Aceragen (ACGN) 10-Q 2 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	Apr. 30, 2019
Document and Entity Information
Entity Registrant Name	IDERA PHARMACEUTICALS, INC.
Trading Symbol	IDRA
Entity Central Index Key	0000861838
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		28,021,756
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1

CONDENSED BALANCE SHEETS

CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 24,198	$ 71,431
Short-term investments	35,666
Prepaid expenses and other current assets	1,736	1,376
Total current assets	61,600	72,807
Property and equipment, net	176	207
Operating lease right-of-use asset	216
Other assets	9	9
Total assets	62,001	73,023
Current liabilities:
Accounts payable	895	1,134
Accrued expenses	5,179	7,884
Operating lease liability	202
Total current liabilities	6,276	9,018
Operating lease liability, net of current portion	35
Other liabilities	18	11
Total liabilities	6,329	9,029
Commitments and contingencies
Stockholders' equity:
Common stock, $0.001 par value, Authorized — 70,000 shares; Issued and outstanding — 28,008 and 27,188 shares at March 31, 2019 and December 31, 2018, respectively	28	27
Additional paid-in capital	730,991	728,342
Accumulated deficit	(675,349)	(664,375)
Accumulated other comprehensive income	2
Total stockholders' equity	55,672	63,994
Total liabilities and stockholders' equity	62,001	73,023
Series A Preferred Stock
Stockholders' equity:
Preferred stock, $0.01 par value, Authorized — 5,000 shares: Series A convertible preferred stock; Designated — 1,500 shares, Issued and outstanding — 1 share

CONDENSED BALANCE SHEETS (Paren

CONDENSED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2019	Dec. 31, 2018
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	70,000,000	70,000,000
Common stock, shares issued	28,008,000	27,188,000
Common stock, shares outstanding	28,008,000	27,188,000
Series A Preferred Stock
Preferred stock, shares designated	1,500,000	1,500,000
Preferred stock, shares issued	1,000	1,000
Preferred stock, shares outstanding	1,000	1,000

CONDENSED STATEMENTS OF OPERATI

CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS
Alliance revenue		$ 255
Operating expenses:
Research and development	$ 8,102	13,556
General and administrative	3,143	3,481
Merger-related costs, net		3,498
Restructuring costs	131
Total operating expenses	11,376	20,535
Loss from operations	(11,376)	(20,280)
Other income (expense):
Interest income	404	211
Interest expense		(7)
Foreign currency exchange loss	(2)	(19)
Net loss	$ (10,974)	$ (20,095)
Net loss per share applicable to common stockholders - basic and diluted (Note 12)	$ (0.40)	$ (0.81)
Weighted-average number of common shares used in computing net loss per share applicable to common stockholders - basic and diluted	27,676	24,879
Comprehensive loss:
Net loss	$ (10,974)	$ (20,095)
Unrealized gain on available-for-sale securities	2
Total other comprehensive income	2
Comprehensive loss	$ (10,972)	$ (20,095)

CONDENSED STATEMENTS OF CASH FL

CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash Flows from Operating Activities:
Net loss	$ (10,974)	$ (20,095)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	1,016	1,589
Issuance of common stock for services rendered	23	23
Accretion of discounts on short-term investments	(181)
Unrealized gain on available-for-sale securities	2
Depreciation and amortization expense	35	169
Gain on disposal of property and equipment	(8)
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(576)	1,341
Accounts payable, accrued expenses, and other liabilities	(2,694)	2,416
Deferred revenue		(190)
Net cash used in operating activities	(13,357)	(14,747)
Cash Flows from Investing Activities:
Purchases of available-for-sale securities	(35,485)
Proceeds from the sale of property and equipment	8
Purchases of property and equipment	(4)	(14)
Net cash used in investing activities	(35,481)	(14)
Cash Flows from Financing Activities:
Proceeds from equity financings, net of issuance costs	1,585
Proceeds from employee stock purchases	26	81
Proceeds from exercise of common stock options and warrants		9,591
Payments on note payable		(78)
Other	(6)	(3)
Net cash provided by financing activities	1,605	9,591
Net decrease in cash and cash equivalents	(47,233)	(5,170)
Cash, cash equivalents and restricted cash, beginning of period	71,431	112,940
Cash, cash equivalents and restricted cash, end of period	$ 24,198	$ 107,770

CONDENSED STATEMENTS OF STOCKHO

CONDENSED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive (Loss)/Income	Total
Beginning balance at Dec. 31, 2017	$ 24	$ 712,165	$ (604,494)		$ 107,695
Beginning balance, shares at Dec. 31, 2017	24,453
Issuance of common stock under employee stock purchase plan		81			81
Issuance of common stock under employee stock purchase plan, shares	7
Issuance of common stock upon exercise of common stock warrants	$ 3	9,588			9,591
Issuance of common stock upon exercise of common stock warrants, shares	2,551
Issuance of common stock for services rendered		23			23
Issuance of common stock for services rendered, shares	1
Stock-based compensation		1,589			1,589
Net loss			(20,095)		(20,095)
Ending balance at Mar. 31, 2018	$ 27	723,446	(624,589)		98,884
Ending balance, shares at Mar. 31, 2018	27,012
Beginning balance at Dec. 31, 2018	$ 27	728,342	(664,375)		$ 63,994
Beginning balance, shares at Dec. 31, 2018	27,188				27,188,000
Sale of common stock, net of issuance costs	$ 1	1,584			$ 1,585
Sale of common stock, net of issuance costs (in shares)	533
Issuance of commitment shares (in shares)	270
Issuance of common stock under employee stock purchase plan		26			26
Issuance of common stock under employee stock purchase plan, shares	11
Issuance of common stock for services rendered		23			23
Issuance of common stock for services rendered, shares	6
Stock-based compensation		1,016			1,016
Unrealized gain on marketable securities				$ 2	2
Net loss			(10,974)		(10,974)
Ending balance at Mar. 31, 2019	$ 28	$ 730,991	$ (675,349)	$ 2	$ 55,672
Ending balance, shares at Mar. 31, 2019	28,008				28,008,000

Business and Organization

Business and Organization	3 Months Ended
	Mar. 31, 2019
Business and Organization
Business and Organization	Note 1. Business and Organization Business Overview Idera Pharmaceuticals, Inc. (“Idera” or the “Company”), a Delaware corporation, is a clinical-stage biopharmaceutical company with a business strategy focused on the clinical development, and ultimately the commercialization, of drug candidates for both oncology and rare disease indications characterized by small, well-defined patient populations with serious unmet medical needs. The Company’s current focus is on its Toll-like receptor, or TLR, agonist, tilsotolimod (IMO-2125), for oncology. The Company believes it can develop and commercialize targeted therapies on its own. To the extent the Company seeks to develop drug candidates for broader disease indications, it has entered into and may explore additional collaborative alliances to support development and commercialization. Liquidity and Financial Condition As of March 31, 2019, the Company had an accumulated deficit of $675.3 million and a cash, cash equivalents and investments balance of $59.9 million. The Company expects to incur substantial operating losses in future periods and will require additional capital as it seeks to advance tilsotolimod and any future drug candidates through development to commercialization. The Company does not expect to generate product revenue, sales-based milestones or royalties until the Company successfully completes development of and obtains marketing approval for The Company believes, based on management’s current operating plan, that its existing balance of cash, cash equivalents and investments on hand as of March 31, 2019 is sufficient to enable the Company to continue as a going concern through the one-year period subsequent to the filing date of this Quarterly Report on Form 10-Q. Further, management has concluded that it is probable that management’s plans can be effectively implemented and will mitigate the relevant conditions that raise substantial doubt about the Company’s ability to continue as a going concern while not impeding the advancement of its drug development. These plans may also include the possible deferral of certain operating expenses unless additional capital is received. The Company has and will continue to evaluate available alternatives to extend its operations beyond this date. Reverse Stock Split On July 27, 2018, the Company effected a 1-for-8 reverse stock split of the Company's outstanding shares of common stock, as authorized at a special meeting of stockholders on June 20, 2018. All share and per share amounts of common stock, options and warrants in the accompanying financial statements and notes thereto have been retroactively adjusted for all periods presented to reflect the reverse stock split.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2019
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	Note 2. Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited financial statements included herein have been prepared by the Company in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). Accordingly, certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. In the opinion of management, all adjustments, consisting of normal recurring adjustments, and disclosures considered necessary for a fair presentation of interim period results have been included. Interim results for the three months ended March 31, 2019 are not necessarily indicative of results that may be expected for the year ending December 31, 2019. For further information, refer to the financial statements and footnotes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2018 (“2018 Form 10-K”), which was filed with the SEC on March 6, 2019. Reclassifications The prior year financial statements contain certain reclassifications to the results of operations for the three months ended March 31, 2018 to conform to the current year presentation and presentation for the year ended December 31, 2018 included in the Company’s 2018 Form 10-K. Merger-related costs of approximately $3.5 million were reclassified from general and administrative expenses to merger-related costs, net for the three months ended March 31, 2018. Cash and Cash Equivalents The Company considers all highly liquid investments with maturities of 90 days or less when purchased to be “cash equivalents.” Cash and cash equivalents at March 31, 2019 and December 31, 2018 consisted of cash, commercial paper and money market funds. Financial Instruments The fair value of the Company’s financial instruments is determined and disclosed in accordance with the three-tier fair value hierarchy specified in Note 3. The Company is required to disclose the estimated fair values of its financial instruments. As of March 31, 2019 and December 31, 2018, the Company’s financial instruments consisted of cash, cash equivalents, investments and receivables and the estimated fair values of such financial instruments approximated their carrying values. As of March 31, 2019, the Company did not have any derivatives, hedging instruments or other similar financial instruments. Revenue Recognition In accordance with Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers , the Company recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. The Company’s revenues have primarily been generated through collaborative research, development and/or commercialization agreements. The terms of these agreements may include payment to the Company of one or more of the following: nonrefundable, up-front license fees; research, development and commercial milestone payments; and other contingent payments due based on the activities of the counterparty or the reimbursement by licensees of costs associated with patent maintenance. Each of these types of revenue are recorded as Alliance revenues in the Company’s statement of operations. See Note 8, “Collaboration and License Agreements” for additional details surrounding the Company’s collaboration arrangements. Note 2. Summary of Significant Accounting Policies (Continued) Income Taxes In accordance with ASC 270, Interim Reporting , and ASC 740, Income Taxes , the Company is required at the end of each interim period to determine the best estimate of its annual effective tax rate and then apply that rate in providing for income taxes on a current year-to-date (interim period) basis. For the three months ended March 31, 2019 and 2018, the Company recorded no tax expense or benefit due to the expected current year loss and its historical losses. The Company has not recorded its net deferred tax asset as of either March 31, 2019 or December 31, 2018 because it maintained a full valuation allowance against all deferred tax assets as of these dates as management has determined that it is not more likely than not that the Company will realize these future tax benefits. As of March 31, 2019 and December 31, 2018, the Company had no uncertain tax positions. New Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB and rules are issued by the SEC that the Company has or will adopt as of a specified date. Unless otherwise noted, management does not believe that any other recently issued accounting pronouncements issued by the FASB or guidance issued by the SEC had, or is expected to have, a material impact on the Company’s present or future financial statements. Recently Adopted Accounting Pronouncements In February 2016, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2016-02, Leases (Topic 842) (“ASU 2016-02”). ASU 2016-02 requires organizations that lease assets, with lease terms of more than 12 months, to recognize on the balance sheet the assets and liabilities for the rights and obligations created by those leases. Consistent with GAAP, the recognition, measurement and presentation of expenses and cash flows arising from a lease by a lessee will depend primarily on its classification as a finance or operating lease. However, unlike current GAAP which requires only capital leases to be recognized on the balance sheet, ASU No. 2016-02 requires both types of leases to be recognized on the balance sheet. This guidance was applicable to the Company's fiscal year beginning January 1, 2019, and the Company adopted ASU 2016-02 in the first quarter of 2019 using the alternative modified retrospective transition method, which allowed the Company to apply the new lease standard to the beginning of the 2019 period and did not require adjusting comparative period financial information. Additionally, the Company elected the package of practical expedients to not reassess prior conclusions related to contracts containing leases, lease classification and initial direct costs. As a result of adopting ASU 2016-02, the primary impact on the Company’s financial statements was the recognition of a right-of-use asset and corresponding liability of approximately $0.3 million on its balance sheet as of January 1, 2019 related to its existing Exton, PA facility operating lease. In June 2018, the FASB issued ASU No. 2018-07, Compensation – Stock Compensation (Topic 718) (“ASU 2018-07”) . ASU 2018-07 simplifies the accounting for nonemployee share-based payment transactions and was adopted by the Company in the first quarter of 2019. The adoption of this ASU did not have a material impact on the Company’s financial statements.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2019
Fair Value Measurements
Fair Value Measurements	Note 3. Fair Value Measurements Assets and Liabilities Measured at Fair Value on a Recurring Basis The Company applies the guidance in ASC 820, Fair Value Measurement , to account for financial assets and liabilities measured on a recurring basis. Fair value is measured at the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that is determined based on assumptions that market participants would use in pricing an asset or liability. The Company uses a fair value hierarchy, which distinguishes between assumptions based on market data (observable inputs) and an entity's own assumptions (unobservable inputs). The guidance requires that fair value measurements be classified and disclosed in one of the following three categories: · Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities; · Level 2: Quoted prices in markets that are not active or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability; and · Level 3: Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity). Determining which category an asset or liability falls within the hierarchy requires significant judgment. The Company evaluates its hierarchy disclosures each reporting period. There were no transfers between Level 1, 2 and 3 during the three months ended March 31, 2019. The table below presents the assets and liabilities measured and recorded in the financial statements at fair value on a recurring basis at March 31, 2019 and December 31, 2018 categorized by the level of inputs used in the valuation of each asset and liability: March 31, 2019 (In thousands) Total Level 1 Level 2 Level 3 Assets Cash $ 221 $ 221 $ — $ — Money market funds 18,580 18,580 — — Other cash equivalents – commercial paper 5,397 — 5,397 — Short-term investments – commercial paper 17,772 — 17,772 — Short-term investments – U.S. treasury bills 17,894 17,894 — — Total assets $ 59,864 $ 36,695 $ 23,169 $ — Total liabilities $ — $ — $ — $ — December 31, 2018 (In thousands) Total Level 1 Level 2 Level 3 Assets Cash $ 8,446 $ 8,446 $ — $ — Money market funds 61,177 61,177 — — Other cash equivalents – commercial paper 1,808 — 1,808 — Total assets $ 71,431 $ 69,623 $ 1,808 $ — Total liabilities $ — $ — $ — $ — The Level 1 assets include money market funds, which are actively traded daily.

Investments

Investments	3 Months Ended
	Mar. 31, 2019
Investments
Investments	Note 4. Investments The Company ’s available-for-sale investments at fair value consisted of the following at March 31, 2019: March 31, 2019 Gross Gross Estimated Unrealized Unrealized Fair (In thousands) Cost (Losses) Gains Value Short-term investments – commercial paper $ 17,772 $ — $ — $ 17,772 Short-term investments – U.S. treasury bills 17,892 — 2 17,894 Total short-term investments $ 35,664 $ — $ 2 $ 35,666 Total investments $ 35,664 $ — $ 2 $ 35,666 The Company had no realized gains or losses from the sale of investments in available-for-sale securities in each of the three months ended March 31, 2019 and 2018. There were no losses or other-than-temporary declines in value included in “Interest income”

Property and Equipment

Property and Equipment	3 Months Ended
	Mar. 31, 2019
Property and Equipment
Property and Equipment	Note 5. Property and Equipment At March 31, 2019 and December 31, 2018, property and equipment, net, consisted of the following: March 31, December 31, (In thousands) 2019 2018 Leasehold improvements $ 107 $ 104 Laboratory equipment and other 762 767 Total property and equipment, at cost 869 871 Less: Accumulated depreciation and amortization 693 664 Property and equipment, net $ 176 $ 207 Depreciation and amortization expense on property and equipment was less than $0.1 million during the three months ended March 31, 2019 and approximately $0.2 million during the three months ended March 31, 2018. There were no non-cash property additions during each of the three months ended March 31, 2019 and 2018.

Accrued Expenses

Accrued Expenses	3 Months Ended
	Mar. 31, 2019
Accrued Expenses
Accrued Expenses	Note 6. Accrued Expenses At March 31, 2019 and December 31, 2018, accrued expenses consisted of the following: March 31, December 31, (In thousands) 2019 2018 Payroll and related costs $ 982 $ 1,962 Clinical and nonclinical trial expenses 2,908 3,958 Professional and consulting fees 329 605 Restructuring expenses 823 1,147 Other 137 212 Total accrued expenses $ 5,179 $ 7,884 Included in accrued Payroll and related costs as of March 31, 2019 and December 31, 2018 is $0.4 million and $0.7 million, respectively, of salary continuation severance benefits to be paid in equal installments through October 31, 2019 to former executives.

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2019
Stockholders' Equity
Stockholders' Equity	Note 7. Stockholders’ Equity Equity Financings Common Stock Purchase Agreement On March 4, 2019, the Company entered into a Purchase Agreement with Lincoln Park Capital Fund, LLC (“Investor”), pursuant to which, upon the terms and subject to the conditions and limitations set forth therein, Investor has committed to purchase an aggregate of $35.0 million of shares of Company common stock from time to time at the Company’s sole discretion (the “Purchase Agreement”). As consideration for entering into the Purchase Agreement, the Company issued 269,749 shares of Company common stock to Investor as a commitment fee (the “Commitment Shares”). The closing price of the Company’s common stock on March 4, 2019 was $2.84 and the Company did not receive any cash proceeds from the issuance of the Commitment Shares. Accordingly, there was no net impact to total stockholders’ equity as a result of the issuance. Additionally, no shares were sold to Investor under the Purchase Agreement through March 31, 2019. "At-The-Market" Equity Program In November 2018, the Company entered into an Equity Distribution Agreement (the “ATM Agreement”) with JMP Securities LLC (“JMP”) pursuant to which the Company may issue and sell shares of its common stock having an aggregate offering price of up to $50.0 million (the “Shares”) through JMP as its agent. Subject to the terms and conditions of the Agreement, JMP will use its commercially reasonable efforts to sell the Shares from time to time, based upon the Company’s instructions, by methods deemed to be an “at the market offering” as defined in Rule 415(a)(4) promulgated under the Securities Act of 1933, as amended, or if specified by the Company, by any other method permitted by law, including but not limited to in negotiated transactions. The Company has no obligation to sell any of the Shares, and the Company or JMP may at any time suspend sales under the ATM Agreement or terminate the ATM Agreement. JMP is entitled to a fixed commission of 3.0% of the gross proceeds from Shares sold. During the three months ended March 31, 2019, the Company sold 532,700 Shares pursuant to the ATM Agreement resulting in net proceeds, after deduction of commissions and other offering expenses, of $1.6 million. Common Stock Warrants In connection with various financing transactions, the Company has issued warrants to purchase shares of the Company’s common stock. The Company accounts for common stock warrants as equity instruments, derivative liabilities or liabilities, depending on the specific terms of the warrant agreement. As of March 31, 2019 and December 31, 2018, all of the Company’s outstanding common stock warrants were equity-classified. The following table summarizes outstanding warrants to purchase shares of the Company’s common stock as of March 31, 2019 and December 31, 2018: Number of Shares March 31, December 31, Weighted-Average Description 2019 2018 Exercise Price Expiration Date Issued in May 2013 financing (pre-funded) 1,977,041 1,977,041 $ 0.08 May 2020 Issued in September 2013 financing (pre-funded) 521,997 521,997 $ 0.08 Sep 2020 Issued in February 2014 financing (pre-funded) 269,844 269,844 $ 0.08 Feb 2021 Total 2,768,882 2,768,882 The table below is a summary of the Company's warrant activity for the three months ended March 31, 2019: Number of Weighted-Average Warrants Exercise Price Outstanding at December 31, 2018 2,768,882 $ 0.08 Issued — — Exercised — — Expired — — Outstanding at March 31, 2019 2,768,882 $ 0.08

Collaboration and License Agree

Collaboration and License Agreements	3 Months Ended
	Mar. 31, 2019
Collaboration and License Agreements
Collaboration and License Agreements	Note 8. Collaboration and License Agreements Collaboration with Vivelix In November 2016, the Company entered into an exclusive license and collaboration agreement with Vivelix pursuant to which the Company granted Vivelix worldwide rights to develop and market IMO-9200, an antagonist of TLR7, TLR8, and TLR9, for non-malignant gastrointestinal disorders, and certain back-up compounds to IMO-9200 (the “Vivelix Agreement”). The Company was previously developing IMO-9200 for potential use in selected autoimmune disease indications. However, the Company determined not to proceed with internal development of IMO-9200 because the large autoimmune disease indications for which IMO-9200 had been developed did not fit within the strategic focus of the Company. Under the terms of the Vivelix Agreement, Vivelix was solely responsible for the development and commercialization of IMO-9200 and any designated back-up compounds. In connection with the Vivelix Agreement, Idera also transferred certain drug material to Vivelix for Vivelix’s use in its development activities. Under the terms of the Vivelix Agreement, the Company received an upfront, non-refundable fee of $15 million and was eligible for future IMO-9200 related development, regulatory and sales milestone payments and sales-based royalties. However, on March 4, 2019, the Company and Vivelix mutually agreed to terminate the Vivelix Agreement. Accordingly, the Company is no longer eligible to receive any future milestone or royalty-based payments and all rights previously granted to Vivelix with respect to IMO-9200 and certain back-up compounds to IMO-9200 reverted back to the Company. For the three months ended March 31, 2018, the Company recognized Alliance revenues of less than $0.1 million related to certain research activities performed by the Company at Vivelix’s request, pursuant to the Vivelix Agreement. No such services were performed during the three months ended March 31, 2019. Collaboration with GSK In November 2015, the Company entered into a collaboration and license agreement with GSK to license, research, develop and commercialize pharmaceutical compounds from the Company’s nucleic acid chemistry technology for the treatment of selected targets in renal disease (the “GSK Agreement”). In connection with the GSK Agreement, GSK identified an initial target for the Company to attempt to identify a potential population of development candidates to address such target under a mutually agreed upon research plan. From the population of identified development candidates, GSK may designate one development candidate in its sole discretion to move forward into clinical development. Once GSK designates a development candidate, GSK would be solely responsible for the development and commercialization activities for that designated development candidate. The GSK Agreement also provided GSK with the option to select up to two additional targets at any time during the first two years of the GSK Agreement for further research under mutually agreed upon research plans. Upon selecting additional targets, GSK then had the option to designate one development candidate for each additional target, at which time GSK would have sole responsibility to develop and commercialize each such designated development candidate. GSK did not select any additional targets for research through expiry of the option period. Under the terms of the GSK Agreement, the Company received a $2.5 million upfront, non-refundable, non-creditable cash payment upon the execution of the GSK Agreement. Additionally, as of March 31, 2019, the Company is eligible to receive an additional $18 million in license, research, clinical development and commercialization milestone payments, of which $1 million would be payable by GSK upon the designation of a development candidate from the initial target and $17 million would be payable by GSK upon the achievement of clinical milestones and commercial milestones. In addition, the Company is eligible to receive royalty payments on sales of licensed products following commercialization at varying rates of up to 5% on annual net sales, as defined in the GSK Agreement. For the three months ended March 31, 2018, the Company recognized Alliance revenues of less than $0.1 million related to the amortization of the deferred up-front payment received at inception of the GSK Agreement, over the 36-month anticipated performance period, which concluded in the fourth quarter of 2018. Accordingly, no such revenues were recognized during the three months ended March 31, 2019.

Restructuring Costs

Restructuring Costs	3 Months Ended
	Mar. 31, 2019
Restructuring Costs
Restructuring Costs	Note 9. Restructuring Costs In July 2018, the Company determined to wind-down its discovery operations, reduce the workforce in Cambridge, Massachusetts that supports such operations, and close its Cambridge facility. In connection with the reduction-in-workforce, 18 positions are being eliminated, primarily in the area of discovery, representing approximately 40% of the Company’s employees. Of the 18 positions being eliminated, 15 were effective July 31, 2018 with the remaining expected to be eliminated by the end of the second quarter of 2019. Restructuring-related charges to date are comprised of (i) one-time termination costs in connection with the reduction in workforce, including severance, benefits and related costs, of approximately $3.2 million; (ii) contract termination costs of approximately $0.2 million in connection with the early lease termination for the Cambridge facility; and (iii) non-cash asset impairments of approximately $0.7 million, which includes $0.5 million of fixed asset impairments and $0.2 million in write-offs of facility-related prepaid expenses; offset by (iv) a non-cash gain of approximately $0.4 million related to the write-off of the remaining deferred rent liability associated with the Cambridge facility lease. The following summarizes restructuring-related activity for the three months ended March 31, 2019: (in thousands) Employee Severance Contract Termination Costs Asset Impairments Total Accrued restructuring balance as of December 31, 2018 $ 1,147 $ — $ — $ 1,147 Charges incurred 131 — — 131 Cash payments (437) — — (437) Accrued restructuring balance as of March 31, 2019 $ 841 $ — $ — $ 841 As of March 31, 2019, the short-term portion of the accrued restructuring balance, or $0.8 million, is included in “Accrued expenses” in the accompanying condensed balance sheets. See Note 6. The long-term portion of less than $0.1 million is included within “Other liabilities” in the accompanying condensed balance sheets.

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2019
Stock-Based Compensation
Stock-Based Compensation	Note 10. Stock-Based Compensation As of March 31, 2019, the only equity compensation plans from which the Company may currently issue new awards are the Company’s 2013 Stock Incentive Plan Equity Incentive and Employee Stock Purchase Plans 2013 Stock Incentive Plan The Company's board of dire Note 10. Stock-Based Compensation (Continued) As of March 31, 2019, options to purchase a total of 2,880,400 shares of common stock and 193,625 restricted stock units were outstanding and up to 323,418 shares of common stock remained available for grant under the 2013 Plan. The Company has not made any awards pursuant to other equity incentive plans, including the Existing Plans, since the Company’s stockholders approved the 2013 Plan. As of March 31, 2019, options to purchase a total of 464,247 shares of common stock were outstanding under the 2008 Plan. In addition, as of March 31, 2019, non-statutory stock options to purchase an aggregate of 393,750 shares of common stock were outstanding that were issued outside of the 2013 Plan to certain employees in 2017, 2015 and 2014 pursuant to the Nasdaq inducement grant exception as a material component of new hires’ employment compensation. 2017 Employee Stock Purchase Plan The Company’s board of directors adopted the 2017 ESPP, which was approved by the Company’s stockholders and became effective on June 7, 2017. The 2017 ESPP provides for the issuance of up to 62,500 shares of common stock to participating employees of the Company or its subsidiaries. Participation is limited to employees that would not own 5% or more of the total combined voting power or value of the stock of the Company after the grant. As of March 31, 2019, 21,198 shares remained available for issuance under the 2017 ESPP. For the three months ended March 31, 2019 and 2018, the Company issued 11,096 and 6,702 shares of common stock, respectively, under the 2017 ESPP and received proceeds of less than $0.1 million during each period, as a result of employee stock purchases. Accounting for Stock-based Compensation The Company recognizes non-cash compensation expense for stock-based awards under the Company’s equity incentive plans over an award’s requisite service period, or vesting period, using the straight-line attribution method, based on their grant date fair value determined using the Black-Scholes option-pricing model. The Company also recognizes non-cash compensation for stock purchases made under the 2017 ESPP. T he fair value of the discounted purchases made under the Company’s 2017 ESPP is calculated using the Black-Scholes option-pricing model. The fair value of the look-back provision plus the 15% discount is recognized as compensation expense over each plan period. Total stock-based compensation expense attributable to stock-based payments made to employees and directors and employee stock purchases included in operating expenses in the Company's statements of operations for the three months March 31, 2019 and 2018 was as follows: Three Months Ended March 31, (in thousands) 2019 2018 Stock-based compensation: Research and development Employee Stock Purchase Plans $ 6 $ 22 Equity Incentive Plans 330 556 $ 336 $ 578 General and administrative Employee Stock Purchase Plans $ 6 $ 14 Equity Incentive Plans 674 997 $ 680 $ 1,011 Total stock-based compensation expense $ 1,016 $ 1,589 During the three months ended March 31, 2019 and 2018, the weighted average fair market value of stock options granted was $1.83 and $9.92, respectively. Note 10. Stock-Based Compensation (Continued) The following weighted average assumptions apply to the options to purchase 480,502 and 514,600 shares of common stock granted to employees and directors during the three months ended March 31, 2019 and 2018, respectively: Three Months Ended March 31, 2019 2018 Average risk-free interest rate Expected dividend yield — — Expected lives (years) 3.6 3.8 Expected volatility Weighted average exercise price (per share) $ 3.14 $ 17.92 All options granted during three months ended March 31, 2019 and 2018 were granted at exercise prices equal to the fair market value of the common stock on the dates of grant . Stock Option Activity The following table summarizes stock option activity for the three months ended March 31, 2019: ($ in thousands, except per share data) Stock Weighted-Average Weighted-Average Aggregate Outstanding at December 31, 2018 3,304,531 $ 18.41 6.6 $ — Granted 480,502 3.14 Exercised — — Forfeited (46,636) 13.52 Expired — — Outstanding at March 31, 2019 (1) 3,738,397 $ 16.51 6.7 $ — Exercisable at March 31, 2019 2,136,642 $ 21.64 4.9 $ — (1) Includes both vested stock options as well as unvested stock options for which the requisite service period has not been rendered but that are expected to vest based on achievement of a service condition. The fair value of options that vested during the three months ended March 31, 2019 was $1.6 million. As of March 31, 2019, there was $6.8 million of unrecognized compensation cost related to unvested options, which the Company expects to recognize over a weighted average period of 2.6 years. Restricted Stock Activity The following table summarizes restricted stock activity for the three months ended March 31, 2019: ($ in thousands, except per share data) Number of Shares Weighted-Average Nonvested shares at December 31, 2018 — $ — Granted 194,550 3.14 Cancelled (925) 3.14 Vested — — Nonvested shares at March 31, 2019 193,625 $ 3.14 As of March 31, 2019, there was $0.6 million of unrecognized compensation expense related to the restricted stock units, which is expected to be recognized over a weighted-average period of 3.8 years.

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2019
Related Party Transactions
Related Party Transactions	Note 11. Related Party Transactions Overview of Related Parties Julian C. Baker, a member of the Company’s board of directors until his resignation in September 2018, is a principal of Baker Bros. Advisors LP. Baker Bros. Advisors LP, and certain of its affiliated funds (collectively, “Baker Brothers”) owned approximately 17% of the Company's common stock as of March 31, 2019. Additionally, one of the Company’s directors, Kelvin M. Neu, is an employee of Baker Bros. Advisors, LP as of March 31, 2019. Mr. Neu will resign from the Company’s board of directors effective June 4, 2019. During the three months ended March 31, 2018, Baker Brothers exercised warrants to purchase 2,539,541 shares of the Company’s common stock at an exercise price of $3.76 per share for a total exercise price of approximately $9.5 million. As of March 31, 2019, Baker Brothers held pre-funded warrants to purchase up to 2,768,882 shares of the Company’s common stock at an exercise price of $0.08 per share. Board Fees Paid in Stock Pursuant to the Company’s director compensation program, in lieu of director board and committee fees incurred of less than $0.1 million during both the three months ended March 31, 2019 and 2018, the Company issued 13,719 and 1,668 shares of common stock, respectively, to certain of its directors. Director board and committee fees are paid in arrears (including fees paid in stock) and the number of shares issued was calculated based on the market closing price of the Company’s common stock on the issuance date.

Net Loss per Common Share

Net Loss per Common Share	3 Months Ended
	Mar. 31, 2019
Net Loss per Common Share
Net Loss per Common Share	Note 12. Net Loss per Common Share Basic and diluted net loss per common share applicable to common stockholders is calculated by dividing net loss applicable to common stockholders by the weighted-average number of shares of common stock outstanding during the period, without consideration of common stock equivalents. The Company’s potentially dilutive shares, which include outstanding stock option awards, common stock warrants and convertible preferred stock, are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive. For the three months ended March 31, 2019 and 2018, diluted net loss per common share applicable to common stockholders was the same as basic net loss per common share applicable to common stockholders as the effects of the Company’s potential common stock equivalents are antidilutive. Total antidilutive securities that were excluded from the calculation of diluted net loss per share, due to their anti-dilutive effect, were 6,702,830 and 5,946,315 as of March 31, 2019 and 2018, respectively, and consisted of stock options, preferred stock and warrants.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2019
Subsequent Events.
Subsequent Events	Note 13. Subsequent Events The Company considers events or transactions that occur after the balance sheet date but prior to the issuance of the financial statements to provide additional evidence relative to certain estimates or to identify matters that require additional disclosure. Subsequent to March 31, 2019, the Company out-licensed certain non-core technology to a third-party under which the Company will receive, among other things, approximately $1.4 million in cash during the second quarter of 2019.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2019
Summary of Significant Accounting Policies
Basis of Presentation	Basis of Presentation The accompanying unaudited financial statements included herein have been prepared by the Company in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). Accordingly, certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. In the opinion of management, all adjustments, consisting of normal recurring adjustments, and disclosures considered necessary for a fair presentation of interim period results have been included. Interim results for the three months ended March 31, 2019 are not necessarily indicative of results that may be expected for the year ending December 31, 2019. For further information, refer to the financial statements and footnotes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2018 (“2018 Form 10-K”), which was filed with the SEC on March 6, 2019.
Reclassifications	Reclassifications The prior year financial statements contain certain reclassifications to the results of operations for the three months ended March 31, 2018 to conform to the current year presentation and presentation for the year ended December 31, 2018 included in the Company’s 2018 Form 10-K. Merger-related costs of approximately $3.5 million were reclassified from general and administrative expenses to merger-related costs, net for the three months ended March 31, 2018.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with maturities of 90 days or less when purchased to be “cash equivalents.” Cash and cash equivalents at March 31, 2019 and December 31, 2018 consisted of cash, commercial paper and money market funds.
Financial Instruments	Financial Instruments The fair value of the Company’s financial instruments is determined and disclosed in accordance with the three-tier fair value hierarchy specified in Note 3. The Company is required to disclose the estimated fair values of its financial instruments. As of March 31, 2019 and December 31, 2018, the Company’s financial instruments consisted of cash, cash equivalents, investments and receivables and the estimated fair values of such financial instruments approximated their carrying values. As of March 31, 2019, the Company did not have any derivatives, hedging instruments or other similar financial instruments.
Revenue Recognition	Revenue Recognition In accordance with Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers , the Company recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. The Company’s revenues have primarily been generated through collaborative research, development and/or commercialization agreements. The terms of these agreements may include payment to the Company of one or more of the following: nonrefundable, up-front license fees; research, development and commercial milestone payments; and other contingent payments due based on the activities of the counterparty or the reimbursement by licensees of costs associated with patent maintenance. Each of these types of revenue are recorded as Alliance revenues in the Company’s statement of operations. See Note 8, “Collaboration and License Agreements” for additional details surrounding the Company’s collaboration arrangements.
Income Taxes	Income Taxes In accordance with ASC 270, Interim Reporting , and ASC 740, Income Taxes , the Company is required at the end of each interim period to determine the best estimate of its annual effective tax rate and then apply that rate in providing for income taxes on a current year-to-date (interim period) basis. For the three months ended March 31, 2019 and 2018, the Company recorded no tax expense or benefit due to the expected current year loss and its historical losses. The Company has not recorded its net deferred tax asset as of either March 31, 2019 or December 31, 2018 because it maintained a full valuation allowance against all deferred tax assets as of these dates as management has determined that it is not more likely than not that the Company will realize these future tax benefits. As of March 31, 2019 and December 31, 2018, the Company had no uncertain tax positions.
New Accounting Pronouncements	New Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB and rules are issued by the SEC that the Company has or will adopt as of a specified date. Unless otherwise noted, management does not believe that any other recently issued accounting pronouncements issued by the FASB or guidance issued by the SEC had, or is expected to have, a material impact on the Company’s present or future financial statements. Recently Adopted Accounting Pronouncements In February 2016, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2016-02, Leases (Topic 842) (“ASU 2016-02”). ASU 2016-02 requires organizations that lease assets, with lease terms of more than 12 months, to recognize on the balance sheet the assets and liabilities for the rights and obligations created by those leases. Consistent with GAAP, the recognition, measurement and presentation of expenses and cash flows arising from a lease by a lessee will depend primarily on its classification as a finance or operating lease. However, unlike current GAAP which requires only capital leases to be recognized on the balance sheet, ASU No. 2016-02 requires both types of leases to be recognized on the balance sheet. This guidance was applicable to the Company's fiscal year beginning January 1, 2019, and the Company adopted ASU 2016-02 in the first quarter of 2019 using the alternative modified retrospective transition method, which allowed the Company to apply the new lease standard to the beginning of the 2019 period and did not require adjusting comparative period financial information. Additionally, the Company elected the package of practical expedients to not reassess prior conclusions related to contracts containing leases, lease classification and initial direct costs. As a result of adopting ASU 2016-02, the primary impact on the Company’s financial statements was the recognition of a right-of-use asset and corresponding liability of approximately $0.3 million on its balance sheet as of January 1, 2019 related to its existing Exton, PA facility operating lease. In June 2018, the FASB issued ASU No. 2018-07, Compensation – Stock Compensation (Topic 718) (“ASU 2018-07”) . ASU 2018-07 simplifies the accounting for nonemployee share-based payment transactions and was adopted by the Company in the first quarter of 2019. The adoption of this ASU did not have a material impact on the Company’s financial statements.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2019
Fair Value Measurements
Schedule of assets and liabilities measured and recorded in financial statements at fair value on a recurring basis	March 31, 2019 (In thousands) Total Level 1 Level 2 Level 3 Assets Cash $ 221 $ 221 $ — $ — Money market funds 18,580 18,580 — — Other cash equivalents – commercial paper 5,397 — 5,397 — Short-term investments – commercial paper 17,772 — 17,772 — Short-term investments – U.S. treasury bills 17,894 17,894 — — Total assets $ 59,864 $ 36,695 $ 23,169 $ — Total liabilities $ — $ — $ — $ — December 31, 2018 (In thousands) Total Level 1 Level 2 Level 3 Assets Cash $ 8,446 $ 8,446 $ — $ — Money market funds 61,177 61,177 — — Other cash equivalents – commercial paper 1,808 — 1,808 — Total assets $ 71,431 $ 69,623 $ 1,808 $ — Total liabilities $ — $ — $ — $ —

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 2019
Investments
Schedule of available-for-sale investments at fair value	March 31, 2019 Gross Gross Estimated Unrealized Unrealized Fair (In thousands) Cost (Losses) Gains Value Short-term investments – commercial paper $ 17,772 $ — $ — $ 17,772 Short-term investments – U.S. treasury bills 17,892 — 2 17,894 Total short-term investments $ 35,664 $ — $ 2 $ 35,666 Total investments $ 35,664 $ — $ 2 $ 35,666

Property and Equipment (Tables)

Property and Equipment (Tables)	3 Months Ended
	Mar. 31, 2019
Property and Equipment
Schedule of net property and equipment at cost	March 31, December 31, (In thousands) 2019 2018 Leasehold improvements $ 107 $ 104 Laboratory equipment and other 762 767 Total property and equipment, at cost 869 871 Less: Accumulated depreciation and amortization 693 664 Property and equipment, net $ 176 $ 207

Accrued Expenses (Tables)

Accrued Expenses (Tables)	3 Months Ended
	Mar. 31, 2019
Accrued Expenses
Schedule of accrued expenses	March 31, December 31, (In thousands) 2019 2018 Payroll and related costs $ 982 $ 1,962 Clinical and nonclinical trial expenses 2,908 3,958 Professional and consulting fees 329 605 Restructuring expenses 823 1,147 Other 137 212 Total accrued expenses $ 5,179 $ 7,884

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2019
Stockholders' Equity
Schedule of warrants outstanding and exercisable for purchase of common stock	Number of Shares March 31, December 31, Weighted-Average Description 2019 2018 Exercise Price Expiration Date Issued in May 2013 financing (pre-funded) 1,977,041 1,977,041 $ 0.08 May 2020 Issued in September 2013 financing (pre-funded) 521,997 521,997 $ 0.08 Sep 2020 Issued in February 2014 financing (pre-funded) 269,844 269,844 $ 0.08 Feb 2021 Total 2,768,882 2,768,882
Summary of warrant activity	The table below is a summary of the Company's warrant activity for the three months ended March 31, 2019: Number of Weighted-Average Warrants Exercise Price Outstanding at December 31, 2018 2,768,882 $ 0.08 Issued — — Exercised — — Expired — — Outstanding at March 31, 2019 2,768,882 $ 0.08

Restructuring Costs (Tables)

Restructuring Costs (Tables)	3 Months Ended
	Mar. 31, 2019
Restructuring Costs
Schedule of restructuring costs	(in thousands) Employee Severance Contract Termination Costs Asset Impairments Total Accrued restructuring balance as of December 31, 2018 $ 1,147 $ — $ — $ 1,147 Charges incurred 131 — — 131 Cash payments (437) — — (437) Accrued restructuring balance as of March 31, 2019 $ 841 $ — $ — $ 841

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2019
Stock-Based Compensation
Schedule of stock-based compensation expense attributable to share-based payments made to employees and directors and included in operating expenses	Three Months Ended March 31, (in thousands) 2019 2018 Stock-based compensation: Research and development Employee Stock Purchase Plans $ 6 $ 22 Equity Incentive Plans 330 556 $ 336 $ 578 General and administrative Employee Stock Purchase Plans $ 6 $ 14 Equity Incentive Plans 674 997 $ 680 $ 1,011 Total stock-based compensation expense $ 1,016 $ 1,589
Schedule of weighted average assumptions applied to options	Three Months Ended March 31, 2019 2018 Average risk-free interest rate Expected dividend yield — — Expected lives (years) 3.6 3.8 Expected volatility Weighted average exercise price (per share) $ 3.14 $ 17.92
Schedule of information related to outstanding and exercisable options	($ in thousands, except per share data) Stock Weighted-Average Weighted-Average Aggregate Outstanding at December 31, 2018 3,304,531 $ 18.41 6.6 $ — Granted 480,502 3.14 Exercised — — Forfeited (46,636) 13.52 Expired — — Outstanding at March 31, 2019 (1) 3,738,397 $ 16.51 6.7 $ — Exercisable at March 31, 2019 2,136,642 $ 21.64 4.9 $ — (1) Includes both vested stock options as well as unvested stock options for which the requisite service period has not been rendered but that are expected to vest based on achievement of a service condition.
Schedule of summary of restricted stock activity	($ in thousands, except per share data) Number of Shares Weighted-Average Nonvested shares at December 31, 2018 — $ — Granted 194,550 3.14 Cancelled (925) 3.14 Vested — — Nonvested shares at March 31, 2019 193,625 $ 3.14

Business and Organization (Deta

Business and Organization (Details) $ in Thousands	Jul. 27, 2018	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Business and Organization
Accumulated deficit		$ 675,349	$ 664,375
Cash, cash equivalents and investments		$ 59,900
Reverse stock split conversion ratio	0.125

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Summary of Significant Accounting Policies
Tax expense (benefit)	$ 0	$ 0
Uncertain tax positions	$ 0		$ 0

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - New Accounting Pronouncements (Details) - USD ($) $ in Thousands	Jan. 01, 2019	Feb. 29, 2016	Mar. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle
Lease, Practical Expedients, Package [true false]	true
Operating lease right-of-use asset	$ 300		$ 216
Operating lease liability	$ 300
Minimum
New Accounting Pronouncements or Change in Accounting Principle
Lease term		12 months

Fair Value Measurements - Trans

Fair Value Measurements - Transfers Between Levels (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Fair Value Measurements
Fair value of assets transfers from level 1 to level 2	$ 0
Fair value of assets transfers from level 2 to level 1	0
Fair value of liabilities transfers from level 1 to level 2	0
Fair value of liabilities transfers from level 2 to level 1	0
Fair value of assets transfers into level 3	0
Fair value of assets transfers out of level 3	0
Fair value of liabilities transfers into level 3	0
Fair value of liabilities transfers out of level 3	$ 0

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Other cash equivalents and Short-term investments	$ 35,666
Fair value on a recurring basis
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total Assets	59,864	$ 71,431
Fair value on a recurring basis | Cash
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Cash and Money market funds	221	8,446
Fair value on a recurring basis | Money market funds
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Cash and Money market funds	18,580	61,177
Fair value on a recurring basis | Other cash equivalents – commercial paper
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Other cash equivalents and Short-term investments	5,397	1,808
Fair value on a recurring basis | Short-term investments – commercial paper
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Other cash equivalents and Short-term investments	17,772
Fair value on a recurring basis | Short-term investments – U.S. treasury bills
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Other cash equivalents and Short-term investments	17,894
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) | Fair value on a recurring basis
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total Assets	36,695	69,623
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) | Fair value on a recurring basis | Cash
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Cash and Money market funds	221	8,446
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) | Fair value on a recurring basis | Money market funds
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Cash and Money market funds	18,580	61,177
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) | Fair value on a recurring basis | Short-term investments – U.S. treasury bills
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Other cash equivalents and Short-term investments	17,894
Significant Other Observable Inputs (Level 2) | Fair value on a recurring basis
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total Assets	23,169	1,808
Significant Other Observable Inputs (Level 2) | Fair value on a recurring basis | Other cash equivalents – commercial paper
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Other cash equivalents and Short-term investments	5,397	$ 1,808
Significant Other Observable Inputs (Level 2) | Fair value on a recurring basis | Short-term investments – commercial paper
Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis
Other cash equivalents and Short-term investments	$ 17,772

Investments - Summary of Availa

Investments - Summary of Available-for-Sale Investments at Fair Value (Details) $ in Thousands	Mar. 31, 2019USD ($)
Schedule of Available-for-sale Securities
Cost	$ 35,664
Gross Unrealized Gains	2
Estimated Fair Value	35,666
Short-term investments
Schedule of Available-for-sale Securities
Cost	35,664
Gross Unrealized Gains	2
Estimated Fair Value	35,666
Short-term investments – commercial paper
Schedule of Available-for-sale Securities
Cost	17,772
Estimated Fair Value	17,772
Short-term investments – U.S. treasury bills
Schedule of Available-for-sale Securities
Cost	17,892
Gross Unrealized Gains	2
Estimated Fair Value	$ 17,894

Investments - Additional Inform

Investments - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Investments
Realized gains or losses	$ 0	$ 0
Losses or other-than-temporary declines	$ 0	$ 0

Property and Equipment - Net Pr

Property and Equipment - Net Property and Equipment at Cost (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment
Total property and equipment, at cost	$ 869	$ 871
Less: accumulated depreciation and amortization	693	664
Property and equipment, net	176	207
Leasehold improvements
Property, Plant and Equipment
Total property and equipment, at cost	107	104
Laboratory equipment and other
Property, Plant and Equipment
Total property and equipment, at cost	$ 762	$ 767

Property and Equipment - Deprec

Property and Equipment - Depreciation and Amortization Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Depreciation and amortization expense on property and equipment		$ 200
Non-cash property additions	$ 0	$ 0
Maximum
Depreciation and amortization expense on property and equipment	$ 100

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Payroll and related costs	$ 982	$ 1,962
Clinical and nonclinical trial expenses	2,908	3,958
Professional and consulting fees	329	605
Restructuring expenses	823	1,147
Other	137	212
Total accrued expenses	5,179	7,884
Former Executive
Salary continuation severance benefits	$ 400	$ 700

Stockholders' Equity - Common S

Stockholders' Equity - Common Stock (Details) - USD ($) $ / shares in Units, $ in Millions	Mar. 04, 2019	Nov. 30, 2018	Mar. 31, 2019
Common Stock
Class of Stock
Stock issued (in shares)			533
"At-The-Market" Equity Program
Class of Stock
Stock issued (in shares)			532,700
Net proceeds from offering of common stock			$ 1.6
Percentage of fixed commission expense of gross proceeds of shares sold in ATM agreement		3.00%
"At-The-Market" Equity Program | Common Stock
Class of Stock
Net proceeds from offering of common stock		$ 50
Lincoln Park Capital Fund, LLC (“Investor”)
Class of Stock
Value of shares investor has committed to purchase from time to time at Company’s sole discretion	$ 35
Stock issued (in shares)	269,749
Stock issued (per share)	$ 2.84
Shares issued			0

Stockholders' Equity - Common_2

Stockholders' Equity - Common Stock Warrants (Details) - $ / shares	Mar. 31, 2019	Dec. 31, 2018
Class of Warrant or Right
Number of Warrants	2,768,882	2,768,882
Warrant exercise price per share	$ 0.08	$ 0.08
Expiration Date - May 2020
Class of Warrant or Right
Number of Warrants	1,977,041	1,977,041
Warrant exercise price per share	$ 0.08	$ 0.08
Expiration Date - September 2020
Class of Warrant or Right
Number of Warrants	521,997	521,997
Warrant exercise price per share	$ 0.08	$ 0.08
Expiration Date - February 2021
Class of Warrant or Right
Number of Warrants	269,844	269,844
Warrant exercise price per share	$ 0.08	$ 0.08

Stockholders' Equity - Common_3

Stockholders' Equity - Common Stock Warrant Activity (Details) - $ / shares	Mar. 31, 2019	Dec. 31, 2018
Stockholders' Equity
Warrant exercise price per share	$ 0.08	$ 0.08

Collaboration and License Agr_2

Collaboration and License Agreements (Details) $ in Thousands	1 Months Ended		3 Months Ended
	Nov. 30, 2016USD ($)	Nov. 30, 2015USD ($)person	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Alliance revenue				$ 255
Vivelix
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Alliance revenue			$ 0
Vivelix | Up-front Payment Arrangement
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Upfront payment received under collaboration agreement	$ 15,000
Vivelix | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Alliance revenue				100
GSK Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Number of development candidates | person		1
Number of optional additional targets | person		2
Deferred revenue recognized during the period			0	$ 100
Research period		2 years		36 months
GSK Agreement | Up-front Payment Arrangement
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Upfront payment received under collaboration agreement		$ 2,500
GSK Agreement | License, Research, Clinical Development and Commercialization
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Milestone payments			18,000
GSK Agreement | Research and Development Plans and Designation of Development Candidates
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Milestone payments			1,000
GSK Agreement | Clinical and Commercial Milestones
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Milestone payments			$ 17,000
GSK Agreement | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions
Maximum royalty percentage on net sales			5.00%

Restructuring Costs (Details)

Restructuring Costs (Details) $ in Thousands	1 Months Ended
	Jul. 31, 2018USD ($)employee	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Restructuring costs
Long-term portion of restructuring accrual		$ 18	$ 11
Cambridge, Massachusetts facility operations
Restructuring costs
Number of positions eliminated | employee	15
Percentage of positions eliminated	40.00%
Number of positions eliminated since inception | employee	18
Termination costs in connection with the reduction in workforce, including severance, benefits and related costs	$ 3,200
Non-cash asset impairments	700
Non-cash gain due to write-off of remaining deferred rent liability	400
Expenses associated with lease termination or prepaid expenses	200
Fixed asset impairments	$ 500

Restructuring Costs - Accrual R

Restructuring Costs - Accrual Rollforward (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Restructuring costs
Accrued restructuring balance, beginning of period	$ 1,147
Charges incurred	131
Cash payments	(437)
Accrued restructuring balance, end of period	841
Cambridge, Massachusetts facility operations
Restructuring costs
Restructuring Reserve, Noncurrent	100
Cambridge, Massachusetts facility operations | Employee Severance and Benefits
Restructuring costs
Accrued restructuring balance, beginning of period	1,147
Charges incurred	131
Cash payments	(437)
Accrued restructuring balance, end of period	$ 841

Stock-Based Compensation - Equi

Stock-Based Compensation - Equity Incentive Plans (Details) - shares	Jul. 26, 2013	Mar. 31, 2019	Dec. 31, 2018
Class of Stock
Common stock options outstanding		3,738,397	3,304,531
Options outstanding under earlier plans		464,247
Grant of inducement stock option		393,750
2013 Stock Incentive Plan
Class of Stock
Common shares available for grant	3,153,057	323,418
Maximum number of additional common shares	868,372
Common stock options outstanding		2,880,400
Restricted stock units outstanding		193,625

Stock-Based Compensation - Empl

Stock-Based Compensation - Employee Stock Purchase Plans (Details) - USD ($) $ in Millions	Jun. 07, 2017	Mar. 31, 2019	Mar. 31, 2018
2017 Employee Stock Purchase Plan
Class of Stock
Maximum percentage of total combined voting power or value of the stock of the Company after the grant	5.00%
Common shares available for grant	21,198
2017 Employee Stock Purchase Plan | Maximum
Class of Stock
Common stock shares authorized for issuance under stock purchase plan	62,500
Employee Stock Purchase Plans
Class of Stock
Common stock share issued		11,096	6,702
Proceeds from employee stock purchase plan		$ 0.1	$ 0.1

Stock-Based Compensation - Acco

Stock-Based Compensation - Accounting for Stock-based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award
Percentage of share-based compensation expense	15.00%
Weighted average grant date fair value of options granted during the period (per share)	$ 1.83	$ 9.92
Stock-based compensation	$ 1,016	$ 1,589
Research and development
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation	336	578
Research and development | Employee Stock Purchase Plans
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation	6	22
Research and development | Equity Incentive Plans
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation	330	556
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation	680	1,011
General and administrative | Employee Stock Purchase Plans
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation	6	14
General and administrative | Equity Incentive Plans
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation	$ 674	$ 997

Stock-Based Compensation - Assu

Stock-Based Compensation - Assumptions Used in Determining Fair Value of Stock Options (Details) - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Summary of Significant Accounting Policies
Options to purchase common stock granted to employees and directors	480,502	514,600
Average risk free interest rate	2.40%	2.10%
Dividend rate	0.00%	0.00%
Expected lives (years)	3 years 7 months 6 days	3 years 9 months 18 days
Expected volatility	82.00%	74.90%
Weighted average exercise price of options granted during the period (per share)	$ 3.14	$ 17.92

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Options, Outstanding, Beginning Balance	3,304,531
Granted	480,502
Forfeited	(46,636)
Options, Outstanding, Ending Balance	3,738,397		3,304,531
Exercisable, Ending Balance	2,136,642
Weighted Average Exercise Price, Beginning Balance	$ 18.41
Granted, Weighted Average Exercise Price	3.14	$ 17.92
Forfeited, Weighted Average Exercise Price	13.52
Weighted Average Exercise Price, Ending Balance	16.51		$ 18.41
Exercisable, Weighted Average Exercise Price	$ 21.64
Outstanding, Ending balance, Weighted Average Remaining Contractual Term	6 years 8 months 12 days		6 years 7 months 6 days
Exercisable Ending Balance, Weighted Average Remaining Contractual Term	4 years 10 months 24 days
Fair value of options, vested	$ 1.6
Unrecognized compensation cost related to nonvested stock-based compensation	$ 6.8
Weighted average remaining period over which unrecognized compensation expense will be recognized	2 years 7 months 6 days
Restricted Stock Activity
Unrecognized compensation cost related to nonvested stock-based compensation	$ 0.6
Weighted average remaining period over which unrecognized compensation expense will be recognized	3 years 9 months 18 days

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock Activity (Details) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)$ / sharesshares
Restricted Stock Activity, Weighted-Average Grant Date Fair Value
Unrecognized compensation expense | $	$ 6.8
Weighted average remaining period over which unrecognized compensation expense will be recognized	2 years 7 months 6 days
Restricted Stock Activity
Restricted Stock Activity, Number of Shares
Granted | shares	194,550
Cancelled | shares	(925)
Nonvested shares, Ending Balance | shares	193,625
Restricted Stock Activity, Weighted-Average Grant Date Fair Value
Granted, Weighted-Average Grant Date Fair Value | $ / shares	$ 3.14
Cancelled, Weighted-Average Grant Date Fair Value | $ / shares	3.14
Nonvested shares, Weighted Average Grant Date Fair Value, Ending Balance | $ / shares	$ 3.14
Unrecognized compensation expense | $	$ 0.6
Weighted average remaining period over which unrecognized compensation expense will be recognized	3 years 9 months 18 days

Related Party Transactions - Ov

Related Party Transactions - Overview of Related Parties (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Related Party Transactions
Exercise price of warrants	$ 0.08		$ 0.08
Number of Warrants	2,768,882		2,768,882
Common stock issued in lieu of board fees	13,719	1,668
Maximum
Related Party Transactions
Proceeds from issuance of common stock in lieu of director board and committee fees	$ 0.1	$ 0.1
Common Stock | Board of Director
Related Party Transactions
Ownership percentage	17.00%
Baker Bros. Advisors LP
Related Party Transactions
Number of warrants exercised	2,539,541
Exercise price of warrants	$ 3.76
Proceeds from exercise of warrants	$ 9.5
Baker Bros. Advisors LP | Pre-funded Warrants
Related Party Transactions
Exercise price of warrants	$ 0.08
Number of Warrants	2,768,882

Net Loss per Common Share (Deta

Net Loss per Common Share (Details) - shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Net Loss per Common Share
Total antidilutive securities	6,702,830	5,946,315

Subsequent Events (Details)

Subsequent Events (Details) $ in Millions	3 Months Ended
	Jun. 30, 2019USD ($)
Subsequent Events
Subsequent Events
Investment received from out-licensed certain non-core technology to a third-party	$ 1.4