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Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2019	Nov. 07, 2019
Document And Entity Information [Abstract]
Entity Registrant Name	Sesen Bio, Inc.
Entity Central Index Key	0001485003
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Emerging Growth Company	true
Entity Small Business	true
Entity Transition Period Flag	true
Entity Shell Company	false
Entity Current Reporting Status	Yes
Entity Common Stock, Shares Outstanding		104,679,391

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 57,865	$ 50,422
Prepaid expenses and other current assets	1,547	1,334
Total current assets	59,412	51,756
Restricted cash	20	20
Property and equipment, net of accumulated depreciation of $4,519 and $4,355, respectively	294	321
Intangible assets	46,400	46,400
Goodwill	13,064	13,064
Other assets	208	0
Total Assets	119,398	111,561
Current liabilities:
Accounts payable	2,583	1,367
Accrued expenses	6,350	4,746
Other current liabilities	159	0
Total current liabilities	9,092	6,113
Contingent consideration		48,400
Deferred tax liability	12,528	12,528
Other liabilities	311	313
Total Liabilities	116,931	67,354
Commitments and contingencies
Stockholders’ Equity:
Preferred stock, $0.001 par value per share; 5,000,000 shares authorized at September 30, 2019 and December 31, 2018; no shares issued and outstanding at September 30, 2019 and December 31, 2018	0	0
Common stock, $0.001 par value per share; 200,000,000 shares authorized at September 30, 2019 and December 31, 2018; 101,267,578 and 77,456,180 shares issued and outstanding at September 30, 2019 and December 31, 2018, respectively	101	77
Additional paid-in capital	262,337	230,154
Accumulated deficit	(259,971)	(186,024)
Total Stockholders’ Equity	2,467	44,207
Total Liabilities and Stockholders’ Equity	$ 119,398	$ 111,561

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Property and equipment, accumulated depreciation	$ 4,519	$ 4,355
Preferred stock, par value ((in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	101,267,578	77,456,180
Common stock, shares outstanding (in shares)	101,267,578	77,456,180

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Operating expenses:
Research and development	$ 6,613	$ 3,372	$ 19,243	$ 9,406
General and administrative	3,238	3,825	8,910	8,128
Change in fair value of contingent consideration	3,600	7,200	46,600	9,900
Total operating expenses	13,451	14,397	74,753	27,434
Loss from Operations	(13,451)	(14,397)	(74,753)	(27,434)
Other income (expense):
Other income, net	319	382	806	498
Net Loss and Comprehensive Loss	$ (13,132)	$ (14,015)	$ (73,947)	$ (26,936)
Net loss per common share - basic and diluted (in dollars per share)	$ (0.13)	$ (0.18)	$ (0.85)	$ (0.48)
Weighted-average common shares outstanding - basic and diluted (in shares)	101,266	77,030	86,575	56,526

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)		34,702,565
Beginning balance (in shares)		43,105,466
Beginning balance at Dec. 31, 2017	$ 18,034	$ 35	$ 170,330	$ (152,331)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(3,963)			(3,963)
Share-based compensation	401		401
Sales of common stock under 2014 ESPP (in shares)		9,565
Sales of common stock under 2014 ESPP	10		10
Exercise of stock options and vesting of restricted stock awards (in shares)		4,430
Exercises of stock options and vestings of restricted stock awards	0
Exercises of common stock warrants (in shares)		420,778
Exercises of common stock warrants	336		336
Issuance of common stock and common stock warrants, net of issuance costs (in shares)		7,968,128
Issuance of common stock and common stock warrants, net of issuance costs	9,040	$ 8	9,032
Ending balance (in shares) at Mar. 31, 2018		43,105,466
Ending balance at Mar. 31, 2018	23,858	$ 43	180,109	(156,294)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)		77,088,570
Beginning balance at Dec. 31, 2017	18,034	$ 35	170,330	(152,331)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(26,936)
Exercises of common stock warrants (in shares)		8,700,000
Ending balance (in shares) at Sep. 30, 2018		77,088,570
Ending balance at Sep. 30, 2018	50,395	$ 77	229,585	(179,267)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)		43,105,466
Beginning balance (in shares)		77,010,999
Beginning balance at Mar. 31, 2018	23,858	$ 43	180,109	(156,294)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(8,958)			(8,958)
Share-based compensation	285		285
Exercise of stock options and vesting of restricted stock awards (in shares)		55,259
Exercises of stock options and vestings of restricted stock awards	29		29
Exercises of common stock warrants (in shares)		8,294,718
Exercises of common stock warrants	6,918	$ 8	6,910
Issuance of common stock and common stock warrants, net of issuance costs (in shares)		25,555,556
Issuance of common stock and common stock warrants, net of issuance costs	41,932	$ 26	41,906
Ending balance (in shares) at Jun. 30, 2018		77,010,999
Ending balance at Jun. 30, 2018	64,064	$ 77	229,239	(165,252)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)		77,010,999
Beginning balance (in shares)		77,088,570
Net loss	(14,015)			(14,015)
Share-based compensation	249		249
Sales of common stock under 2014 ESPP (in shares)		11,427
Sales of common stock under 2014 ESPP	11		11
Exercise of stock options and vesting of restricted stock awards (in shares)		16,144
Exercises of stock options and vestings of restricted stock awards	27		27
Exercises of common stock warrants (in shares)		50,000
Exercises of common stock warrants	59		59
Ending balance (in shares) at Sep. 30, 2018		77,088,570
Ending balance at Sep. 30, 2018	50,395	$ 77	229,585	(179,267)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)		77,088,570
Beginning balance (in shares)		77,456,180
Beginning balance (in shares)		77,464,781
Beginning balance at Dec. 31, 2018	44,207	$ 77	230,154	(186,024)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(6,480)			(6,480)
Share-based compensation	326		326
Sales of common stock under 2014 ESPP (in shares)		8,601
Sales of common stock under 2014 ESPP	7		7
Ending balance (in shares) at Mar. 31, 2019		77,464,781
Ending balance at Mar. 31, 2019	38,060	$ 77	230,487	(192,504)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)		101,267,578
Beginning balance at Dec. 31, 2018	44,207	$ 77	230,154	(186,024)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ (73,947)
Exercise of stock options and vesting of restricted stock awards (in shares)	30,000
Exercises of common stock warrants (in shares)	3,361,000	3,400,000
Ending balance (in shares) at Sep. 30, 2019		101,267,578
Ending balance at Sep. 30, 2019	$ 2,467	$ 101	262,337	(259,971)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)		77,464,781
Beginning balance (in shares)		101,265,896
Beginning balance at Mar. 31, 2019	38,060	$ 77	230,487	(192,504)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(54,335)			(54,335)
Share-based compensation	356		356
Exercise of stock options and vesting of restricted stock awards (in shares)		30,000
Exercises of stock options and vestings of restricted stock awards	45		45
Exercises of common stock warrants (in shares)		3,361,115
Exercises of common stock warrants	3,434	$ 4	3,430
Issuance of common stock and common stock warrants, net of issuance costs (in shares)		20,410,000
Issuance of common stock and common stock warrants, net of issuance costs	27,809	$ 20	27,789
Ending balance (in shares) at Jun. 30, 2019		101,265,896
Ending balance at Jun. 30, 2019	15,369	$ 101	262,107	(246,839)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)		101,265,896
Beginning balance (in shares)		101,267,578
Net loss	(13,132)			(13,132)
Share-based compensation	229		229
Sales of common stock under 2014 ESPP (in shares)		1,682
Sales of common stock under 2014 ESPP	1		1
Ending balance (in shares) at Sep. 30, 2019		101,267,578
Ending balance at Sep. 30, 2019	$ 2,467	$ 101	$ 262,337	$ (259,971)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)		101,267,578

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2018
Statement of Stockholders' Equity [Abstract]
Issuance of common stock and common stock warrants, issuance costs	$ 2,193	$ 4,070	$ 959

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended		12 Months Ended
	Sep. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Cash Flows from Operating Activities:
Net loss	$ (13,132)	$ (6,480)	$ (14,015)	$ (3,963)	$ (73,947)	$ (26,936)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation					164	156
Share-based compensation					911	935
Change in fair value of contingent consideration	3,600		7,200		46,600	9,900
Gain on sale of equipment					0	(5)
Changes in operating assets and liabilities:
Prepaid expenses and other assets					(421)	(1,169)
Accounts payable					1,216	484
Accrued expenses and other liabilities					1,761	1,453
Net Cash Used in Operating Activities					(23,716)	(15,182)	$ (22,800)
Cash Flows from Investing Activities:
(Purchases) sales of equipment					(137)
(Purchases) sales of equipment						5
Net Cash (Used in) Provided by Investing Activities					(137)	5
Cash Flows from Financing Activities:
Proceeds from issuance of common stock and common stock warrants, net of issuance costs					27,809	50,971
Proceeds from exercises of common stock warrants					3,434	7,315
Proceeds from exercises of stock options					45	56
Proceeds from sales of common stock under 2014 ESPP					8	21
Net Cash Provided by Financing Activities					31,296	58,363
Net Increase in Cash, Cash Equivalents and Restricted Cash					7,443	43,186
Cash, Cash Equivalents and Restricted Cash - Beginning of Period		$ 50,442		$ 14,690	50,442	14,690	14,690
Cash, Cash Equivalents and Restricted Cash - End of Period	$ 57,885		$ 57,876		57,885	$ 57,876	$ 50,442
Supplemental disclosure of non-cash operating activities:
Right-of-use assets related to the adoption of ASC 842					236
Cash paid for amounts included in the measurement of lease liabilities					$ 115

DESCRIPTION OF BUSINESS	9 Months Ended
DESCRIPTION OF BUSINESS	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	DESCRIPTION OF BUSINESS Sesen Bio, Inc. ("Sesen" or the “Company”), a Delaware corporation, is a late-stage clinical company developing targeted fusion protein therapeutics ("TFPTs") composed of an anti-cancer antibody fragment tethered to a protein toxin for the treatment of cancer. The Company genetically fuses the cancer-targeting antibody fragment and the cytotoxic protein payload into a single molecule which is produced through the Company's proprietary one-step, microbial manufacturing process. The Company targets tumor cell surface antigens with limited expression on normal cells. Binding of the target antigen by the TFPT allows for rapid internalization into the targeted cancer cell. The Company has designed its targeted fusion proteins to overcome the fundamental efficacy and safety challenges inherent in existing antibody-drug conjugates ("ADCs"), where a payload is chemically attached to a targeting antibody. The Company’s most advanced product candidate, VB4-845, also known as Vicinium®, is a locally-administered targeted fusion protein composed of an anti-EpCAM, or epithelial cell adhesion molecule, antibody fragment tethered to a truncated form of Pseudomonas exotoxin A for the treatment of high-risk, non-muscle invasive bladder cancer ("NMIBC"). The Company has an ongoing single-arm, multi-center, open-label Phase 3 clinical trial of Vicinium as a monotherapy in patients with high-risk, bacillus Calmette-Guérin ("BCG") unresponsive NMIBC, called the VISTA Trial. The VISTA Trial completed enrollment in April 2018 with a total of 133 patients, and the Company is continuing to collect and assess the trial data. Liquidity and Going Concern As of September 30, 2019, the Company had cash and cash equivalents of $57.9 million, net working capital of $50.3 million and an accumulated deficit of $260.0 million. The Company incurred negative cash flows from operating activities of $22.8 million for the year ended December 31, 2018 and $23.7 million for the nine months ended September 30, 2019. Since its inception, the Company has received no revenue from sales of its products currently under development, and management anticipates that operating losses will continue for the foreseeable future as the Company continues its ongoing Phase 3 clinical trial for Vicinium and seeks marketing approval from the United States Food and Drug Administration ("FDA"). The Company has financed its operations to date primarily through private placements of its common stock, preferred stock and convertible bridge notes, venture debt borrowings, its initial public offering ("IPO"), follow-on public offerings, sales effected in an "at-the-market" ("ATM") offering and a License Agreement with F. Hoffmann-La Roche Ltd and Hoffman-La Roche Inc. (collectively, "Roche") (the "License Agreement"). See “Note 8. Stockholders’ Equity” below for information regarding the Company’s recently completed equity financings. Under Accounting Standards Codification ("ASC") Topic 205-40, Presentation of Financial Statements - Going Concern, management is required at each reporting period to evaluate whether there are conditions and events, considered in the aggregate, that raise substantial doubt about an entity's ability to continue as a going concern within one year after the date that the financial statements are issued. This evaluation initially does not take into consideration the potential mitigating effect of management's plans that have not been fully implemented as of the date the financial statements are issued. When substantial doubt exists, management evaluates whether the mitigating effect of its plans sufficiently alleviates the substantial doubt about the Company's ability to continue as a going concern. The mitigating effect of management's plans, however, is only considered if both (i) it is probable that the plans will be effectively implemented within one year after the date that the financial statements are issued and (ii) it is probable that the plans, when implemented, will mitigate the relevant conditions or events that raise substantial doubt about the entity's ability to continue as a going concern within one year after the date that the financial statements are issued. Generally, to be considered probable of being effectively implemented, the plans must have been approved by the Company's Board of Directors before the date that the financial statements are issued. The Company's future success is dependent on its ability to develop its product candidates and ultimately upon its ability to attain profitable operations. In order to commercialize its product candidates, the Company needs to complete clinical development and comply with comprehensive regulatory requirements. The Company is subject to a number of risks similar to other late-stage clinical companies, including, but not limited to, successful discovery and development of its product candidates, raising additional capital, development by its competitors of new technological innovations, protection of proprietary technology and market acceptance of its products. The successful discovery and development of product candidates requires substantial working capital, and management expects to seek additional funds through equity or debt financings or through additional collaboration, licensing transactions or other sources. The Company may be unable to obtain equity or debt financings or enter into additional collaboration or licensing transactions at favorable terms, or at all. To the extent that the Company raises additional capital through the sale of equity or convertible debt securities, the ownership interests of existing stockholders will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect the rights of existing stockholders. Debt financing, if available, may involve agreements that include liens or other restrictive covenants limiting the Company's ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. If the Company raises additional funds through government or other third-party funding, strategic collaborations and alliances or licensing arrangements, it may have to relinquish valuable rights to its technologies, future revenue streams, research programs or product candidates or grant licenses on terms that may not be favorable. If the Company is unable to raise additional funds when needed, it may be required to implement cost reduction strategies and delay, limit, reduce or terminate its product development or future commercialization efforts or grant rights to develop and market products or product candidates that management would otherwise prefer to develop and market. The Company's management does not believe that its cash and cash equivalents of $57.9 million as of September 30, 2019 is sufficient to fund the Company's current operating plan for at least twelve months after the issuance of these condensed consolidated financial statements. The history of significant losses, the negative cash flows from operations, the limited cash resources currently on hand and the dependence by the Company on its ability - about which there can be no certainty - to obtain additional financing to fund its operations after the current cash resources are exhausted raises substantial doubt about the Company's ability to continue as a going concern. These condensed consolidated financial statements were prepared under the assumption that the Company will continue as a going concern and do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of this uncertainty.

BASIS OF PRESENTATION	9 Months Ended
BASIS OF PRESENTATION	Sep. 30, 2019
Accounting Policies [Abstract]
BASIS OF PRESENTATION	BASIS OF PRESENTATION The accompanying financial statements have been prepared in accordance with United States generally accepted accounting principles (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the ASC and Accounting Standards Updates (“ASUs”), promulgated by the Financial Accounting Standards Board (“FASB”). Interim Financial Statements The accompanying unaudited interim condensed consolidated financial statements have been prepared from the books and records of the Company in accordance with GAAP for interim financial information and Rule 10-01 of Regulation S-X promulgated by the United States Securities and Exchange Commission (“SEC”), which permit reduced disclosures for interim periods. All adjustments, consisting only of normal recurring adjustments, necessary for a fair presentation of the accompanying condensed consolidated balance sheets and statements of operations and comprehensive loss, stockholders’ equity and cash flows have been made. Although these interim financial statements do not include all of the information and footnotes required for complete annual financial statements, management believes the disclosures are adequate to make the information presented not misleading. These unaudited interim results of operations and cash flows for the three and nine months ended September 30, 2019 are not necessarily indicative of the results that may be expected for the full year. These unaudited interim condensed consolidated financial statements and footnotes should be read in conjunction with the Company’s audited annual consolidated financial statements and footnotes included in its Annual Report on Form 10-K, as filed with the SEC on March 1, 2019, wherein a more complete discussion of significant accounting policies and certain other information can be found. Use of Estimates The preparation of financial statements in accordance with GAAP and the rules and regulations of the SEC requires the use of estimates and assumptions, based on judgments considered reasonable, which affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. The Company bases its estimates and assumptions on historical experience, known trends and events and various other factors that management believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Although management believes its estimates and assumptions are reasonable when made, they are based upon information available at the time they are made. Management evaluates the estimates and assumptions on an ongoing basis and, if necessary, makes adjustments. Due to the risks and uncertainties involved in the Company’s business and evolving market conditions, and given the subjective element of the estimates and assumptions made, actual results may differ from estimated results. The most significant estimates and judgments impact the fair value of intangible assets, goodwill and contingent consideration; income taxes (including the valuation allowance for deferred tax assets); research and development expenses; and going concern considerations. Principles of Consolidation The Company’s consolidated financial statements include the accounts of the Company, its wholly owned subsidiary, Viventia Bio, Inc. ("Viventia"), and its indirect subsidiaries, Viventia Bio USA Inc. and Viventia Biotech (EU) Limited. All intercompany transactions and balances have been eliminated in consolidation. Foreign Currency Translation The functional currency of the Company and each of its subsidiaries is the U.S. dollar. Reclassifications On the Company's condensed consolidated statements of cash flows, proceeds from exercises of common stock warrants is now shown separately from proceeds from issuance of common stock and common stock warrants, net of issuance costs.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

9 Months Ended

Sep. 30, 2019

Accounting Policies [Abstract]

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

The Company's complete summary of significant accounting policies can be found in "Item 15. Exhibits and Financial Statement Schedules - Note 2. Significant Accounting Policies" in the audited annual financial statements included in its Annual Report on Form 10-K for the year ended December 31, 2018. The lease accounting policy shown below was not included there due to its adoption effective on January 1, 2019.

Leases

Effective January 1, 2019, the Company adopted ASC Topic 842, Leases (“ASC 842”) using the optional transition method outlined in ASU No. 2018-11, Leases (Topic 842), Targeted Improvements. The adoption of ASC 842 represents a change in accounting principle that aims to increase transparency and comparability among organizations by requiring the recognition of right-of-use assets and lease liabilities on the balance sheet for both operating and finance leases. In addition, the standard requires enhanced disclosures that meet the objective of enabling financial statement users to assess the amount, timing, and uncertainty of cash flows arising from leases. The reported results for the three and nine months ended September 30, 2019 reflect the application of ASC 842 guidance, while the reported results for prior year periods were prepared in accordance with the previous ASC Topic 840, Leases ("ASC 840") guidance. The adoption of ASC 842 resulted in the recognition of operating lease right-of-use assets and corresponding lease liabilities of $0.2 million on the Company’s consolidated balance sheet. The adoption of this guidance did not have a material impact on the Company’s financial condition, results of operations or cash flows; however, the adoption did result in significant changes to the Company’s financial statement disclosures.

As part of the adoption of ASC 842, the Company utilized certain practical expedients outlined in the guidance. These practical expedients include:


•	Accounting policy election to use the short-term lease exception by asset class;


•	Election of the practical expedient package during transition, which includes:


–	An entity need not reassess whether any expired or existing contracts are or contain leases;


–	An entity need not reassess the classification for any expired or existing leases. As a result, all leases that were classified as operating leases in accordance with ASC 840 are classified as operating leases under ASC 842, and all leases that were classified as capital leases in accordance with ASC 840 are classified as finance leases under ASC 842; and


–	An entity need not reassess initial direct costs for any existing leases.

The Company’s lease portfolio as of the adoption date includes: a property lease for its manufacturing facility, a property lease for its headquarters in Cambridge, MA, and a property lease for office space in Philadelphia, PA. The Company determines if an arrangement is a lease at the inception of the contract and has made a policy election to not separate out non-lease components from lease components, for all classes of underlying assets. The asset components of the Company’s operating leases are recorded as operating lease right-of-use assets and reported within other assets on the Company's consolidated balance sheet. The short-term and long-term liability components are recorded in other current liabilities and other liabilities, respectively, on the Company’s consolidated balance sheet. As of September 30, 2019, the Company did not have any finance leases.

Right-of-use assets and operating lease liabilities are recognized based on the present value of lease payments over the lease term at the commencement date. Existing leases in the Company’s lease portfolio as of the adoption date were valued as of January 1, 2019. The Company uses an incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments, if an implicit rate of return is not provided with the lease contract. Operating lease right-of-use assets are adjusted for incentives received.

Operating lease costs are recognized on a straight-line basis over the lease term, in accordance with ASC 842, and also include variable operating costs incurred during the period. Lease costs also include amounts related to short-term leases.

RECENT ACCOUNTING PRONOUNCEMENTS	9 Months Ended
RECENT ACCOUNTING PRONOUNCEMENTS	Sep. 30, 2019
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
RECENT ACCOUNTING PRONOUNCEMENTS	RECENT ACCOUNTING PRONOUNCEMENTS JOBS Act Accounting Election The Company is an "emerging growth company," as defined in the Jumpstart Our Business Startups Act of 2012 ("JOBS Act"). Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act until such time as those standards apply to private companies. The Company has irrevocably elected to "opt out" of this provision and, as a result, will adopt any new or revised accounting standards issued by the FASB when they required to be adopted by public companies. Adopted in 2019 In January 2017, the FASB issued ASU No. 2017-04, Simplifying the Test for Goodwill Impairment ("ASU 2017-04"). ASU 2017-04 simplifies the accounting for goodwill impairment by removing Step 2 of the goodwill impairment test, which requires a hypothetical purchase price allocation. ASU 2017-04 is effective for annual or interim goodwill impairment tests in fiscal years beginning after December 15, 2019, and should be applied on a prospective basis. The Company adopted this guidance effective January 1, 2019, and it did not have a material impact on the Company’s financial position, results of operations or cash flows. In June 2018, the FASB issued ASU No. 2018-07, Compensation-Stock Compensation (Topic 718) (“Topic 718”): Improvements to Nonemployee Share-Based Payment Accounting (“ASU 2018-07”). ASU 2018-07 expands the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from non-employees, and as a result, the accounting for share-based payments to non-employees will be substantially aligned. ASU 2018-07 is effective for fiscal years beginning after December 15, 2018, including interim periods within that fiscal year. The Company adopted this guidance effective January 1, 2019, and it did not have a material impact on the Company’s financial position, results of operations or cash flows. In July 2018, the FASB issued ASU No. 2018-09, Codification Improvements (“ASU 2018-09”). ASU 2018-09 provides amendments to a wide variety of topics in the FASB’s ASC, which applies to all reporting entities within the scope of the affected accounting guidance. The transition and effective date guidance are based on the facts and circumstances of each amendment. Some of the amendments in ASU 2018-09 do not require transition guidance and were effective upon the issuance of ASU 2018-09. However, many of the amendments do have transition guidance with effective dates for annual periods beginning after December 15, 2018. The Company adopted this guidance effective January 1, 2019, and it did not have a material impact on the Company’s financial position, results of operations or cash flows. Pending Adoption In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments ("ASU 2016-13"). ASU 2016-13 requires measurement and recognition of expected credit losses for financial assets held. The amendments in ASU 2016-13 eliminate the probable threshold for initial recognition of a credit loss in current GAAP and reflect an entity’s current estimate of all expected credit losses. ASU 2016-13 is effective for interim and annual reporting periods beginning January 1, 2020, and is to be applied using a modified retrospective transition method. Earlier adoption is permitted. While the Company is continuing to evaluate the impact of adoption, it does not currently expect the adoption of ASU 2016-13 to have a material impact on the Company's financial position, results of operations or cash flows. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurements ("ASU 2018-13"). ASU 2018-13 modifies fair value measurement disclosure requirements. The effective date for ASU 2018-13 is for annual and interim periods beginning after December 15, 2019. Early adoption is permitted. Because this ASU changes only the disclosure requirements and not the underlying accounting, the Company does not expect the adoption of ASU 2018-13 to have a material impact on the Company's financial position, results of operations or cash flows. In August 2018, the FASB issued ASU 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract ("ASU 2018-15"). ASU 2018-15 requires a customer in a cloud computing arrangement that is a service contract to follow the internal-use software guidance to determine which implementation costs to defer and recognize as an asset. The effective date for ASU 2018-15 is for annual and interim periods beginning after December 15, 2019. Early adoption is permitted. The amendments in this ASU should be applied either retrospectively or prospectively to all implementation costs incurred after the date of adoption. While the Company is continuing to evaluate the impact of adoption, it does not currently expect the adoption of ASU 2016-13 to have a material impact on the Company's financial position, results of operations or cash flows.

FAIR VALUE MEASUREMENT AND FINANCIAL INSTRUMENTS

9 Months Ended

Sep. 30, 2019

Fair Value Disclosures [Abstract]

FAIR VALUE MEASUREMENT AND FINANCIAL INSTRUMENTS

The carrying values of cash and cash equivalents, restricted cash, prepaid expenses and other current assets, and accounts payable on the Company’s consolidated balance sheets approximated their fair values as of September 30, 2019 and December 31, 2018 due to their short-term nature.

Certain of the Company’s financial instruments are measured at fair value using a three-level hierarchy that prioritizes the inputs used to measure fair value. This fair value hierarchy prioritizes the use of observable inputs and minimizes the use of unobservable inputs. The three levels of inputs used to measure fair value are as follows:


Level 1:	Inputs are quoted prices for identical instruments in active markets,


Level 2:	Inputs are quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; or model-derived valuations whose inputs are observable or whose significant value drivers are observable.


Level 3:	Inputs are unobservable and reflect the Company’s own assumptions, based on the best information available, including the Company’s own data.

The following tables set forth the carrying amounts and fair values of the Company's financial instruments measured at fair value on a recurring basis as of September 30, 2019 and December 31, 2018 (in thousands):



	September 30, 2019
					Fair Value Measurement Based on
	Carrying Amount		Fair Value		Quoted Prices in Active Markets (Level 1)		Significant other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Money market funds (cash equivalents)	$	30,995	$	30,995	$	30,995	$	—	$	—
Liabilities:
Contingent consideration	$	95,000	$	95,000	$	—	$	—	$	95,000



	December 31, 2018
					Fair Value Measurement Based on
	Carrying Amount		Fair Value		Quoted Prices in Active Markets (Level 1)		Significant other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Money market funds (cash equivalents)	$	40,365	$	40,365	$	40,365	$	—	$	—
Liabilities:
Contingent consideration	$	48,400	$	48,400	$	—	$	—	$	48,400

The Company evaluates transfers between fair value levels at the end of each reporting period. There were no transfers of assets or liabilities between fair value levels during the nine months ended September 30, 2019.

Contingent Consideration

On September 20, 2016, the Company acquired Viventia through the issuance of common stock plus contingent consideration, pursuant to the terms of a Share Purchase Agreement (the "Acquisition"). The Company recorded the acquired assets and liabilities based on their estimated fair values as of the acquisition date and finalized its purchase accounting for the Acquisition during the third quarter of 2017. The contingent consideration relates to amounts potentially payable to Viventia's shareholders under the Share Purchase Agreement. Contingent consideration is measured at its estimated fair value at each reporting period, with fluctuations in value resulting in a non-cash charge to earnings (or loss) during the period. The estimated fair value measurement is based on significant inputs, including internally developed financial forecasts, probabilities of success, and timing of certain milestone events and achievements, which are not observable in the market, representing a Level 3 measurement within the fair value hierarchy. The valuation of contingent consideration requires the use of significant assumptions and judgments, which management believes are consistent with those that would be made by a market participant. Management reviews its assumptions and judgments on an ongoing basis as additional market and other data is obtained, and any future changes in the assumptions and judgments utilized by management may cause the estimated fair value of contingent consideration to fluctuate materially, resulting in earnings volatility.

The following table sets forth a summary of the change in the fair value of the Company's contingent consideration liability, measured on a recurring basis at each reporting period, for the nine months ended September 30, 2019 (in thousands):



Balance at December 31, 2018	$	48,400
Change in fair value of contingent consideration	(1,000		)
Balance at March 31, 2019	47,400
Change in fair value of contingent consideration⁽¹⁾	44,000
Balance at June 30, 2019	91,400
Change in fair value of contingent consideration⁽²⁾	3,600
Balance at September 30, 2019	$	95,000

The fair value of the Company’s contingent consideration was determined using probabilities of successful achievement of regulatory milestones and commercial sales, the period in which these milestones and sales are expected to be achieved ranging from 2021 to 2033, the level of commercial sales of Vicinium forecasted for the United States, Europe, Japan and other potential markets, and discount rates ranging from 6.6% to 13.7% as of December 31, 2018 and 5.8% to 12.2% as of September 30, 2019. There have been no changes to the valuation methods utilized during the nine months ended September 30, 2019.

⁽¹⁾During the quarter ended June 30, 2019, management reassessed the total addressable global market for NMIBC and determined that both the global market size and the estimated potential Vicinium commercial sales within the global market were likely higher than the Company’s previous estimates. Specific drivers of the increased revenue estimates include the expectation that Vicinium could achieve peak market penetration earlier than previously estimated and the expectation that Vicinium sales outside the United States could be two to three times the expected sales volumes in the United States. As contingent consideration incorporates a royalty rate of 2% on all commercial net sales of Vicinium through December 2033, an increase in expected future net sales correlated to a $44.0 million increase in the estimated fair value of the Company’s contingent consideration as of June 30, 2019.

⁽²⁾The $3.6 million increase in the estimated fair value of contingent consideration was primarily attributable to a slightly lower discount rate, based on prevailing market conditions as of September 30, 2019, applicable to the earnout royalty payments potentially payable to Viventia's shareholders under the Share Purchase Agreement.

- Definition

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

+ References + Details

LEASES

9 Months Ended

Sep. 30, 2019

Leases [Abstract]

LEASES

On January 1, 2019, the Company adopted ASC 842 using the optional transition method. The Company’s lease portfolio includes:

An operating lease for its manufacturing facility in Winnipeg, Manitoba, which consists of a 31,100 square foot manufacturing, laboratory, warehouse and office facility, under a five-year renewable lease through September 2020 with a right to renew the lease for one subsequent five-year term. The minimum monthly rent under this lease is $12,600 per month. In addition to rent expense, the Company expects to incur $12,300 per month in related operating expenses. Operating lease cost under this lease, including the related operating costs, was $76,000 and $222,000 for the three and nine months ended September 30, 2019, respectively. Previously under ASC 840, rent expense for this lease, including related operating costs, was $78,000 and $239,000 for the three and nine months ended September 30, 2018, respectively.

A short-term property lease for its current corporate headquarters in Cambridge, MA that extends through December 31, 2019. The minimum monthly rent for this office space is $7,900 per month. The Company recorded $24,000 and $75,000 in short-term lease cost for the three and nine months ended September 30, 2019, respectively. Previously under ASC 840, the Company recorded $35,000 and $97,000 in rent expense for the three and nine months ended September 30, 2018, respectively, for this lease; and

A short-term property lease for office space in Philadelphia, PA that extends through December 31, 2019. Currently, the minimum monthly rent under this lease is $11,000 per month. The Company recorded $35,000 and $113,000 in short term lease cost for the three and nine months ended September 30, 2019, respectively. Previously under ASC 840, the Company recorded $36,000 and $92,000 in rent expense for the three and nine months ended September 30, 2018, respectively, for this lease.

The asset component of the Company’s operating leases is recorded as operating lease right-of-use assets and reported within other assets on the Company's consolidated balance sheet. The short-term liability is recorded in other current liabilities on the Company’s consolidated balance sheet. Operating lease cost is recognized on a straight-line basis over the lease term.

The components of lease cost for the three and nine months ended September 30, 2019 are as follows (in thousands):



Lease Cost:	Three Months ended September 30, 2019		Nine Months ended September 30, 2019
Operating lease (including related operating costs)	$	76	$	222
Short-term property leases	59		188
Total lease costs	$	135	$	410



Supplemental Information:	Nine Months ended September 30, 2019
Weighted-average remaining lease term - operating leases (in years)	1.0
Weighted-average discount rate - operating leases	12%

Future minimum lease payments under non-cancelable operating leases as of September 30, 2019 are as follows (in thousands):



Years ending December 31,	Minimum Lease Payments
2019⁽¹⁾	$	38
2020	113
Total future minimum lease payments	151
Less: Amounts representing present value adjustment	6
Operating lease liabilities as of September 30, 2019	145
Less: Current portion of operating lease liabilities	145
Operating lease liabilities, net of current portion	$	—

⁽¹⁾ Represents remainder of 2019.

ACCRUED EXPENSES

9 Months Ended

Sep. 30, 2019

Payables and Accruals [Abstract]

ACCRUED EXPENSES

The following table sets forth the composition of accrued expenses as of September 30, 2019 and December 31, 2018 (in thousands):



	September 30, 2019		December 31, 2018
Research and development	$	4,203	$	2,928
Payroll-related expenses	1,044		1,045
Severance to former Executives and other employees	613		278
Professional fees	466		464
Other	24		31
Total Accrued Expenses	$	6,350	$	4,746

Management Changes

On August 26, 2019, the Company announced that Richard Fitzgerald departed as its Chief Financial Officer, effective immediately. In connection with his separation from the Company, Mr. Fitzgerald and the Company entered into a Separation Agreement and General Release dated as of September 9, 2019 (the “Fitzgerald Separation Agreement”), pursuant to which the Company provided Mr. Fitzgerald with twelve months of separation payments and benefits. The Company recorded $0.3 million of expense, which will be paid through the normal payroll cycle through August 2020.

On August 2, 2019, Dennis Kim, M.D., MPH departed as the Company's Chief Medical Officer, effective immediately. In connection with his separation from the Company, Dr. Kim and the Company entered into a Separation Agreement and General Release dated as of August 2, 2019 (the “Kim Separation Agreement”), pursuant to which the Company provided Dr. Kim with six months of separation payments in the amount of $0.2 million. In addition, Dr. Kim and the Company entered into a Consulting Agreement dated as of August 3, 2019 (the "Kim Consulting Agreement"), pursuant to which the Company agreed to pay Dr. Kim $0.1 million in consulting fees and transition expenses over the following three months ending November 2, 2019. The Company recorded $0.3 million of expenses related to these agreements. The Kim Consulting Agreement payments will be made in a lump sum when the agreement concludes in November 2019. The separation payments will be paid through the normal payroll cycle through January 2020.

On August 7, 2018, the Company announced that Stephen A. Hurly departed as its President and Chief Executive Officer, effective immediately. In connection with his separation from the Company, Mr. Hurly and the Company entered into a Separation Agreement and General Release dated as of September 28, 2018 (the “Hurly Separation Agreement”), pursuant to which the Company provided Mr. Hurly with twelve months of separation payments and benefits. The Company recorded $0.6 million of expense, consisting of Mr. Hurly’s base salary at the time of his departure of $0.4 million plus his target annual bonus for 2018 of $0.2 million, which was paid through the normal payroll cycle through August 2019, when the Company completed its obligations related to the Hurly Separation Agreement.

The remaining amounts of accrued severance as of September 30, 2019 relate to terminations of other employees during 2019.

STOCKHOLDERS' EQUITY

9 Months Ended

Sep. 30, 2019

Equity [Abstract]

STOCKHOLDERS' EQUITY

Equity Financings

In June 2019, the Company raised $27.8 million of net proceeds from the sale of 20.4 million shares of common stock and accompanying warrants to purchase an additional 20.4 million shares of common stock in an underwritten public offering (the "June 2019 Financing"). The combined purchase price for each share of common stock and accompanying warrant was $1.47. Subject to certain ownership limitations, the warrants issued in the June 2019 Financing were exercisable immediately upon issuance at an exercise price of $1.47 per share of common stock, subject to adjustments as provided under the terms of such warrants, and have a one-year term expiring on June 21, 2020.

In June 2018, the Company raised $41.9 million of net proceeds from the sale of 25.6 million shares of common stock at a price of $1.80 per share in an underwritten public offering.

In March 2018, the Company raised $9.0 million of net proceeds from the sale of 8.0 million shares of common stock at a price of $1.13 per share in a registered direct public offering and the sale of warrants to purchase 8.0 million shares of the Company's common stock with an exercise price of $1.20 per share (the "2018 Warrants"), at a sale price of $0.125 per warrant, in a concurrent private placement (collectively, the “March 2018 Financing”). Subject to certain ownership limitations, the warrants issued in the March 2018 Financing were exercisable immediately upon issuance at an exercise price of $1.20 per share of common stock, subject to adjustments as provided under the terms of such warrants, and have a five year term expiring on March 23, 2023.

Preferred Stock

Pursuant to its Amended and Restated Certificate of Incorporation (the "Certificate of Incorporation"), the Company is authorized to issue 5.0 million shares of "blank check" preferred stock, $0.001 par value per share, which enables its Board of Directors, from time to time, to create one or more series of preferred stock. Each series of preferred stock issued shall have the rights, preferences, privileges and restrictions as designated by the Board of Directors. The issuance of any series of preferred stock could affect, among other things, the dividend, voting and liquidation rights of the Company's common stock. The Company had no preferred stock issued and outstanding as of September 30, 2019 and December 31, 2018.

Common Stock

Pursuant to its Certificate of Incorporation, the Company is authorized to issue 200.0 million shares of common stock, $0.001 par value per share, of which 101.3 million and 77.5 million shares were issued and outstanding as of September 30, 2019 and December 31, 2018, respectively. In addition, the Company had reserved for issuance the following amounts of shares of its common stock for the purposes described below as of September 30, 2019 and December 31, 2018 (in thousands):



	September 30, 2019	December 31, 2018
Shares of common stock issued	101,268	77,456
Shares of common stock reserved for issuance for:
Warrants to purchase common stock	26,307	9,258
Stock options	6,450	3,942
Shares available for grant under 2014 Stock Incentive Plan	8,599	2,001
Shares available for sale under 2014 Employee Stock Purchase Plan	28	38
Total shares of common stock issued and reserved for issuance	142,652	92,695

Warrants

All of the Company’s outstanding warrants are non-tradeable and permanently classified as equity because they meet the derivative scope exception under ASC Topic 815-40, Derivatives and Hedging - Contracts in Entity’s Own Equity ("ASC 815-40"). The following table sets forth the Company's warrant activity for the nine months ended September 30, 2019 (in thousands):



			Year-to-Date Warrant Activity
Issued	Exercise Price	Expiration	December 31, 2018	Issued	(Exercised)		September 30, 2019
Jun-2019	$1.47	Jun-2020	—	20,410	—		20,410
Mar-2018	$1.20	Mar-2023	7,211	—	(1,861	)	5,350
Nov-2017	$0.80	Nov-2022	1,992	—	(1,500	)	492
May-2015	$11.83	Nov-2024	28	—	—		28
Nov-2014	$11.04	Nov-2024	27	—	—		27
			9,258	20,410	(3,361	)	26,307

During the nine months ended September 30, 2019, the Company received proceeds of $3.4 million from the exercise of 3.4 million outstanding warrants to purchase common stock issued in connection with (i) its underwritten public offering in November 2017 (the "November 2017 Financing") and (ii) the March 2018 Financing.

During the nine months ended September 30, 2018, the Company received proceeds of $7.3 million from the exercise of 8.7 million outstanding warrants to purchase common stock issued in connection with (i) the November 2017 Financing and (ii) the March 2018 Financing.

See "Note 14. Subsequent Event" for additional information related to the Company's outstanding warrants.

LOSS PER SHARE

9 Months Ended

Sep. 30, 2019

Earnings Per Share [Abstract]

LOSS PER SHARE

The Company’s basic loss per common share is computed by dividing net loss by the weighted-average number of shares of common stock outstanding during the period. A net loss cannot be diluted, so when the Company is in a net loss position, basic and diluted loss per common share are the same. If in the future the Company achieves profitability, the denominator of a diluted earnings per common share calculation will include both the weighted-average number of shares outstanding and the number of common stock equivalents, if the inclusion of such common stock equivalents would be dilutive. Dilutive common stock equivalents potentially include warrants, stock options and non-vested restricted stock awards and units using the treasury stock method, along with the effect, if any, from outstanding convertible securities. The Company’s outstanding warrants to purchase common stock have participation rights to any dividends that may be declared in the future and are therefore considered to be participating securities. Participating securities have the effect of diluting both basic and diluted earnings per share during periods of income. During periods of loss, no loss is allocated to the participating securities since the holders have no contractual obligation to share in the losses of the Company.

The following potentially dilutive securities outstanding as of September 30, 2019 and 2018 have been excluded from the denominator of the diluted loss per share of common stock outstanding calculation (in thousands):



	September 30,
	2019	2018
Stock options	6,450	4,568
Warrants	26,307	9,258
	32,757	13,826

SHARE-BASED COMPENSATION

9 Months Ended

Sep. 30, 2019

Share-based Payment Arrangement [Abstract]

SHARE-BASED COMPENSATION

The amount of share-based compensation expense recognized by the Company by line item on its consolidated statements of operations for the three and nine months ended September 30, 2019 and 2018 is as follows (in thousands):



	Three Months ended September 30,					Nine Months ended September 30,
	2019			2018		2019		2018
Research and development	$	(20	)	$	99	$	119	$	387
General and administrative	249			149		$	792	548
	$	229		$	248	$	911	$	935

2014 Stock Incentive Plan

The Company's 2014 Stock Incentive Plan, as amended ("2014 Plan"), was adopted by its Board of Directors in December 2013 and subsequently approved by its stockholders in January 2014. The 2014 Plan became effective immediately prior to the closing of the Company's IPO in February 2014 and provides for the grant of incentive and non-qualified stock options, restricted stock awards and units, stock appreciation rights and other stock-based awards, with amounts and terms of grants determined by the Company's Board of Directors at the time of grant, to the Company's employees, officers, directors, consultants and advisors. Currently there are only stock options outstanding under the 2014 Plan, which generally vest over a four-year period at the rate of 25% of the grant vesting on the first anniversary of the date of grant and 6.25% of the grant vesting at the end of each successive three-month period thereafter. Stock options granted under the 2014 Plan are exercisable for a period of ten years from the date of grant. There were 4.3 million stock options outstanding under the 2014 Plan as of September 30, 2019.

At the Annual Meeting of Stockholders in June 2019, the Company's stockholders approved an amendment to the 2014 Plan that (i) increased by 7.9 million the number of shares of common stock reserved for issuance under the 2014 Plan and (ii) eliminated the “evergreen” or automatic replenishment provision of the 2014 Plan, pursuant to which the number of shares of common stock authorized for issuance under the 2014 Plan was automatically increased on an annual basis. As of September 30, 2019, there were 8.6 million shares of common stock available for issuance under the 2014 Plan.

Out-of-Plan Inducement Grants

From time to time, the Company has granted equity awards to its newly hired executives in accordance with Nasdaq's employment inducement grant exemption (Listing Rule 5635(c)(4)). Such grants are made outside of the 2014 Plan and act as an inducement material to the executive's acceptance of employment with the Company. As of September 30, 2019, there were 2.1 million stock options outstanding which were granted as employment inducement awards outside of the 2014 Plan.

Stock Options

The following table summarizes the Company’s total stock option activity, including awards granted under the 2014 Plan and inducement grants made outside of the 2014 Plan, for the nine months ended September 30, 2019:



	Number of Shares under Option (in thousands)		Weighted-average Exercise Price per Option	Weighted-average Remaining Contractual Life (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2018	3,942		$2.12	9.1	$	57
Granted	3,986		$1.02
Exercised	(30	)	$1.50
Canceled or forfeited	(1,448	)	$1.76
Outstanding at September 30, 2019	6,450		$1.52	9.1	$	680
Exercisable at September 30, 2019	1,744		$2.42	8.1	$	84

The Company recognized $0.2 million and $0.2 million of share-based compensation expense related to stock options for the three months ended September 30, 2019 and 2018, respectively, and $0.9 million and $0.9 million for the nine months ended September 30, 2019 and 2018, respectively. At September 30, 2019, there was $3.5 million of total unrecognized compensation expense related to unvested stock options for employees and non-employee consultants which the Company expects to recognize over a weighted-average period of 3.1 years. The weighted-average grant-date fair value of stock options granted during the nine months ended September 30, 2019 was estimated at $0.69 per option. The total intrinsic value of stock options exercised during the nine months ended September 30, 2019 was de minimis.

For the nine months ended September 30, 2019, the grant-date fair value of stock options was estimated at the time of grant using the following weighted-average inputs and assumptions in the Black-Scholes option pricing model:



Fair value of common stock	$0.69
Exercise price	$1.02
Expected term (in years)	5.98
Risk-free interest rate	2.1%
Expected volatility	78.1%
Dividend yield	—%

In October 2017, the Company issued stock option awards to certain employees which contained performance vesting conditions. These options vested in installments based on the achievement of certain strategic and clinical milestones. In January 2018, March 2018, June 2018 and July 2019, the Compensation Committee determined that certain performance milestones were met. Share-based compensation expense associated with these performance-based stock options was recognized over the service and performance period for performance conditions considered probable of achievement using management’s best estimate. The Company recognized de minimis expense related to these performance-based awards for the three and nine months ended September 30, 2019. There was no unrecognized compensation expense remaining related to these performance-based awards as of September 30, 2019. The Company recognized $(43,000) and $0.2 million of expense related to these performance-based awards for the three and nine months ended September 30, 2018, respectively. The negative expense was attributable to awards granted to the Company's former President and Chief Executive Officer which were canceled following his separation from the Company.

EMPLOYEE BENEFIT PLANS	9 Months Ended
EMPLOYEE BENEFIT PLANS	Sep. 30, 2019
Retirement Benefits [Abstract]
EMPLOYEE BENEFIT PLANS	EMPLOYEE BENEFIT PLANS 2014 Employee Stock Purchase Plan The Company's 2014 Employee Stock Purchase Plan ("2014 ESPP") was adopted by its Board of Directors in December 2013 and subsequently approved by its stockholders in January 2014. The 2014 ESPP became effective immediately prior to the closing of the Company's IPO in February 2014 and established an initial reserve of 0.2 million shares of the Company's common stock for issuance to participating employees. The purpose of the 2014 ESPP is to enhance employee interest in the success and progress of the Company by encouraging employee ownership of common stock of the Company. The 2014 ESPP provides employees with the opportunity to purchase shares of the Company’s common stock at a 15% discount to the market price through payroll deductions or lump sum cash investments. The Company estimates the number of shares to be issued at the end of an offering period and recognizes expense over the requisite service period. Shares of the Company's common stock issued and sold pursuant to the 2014 ESPP are shown on the consolidated statements of changes in stockholders' equity. As of September 30, 2019, there were approximately 28,000 shares of the Company's common stock available for sale under the 2014 ESPP. 401(k) Defined Contribution Plan The Company maintains a 401(k) defined contribution retirement plan which covers all of its U.S. employees. Employees are eligible to participate on the first of the month following their date of hire. Under the 401(k) plan, participating employees may defer up to 100% of their pre-tax salary, subject to certain statutory limitations. Employee contributions vest immediately. The plan allows for a discretionary match per participating employee up to a maximum $4,000 per year.

LICENSE AGREEMENT WITH ROCHE	9 Months Ended
LICENSE AGREEMENT WITH ROCHE	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
LICENSE AGREEMENT WITH ROCHE	LICENSE AGREEMENT WITH ROCHE On June 10, 2016, the Company entered into the License Agreement with Roche, which became effective on August 16, 2016. Under the License Agreement, the Company granted Roche an exclusive, worldwide license, including the right to sublicense, to its patent rights and know-how related to the Company’s monoclonal antibody EBI-031 or all other IL-6 antagonistic anti-IL-6 monoclonal antibodies, to make, have made, use, have used, register, have registered, sell, have sold, offer for sale, import and export any product containing such an antibody or any companion diagnostic used to predict or monitor response to treatment with such a product. During 2016, the Company received an upfront license fee of $7.5 million and a milestone payment of $22.5 million. The Company is entitled to receive up to $240.0 million in additional consideration upon the achievement of specified regulatory, development and commercial milestones. Specifically, an aggregate amount of up to $175.0 million is payable to the Company for the achievement of specified milestones with respect to the first indication: $50.0 million in development milestones, $50.0 million in regulatory milestones and $75.0 million in commercialization milestones. Additional amounts of up to $65.0 million are payable upon the achievement of specified development and regulatory milestones in a second indication. In addition, the Company is entitled to receive royalty payments in accordance with a tiered royalty rate scale, with rates ranging from 7.5% to 15% of net sales of potential future products containing EBI-031 and up to 50% of these rates on net sales of potential future products containing other IL-6 compounds, with each of the royalties subject to reduction under certain circumstances and to buy-out options. The License Agreement is subject to the provisions of ASC 606, Revenue from Contracts with Customers ("ASC 606"), which was adopted effective January 1, 2018 utilizing a modified retrospective method. The Company concluded that all performance obligations had been achieved as of the adoption date and therefore the full transaction price was considered earned. The transaction price was determined to be the $30.0 million received in 2016. Additional consideration to be paid to the Company upon the achievement of certain milestones will be included if it is expected that the amounts will be received and the amounts would not be subject to a constraint. As of the date of the adoption, no amounts were expected to be received from the achievement of any milestones due to the nature of the milestones and the development status of the product candidates at the time of the adoption. As a result, there were no amounts required to be recorded as a cumulative adoption adjustment as the consideration recognized under ASC 606 was consistent with the amounts recognized under the previous accounting literature. During the three and nine months ended September 30, 2019 and 2018, there were no adjustments to the transaction price required and no revenue was recognized because all performance obligations of the Company had previously been satisfied and management did not expect any amounts to be received from any milestones within the License Agreement. This is due to the nature of the milestones and the development status of the product candidates as of the end of each reporting period.

RELATED PARTY TRANSACTIONS	9 Months Ended
RELATED PARTY TRANSACTIONS	Sep. 30, 2019
Related Party Transactions [Abstract]
RELATED PARTY TRANSACTIONS	RELATED PARTY TRANSACTIONS The Company leases its Winnipeg, Manitoba facility from an affiliate of Leslie L. Dan, a director of the Company until his retirement effective July 16, 2019, under a five-year renewable lease through September 2020 with a right to renew the lease for one subsequent five-year term. Operating lease costs under this lease, which include related operating expenses, were $76,000 and $222,000 for the three and nine months ended September 30, 2019, respectively. Previously under ASC 840, rent expenses for this lease were $78,000 and $239,000 for the three and nine months ended September 30, 2018, respectively. The Company pays fees, under an intellectual property license agreement, to Protoden Technologies, Inc. (“Protoden”), a company owned by Clairmark Investments Ltd. (“Clairmark”), an affiliate of Mr. Dan. Pursuant to this license agreement, the Company has an exclusive, perpetual, irrevocable and non-royalty bearing license, with the right to sublicense, under certain patents and technology to make, use and sell products that utilize such patents and technology for an annual fee of $0.1 million. Upon expiration of the term on January 1, 2025, the licenses granted to the Company will require no further payments to Protoden. During each of the nine months ended September 30, 2019 and 2018, $0.1 million was paid to Clairmark.

SUBSEQUENT EVENT

9 Months Ended

Sep. 30, 2019

Subsequent Events [Abstract]

SUBSEQUENT EVENT

Modifications to Outstanding Warrants

In November 2017, as part of an underwritten public offering, the Company issued warrants to purchase 10.0 million shares of common stock with an exercise price of $0.80 per share (the "2017 Warrants"), of which 0.5 million warrants remained outstanding as of September 30, 2019. On October 29, 2019, the Company announced that it had entered into transactions with holders of its outstanding 2018 Warrants and 2017 Warrants to purchase the Company's common stock. The following table sets forth the Company's warrant activity subsequent to September 30, 2019 which resulted from the exercises and modifications described below:



			Subsequent Event Warrant Activity
Issued	Exercise Price	Expiration	September 30, 2019	(Exercised)		October 31, 2019
Jun-2019	$1.47	Jun-2020	20,410	—		20,410
Mar-2018	$0.95*	Mar-2023	5,350	(3,407	)	1,943
Nov-2017	$0.55*	Nov-2022	492	(5	)	487
May-2015	$11.83	Nov-2024	28	—		28
Nov-2014	$11.04	Nov-2024	27	—		27
			26,307	(3,412	)	22,895

* Exercise price shown (i) reflects modification described below and (ii) subject to further adjustment based on down round provision added by amendment described below.

2018 Warrants

On October 28, 2019, the Company entered into transactions with the holders of its outstanding 2018 Warrants pursuant to which such holders either (i) exercised their warrants pursuant to a Warrant Exercise Agreement (the "2018 Warrant Exercise Agreements") or (ii) amended their warrants pursuant to a Warrant Amendment Agreement (the "2018 Warrant Amendment Agreements"). As consideration for those holders executing the 2018 Warrant Exercise Agreements, the Company reduced the exercise price of the warrants from $1.20 to $0.60 per share of the Company's common stock, resulting in proceeds of $2.0 million from the exercise of 3.4 million warrants. Pursuant to the 2018 Warrant Amendment Agreements, the prohibition on certain variable rate transactions included in the 2018 Warrants was amended to exclude ATM offerings and the exercise price of the warrants was reduced from $1.20 to the lesser of (a) $0.95 per share of common stock and (b) the exercise price as determined from time to time pursuant to the anti-dilution provisions in the 2018 Warrant Amendment Agreements.

In connection with the 2018 Warrant Exercise Agreements and 2018 Warrant Amendment Agreements, the Company entered into an amendment to the Securities Purchase Agreement dated March 21, 2018 related to the March 2018 Financing, by and among the Company and each purchaser identified on the signature pages thereto, with certain holders representing greater than 50.1% of the securities issued based on initial subscription amounts, pursuant to which the prohibition on variable rate transactions, including ATM offerings, contained in section 4.12(b) was deleted in its entirety.

2017 Warrants

On October 28, 2019, the Company entered into transactions with the holders of its outstanding 2017 Warrants pursuant to which such holders either (i) exercised their warrants pursuant to a Warrant Exercise Agreement (the "2017 Warrant Exercise Agreements") or (ii) amended their warrants pursuant to a Warrant Amendment Agreement (the "2017 Warrant Amendment Agreements"). As consideration for those holders executing the 2017 Warrant Exercise Agreements, the Company reduced the exercise price of the warrants from $0.80 to $0.55 per share of the Company's common stock. Pursuant to the 2017 Warrant Amendment Agreements, the prohibition on certain variable rate transactions included in the 2017 Warrants was amended to exclude ATM offerings and the exercise price of the warrants was reduced from $0.80 to the lesser of (a) $0.55 per share of common stock and (b) the exercise price as determined from time to time pursuant to the anti-dilution provisions in the 2017 Warrant Amendment Agreements.

Accounting Implications

The Company is currently reviewing the accounting implications of the modifications to its 2018 Warrants and 2017 Warrants, which will be reflected in the Company's fourth quarter results included in the Annual Report on Form 10-K for the year ended December 31, 2019. ASU No. 2017-11, (Part I) Accounting for Certain Financial Instruments with Down Round Features ("ASU 2017-11") was effective for public companies beginning on January 1, 2019. The amendments in ASU 2017-11 changed the classification analysis of certain equity-linked financial instruments with down round features. Prior to ASU 2017-11, warrants with down round features were not considered indexed to an entity's own stock under the derivative scope exception in ASC 815-40, resulting in classification as a liability that must be remeasured at fair value at each reporting period. Under the new guidance, when determining whether certain financial instruments should be classified as liabilities or equity under ASC 815-40, a down round feature no longer precludes equity classification when assessing whether the instrument is indexed to the entity's own stock. The Company is still required to determine whether its 2018 Warrants and 2017 Warrants should continue to be classified in equity based on the derivative scope exception under the guidance in ASC 815-40, and such determination has not yet been made. Additionally, under ASU 2017-11, when a down round feature is included in an equity-classified freestanding financial instrument, the value of the effect of the down round feature is treated as a dividend when it is triggered and as a numerator adjustment in the basic earnings per share calculation. This reflects the occurrence of an economic transfer of value to the holder of the instrument.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)

9 Months Ended

Sep. 30, 2019

Accounting Policies [Abstract]

Interim Financial Statements

The accompanying unaudited interim condensed consolidated financial statements have been prepared from the books and records of the Company in accordance with GAAP for interim financial information and Rule 10-01 of Regulation S-X promulgated by the United States Securities and Exchange Commission (“SEC”), which permit reduced disclosures for interim periods. All adjustments, consisting only of normal recurring adjustments, necessary for a fair presentation of the accompanying condensed consolidated balance sheets and statements of operations and comprehensive loss, stockholders’ equity and cash flows have been made. Although these interim financial statements do not include all of the information and footnotes required for complete annual financial statements, management believes the disclosures are adequate to make the information presented not misleading. These unaudited interim results of operations and cash flows for the three and nine months ended September 30, 2019 are not necessarily indicative of the results that may be expected for the full year. These unaudited interim condensed consolidated financial statements and footnotes should be read in conjunction with the Company’s audited annual consolidated financial statements and footnotes included in its Annual Report on Form 10-K, as filed with the SEC on March 1, 2019, wherein a more complete discussion of significant accounting policies and certain other information can be found.

Use of Estimates

The preparation of financial statements in accordance with GAAP and the rules and regulations of the SEC requires the use of estimates and assumptions, based on judgments considered reasonable, which affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. The Company bases its estimates and assumptions on historical experience, known trends and events and various other factors that management believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Although management believes its estimates and assumptions are reasonable when made, they are based upon information available at the time they are made. Management evaluates the estimates and assumptions on an ongoing basis and, if necessary, makes adjustments. Due to the risks and uncertainties involved in the Company’s business and evolving market conditions, and given the subjective element of the estimates and assumptions made, actual results may differ from estimated results. The most significant estimates and judgments impact the fair value of intangible assets, goodwill and contingent consideration; income taxes (including the valuation allowance for deferred tax assets); research and development expenses; and going concern considerations.

Principles of Consolidation

The Company’s consolidated financial statements include the accounts of the Company, its wholly owned subsidiary, Viventia Bio, Inc. ("Viventia"), and its indirect subsidiaries, Viventia Bio USA Inc. and Viventia Biotech (EU) Limited. All intercompany transactions and balances have been eliminated in consolidation.

Foreign Currency Translation

The functional currency of the Company and each of its subsidiaries is the U.S. dollar.

Reclassifications

On the Company's condensed consolidated statements of cash flows, proceeds from exercises of common stock warrants is now shown separately from proceeds from issuance of common stock and common stock warrants, net of issuance costs.

Leases

As part of the adoption of ASC 842, the Company utilized certain practical expedients outlined in the guidance. These practical expedients include:


•	Accounting policy election to use the short-term lease exception by asset class;


•	Election of the practical expedient package during transition, which includes:


–	An entity need not reassess whether any expired or existing contracts are or contain leases;


–	An entity need not reassess the classification for any expired or existing leases. As a result, all leases that were classified as operating leases in accordance with ASC 840 are classified as operating leases under ASC 842, and all leases that were classified as capital leases in accordance with ASC 840 are classified as finance leases under ASC 842; and


–	An entity need not reassess initial direct costs for any existing leases.

Recent Accounting Pronouncements

JOBS Act Accounting Election

The Company is an "emerging growth company," as defined in the Jumpstart Our Business Startups Act of 2012 ("JOBS Act"). Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act until such time as those standards apply to private companies. The Company has irrevocably elected to "opt out" of this provision and, as a result, will adopt any new or revised accounting standards issued by the FASB when they required to be adopted by public companies.

Adopted in 2019

In January 2017, the FASB issued ASU No. 2017-04, Simplifying the Test for Goodwill Impairment ("ASU 2017-04"). ASU 2017-04 simplifies the accounting for goodwill impairment by removing Step 2 of the goodwill impairment test, which requires a hypothetical purchase price allocation. ASU 2017-04 is effective for annual or interim goodwill impairment tests in fiscal years beginning after December 15, 2019, and should be applied on a prospective basis. The Company adopted this guidance effective January 1, 2019, and it did not have a material impact on the Company’s financial position, results of operations or cash flows.

In June 2018, the FASB issued ASU No. 2018-07, Compensation-Stock Compensation (Topic 718) (“Topic 718”): Improvements to Nonemployee Share-Based Payment Accounting (“ASU 2018-07”). ASU 2018-07 expands the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from non-employees, and as a result, the accounting for share-based payments to non-employees will be substantially aligned. ASU 2018-07 is effective for fiscal years beginning after December 15, 2018, including interim periods within that fiscal year. The Company adopted this guidance effective January 1, 2019, and it did not have a material impact on the Company’s financial position, results of operations or cash flows.

In July 2018, the FASB issued ASU No. 2018-09, Codification Improvements (“ASU 2018-09”). ASU 2018-09 provides amendments to a wide variety of topics in the FASB’s ASC, which applies to all reporting entities within the scope of the affected accounting guidance. The transition and effective date guidance are based on the facts and circumstances of each amendment. Some of the amendments in ASU 2018-09 do not require transition guidance and were effective upon the issuance of ASU 2018-09. However, many of the amendments do have transition guidance with effective dates for annual periods beginning after December 15, 2018. The Company adopted this guidance effective January 1, 2019, and it did not have a material impact on the Company’s financial position, results of operations or cash flows.

Pending Adoption

In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments ("ASU 2016-13"). ASU 2016-13 requires measurement and recognition of expected credit losses for financial assets held. The amendments in ASU 2016-13 eliminate the probable threshold for initial recognition of a credit loss in current GAAP and reflect an entity’s current estimate of all expected credit losses. ASU 2016-13 is effective for interim and annual reporting periods beginning January 1, 2020, and is to be applied using a modified retrospective transition method. Earlier adoption is permitted. While the Company is continuing to evaluate the impact of adoption, it does not currently expect the adoption of ASU 2016-13 to have a material impact on the Company's financial position, results of operations or cash flows.

In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurements ("ASU 2018-13"). ASU 2018-13 modifies fair value measurement disclosure requirements. The effective date for ASU 2018-13 is for annual and interim periods beginning after December 15, 2019. Early adoption is permitted. Because this ASU changes only the disclosure requirements and not the underlying accounting, the Company does not expect the adoption of ASU 2018-13 to have a material impact on the Company's financial position, results of operations or cash flows.

In August 2018, the FASB issued ASU 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract ("ASU 2018-15"). ASU 2018-15 requires a customer in a cloud computing arrangement that is a service contract to follow the internal-use software guidance to determine which implementation costs to defer and recognize as an asset. The effective date for ASU 2018-15 is for annual and interim periods beginning after December 15, 2019. Early adoption is permitted. The amendments in this ASU should be applied either retrospectively or prospectively to all implementation costs incurred after the date of adoption. While the Company is continuing to evaluate the impact of adoption, it does not currently expect the adoption of ASU 2016-13 to have a material impact on the Company's financial position, results of operations or cash flows.

FAIR VALUE MEASUREMENT AND FINANCIAL INSTRUMENTS (Tables)

9 Months Ended

Sep. 30, 2019

Fair Value Disclosures [Abstract]

Summary of Carrying Amounts and Fair Values of Financial Instruments Measured



	September 30, 2019
					Fair Value Measurement Based on
	Carrying Amount		Fair Value		Quoted Prices in Active Markets (Level 1)		Significant other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Money market funds (cash equivalents)	$	30,995	$	30,995	$	30,995	$	—	$	—
Liabilities:
Contingent consideration	$	95,000	$	95,000	$	—	$	—	$	95,000



	December 31, 2018
					Fair Value Measurement Based on
	Carrying Amount		Fair Value		Quoted Prices in Active Markets (Level 1)		Significant other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Money market funds (cash equivalents)	$	40,365	$	40,365	$	40,365	$	—	$	—
Liabilities:
Contingent consideration	$	48,400	$	48,400	$	—	$	—	$	48,400

Summary of Contingent Consideration Liability



Balance at December 31, 2018	$	48,400
Change in fair value of contingent consideration	(1,000		)
Balance at March 31, 2019	47,400
Change in fair value of contingent consideration⁽¹⁾	44,000
Balance at June 30, 2019	91,400
Change in fair value of contingent consideration⁽²⁾	3,600
Balance at September 30, 2019	$	95,000

LEASES (Tables)

9 Months Ended

Sep. 30, 2019

Leases [Abstract]

Schedule of Lease Cost

The components of lease cost for the three and nine months ended September 30, 2019 are as follows (in thousands):



Lease Cost:	Three Months ended September 30, 2019		Nine Months ended September 30, 2019
Operating lease (including related operating costs)	$	76	$	222
Short-term property leases	59		188
Total lease costs	$	135	$	410



Supplemental Information:	Nine Months ended September 30, 2019
Weighted-average remaining lease term - operating leases (in years)	1.0
Weighted-average discount rate - operating leases	12%

Schedule of Future Minimum Lease Payments Under Non-Cancelable Operating Leases

Future minimum lease payments under non-cancelable operating leases as of September 30, 2019 are as follows (in thousands):



Years ending December 31,	Minimum Lease Payments
2019⁽¹⁾	$	38
2020	113
Total future minimum lease payments	151
Less: Amounts representing present value adjustment	6
Operating lease liabilities as of September 30, 2019	145
Less: Current portion of operating lease liabilities	145
Operating lease liabilities, net of current portion	$	—

⁽¹⁾ Represents remainder of 2019.

ACCRUED EXPENSES (Tables)

9 Months Ended

Sep. 30, 2019

Payables and Accruals [Abstract]

Schedule of Accrued Expenses

The following table sets forth the composition of accrued expenses as of September 30, 2019 and December 31, 2018 (in thousands):



	September 30, 2019		December 31, 2018
Research and development	$	4,203	$	2,928
Payroll-related expenses	1,044		1,045
Severance to former Executives and other employees	613		278
Professional fees	466		464
Other	24		31
Total Accrued Expenses	$	6,350	$	4,746

STOCKHOLDERS' EQUITY (Tables)

9 Months Ended

Sep. 30, 2019

Equity [Abstract]

Summary of Common Stock

In addition, the Company had reserved for issuance the following amounts of shares of its common stock for the purposes described below as of September 30, 2019 and December 31, 2018 (in thousands):



	September 30, 2019	December 31, 2018
Shares of common stock issued	101,268	77,456
Shares of common stock reserved for issuance for:
Warrants to purchase common stock	26,307	9,258
Stock options	6,450	3,942
Shares available for grant under 2014 Stock Incentive Plan	8,599	2,001
Shares available for sale under 2014 Employee Stock Purchase Plan	28	38
Total shares of common stock issued and reserved for issuance	142,652	92,695

Summary of Warrants Outstanding and Warrant Activity

The following table sets forth the Company's warrant activity for the nine months ended September 30, 2019 (in thousands):



			Year-to-Date Warrant Activity
Issued	Exercise Price	Expiration	December 31, 2018	Issued	(Exercised)		September 30, 2019
Jun-2019	$1.47	Jun-2020	—	20,410	—		20,410
Mar-2018	$1.20	Mar-2023	7,211	—	(1,861	)	5,350
Nov-2017	$0.80	Nov-2022	1,992	—	(1,500	)	492
May-2015	$11.83	Nov-2024	28	—	—		28
Nov-2014	$11.04	Nov-2024	27	—	—		27
			9,258	20,410	(3,361	)	26,307

The following table sets forth the Company's warrant activity subsequent to September 30, 2019 which resulted from the exercises and modifications described below:



			Subsequent Event Warrant Activity
Issued	Exercise Price	Expiration	September 30, 2019	(Exercised)		October 31, 2019
Jun-2019	$1.47	Jun-2020	20,410	—		20,410
Mar-2018	$0.95*	Mar-2023	5,350	(3,407	)	1,943
Nov-2017	$0.55*	Nov-2022	492	(5	)	487
May-2015	$11.83	Nov-2024	28	—		28
Nov-2014	$11.04	Nov-2024	27	—		27
			26,307	(3,412	)	22,895

* Exercise price shown (i) reflects modification described below and (ii) subject to further adjustment based on down round provision added by amendment described below.

- Definition

Tabular disclosure of an entity's stock, including par or stated value per share, number and dollar amount of share subscriptions, shares authorized, shares issued, shares outstanding, number and dollar amount of shares held in an employee trust, dividend per share, total dividends, share conversion features, par value plus additional paid in capital, the value of treasury stock and other information necessary to a fair presentation, and EPS information. Stock by class includes common, convertible, and preferred stocks which are not redeemable or redeemable solely at the option of the issuer. Includes preferred stock with redemption features that are solely within the control of the issuer and mandatorily redeemable stock if redemption is required to occur only upon liquidation or termination of the reporting entity. If more than one issue is outstanding, state the title of each issue and the corresponding dollar amount; dollar amount of any shares subscribed but unissued and the deduction of subscriptions receivable there from; number of shares authorized, issued, and outstanding.

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+ Details

LOSS PER SHARE (Tables)

9 Months Ended

Sep. 30, 2019

Earnings Per Share [Abstract]

Schedule of Potentially Dilutive Securities



	September 30,
	2019	2018
Stock options	6,450	4,568
Warrants	26,307	9,258
	32,757	13,826

SHARE-BASED COMPENSATION (Tables)

9 Months Ended

Sep. 30, 2019

Share-based Payment Arrangement [Abstract]

Schedule of Share-Based Compensation Expense



	Three Months ended September 30,					Nine Months ended September 30,
	2019			2018		2019		2018
Research and development	$	(20	)	$	99	$	119	$	387
General and administrative	249			149		$	792	548
	$	229		$	248	$	911	$	935

Schedule of Stock Option Activity



	Number of Shares under Option (in thousands)		Weighted-average Exercise Price per Option	Weighted-average Remaining Contractual Life (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2018	3,942		$2.12	9.1	$	57
Granted	3,986		$1.02
Exercised	(30	)	$1.50
Canceled or forfeited	(1,448	)	$1.76
Outstanding at September 30, 2019	6,450		$1.52	9.1	$	680
Exercisable at September 30, 2019	1,744		$2.42	8.1	$	84

Schedule of Weighted-Average Inputs and Assumptions in Black-Scholes Option



Fair value of common stock	$0.69
Exercise price	$1.02
Expected term (in years)	5.98
Risk-free interest rate	2.1%
Expected volatility	78.1%
Dividend yield	—%

SUBSEQUENT EVENT (Tables)

9 Months Ended

Sep. 30, 2019

Subsequent Events [Abstract]

Summary of Warrants Outstanding and Warrant Activity

The following table sets forth the Company's warrant activity for the nine months ended September 30, 2019 (in thousands):



			Year-to-Date Warrant Activity
Issued	Exercise Price	Expiration	December 31, 2018	Issued	(Exercised)		September 30, 2019
Jun-2019	$1.47	Jun-2020	—	20,410	—		20,410
Mar-2018	$1.20	Mar-2023	7,211	—	(1,861	)	5,350
Nov-2017	$0.80	Nov-2022	1,992	—	(1,500	)	492
May-2015	$11.83	Nov-2024	28	—	—		28
Nov-2014	$11.04	Nov-2024	27	—	—		27
			9,258	20,410	(3,361	)	26,307

The following table sets forth the Company's warrant activity subsequent to September 30, 2019 which resulted from the exercises and modifications described below:



			Subsequent Event Warrant Activity
Issued	Exercise Price	Expiration	September 30, 2019	(Exercised)		October 31, 2019
Jun-2019	$1.47	Jun-2020	20,410	—		20,410
Mar-2018	$0.95*	Mar-2023	5,350	(3,407	)	1,943
Nov-2017	$0.55*	Nov-2022	492	(5	)	487
May-2015	$11.83	Nov-2024	28	—		28
Nov-2014	$11.04	Nov-2024	27	—		27
			26,307	(3,412	)	22,895

* Exercise price shown (i) reflects modification described below and (ii) subject to further adjustment based on down round provision added by amendment described below.

DESCRIPTION OF BUSINESS (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
DESCRIPTION OF BUSINESS (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 57,865		$ 50,422
Net working capital	50,300
Accumulated deficit	259,971		186,024
Negative cash flows from operating activities incurred	$ 23,716	$ 15,182	$ 22,800

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Recently Adopted Accounting Standards (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease liability	$ 145
ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use asset		$ 200
Operating lease liability		$ 200

FAIR VALUE MEASUREMENT AND FINANCIAL INSTRUMENTS - Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Liabilities:
Contingent consideration				$ 48,400
Significant Unobservable Inputs (Level 3)
Liabilities:
Contingent consideration	$ 95,000	$ 91,400	$ 47,400
Carrying Amount
Assets:
Money market funds (cash equivalents)	30,995			40,365
Liabilities:
Contingent consideration	95,000			48,400
Fair Value \| Recurring
Assets:
Money market funds (cash equivalents)	30,995			40,365
Liabilities:
Contingent consideration	95,000			48,400
Fair Value \| Recurring \| Quoted Prices in Active Markets (Level 1)
Assets:
Money market funds (cash equivalents)	30,995			40,365
Liabilities:
Contingent consideration	0			0
Fair Value \| Recurring \| Significant other Observable Inputs (Level 2)
Assets:
Money market funds (cash equivalents)	0			0
Liabilities:
Contingent consideration	0			0
Fair Value \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Money market funds (cash equivalents)	0			0
Liabilities:
Contingent consideration	$ 95,000			$ 48,400

FAIR VALUE MEASUREMENT AND FINANCIAL INSTRUMENTS - Summary of Changes in Fair Value of Contingent Consideration (Details) $ in Thousands	3 Months Ended
	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance			$ 48,400
Unobservable Inputs (Level 3)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	$ 91,400	$ 47,400
Change in fair value of contingent consideration	3,600	44,000	(1,000)
Ending balance	$ 95,000	$ 91,400	$ 47,400
Discount Rate \| Minimum
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Contingent consideration liability measurements used (in percentage)	0.058			0.066
Discount Rate \| Maximum
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Contingent consideration liability measurements used (in percentage)	0.122			0.137
Royalty Rate
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Contingent consideration liability measurements used (in percentage)	0.02

LEASES - Narrative (Details)	3 Months Ended		9 Months Ended
LEASES - Narrative (Details)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) ft² term	Sep. 30, 2018 USD ($)
Lessee, Lease, Description [Line Items]
Operating lease cost (including related operating costs)	$ 76,000		$ 222,000
Short-term property leases	$ 59,000		$ 188,000
Canada
Lessee, Lease, Description [Line Items]
Office space, square foot \| ft²			31,100
Lease term	5 years		5 years
Renewal option \| term			1
Renewal term	5 years		5 years
Monthly rent			$ 12,600
Related operating expenses			12,300
Operating lease cost (including related operating costs)	$ 76,000		222,000
Rent expense Under ASC 840		$ 78,000		$ 239,000
Massachusetts
Lessee, Lease, Description [Line Items]
Monthly rent			7,900
Rent expense Under ASC 840		35,000		97,000
Short-term property leases	24,000		75,000
Pennsylvania
Lessee, Lease, Description [Line Items]
Monthly rent			11,000
Rent expense Under ASC 840		$ 36,000		$ 92,000
Short-term property leases	$ 35,000		$ 113,000

LEASES - Lease Costs (Details) $ in Thousands	3 Months Ended	9 Months Ended
LEASES - Lease Costs (Details) $ in Thousands	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)
Lease Cost:
Operating lease (including related operating costs)	$ 76	$ 222
Short-term property leases	59	188
Total lease costs	$ 135	$ 410
Supplemental Information:
Weighted-average remaining lease term - operating leases (in years)	1 year	1 year
Weighted-average discount rate - operating leases	12.00%	12.00%

LEASES - Minimum Aggregate Future Lease Commitments (Details) $ in Thousands	Sep. 30, 2019 USD ($)
Leases [Abstract]
2019	$ 38
2020	113
Total future minimum lease payments	151
Less: Amounts representing present value adjustment	6
Operating lease liabilities as of September 30, 2019	145
Less: Current portion of operating lease liabilities	145
Operating lease liabilities, net of current portion	$ 0

ACCRUED EXPENSES (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Research and development	$ 4,203	$ 2,928
Payroll-related expenses	1,044	1,045
Severance to former Executives and other employees	613	278
Professional fees	466	464
Other	24	31
Total Accrued Expenses	$ 6,350	$ 4,746

ACCRUED EXPENSES - Narrative (Details) - USD ($) $ in Thousands	Sep. 09, 2019	Aug. 02, 2019	Sep. 28, 2018	Sep. 30, 2019	Aug. 03, 2019	Dec. 31, 2018
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Expense recorded related to management changes				$ 613		$ 278
Former Chief Financial Officer
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Separation Agreement, period of separation payments and benefits agreed to	12 months
Expense recorded related to management changes	$ 300
Former Chief Medical Officer
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Separation Agreement, period of separation payments and benefits agreed to		6 months
Expense recorded related to management changes					$ 300
Separation payments		$ 200
Consulting fees and transition expenses					$ 100
Former President and Chief Executive Officer
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Separation Agreement, period of separation payments and benefits agreed to			12 months
Expense recorded related to management changes			$ 600
Base salary			400
Bonuses			$ 200

STOCKHOLDERS' EQUITY - Equity Financing (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2018
Equity [Abstract]
Proceeds from sale of stock	$ 27.8	$ 41.9	$ 9.0
Sale of stock, shares issued (in shares)	20.4	25.6	8.0
Number of warrants (in shares)	20.4		8.0
Stock and warrants price per share (in dollars per share)	$ 1.47
Exercise price per warrant (in dollars per share)	$ 1.47		$ 1.20
Warrants exercise period	1 year		5 years
Stock price per share (in dollars per share)		$ 1.80	$ 1.13
Warrant price per unit (in dollars per share)			$ 0.125

STOCKHOLDERS' EQUITY - Preferred Stock (Details) - $ / shares	Sep. 30, 2019	Dec. 31, 2018
Equity [Abstract]
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0

STOCKHOLDERS' EQUITY - Common Stock (Details) - $ / shares	Sep. 30, 2019	Dec. 31, 2018
Equity [Abstract]
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares issued (in shares)	101,267,578	77,456,180
Common stock, shares outstanding (in shares)	101,267,578	77,456,180

STOCKHOLDERS' EQUITY - Summary of Common Stock Issued and Reserved for Issuance (Details) - shares	Sep. 30, 2019	Dec. 31, 2018
Class of Warrant or Right [Line Items]
Common stock, shares issued (in shares)	101,267,578	77,456,180
Shares of common stock reserved for issuance for:
Total shares of common stock issued and reserved for issuance (in shares)	142,652,000	92,695,000
Warrants to purchase common stock
Shares of common stock reserved for issuance for:
Shares of common stock reserved for issuance (in shares)	26,307,000	9,258,000
Stock options
Shares of common stock reserved for issuance for:
Shares of common stock reserved for issuance (in shares)	6,450,000	3,942,000
Shares available for grant under 2014 Stock Incentive Plan
Shares of common stock reserved for issuance for:
Shares of common stock reserved for issuance (in shares)	8,599,000	2,001,000
Shares available for sale under 2014 Employee Stock Purchase Plan
Shares of common stock reserved for issuance for:
Shares of common stock reserved for issuance (in shares)	28,000	38,000

STOCKHOLDERS' EQUITY - Warrants (Details) - $ / shares shares in Thousands	9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2018
Class of Warrant or Right [Line Items]
Exercise price per warrant (in dollars per share)		$ 1.47	$ 1.20
Warrant Or Right Outstanding [Roll Forward]
Warrants outstanding, beginning balance (in shares)	9,258
Warrants Issued (in shares)	20,410
Warrants Exercised (in shares)	(3,361)
Warrants outstanding, ending balance (in shares)	26,307
Warrants, Expiring June 2020
Class of Warrant or Right [Line Items]
Exercise price per warrant (in dollars per share)	$ 1.47
Warrant Or Right Outstanding [Roll Forward]
Warrants outstanding, beginning balance (in shares)	0
Warrants Issued (in shares)	20,410
Warrants Exercised (in shares)	0
Warrants outstanding, ending balance (in shares)	20,410
Warrants, Expiring March 2023
Class of Warrant or Right [Line Items]
Exercise price per warrant (in dollars per share)	$ 1.20
Warrant Or Right Outstanding [Roll Forward]
Warrants outstanding, beginning balance (in shares)	7,211
Warrants Issued (in shares)	0
Warrants Exercised (in shares)	(1,861)
Warrants outstanding, ending balance (in shares)	5,350
Warrants, Expiring November 2022
Class of Warrant or Right [Line Items]
Exercise price per warrant (in dollars per share)	$ 0.80
Warrant Or Right Outstanding [Roll Forward]
Warrants outstanding, beginning balance (in shares)	1,992
Warrants Issued (in shares)	0
Warrants Exercised (in shares)	(1,500)
Warrants outstanding, ending balance (in shares)	492
Warrants, Expiring November 2024, Issued May 2015
Class of Warrant or Right [Line Items]
Exercise price per warrant (in dollars per share)	$ 11.83
Warrant Or Right Outstanding [Roll Forward]
Warrants outstanding, beginning balance (in shares)	28
Warrants Issued (in shares)	0
Warrants Exercised (in shares)	0
Warrants outstanding, ending balance (in shares)	28
Warrants, Expiring November 2024, Issued November 2014
Class of Warrant or Right [Line Items]
Exercise price per warrant (in dollars per share)	$ 11.04
Warrant Or Right Outstanding [Roll Forward]
Warrants outstanding, beginning balance (in shares)	27
Warrants Issued (in shares)	0
Warrants Exercised (in shares)	0
Warrants outstanding, ending balance (in shares)	27

STOCKHOLDERS' EQUITY - Warrants Narrative (Details) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended
	Jun. 30, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Class of Warrant or Right [Line Items]
Proceeds from exercises of common stock warrants					$ 3,434	$ 7,315
Exercises of common stock warrants (in shares)					3,361,000
Common Stock
Class of Warrant or Right [Line Items]
Exercises of common stock warrants (in shares)	3,361,115	50,000	8,294,718	420,778	3,400,000	8,700,000

LOSS PER SHARE (Details) - shares shares in Thousands	9 Months Ended
LOSS PER SHARE (Details) - shares shares in Thousands	Sep. 30, 2019	Sep. 30, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock equivalents excluded from calculation of diluted net (loss) income per share (in shares)	32,757	13,826
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock equivalents excluded from calculation of diluted net (loss) income per share (in shares)	6,450	4,568
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock equivalents excluded from calculation of diluted net (loss) income per share (in shares)	26,307	9,258

SHARE-BASED COMPENSATION - Share-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 229	$ 248	$ 911	$ 935
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	(20)	99	119	387
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 249	$ 149	$ 792	$ 548

SHARE-BASED COMPENSATION - Narrative (Details) - USD ($) $ / shares in Units, shares in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding (in shares)		6,450		6,450		3,942
Share-based compensation expense		$ 229,000	$ 248,000	$ 911,000	$ 935,000
Unrecognized compensation expense		$ 3,500,000		$ 3,500,000
Weighted-average grant-date fair value of stock options granted (in dollars per share)				$ 0.69
Inducement awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding (in shares)		2,100		2,100
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense		$ 200,000	200,000	$ 900,000	900,000
Weighted-average period				3 years 1 month 6 days
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense			$ (43,000)		$ 200,000
Unrecognized compensation expense		$ 0		$ 0
2014 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding (in shares)		4,300		4,300
Shares of common stock reserved for issuance (in shares)	7,900
Shares available for future issuance (in shares)		8,600		8,600
2014 Stock Incentive Plan \| Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period				4 years
Period exercisable from date of grant				10 years
2014 Stock Incentive Plan \| Vesting on the First Anniversary of Date of Grant \| Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant vesting on the first anniversary percentage				25.00%
2014 Stock Incentive Plan \| Vesting at End of Each Successive Three-Month Period Thereafter \| Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant vesting on the first anniversary percentage				6.25%

SHARE-BASED COMPENSATION - Stock Options (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Number of Shares under Option (in thousands)
Outstanding at beginning of period (in shares)	3,942
Granted (in shares)	3,986
Exercised (in shares)	(30)
Canceled or forfeited (in shares)	(1,448)
Outstanding at end of period (in shares)	6,450	3,942
Exercisable at end of period (in shares)	1,744
Weighted-average Exercise Price per Option
Outstanding at beginning of period (in dollars per share)	$ 2.12
Granted (in dollars per share)	1.02
Exercised (in dollars per share)	1.50
Canceled or forfeited (in dollars per share)	1.76
Outstanding at end of period (in dollars per share)	1.52	$ 2.12
Exercisable (in dollars per share)	$ 2.42
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted-average Remaining Contractual Life (in years), Outstanding	9 years 1 month 6 days	9 years 1 month 6 days
Weighted-average Remaining Contractual Life (in years), Exercisable	8 years 1 month 6 days
Aggregate Intrinsic Value, Outstanding	$ 680	$ 57
Aggregate Intrinsic Value, Exercisable	$ 84

SHARE-BASED COMPENSATION - Weighted-Average Inputs and Assumptions (Details)	9 Months Ended
	Sep. 30, 2019 $ / shares
Share-based Payment Arrangement [Abstract]
Fair value of common stock (in dollars per share)	$ 0.69
Exercise price (in dollars per share)	$ 1.02
Expected term (in years)	5 years 11 months 23 days
Risk-free interest rate	2.10%
Expected volatility	78.10%
Dividend yield	0.00%

EMPLOYEE BENEFIT PLANS (Details) - USD ($) shares in Thousands	9 Months Ended
	Sep. 30, 2019	Feb. 28, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Defined contribution retirement plan, maximum employee contribution deferred	100.00%
Discretionary match per participating employee, maximum	$ 4,000
2014 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for issuance (in shares)		200
Common stock purchase price, discount rate	15.00%
Common stock available for sale (in shares)	28

LICENSE AGREEMENT WITH ROCHE (Details) - USD ($)			3 Months Ended		7 Months Ended	9 Months Ended
LICENSE AGREEMENT WITH ROCHE (Details) - USD ($)	Jan. 01, 2018	Jun. 10, 2016	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2016	Sep. 30, 2019	Sep. 30, 2018
Organization And Basis Of Presentation [Line Items]
Adjustments to transaction price			$ 0	$ 0		$ 0	$ 0
Revenue recognized			$ 0	$ 0		$ 0	$ 0
Roche
Organization And Basis Of Presentation [Line Items]
Revenue recognized, transaction price	$ 30,000,000
Roche
Organization And Basis Of Presentation [Line Items]
Up-front license fee					$ 7,500,000
Amount payable upon achievement of specified milestones					$ 22,500,000
Additional up-front fee		$ 240,000,000
Roche \| First Indication
Organization And Basis Of Presentation [Line Items]
Amount payable upon achievement of specified milestones		175,000,000
Roche \| Collaborative Arrangement, Revenue Based on Development Milestone
Organization And Basis Of Presentation [Line Items]
Amount payable upon achievement of specified milestones		50,000,000
Roche \| Collaborative Arrangement, Revenue Based on Regulatory Milestone
Organization And Basis Of Presentation [Line Items]
Amount payable upon achievement of specified milestones		50,000,000
Roche \| Collaborative Arrangement, Revenue Based on Commercialization Milestone
Organization And Basis Of Presentation [Line Items]
Amount payable upon achievement of specified milestones		75,000,000
Roche \| Second Indication
Organization And Basis Of Presentation [Line Items]
Amount payable upon achievement of specified milestones		$ 65,000,000
Roche \| EBI-031 \| Minimum
Organization And Basis Of Presentation [Line Items]
Royalty rate (in percentage)		7.50%
Roche \| EBI-031 \| Maximum
Organization And Basis Of Presentation [Line Items]
Royalty rate (in percentage)		15.00%
Roche \| IL-6
Organization And Basis Of Presentation [Line Items]
Royalty rate (in percentage)		50.00%

RELATED PARTY TRANSACTIONS (Details) - Affiliate of Former Director $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) option	Sep. 30, 2018 USD ($)
Protoden Intellectual Property
Related Party Transaction [Line Items]
Amount of related party transaction			$ 100	$ 100
Annual fee under license agreement			$ 100
Lease Facility In Winnipeg, Manitoba
Related Party Transaction [Line Items]
Lease term	5 years		5 years
Renewal option \| option			1
Lease renewal term	5 years		5 years
Amount of related party transaction	$ 76	$ 78	$ 222	$ 239

SUBSEQUENT EVENT - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended				9 Months Ended
	Oct. 28, 2019	Oct. 31, 2019	Jun. 30, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Oct. 27, 2019	Dec. 31, 2018	Nov. 30, 2017
Subsequent Event [Line Items]
Number of warrants issued (in shares)			20,400,000			8,000,000
Exercise price per warrant (in dollars per share)			$ 1.47			$ 1.20
Warrants remaining outstanding (in shares)							26,307,000			9,258,000
Proceeds from exercises of common stock warrants							$ 3,434	$ 7,315
Exercise of stock warrants (in shares)							3,361,000
2017 Warrants
Subsequent Event [Line Items]
Exercise price per warrant (in dollars per share)							$ 0.80
Warrants remaining outstanding (in shares)							492,000			1,992,000
Exercise of stock warrants (in shares)							1,500,000
2018 Warrants
Subsequent Event [Line Items]
Exercise price per warrant (in dollars per share)							$ 1.20
Warrants remaining outstanding (in shares)							5,350,000			7,211,000
Exercise of stock warrants (in shares)							1,861,000
Common Stock
Subsequent Event [Line Items]
Exercise of stock warrants (in shares)			3,361,115	50,000	8,294,718	420,778	3,400,000	8,700,000
Common Stock \| 2017 Warrants
Subsequent Event [Line Items]
Number of warrants issued (in shares)											10,000,000
Exercise price per warrant (in dollars per share)											$ 0.80
Warrants remaining outstanding (in shares)											500,000
Subsequent Event
Subsequent Event [Line Items]
Warrants remaining outstanding (in shares)		22,895,000
Exercise of stock warrants (in shares)		3,412,000
Subsequent Event \| 2017 Warrants
Subsequent Event [Line Items]
Exercise price per warrant (in dollars per share)		$ 0.55
Warrants remaining outstanding (in shares)		487,000
Exercise of stock warrants (in shares)		5,000
Subsequent Event \| 2018 Warrants
Subsequent Event [Line Items]
Exercise price per warrant (in dollars per share)		$ 0.95
Warrants remaining outstanding (in shares)		1,943,000
Exercise of stock warrants (in shares)		3,407,000
Subsequent Event \| 2018 Warrant Amendment, Amendment to Securities Purchase Agreement
Subsequent Event [Line Items]
Minimum percentage of securities issued	50.10%
Subsequent Event \| Common Stock \| 2017 Warrants
Subsequent Event [Line Items]
Exercise price per warrant (in dollars per share)	$ 0.55	$ 0.55							$ 0.80
Subsequent Event \| Common Stock \| 2018 Warrants
Subsequent Event [Line Items]
Exercise price per warrant (in dollars per share)	$ 0.60	$ 0.95							$ 1.20
Proceeds from exercises of common stock warrants	$ 2,000
Exercise of stock warrants (in shares)	3,400,000

SUBSEQUENT EVENT (Details) - $ / shares shares in Thousands	1 Months Ended	9 Months Ended
SUBSEQUENT EVENT (Details) - $ / shares shares in Thousands	Oct. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2018
Subsequent Event [Line Items]
Exercise price per warrant (in dollars per share)			$ 1.47	$ 1.20
Warrant Or Right Outstanding [Roll Forward]
Warrants outstanding, beginning balance (in shares)	26,307	9,258
Warrants Exercised (in shares)		(3,361)
Warrants outstanding, ending balance (in shares)		26,307
Warrants, Expiring June 2020
Subsequent Event [Line Items]
Exercise price per warrant (in dollars per share)		$ 1.47
Warrant Or Right Outstanding [Roll Forward]
Warrants outstanding, beginning balance (in shares)	20,410	0
Warrants Exercised (in shares)		0
Warrants outstanding, ending balance (in shares)		20,410
Warrants, Expiring March 2023
Subsequent Event [Line Items]
Exercise price per warrant (in dollars per share)		$ 1.20
Warrant Or Right Outstanding [Roll Forward]
Warrants outstanding, beginning balance (in shares)	5,350	7,211
Warrants Exercised (in shares)		(1,861)
Warrants outstanding, ending balance (in shares)		5,350
Warrants, Expiring November 2022
Subsequent Event [Line Items]
Exercise price per warrant (in dollars per share)		$ 0.80
Warrant Or Right Outstanding [Roll Forward]
Warrants outstanding, beginning balance (in shares)	492	1,992
Warrants Exercised (in shares)		(1,500)
Warrants outstanding, ending balance (in shares)		492
Warrants, Expiring November 2024, Issued May 2015
Subsequent Event [Line Items]
Exercise price per warrant (in dollars per share)		$ 11.83
Warrant Or Right Outstanding [Roll Forward]
Warrants outstanding, beginning balance (in shares)	28	28
Warrants Exercised (in shares)		0
Warrants outstanding, ending balance (in shares)		28
Warrants, Expiring November 2024, Issued November 2014
Subsequent Event [Line Items]
Exercise price per warrant (in dollars per share)		$ 11.04
Warrant Or Right Outstanding [Roll Forward]
Warrants outstanding, beginning balance (in shares)	27	27
Warrants Exercised (in shares)		0
Warrants outstanding, ending balance (in shares)		27
Subsequent Event
Warrant Or Right Outstanding [Roll Forward]
Warrants Exercised (in shares)	(3,412)
Warrants outstanding, ending balance (in shares)	22,895
Subsequent Event \| Warrants, Expiring June 2020
Subsequent Event [Line Items]
Exercise price per warrant (in dollars per share)	$ 1.47
Warrant Or Right Outstanding [Roll Forward]
Warrants Exercised (in shares)	0
Warrants outstanding, ending balance (in shares)	20,410
Subsequent Event \| Warrants, Expiring March 2023
Subsequent Event [Line Items]
Exercise price per warrant (in dollars per share)	$ 0.95
Warrant Or Right Outstanding [Roll Forward]
Warrants Exercised (in shares)	(3,407)
Warrants outstanding, ending balance (in shares)	1,943
Subsequent Event \| Warrants, Expiring November 2022
Subsequent Event [Line Items]
Exercise price per warrant (in dollars per share)	$ 0.55
Warrant Or Right Outstanding [Roll Forward]
Warrants Exercised (in shares)	(5)
Warrants outstanding, ending balance (in shares)	487
Subsequent Event \| Warrants, Expiring November 2024, Issued May 2015
Subsequent Event [Line Items]
Exercise price per warrant (in dollars per share)	$ 11.83
Warrant Or Right Outstanding [Roll Forward]
Warrants Exercised (in shares)	0
Warrants outstanding, ending balance (in shares)	28
Subsequent Event \| Warrants, Expiring November 2024, Issued November 2014
Subsequent Event [Line Items]
Exercise price per warrant (in dollars per share)	$ 11.04
Warrant Or Right Outstanding [Roll Forward]
Warrants Exercised (in shares)	0
Warrants outstanding, ending balance (in shares)	27