 and December 31, 2015. This revenue is expected to be recognized by the Company over the ten year period that begins after Actavis’ first sale of the applicable product under the Actavis Agreement.

Product Revenue Reserves and Al

Product Revenue Reserves and Allowances	3 Months Ended
	Mar. 31, 2016
Text Block [Abstract]
Product Revenue Reserves and Allowances	5. Product Revenue Reserves and Allowances The following table summarizes activity in each of the product revenue reserve and allowance categories for the three months ended March 31, 2016: (in thousands) Trade Rebates and Product Other Total Balance at December 31, 2015 $ 138 $ 362 $ 32 $ 8 $ 540 Provisions related to sales in the current year 354 1,031 74 15 1,474 Adjustments related to sales in the prior year — (127 ) — — (127 ) Credits and payments made (205 ) (693 ) (5 ) (2 ) (905 ) Balance at March 31, 2016 $ 287 $ 573 $ 101 $ 21 $ 982

Fair Value of Financial Instrum

Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	6. Fair Value of Financial Instruments The carrying values of cash, restricted cash, prepaid expenses, accounts receivable, accounts payable and accrued expenses, and other short-term assets and liabilities approximate their respective fair values due to the short-term maturities of these assets and liabilities. Fair value is an exit price, representing the amount that would be received from the sale of an asset or paid to transfer a liability in an orderly transaction between market participants. Fair value is determined based on observable and unobservable inputs. Observable inputs reflect readily obtainable data from independent sources, while unobservable inputs reflect certain market assumptions. As a basis for considering such assumptions, GAAP establishes a three-tier value hierarchy, which prioritizes the inputs used to develop the assumptions and for measuring fair value as follows: (Level 1) observable inputs such as quoted prices in active markets for identical assets; (Level 2) inputs other than the quoted prices in active markets that are observable either directly or indirectly; and (Level 3) unobservable inputs in which there is little or no market data, which requires the Company to develop its own assumptions. This hierarchy requires the Company to use observable market data, when available, and to minimize the use of unobservable inputs when determining fair value. Recurring Fair Value Measurements The following tables show assets measured at fair value on a recurring basis as of March 31, 2016 and December 31, 2015: March 31, 2016 (in thousands) Level 1 Level 2 Level 3 Cash equivalents: Money market funds $ 3,047 $ — $ — Commercial paper — 13,991 — Corporate debt securities — 9,001 — U.S. government agency securities — 9,999 — Total cash equivalents $ 3,047 $ 32,991 $ — Marketable securities: Commercial paper $ — $ 43,922 $ — Corporate debt securities — 21,251 — U.S. government agency securities — 18,980 — Total marketable securities $ — $ 84,153 $ — December 31, 2015 (in thousands) Level 1 Level 2 Level 3 Cash equivalents: Money market funds $ 704 $ — $ — Total cash equivalents $ 704 $ — $ — There were no changes in valuation techniques or transfers between the fair value measurement levels during the three months ended March 31, 2016 or during the year ended December 31, 2015. There were no liabilities measured at fair value on a recurring basis as of March 31, 2016 or December 31, 2015. Non-Recurring Fair Value Measurements Certain assets, including in-process research and development intangible assets, may be measured at fair value on a non-recurring basis in periods subsequent to initial recognition. No non-recurring fair value measurements were required during the three months ended March 31, 2016 or 2015. Other Fair Value Measurements The estimated fair value of the $125.0 million aggregate principal amount of the Convertible Notes was $186.4 million as of March 31, 2016. The Company estimated the fair value of the Convertible Notes by using a quoted market rate in an inactive market, which is classified as a Level 2 input. The carrying value of the Convertible Notes is $90.5 million as of March 31, 2016 due to the bifurcation of the conversion feature of the Convertible Notes as described more fully in Note 10, “Borrowings.” As discussed in Note 10, “Borrowings,” in December 2015, the Company closed a private placement of $175.0 million aggregate principal amount of 11.50% senior secured notes due 2022 (the “2022 Notes”). The carrying value of the 2022 Notes was $169.3 million as of March 31, 2016. The Company estimated the fair value of the 2022 Notes by using publicly-available information related to one of the 2022 Notes borrower’s portfolio of debt investments based on unobservable inputs, which is classified as a Level 3 input. The estimated fair value of the 2022 Notes was $172.6 million as of March 31, 2016.

Marketable Securities

Marketable Securities	3 Months Ended
	Mar. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	7. Marketable Securities The Company classifies marketable securities with a remaining maturity when purchased of greater than three months as available-for-sale. Available-for-sale securities may consist of U.S. government agency securities, commercial paper, corporate notes and bonds and certificates of deposit, which are maintained by an investment manager. Available-for-sale securities are carried at fair value, with the unrealized gains and losses included in other comprehensive income (loss) as a component of stockholders’ deficit until realized. The amortized cost of securities in this category is adjusted for amortization of premiums and accretion of discounts to maturity. Realized gains and losses are recognized within interest income. As of December 31, 2015, the Company maintained only cash equivalents comprised of money market funds. Cash equivalents and marketable securities as of March 31, 2016 consisted of the following: March 31, 2016 (in thousands) Amortized Unrealized Unrealized Fair Cash equivalents: Money market funds $ 3,047 $ — $ — $ 3,047 Commercial paper 13,993 — (2 ) 13,991 Corporate debt securities 9,002 — (1 ) 9,001 U.S. government agency securities 9,999 — — 9,999 Total cash equivalents $ 36,041 $ — $ (3 ) $ 36,038 Marketable securities: Commercial paper $ 43,929 $ — $ (7 ) 43,922 Corporate debt securities 21,254 — (3 ) 21,251 U.S. government agency securities 18,981 1 (2 ) 18,980 Total marketable securities $ 84,164 $ 1 $ (12 ) $ 84,153 There were no realized gains or losses on available-for-sale securities during the three months ended March 31, 2016 or 2015. As of March 31, 2016, the Company held 20 individual cash equivalents or available-for-sale securities that had been in an unrealized loss position for less than twelve months, and the aggregate fair value of such securities was $91.2 million. As of March 31, 2016, the Company did not intend to sell, and it was not more likely than not that the Company would be required to sell, the securities in an unrealized loss position before recovery of their amortized cost bases. The Company determined that there was no material change in the credit risk of the investments. As a result, the Company determined it did not hold any securities with an other-than-temporary-impairment as of March 31, 2016.

Inventory

Inventory	3 Months Ended
	Mar. 31, 2016
Inventory Disclosure [Abstract]
Inventory	8. Inventory Inventory as of March 31, 2016 and December 31, 2015 consisted of the following: (in thousands) March 31, 2016 December 31, 2015 Raw materials $ 1,862 $ 900 Work in process 6,166 2,743 Finished goods 55 74 Total inventory $ 8,083 $ 3,717 Inventory acquired prior to receipt of marketing approval of ONIVYDE was expensed as research and development expense as incurred. The Company began to capitalize the costs associated with the production of ONIVYDE upon receipt of approval from the U.S. Food and Drug Administration on October 22, 2015.

Accounts Payable, Accrued Expen

Accounts Payable, Accrued Expenses and Other	3 Months Ended
	Mar. 31, 2016
Payables and Accruals [Abstract]
Accounts Payable, Accrued Expenses and Other	9. Accounts Payable, Accrued Expenses and Other Accounts payable, accrued expenses and other as of March 31, 2016 and December 31, 2015 consisted of the following: (in thousands) March 31, December 31, Accounts payable $ 10,784 $ 5,049 Accrued goods and services 12,574 14,295 Accrued clinical trial costs 12,433 12,764 Accrued drug purchase costs 1,662 7,460 Accrued payroll and related benefits 5,866 9,009 Accrued interest 6,666 3,041 Accrued dividends payable 19 19 Deferred tax incentives 445 445 Total accounts payable, accrued expenses and other $ 50,449 $ 52,082

Borrowings

Borrowings	3 Months Ended
	Mar. 31, 2016
Debt Disclosure [Abstract]
Borrowings	10. Borrowings 2022 Notes On December 22, 2015, the Company closed a private placement of $175.0 million aggregate principal amount of 11.50% 2022 Notes. As a result of this placement, the Company received net proceeds of approximately $168.5 million, after deducting private placement and offering expenses payable by the Company. The 2022 Notes bear interest at a rate of 11.50% per year, payable semi-annually on June 15 and December 15 of each year, beginning on June 15, 2016. The Company will pay semi-annual installments of principal on the 2022 Notes of $21,875,000 each, subject to adjustment as provided in the 2022 Notes, on June 15 and December 15 of each year, beginning on June 15, 2019. The 2022 Notes will mature on December 15, 2022, unless earlier redeemed or repurchased in accordance with their terms prior to such date. The 2022 Notes are senior secured obligations of the Company and will be equal in right of payment to all existing and future pari passu indebtedness of the Company (including the Company’s outstanding Convertible Notes), will be senior in right of payment to all existing and future subordinated indebtedness of the Company, will have the benefit of a security interest in the 2022 Notes collateral and will be junior in lien priority in respect of any asset-based lending collateral that secures any first priority lien obligations from time to time. The 2022 Notes contain customary covenants, including covenants that limit or restrict the Company’s ability to incur liens, incur indebtedness, and make certain restricted payments, but do not contain covenants related to future financial performance. The 2022 Notes are secured by a first priority lien on substantially all of the Company’s assets. The Company assessed the 2022 Notes pursuant to Accounting Standards Codification (“ASC”) 815 to determine if any features necessitated bifurcation from the host instrument. The Company concluded that none of the embedded redemption features within the 2022 Notes require bifurcation as these features are clearly and closely related to the host instrument. Debt issuance costs incurred by the Company are accounted for as a direct deduction to the carrying value of the 2022 Notes and are amortized to interest expense using the effective interest method over the life of the 2022 Notes. For the three months ended March 31, 2016, interest expense related to the 2022 Notes was approximately $5.2 million. Convertible Notes In July 2013, the Company issued $125.0 million aggregate principal amount of Convertible Notes in an underwritten public offering. As a result of the Convertible Notes offering, the Company received net proceeds of approximately $120.6 million, after deducting underwriting discounts and commissions and offering expenses payable by the Company. The Convertible Notes bear interest at a rate of 4.50% per year, payable semiannually in arrears on January 15 and July 15 of each year, beginning on January 15, 2014. The Convertible Notes are general unsecured senior obligations of the Company and rank (i) pari passu in seniority with respect to the 2022 Notes, (ii) senior in right of payment to any of the Company’s indebtedness that is expressly subordinated in right of payment to the Convertible Notes, (iii) equal in right of payment to any of the Company’s unsecured indebtedness that is not so subordinated, (iv) effectively junior in right of payment to any of the Company’s secured indebtedness to the extent of the value of the assets securing such indebtedness and (v) structurally junior to all indebtedness and other liabilities (including trade payables) of the Company’s subsidiaries. The Convertible Notes will mature on July 15, 2020 (the “Maturity Date”), unless earlier repurchased by the Company or converted at the option of holders. Holders may convert their Convertible Notes at their option at any time prior to the close of business on the business day immediately preceding April 15, 2020 only under the following circumstances: • during any calendar quarter commencing after September 30, 2013 (and only during such calendar quarter), if the last reported sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day; • during the five business day period after any five consecutive trading day period (the “measurement period”) in which the trading price (as defined in the Convertible Notes) per $1,000 principal amount of Convertible Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of the Company’s common stock and the conversion rate on each such trading day; or • upon the occurrence of specified corporate events set forth in the indenture governing the Convertible Notes. On or after April 15, 2020 until the close of business on the business day immediately preceding the Maturity Date, holders may convert their Convertible Notes at any time, regardless of the foregoing circumstances. Following the repayment and satisfaction in full of the Company’s obligations to Hercules under the Loan Agreement, which occurred in December 2015, upon any conversion of the Convertible Notes, the Convertible Notes may be settled, at the Company’s election, in cash, shares of the Company’s common stock or a combination of cash and shares of the Company’s common stock. The initial conversion rate of the Convertible Notes is 160 shares of the Company’s common stock per $1,000 principal amount of Convertible Notes, which is equivalent to an initial conversion price of $6.25 per share of common stock. The conversion rate will be subject to adjustment in some events, but will not be adjusted for any accrued and unpaid interest. In addition, following certain corporate events that occur prior to the Maturity Date, the Company will increase the conversion rate for a holder who elects to convert its Convertible Notes in connection with such a corporate event in certain circumstances. The Company has separately accounted for the liability and equity components of the Convertible Notes by bifurcating gross proceeds between the indebtedness, or liability component, and the embedded conversion option, or equity component. This bifurcation was done by estimating an effective interest rate as of the date of issuance for similar notes which do not contain an embedded conversion option. The gross proceeds received from the issuance of the Convertible Notes less the initial amount allocated to the indebtedness resulted in a $53.8 million allocation to the embedded conversion option. The embedded conversion option was recorded in stockholders’ deficit and as debt discount, to be subsequently amortized as interest expense over the term of the Convertible Notes. Underwriting discounts and commissions and offering expenses totaled $4.4 million and were allocated to the indebtedness and the embedded conversion option based on their relative values. For each of the three months ended March 31, 2016 and 2015, interest expense related to the outstanding principal balance of the Convertible Notes was $3.4 million. Please refer to Note 13, “Subsequent Events,” for further information on the conversion agreements entered into with certain of the holders of the Convertible Notes on April 13, 2016 whereby these holders agreed to convert an aggregate principal amount of $64.2 million of Convertible Notes held by them in exchange for shares of the Company’s common stock on an initial closing date as well as additional shares of the Company’s common stock on subsequent closing dates. Future Minimum Payments under Outstanding Borrowings Future minimum payments under outstanding borrowings as of March 31, 2016 are as follows: (in thousands) Convertible 2022 Notes Remainder of 2016 $ 2,812 $ 19,734 2017 5,625 20,125 2018 5,625 20,125 2019 5,625 62,617 2020 and thereafter 130,623 157,664 Total $ 150,310 $ 280,265 Less interest (25,312 ) (105,265 ) Less unamortized discount (34,494 ) (5,661 ) Less current portion — — Long-term debt $ 90,504 $ 169,339

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	11. Stock-Based Compensation As of December 31, 2015, there were 2.5 million shares of common stock available to be granted under the Company’s 2011 Stock Incentive Plan (the “2011 Plan”). The 2011 Plan is administered by the Company’s board of directors and permits the Company to grant incentive and non-qualified stock options, stock appreciation rights, restricted stock, restricted stock units and other stock-based awards. In February 2016, 4.1 million additional shares of common stock became available for grant to employees, officers, directors and consultants under the 2011 Plan. At March 31, 2016, there were 3.5 million shares remaining available for grant under the 2011 Plan. During the three months ended March 31, 2016 and 2015, the Company issued options to purchase 3.1 million and 2.3 million shares of common stock, respectively. These options generally vest over a three-year period for employees. Options granted to directors vest immediately. The fair value of stock options granted to employees during the three months ended March 31, 2016 and 2015 was estimated at the date of grant using the following assumptions: Three Months Ended 2016 2015 Risk-free interest rate 1.3 – 1.5% 1.6. – 1.8% Expected dividend yield 0% 0% Expected term 5.8 years 5.9 years Expected volatility 67 – 68% 67% The Company uses the simplified method to calculate the expected term, as it does not have sufficient historical exercise data to provide a reasonable basis upon which to estimate expected term. The computation of expected volatility is based on the historical volatility of comparable companies from a representative peer group selected based on industry and market capitalization. The risk-free interest rate is based on a treasury instrument whose term is consistent with the expected life of the stock options. Management estimates expected forfeitures based on historical experience and recognizes compensation costs only for those equity awards expected to vest. The Company recognized stock-based compensation expense during the three months ended March 31, 2016 and 2015 as follows: Three Months (in thousands) 2016 2015 Employee awards: Research and development $ 1,868 $ 1,967 General and administrative 1,665 1,377 Stock-based compensation for employee awards 3,533 3,344 Stock-based compensation for non-employee awards — 26 Total stock-based compensation $ 3,533 $ 3,370 The following table summarizes stock option activity during the three months ended March 31, 2016: Weighted-Average Aggregate (in thousands, except per share amounts) Shares Weighted-Average Contractual Term Intrinsic Outstanding at December 31, 2015 19,211 $ 5.72 6.24 $ 47,963 Granted 3,130 $ 5.45 Exercised (539 ) $ 3.12 Forfeited (155 ) $ 7.69 Outstanding at March 31, 2016 21,647 $ 5.73 6.65 $ 61,405 Vested and expected to vest at March 31, 2016 21,182 $ 5.71 6.59 $ 60,457 Exercisable at March 31, 2016 14,979 $ 5.20 5.50 $ 49,061 The weighted-average grant date fair value per share of stock options granted during the three months ended March 31, 2016 and 2015 was $3.27 and $5.52, respectively. The aggregate intrinsic value is calculated as the difference between the exercise price of the stock options and the fair value of the underlying common stock. The aggregate intrinsic value of stock options exercised during the three months ended March 31, 2016 and 2015 was $2.1 million and $13.5 million, respectively. As of March 31, 2016, there was $24.0 million of total unrecognized stock-based compensation expense related to unvested employee stock awards. The Company expects to recognize this expense over a weighted-average period of approximately 2.2 years.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	3 Months Ended
	Mar. 31, 2016
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	12. Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers (Topic 606),” which supersedes all existing revenue recognition requirements, including most industry-specific guidance. The new standard requires a company to recognize revenue when it transfers goods or services to customers in an amount that reflects the consideration that the company expects to receive for those goods or services. This guidance was originally effective for interim and annual periods beginning after December 15, 2016 and allows for adoption using a full retrospective method, or a modified retrospective method. Early adoption was originally not permitted. Subsequent to the issuance of ASU 2014-09, the FASB also issued the following updates related to ASC 606: • In August 2015, the FASB issued ASU 2015-14, “Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date,” whereby the effective date for the new revenue standard was deferred by one year. As a result of ASU 2015-14, the new revenue standard is now effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017, and early adoption is now permitted for annual periods beginning after December 15, 2016, including interim periods within that annual period. • In March 2016, the FASB issued ASU 2016-08, “Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net),” to clarify the implementation guidance on principal versus agent considerations. • In April 2016, the FASB issued ASU 2016-10, “Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing,” to clarify the principle for determining whether a good or service is “separately identifiable” from other promises in the contract and to clarify the categorization of licenses of intellectual property. The Company is currently evaluating the potential impact that the adoption of this guidance and the related transition guidance may have on the consolidated financial statements, including the adoption method to be utilized. In August 2014, the FASB issued ASU 2014-15, “Presentation of Financial Statements – Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern,” outlining management’s responsibility to perform interim and annual assessments of an entity’s ability to continue as a going concern within one year of the date the financial statements are issued and providing guidance on determining when and how to disclose going concern uncertainties in the financial statements. This guidance will be effective for annual and interim reporting periods ending after December 15, 2016, and early adoption is permitted. The adoption of this guidance will not have a material impact on the Company’s consolidated financial statements, but may impact the Company’s footnote disclosures. In January 2016, the FASB issued ASU 2016-01, “Financial Statements – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Liabilities,” which contains a number of provisions related to the measurement, presentation and disclosure of financial instruments. This guidance will be effective for annual reporting periods beginning after December 15, 2017, including interim periods within those annual periods. Early adoption of this guidance is not permitted with the exception of certain specific presentation requirements that are not currently applicable to the Company. The Company does not anticipate a material impact to the consolidated financial statements as a result of the adoption of this guidance. In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842),” which supersedes all existing lease accounting guidance within ASC 840. The new standard requires that lease assets and lease liabilities be recognized by lessees for those leases previously classified as operating leases under ASC 840, with limited exceptions. This update also creates a new definition of a lease and provides guidance as to whether a contract is or contains a lease. This guidance will be effective for annual reporting periods beginning after December 15, 2018, including interim periods within those annual reporting periods, and early adoption is permitted. The Company is currently evaluating the potential impact that the adoption of this guidance may have on the consolidated financial statements. In March 2016, the FASB issued ASU 2016-03, “Derivatives and Hedging (Topic 815): Contingent Put and Call Options in Debt Instruments,” which clarifies the requirements for assessing whether contingent call or put options that can accelerate the repayment of principal on debt instruments are clearly and closely related to their debt hosts. This guidance will be effective for annual reporting periods beginning after December 15, 2016, including interim periods within those annual reporting periods, and early adoption is permitted. The Company does not anticipate a material impact to the consolidated financial statements as a result of the adoption of this guidance. In March 2016, the FASB issued ASU 2016-09, “Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting,” which simplifies several areas of accounting for share-based payment transactions, including the income tax consequences, classification of awards as either liabilities or equity and classification of excess tax benefits on the statement of cash flows. This guidance also permits a new entity-wide accounting policy election to either estimate the number of awards that are expected to vest or account for forfeitures when they occur. This guidance will be effective for annual reporting periods beginning after December 15, 2016, including interim periods within those annual reporting periods, and early adoption is permitted. An entity that elects early adoption must adopt all of the amendments in the same period. The Company is currently evaluating the potential impact that the adoption of this guidance may have on the consolidated financial statements. Other accounting standards that have been issued by the FASB or other standards-setting bodies that do not require adoption until a future date are not expected to have a material impact on the Company’s consolidated financial statements upon adoption.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2016
Subsequent Events [Abstract]
Subsequent Events	13. Subsequent Events On April 13, 2016, the Company entered into separate, privately-negotiated conversion agreements (the “Conversion Agreements”) with certain holders of the Convertible Notes. Under the Conversion Agreements, such holders agreed to convert an aggregate principal amount of $64.2 million of Convertible Notes held by them. The Company initially settled each $1,000 principal amount of Convertible Notes surrendered for conversion by delivering 136 shares of the Company’s common stock on April 18, 2016. In total, the Company issued an aggregate of 8,732,152 shares of its common stock on this initial closing date. In addition, pursuant to the Conversion Agreements, at the additional closings (as defined in the Conversion Agreements), the Company issued an aggregate of 3,635,512 shares of the Company’s common stock representing an aggregate of $27.7 million as additional payments in respect of the conversion of the Convertible Notes. The number of additional shares was determined based on the daily VWAP (as defined in the Conversion Agreements) of the Company’s common stock for each of the trading days in the 10-day trading period following the date of the Conversion Agreements.

Recent Accounting Pronounceme19

Recent Accounting Pronouncements (Policies)	3 Months Ended
	Mar. 31, 2016
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers (Topic 606),” which supersedes all existing revenue recognition requirements, including most industry-specific guidance. The new standard requires a company to recognize revenue when it transfers goods or services to customers in an amount that reflects the consideration that the company expects to receive for those goods or services. This guidance was originally effective for interim and annual periods beginning after December 15, 2016 and allows for adoption using a full retrospective method, or a modified retrospective method. Early adoption was originally not permitted. Subsequent to the issuance of ASU 2014-09, the FASB also issued the following updates related to ASC 606: • In August 2015, the FASB issued ASU 2015-14, “Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date,” whereby the effective date for the new revenue standard was deferred by one year. As a result of ASU 2015-14, the new revenue standard is now effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017, and early adoption is now permitted for annual periods beginning after December 15, 2016, including interim periods within that annual period. • In March 2016, the FASB issued ASU 2016-08, “Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net),” to clarify the implementation guidance on principal versus agent considerations. • In April 2016, the FASB issued ASU 2016-10, “Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing,” to clarify the principle for determining whether a good or service is “separately identifiable” from other promises in the contract and to clarify the categorization of licenses of intellectual property. The Company is currently evaluating the potential impact that the adoption of this guidance and the related transition guidance may have on the consolidated financial statements, including the adoption method to be utilized. In August 2014, the FASB issued ASU 2014-15, “Presentation of Financial Statements – Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern,” outlining management’s responsibility to perform interim and annual assessments of an entity’s ability to continue as a going concern within one year of the date the financial statements are issued and providing guidance on determining when and how to disclose going concern uncertainties in the financial statements. This guidance will be effective for annual and interim reporting periods ending after December 15, 2016, and early adoption is permitted. The adoption of this guidance will not have a material impact on the Company’s consolidated financial statements, but may impact the Company’s footnote disclosures. In January 2016, the FASB issued ASU 2016-01, “Financial Statements – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Liabilities,” which contains a number of provisions related to the measurement, presentation and disclosure of financial instruments. This guidance will be effective for annual reporting periods beginning after December 15, 2017, including interim periods within those annual periods. Early adoption of this guidance is not permitted with the exception of certain specific presentation requirements that are not currently applicable to the Company. The Company does not anticipate a material impact to the consolidated financial statements as a result of the adoption of this guidance. In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842),” which supersedes all existing lease accounting guidance within ASC 840. The new standard requires that lease assets and lease liabilities be recognized by lessees for those leases previously classified as operating leases under ASC 840, with limited exceptions. This update also creates a new definition of a lease and provides guidance as to whether a contract is or contains a lease. This guidance will be effective for annual reporting periods beginning after December 15, 2018, including interim periods within those annual reporting periods, and early adoption is permitted. The Company is currently evaluating the potential impact that the adoption of this guidance may have on the consolidated financial statements. In March 2016, the FASB issued ASU 2016-03, “Derivatives and Hedging (Topic 815): Contingent Put and Call Options in Debt Instruments,” which clarifies the requirements for assessing whether contingent call or put options that can accelerate the repayment of principal on debt instruments are clearly and closely related to their debt hosts. This guidance will be effective for annual reporting periods beginning after December 15, 2016, including interim periods within those annual reporting periods, and early adoption is permitted. The Company does not anticipate a material impact to the consolidated financial statements as a result of the adoption of this guidance. In March 2016, the FASB issued ASU 2016-09, “Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting,” which simplifies several areas of accounting for share-based payment transactions, including the income tax consequences, classification of awards as either liabilities or equity and classification of excess tax benefits on the statement of cash flows. This guidance also permits a new entity-wide accounting policy election to either estimate the number of awards that are expected to vest or account for forfeitures when they occur. This guidance will be effective for annual reporting periods beginning after December 15, 2016, including interim periods within those annual reporting periods, and early adoption is permitted. An entity that elects early adoption must adopt all of the amendments in the same period. The Company is currently evaluating the potential impact that the adoption of this guidance may have on the consolidated financial statements. Other accounting standards that have been issued by the FASB or other standards-setting bodies that do not require adoption until a future date are not expected to have a material impact on the Company’s consolidated financial statements upon adoption.

Basis of Presentation and Con20

Basis of Presentation and Consolidation (Tables)	3 Months Ended
	Mar. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Non-Controlling Interest in Subsidiary	The Company’s ownership of Silver Creek was 56% as of both March 31, 2016 and December 31, 2015. The change in the non-controlling interest related to Silver Creek was as follows: (in thousands) Non-Controlling Interest Balance at December 31, 2015 $ 239 Net loss attributable to Silver Creek (185 ) Balance at March 31, 2016 $ 54 (in thousands) Non-Controlling Interest Balance at December 31, 2014 $ 69 Net income attributable to Silver Creek 327 Balance at March 31, 2015 $ 396

Net Loss Per Common Share (Tabl

Net Loss Per Common Share (Tables)	3 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Schedule of Securities Excluded from Computation of Diluted Loss Per Share	Securities excluded from the calculation of diluted loss per share are shown in the chart below: Three Months Ended March 31, (in thousands) 2016 2015 Outstanding options to purchase common stock 21,647 20,285 Common stock warrants — 741 Conversion of the Convertible Notes 25,000 25,000

License and Collaboration Agr22

License and Collaboration Agreements (Tables)	3 Months Ended
	Mar. 31, 2016
Baxalta [Member]
Schedule of Assets and Liabilities under Collaborative Arrangements	As of March 31, 2016 and December 31, 2015, the Company maintained the following assets and liabilities related to the Baxalta Agreement: (in thousands) March 31, 2016 December 31, 2015 Accounts receivable, billed $ 1,250 $ 1,336 Accounts receivable, unbilled 914 626 Deferred revenues 88,217 97,365

Product Revenue Reserves and 23

Product Revenue Reserves and Allowances (Tables)	3 Months Ended
	Mar. 31, 2016
Text Block [Abstract]
Summary of Product Revenue Reserve and Allowance Categories	The following table summarizes activity in each of the product revenue reserve and allowance categories for the three months ended March 31, 2016: (in thousands) Trade Rebates and Product Other Total Balance at December 31, 2015 $ 138 $ 362 $ 32 $ 8 $ 540 Provisions related to sales in the current year 354 1,031 74 15 1,474 Adjustments related to sales in the prior year — (127 ) — — (127 ) Credits and payments made (205 ) (693 ) (5 ) (2 ) (905 ) Balance at March 31, 2016 $ 287 $ 573 $ 101 $ 21 $ 982

Fair Value of Financial Instr24

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Schedule of Assets Measured at Fair Value on a Recurring Basis	The following tables show assets measured at fair value on a recurring basis as of March 31, 2016 and December 31, 2015: March 31, 2016 (in thousands) Level 1 Level 2 Level 3 Cash equivalents: Money market funds $ 3,047 $ — $ — Commercial paper — 13,991 — Corporate debt securities — 9,001 — U.S. government agency securities — 9,999 — Total cash equivalents $ 3,047 $ 32,991 $ — Marketable securities: Commercial paper $ — $ 43,922 $ — Corporate debt securities — 21,251 — U.S. government agency securities — 18,980 — Total marketable securities $ — $ 84,153 $ — December 31, 2015 (in thousands) Level 1 Level 2 Level 3 Cash equivalents: Money market funds $ 704 $ — $ — Total cash equivalents $ 704 $ — $ —

Marketable Securities (Tables)

Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Schedule of Cash Equivalents and Marketable Securities	As of December 31, 2015, the Company maintained only cash equivalents comprised of money market funds. Cash equivalents and marketable securities as of March 31, 2016 consisted of the following: March 31, 2016 (in thousands) Amortized Unrealized Unrealized Fair Cash equivalents: Money market funds $ 3,047 $ — $ — $ 3,047 Commercial paper 13,993 — (2 ) 13,991 Corporate debt securities 9,002 — (1 ) 9,001 U.S. government agency securities 9,999 — — 9,999 Total cash equivalents $ 36,041 $ — $ (3 ) $ 36,038 Marketable securities: Commercial paper $ 43,929 $ — $ (7 ) 43,922 Corporate debt securities 21,254 — (3 ) 21,251 U.S. government agency securities 18,981 1 (2 ) 18,980 Total marketable securities $ 84,164 $ 1 $ (12 ) $ 84,153

Inventory (Tables)

Inventory (Tables)	3 Months Ended
	Mar. 31, 2016
Inventory Disclosure [Abstract]
Schedule of Inventory	Inventory as of March 31, 2016 and December 31, 2015 consisted of the following: (in thousands) March 31, 2016 December 31, 2015 Raw materials $ 1,862 $ 900 Work in process 6,166 2,743 Finished goods 55 74 Total inventory $ 8,083 $ 3,717

Accounts Payable, Accrued Exp27

Accounts Payable, Accrued Expenses and Other (Tables)	3 Months Ended
	Mar. 31, 2016
Payables and Accruals [Abstract]
Schedule of Accounts Payable, Accrued Expenses and Other	Accounts payable, accrued expenses and other as of March 31, 2016 and December 31, 2015 consisted of the following: (in thousands) March 31, December 31, Accounts payable $ 10,784 $ 5,049 Accrued goods and services 12,574 14,295 Accrued clinical trial costs 12,433 12,764 Accrued drug purchase costs 1,662 7,460 Accrued payroll and related benefits 5,866 9,009 Accrued interest 6,666 3,041 Accrued dividends payable 19 19 Deferred tax incentives 445 445 Total accounts payable, accrued expenses and other $ 50,449 $ 52,082

Borrowings (Tables)

Borrowings (Tables)	3 Months Ended
	Mar. 31, 2016
Debt Disclosure [Abstract]
Schedule of Future Minimum Payments under the Loans Payable	Future minimum payments under outstanding borrowings as of March 31, 2016 are as follows: (in thousands) Convertible Notes 2022 Notes Remainder of 2016 $ 2,812 $ 19,734 2017 5,625 20,125 2018 5,625 20,125 2019 5,625 62,617 2020 and thereafter 130,623 157,664 Total $ 150,310 $ 280,265 Less interest (25,312 ) (105,265 ) Less unamortized discount (34,494 ) (5,661 ) Less current portion — — Long-term debt $ 90,504 $ 169,339

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Assumptions Used to Calculate Fair Value of Options Granted to Employees	The fair value of stock options granted to employees during the three months ended March 31, 2016 and 2015 was estimated at the date of grant using the following assumptions: Three Months Ended 2016 2015 Risk-free interest rate 1.3 – 1.5% 1.6. – 1.8% Expected dividend yield 0% 0% Expected term 5.8 years 5.9 years Expected volatility 67 – 68% 67%
Schedule of Recognized Stock-Based Compensation Expense	The Company recognized stock-based compensation expense during the three months ended March 31, 2016 and 2015 as follows: Three Months Ended (in thousands) 2016 2015 Employee awards: Research and development $ 1,868 $ 1,967 General and administrative 1,665 1,377 Stock-based compensation for employee awards 3,533 3,344 Stock-based compensation for non-employee awards — 26 Total stock-based compensation $ 3,533 $ 3,370
Summary of Stock Option Activity	The following table summarizes stock option activity during the three months ended March 31, 2016: Weighted-Average Aggregate (in thousands, except per share amounts) Shares Weighted-Average Contractual Term Intrinsic Outstanding at December 31, 2015 19,211 $ 5.72 6.24 $ 47,963 Granted 3,130 $ 5.45 Exercised (539 ) $ 3.12 Forfeited (155 ) $ 7.69 Outstanding at March 31, 2016 21,647 $ 5.73 6.65 $ 61,405 Vested and expected to vest at March 31, 2016 21,182 $ 5.71 6.59 $ 60,457 Exercisable at March 31, 2016 14,979 $ 5.20 5.50 $ 49,061

Basis of Presentation and Con30

Basis of Presentation and Consolidation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents	$ 28,833	$ 48,237	$ 185,606	$ 35,688
Preferred stock issued		0	0
Net proceeds from stock issuance	$ 1,129
Silver Creek Series B Preferred Stock [Member]
Summary Of Significant Accounting Policies [Line Items]
Preferred stock issued	900,000	0
Preferred stock price per share	$ 1.35
Net proceeds from stock issuance	$ 1,100
Silver Creek [Member]
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents		$ 200
Ownership interest percentage		56.00%	56.00%

Basis of Presentation and Con31

Basis of Presentation and Consolidation - Schedule of Non-Controlling Interest in Subsidiary (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Temporary Equity Disclosure [Abstract]
Balance at the beginning of the period	$ 239	$ 69
Net income (loss) attributable to Silver Creek	(185)	327
Balance at the end of the period	$ 54	$ 396

Net Loss Per Common Share - Add

Net Loss Per Common Share - Additional Information (Detail) - Convertible Notes [Member] - USD ($) $ in Millions	Mar. 31, 2016	Jul. 31, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Aggregate principal amount		$ 125
Interest rate (as a percent)	4.50%	4.50%

Net Loss Per Common Share - Sch

Net Loss Per Common Share - Schedule of Securities Excluded from Computation of Diluted Loss Per Share (Detail) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Stock Compensation Plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities excluded from calculation of diluted loss per share	21,647	20,285
Common Stock Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities excluded from calculation of diluted loss per share		741
Conversion of the Convertible Notes [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities excluded from calculation of diluted loss per share	25,000	25,000

License and Collaboration Agr34

License and Collaboration Agreements - Additional Information (Detail) - USD ($)

Sep. 23, 2014

Nov. 25, 2013

May. 05, 2011

Oct. 31, 2015

Aug. 31, 2015

Jul. 31, 2015

Apr. 30, 2015

Jan. 31, 2015

Sep. 30, 2014

Mar. 31, 2016

Jun. 30, 2015

Mar. 31, 2015

Mar. 31, 2016

Dec. 31, 2015

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Deferred revenues, current

$ 45,097,000

$ 45,097,000

$ 50,137,000

Research and development expenses

32,882,000

$ 35,679,000

Deferred Revenue, Noncurrent

47,103,000

47,103,000

51,197,000

Baxalta [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Proportional performance revenue recognition model

11,300,000

14,800,000

Substantive milestones

$ 0

0

Baxalta [Member] | License and Collaboration Agreements [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Upfront license fee received

$ 100,000,000

Royalty for improved products

The Company is also entitled to tiered, escalating royalties ranging from sub-teen double digits to low twenties percentages of net sales of ONIVYDE in the Licensed Territory.

Notice period of termination

180 days

Revenue recognized related to a substantive milestone payment

$ 47,500,000

$ 15,000,000

$ 20,000,000

Deferred revenues

$ 88,217,000

88,217,000

97,365,000

Deferred revenues, current

45,100,000

45,100,000

Baxalta [Member] | License and Collaboration Agreements [Member] | Sales Milestone [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Maximum amount of milestone payments that can be received

$ 250,000,000

Baxalta [Member] | License and Collaboration Agreements [Member] | Research and Development Milestones [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Maximum amount of milestone payments that can be received

100,000,000

Baxalta [Member] | License and Collaboration Agreements [Member] | Regulatory Milestones [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Milestone license fee received

20,000,000

Maximum amount of milestone payments that can be received

520,000,000

Baxalta [Member] | License and Collaboration Agreements [Member] | Clinical Trials in Pancreatic Cancer [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Milestone license fee received

62,500,000

Collaboration agreement costs

98,800,000

Baxalta [Member] | Non-Substantive Collaborative Arrangement [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Milestone license fee received

62,500,000

Milestone license fee

90,000,000

Baxalta [Member] | Substantive Collaborative Arrangement [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Milestone license fee received

20,000,000

Milestone license fee

$ 530,000,000

PharmaEngine [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Upfront license fees paid

$ 10,000,000

PharmaEngine [Member] | Development and Regulatory Milestone [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Maximum milestone payment obligation

80,000,000

PharmaEngine [Member] | Sales Milestone [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Maximum milestone payment obligation

$ 130,000,000

PharmaEngine [Member] | License and Collaboration Agreements [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Milestone payment

$ 11,000,000

$ 7,000,000

Research and development expenses

$ 100,000

$ 200,000

PharmaEngine [Member] | License and Collaboration Agreements [Member] | New Drug Application [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Milestone payment

$ 5,000,000

Actavis [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Notice period of termination

90 days

Maximum amount of milestone and development payments that can be received

$ 15,100,000

Collaborative arrangement gross payments received

$ 3,900,000

Aggregate milestone payments eligible to receive, decrease

$ 400,000

Agreement expiration term respect to each product

10 years

Additional renewal term

2 years

Deferred Revenue, Noncurrent

$ 4,000,000

$ 4,000,000

$ 4,000,000

Expected revenue recognition period begins after first sale of applicable product

10 years

License and Collaboration Agr35

License and Collaboration Agreements - Schedule of Assets and Liabilities under Collaborative Arrangements (Detail) - License and Collaboration Agreements [Member] - Baxalta [Member] - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Accounts receivable, billed	$ 1,250	$ 1,336
Accounts receivable, unbilled	914	626
Deferred revenues	$ 88,217	$ 97,365

Product Revenue Reserves and 36

Product Revenue Reserves and Allowances - Summary of Product Revenue Reserve and Allowance Categories (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)
Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning balance	$ 540
Provisions related to sales in the current year	1,474
Adjustments related to sales in the prior year	(127)
Credits and payments made	(905)
Ending balance	982
Trade Allowances [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning balance	138
Provisions related to sales in the current year	354
Credits and payments made	(205)
Ending balance	287
Rebates and Chargeback Discounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning balance	362
Provisions related to sales in the current year	1,031
Adjustments related to sales in the prior year	(127)
Credits and payments made	(693)
Ending balance	573
Product Returns [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning balance	32
Provisions related to sales in the current year	74
Credits and payments made	(5)
Ending balance	101
Other Incentives [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning balance	8
Provisions related to sales in the current year	15
Credits and payments made	(2)
Ending balance	$ 21

Fair Value of Financial Instr37

Fair Value of Financial Instruments - Schedule of Assets Measured at Fair Value on a Recurring Basis (Detail) - Recurring Basis [Member] - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 3,047	$ 704
Level 1 [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	3,047	$ 704
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	32,991
Marketable securities	84,153
Level 2 [Member] | Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	13,991
Marketable securities	43,922
Level 2 [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	9,001
Marketable securities	21,251
Level 2 [Member] | US Government Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	9,999
Marketable securities	$ 18,980

Fair Value of Financial Instr38

Fair Value of Financial Instruments - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Mar. 31, 2016	Dec. 22, 2015	Mar. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Transfers between fair value measurement levels	$ 0	$ 0
Non-recurring fair value measurements		0		$ 0
Recurring Basis [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities measured at fair value	0	0
Senior Convertible Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Aggregate principal amount of loan		125,000,000
Carrying value of debt		90,500,000
Senior Convertible Notes [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of debt		186,400,000
2022 Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Aggregate principal amount of loan			$ 175,000,000
Fair value of debt		172,600,000
Carrying value of debt		$ 169,300,000
Private placement	$ 175,000,000
Interest rate (as a percent)			11.50%
2022 Notes [Member] | Private Placement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate (as a percent)	11.50%

Marketable Securities - Schedul

Marketable Securities - Schedule of Marketable Securities (Detail) $ in Thousands	Mar. 31, 2016USD ($)
Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 43,929
Unrealized Losses	(7)
Fair Value	43,922
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	21,254
Unrealized Losses	(3)
Fair Value	21,251
US Government Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	18,981
Unrealized Gains	1
Unrealized Losses	(2)
Fair Value	18,980
Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	13,993
Unrealized Losses	(2)
Fair Value	13,991
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	9,002
Unrealized Losses	(1)
Fair Value	9,001
US Government Agencies Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	9,999
Fair Value	9,999
Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,047
Fair Value	3,047
Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	36,041
Unrealized Losses	(3)
Fair Value	36,038
Marketable Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	84,164
Unrealized Gains	1
Unrealized Losses	(12)
Fair Value	$ 84,153

Marketable Securities - Additio

Marketable Securities - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2016USD ($)Security	Mar. 31, 2015USD ($)
Amortized Cost and Fair Value Debt Securities [Abstract]
Realized gains (losses) on sale of available-for-sale securities	$ 0	$ 0
Aggregate fair value	$ 91,200,000
Number of securities in unrealized loss position for less than 12 months | Security	20
Other-than-temporary-impairment investments	$ 0

Inventory - Schedule of Invento

Inventory - Schedule of Inventory (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Raw materials	$ 1,862	$ 900
Work in process	6,166	2,743
Finished goods	55	74
Total inventory	$ 8,083	$ 3,717

Accounts Payable, Accrued Exp42

Accounts Payable, Accrued Expenses and Other - Schedule of Accounts Payable, Accrued Expenses and Other (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Payables and Accruals [Abstract]
Accounts payable	$ 10,784	$ 5,049
Accrued goods and services	12,574	14,295
Accrued clinical trial costs	12,433	12,764
Accrued drug purchase costs	1,662	7,460
Accrued payroll and related benefits	5,866	9,009
Accrued interest	6,666	3,041
Accrued dividends payable	19	19
Deferred tax incentives	445	445
Total accounts payable, accrued expenses and other	$ 50,449	$ 52,082

Borrowings - 2022 Notes - Addit

Borrowings - 2022 Notes - Additional Information (Detail) - USD ($)	Dec. 22, 2015	Mar. 31, 2016	Mar. 31, 2015
Schedule Of Debt Instruments [Line Items]
Debt maturity date		Jul. 15, 2020
Interest expense		$ 8,580,000	$ 4,566,000
2022 Notes [Member]
Schedule Of Debt Instruments [Line Items]
Debt instrument, aggregate principal amount	$ 175,000,000
Net proceeds from the debt issuance	$ 168,500,000
Interest rate (as a percent)	11.50%
Semi-annual installments of principal	$ 21,875,000
Debt maturity date	Dec. 15, 2022
Interest expense		$ 5,200,000

Borrowings - Convertible Notes

Borrowings - Convertible Notes - Additional Information (Detail)	Apr. 18, 2016	Apr. 13, 2016USD ($)	Jul. 31, 2013USD ($)$ / shares	Jul. 31, 2013USD ($)$ / shares	Mar. 31, 2016USD ($)	Mar. 31, 2015USD ($)
Schedule Of Debt Instruments [Line Items]
Debt maturity date					Jul. 15, 2020
Interest expense					$ 8,580,000	$ 4,566,000
Subsequent Event [Member]
Schedule Of Debt Instruments [Line Items]
Conversion of aggregate principal amount		$ 64,200,000
Convertible Notes [Member]
Schedule Of Debt Instruments [Line Items]
Aggregate principal amount of Convertible Notes			$ 125,000,000	$ 125,000,000
Net proceeds from the debt issuance				$ 120,600,000
Interest rate (as a percent)			4.50%	4.50%	4.50%
Number of consecutive trading days during which the closing price of the entity's common stock must exceed the conversion price for at least 20 days in order for the notes to be convertible			30 days
Convertibility of debt, closing price of stock test, percentage of stock price to conversion price for the notes that must be exceeded			130.00%
Number of consecutive business days immediately after any five consecutive trading day period during the note measurement period			5 days
Number of consecutive trading days before five consecutive business days during the note measurement period			5 days
Conversion ratio, principal amount			$ 1,000	$ 1,000
Conversion rate of common stock shares per $1,000 principal amount			160
Initial conversion price of shares (in dollars per share) | $ / shares			$ 6.25	$ 6.25
Embedded conversion option			$ 53,800,000	$ 53,800,000
Underwriting discounts and commissions and offering expenses			$ 4,400,000
Interest expense					$ 3,400,000	$ 3,400,000
Convertible Notes [Member] | Subsequent Event [Member]
Schedule Of Debt Instruments [Line Items]
Conversion ratio, principal amount		1,000
Conversion rate of common stock shares per $1,000 principal amount	136
Conversion of aggregate principal amount		$ 64,200,000
Convertible Notes [Member] | Minimum [Member]
Schedule Of Debt Instruments [Line Items]
Number of days within 30 consecutive trading days in which the closing price of the entity's common stock must exceed the conversion price for the notes to be convertible			20 days
Convertible Notes [Member] | Maximum [Member]
Schedule Of Debt Instruments [Line Items]
Convertibility of debt, trading price of debt test, percentage of closing price of stock used in calculation			98.00%

Borrowings - Schedule of Future

Borrowings - Schedule of Future Minimum Payments under the Loans Payable (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Long-term debt	$ 259,843	$ 257,655
Convertible Notes [Member]
Debt Instrument [Line Items]
Remainder of 2016	2,812
2,017	5,625
2,018	5,625
2,019	5,625
2020 and thereafter	130,623
Loans payable, gross including contractual interest	150,310
Less interest	(25,312)
Less unamortized discount	(34,494)
Less current portion	0
Long-term debt	90,504
2022 Notes [Member]
Debt Instrument [Line Items]
Remainder of 2016	19,734
2,017	20,125
2,018	20,125
2,019	62,617
2020 and thereafter	157,664
Loans payable, gross including contractual interest	280,265
Less interest	(105,265)
Less unamortized discount	(5,661)
Less current portion	0
Long-term debt	$ 169,339

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended
	Feb. 29, 2016	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Granted		3,130,000
Weighted-average grant date fair value per share of stock options		$ 3.27	$ 5.52
Aggregate intrinsic value of options exercised		$ 2.1	$ 13.5
Unrecognized compensation cost related to nonvested stock awards		$ 24
Weighted average period over which unrecognized compensation cost is expected to be recognized		2 years 2 months 12 days
Stock Incentive Plan 2011 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock available for grant (in shares)		3,500,000		2,500,000
Additional common stock available for issuance (in shares)	4,100,000
Number of Shares, Granted		3,100,000	2,300,000
Stock Incentive Plan 2011 [Member] | Employee [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options vesting period		3 years

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Assumptions Used to Calculate Fair Value of Options Granted to Employees (Detail) - Options to Purchase Common Stock [Member]	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility		67.00%
Expected dividend yield	0.00%	0.00%
Expected term	5 years 9 months 18 days	5 years 10 months 24 days
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.30%	1.60%
Expected volatility	67.00%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.50%	1.80%
Expected volatility	68.00%

Stock-Based Compensation - Sc48

Stock-Based Compensation - Schedule of Recognized Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense for employee awards	$ 3,533	$ 3,344
Stock-based compensation for non-employee awards		26
Total stock-based compensation	3,533	3,370
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense for employee awards	1,868	1,967
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense for employee awards	$ 1,665	$ 1,377

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of Shares, Outstanding, Beginning balance	19,211
Number of Shares, Granted	3,130
Number of Shares, Exercised	(539)
Number of Shares, Forfeited	(155)
Number of Shares, Outstanding, Ending balance	21,647	19,211
Number of shares vested and expected to vest	21,182
Number of stock option exercisable	14,979
Weighted Average Exercise Price, Outstanding, Beginning balance	$ 5.72
Weighted Average Exercise Price, Granted	5.45
Weighted Average Exercise Price, Exercised	3.12
Weighted Average Exercise Price, Forfeited	7.69
Weighted Average Exercise Price, Outstanding, Ending balance	5.73	$ 5.72
Weighted average exercise price of shares vested and expected to vest (in dollars per share)	5.71
Weighted average exercise price for exercisable option (in dollars per share)	$ 5.20
Weighted Average Remaining Contractual Term	6 years 7 months 24 days	6 years 2 months 27 days
Weighted Average Remaining Contractual Term, Vested and expected to vest	6 years 7 months 2 days
Weighted Average Remaining Contractual Term, Exercisable	5 years 6 months
Aggregate Intrinsic Value, Outstanding	$ 61,405	$ 47,963
Aggregate Intrinsic Value, Vested and expected to vest	60,457
Aggregate Intrinsic Value, Exercisable	$ 49,061

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail)	Apr. 18, 2016shares	Apr. 13, 2016USD ($)shares	Jul. 31, 2013USD ($)	Mar. 31, 2016shares	Dec. 31, 2015shares
Subsequent Event [Line Items]
Issuance of common stock | shares				116,411,000	115,871,000
Convertible Notes [Member]
Subsequent Event [Line Items]
Conversion ratio, principal amount			$ 1,000
Conversion rate of common stock shares per $1,000 principal amount			160
Subsequent Event [Member]
Subsequent Event [Line Items]
Conversion of aggregate principal amount		$ 64,200,000
Subsequent Event [Member] | Convertible Notes [Member]
Subsequent Event [Line Items]
Conversion of aggregate principal amount		64,200,000
Conversion ratio, principal amount		$ 1,000
Conversion rate of common stock shares per $1,000 principal amount	136
Issuance of common stock | shares	8,732,152	3,635,512
Value of additional shares issued for conversion		$ 27,700,000
Trading period		10 days