Phio Pharmaceuticals (PHIO) 10-K 26 Mar 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Mar. 15, 2018	Jun. 30, 2017
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Trading Symbol	RXII
Entity Registrant Name	RXi Pharmaceuticals Corp
Entity Central Index Key	1,533,040
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		2,594,962
Entity Public Float			$ 13,542,277

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 3,581	$ 12,906
Restricted cash	50	50
Prepaid expenses and other current assets	201	150
Total current assets	3,832	13,106
Property and equipment, net of accumulated depreciation of $900 and $831, in 2017 and 2016, respectively	248	114
Notes receivable		150
Other assets	18	27
Total assets	4,098	13,397
Current liabilities:
Accounts payable	511	917
Accrued expenses	1,754	1,625
Total current liabilities	2,265	2,542
Commitments and contingencies (Note 7)
Stockholders' equity:
Preferred stock, par value
Common stock, $0.0001 par value, 100,000,000 shares authorized; 2,429,993 and 1,300,318 shares issued and outstanding at December 31, 2017 and December 31, 2016, respectively	0	0
Additional paid-in capital	80,384	73,429
Accumulated deficit	(78,551)	(66,099)
Total stockholders' equity	1,833	10,855
Total liabilities and stockholders' equity	$ 4,098	13,397
Series B Convertible Preferred Stock [Member]
Stockholders' equity:
Preferred stock, par value		3,525
Total stockholders' equity		$ 3,525

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accumulated depreciation	$ 900	$ 831
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	10,000,000
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	2,429,993	2,429,993
Common stock, shares outstanding	1,300,318	1,300,318
Series B Convertible Preferred Stock [Member]
Preferred stock, shares authorized	0	8,100
Preferred Stock, shares issued	0	5,737
Preferred Stock, shares outstanding	0	5,737

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Revenues	$ 15	$ 19
Operating expenses:
Research and development	5,370	5,415
Acquired in-process research and development	4,696
General and administrative	4,011	3,619
Total operating expenses	14,077	9,034
Operating loss	(14,062)	(9,015)
Other income (expense):
Interest (expense) income, net	(1)	15
Other (expense) income, net	(10)	6
Total other (expense) income, net	(11)	21
Loss before income taxes	(14,073)	(8,994)
Income tax benefit	1,621
Net loss	(12,452)	(8,994)
Accretion of beneficial conversion feature related to Series B Convertible Preferred Stock		(2,075)
Net loss attributable to common stockholders	$ (12,452)	$ (11,069)
Net loss per common share attributable to common stockholders: Basic and diluted	$ (5.52)	$ (16.41)
Weighted average common shares: Basic and diluted	2,257,754	674,608

Statements of Convertible Prefe

Statements of Convertible Preferred Stock and Stockholders' Equity - USD ($) $ in Thousands	Total	Series B Convertible Preferred Stock [Member]	Series C Convertible Preferred Stock [Member]	Common Stock [Member]	Common Stock [Member]Series B Convertible Preferred Stock [Member]	Common Stock [Member]Series C Convertible Preferred Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]
Beginning balance at Dec. 31, 2015	$ 8,890						$ 65,995	$ (57,105)
Beginning balance, shares at Dec. 31, 2015				653,485
Issuance of common stock under Lincoln Park Capital, LLC purchase agreement	152						152
Issuance of common stock under Lincoln Park Capital, LLC purchase agreement, shares				6,500
Issuance of common stock and warrants in connection with 2016 public offering	2,987						2,987
Issuance of common stock under Lincoln Park Capital, LLC purchase agreement, shares				379,777
Issuance of Series B convertible preferred stock and warrants in connection with 2016 public offering	$ 7,064	$ 4,966					2,098
Issuance of Series B convertible preferred stock and warrants in connection with 2016 public offering, shares		8,082
Beneficial conversion feature related to Series B convertible preferred stock		$ (2,075)					2,075
Accretion of beneficial conversion feature related to Series B convertible preferred stock		2,075					(2,075)
Conversions of convertible preferred stock into common stock		$ (1,441)					1,441
Conversions of convertible preferred stock into common stock, shares	0	(2,345)		260,556	260,555
Stock-based compensation expense	$ 756						756
Net loss	(8,994)							(8,994)
Ending balance at Dec. 31, 2016	$ 10,855	$ 3,525					73,429	(66,099)
Ending balance, shares at Dec. 31, 2016	1,300,318			1,300,318
Ending balance, shares at Dec. 31, 2016		5,737
Acquisition of MirImmune Inc.	$ 2,824						2,824
Acquisition of MirImmune Inc, Shares	275,036		1,118,224	275,036
Issuance of common stock under Lincoln Park Capital, LLC purchase agreement	$ 290						290
Issuance of common stock under Lincoln Park Capital, LLC purchase agreement, shares				105,000
Conversions of convertible preferred stock into common stock		$ (3,525)					3,525
Conversions of convertible preferred stock into common stock, shares	0	(5,737)	(1,118,224)		637,445	111,822
Issuance of common stock under employee stock purchase plan	$ 2						2
Issuance of common stock under employee stock purchase plan, shares				372
Stock-based compensation expense	314						314
Net loss	(12,452)							(12,452)
Ending balance at Dec. 31, 2017	$ 1,833						$ 80,384	$ (78,551)
Ending balance, shares at Dec. 31, 2017	1,300,318			2,429,993
Ending balance, shares at Dec. 31, 2017		0

Statements of Convertible Pref6

Statements of Convertible Preferred Stock and Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Common Stock [Member]
Offering costs	$ 74	$ 431
Series B Convertible Preferred Stock [Member]
Offering costs		$ 1,018

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net loss	$ (12,452)	$ (8,994)
Adjustment to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	70	53
Non-cash stock-based compensation expense	314	756
Acquired in-process research and development expense	4,696
Deferred taxes	(1,621)
Value of non-marketable equity securities recognized as revenue	9	(9)
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(51)	161
Accounts payable	(608)	(246)
Accrued expenses	129	519
Net cash used in operating activities	(9,514)	(7,760)
Cash flows from investing activities:
Purchase of short-term investments		(2,000)
Maturities of short-term investments		7,500
Cash acquired in MirImmune Inc. acquisition	100
Issuance of notes receivable		(150)
Cash paid for purchase of property and equipment	(203)	(4)
Net cash (used in) provided by investing activities	(103)	5,346
Cash flows from financing activities:
Net proceeds from the issuance of common stock and/or preferred stock	290	10,203
Proceeds from the issuance of common stock in connection with the employee stock purchase plan	2
Net cash provided by financing activities	292	10,203
Net (decrease) increase in cash, cash equivalents and restricted cash	(9,325)	7,789
Cash, cash equivalents and restricted cash at the beginning of period	12,956	5,167
Cash, cash equivalents and restricted cash at the end of period	3,631	12,956
Supplemental disclosure of non-cash investing and financing activities:
Cancellation of notes receivable	150
Accounts payable assumed	5
Fair value of securities issued	2,824
Series B Convertible Preferred Stock [Member]
Supplemental disclosure of non-cash investing and financing activities:
Fair value of Series B convertible preferred stock beneficial conversion feature		2,075
Accretion of Series B convertible preferred stock		2,075
Conversions of convertible preferred stock into common stock	3,525	$ 1,441
Series C Convertible Preferred Stock [Member]
Supplemental disclosure of non-cash investing and financing activities:
Conversions of convertible preferred stock into common stock	$ 816

Nature of Operations

Nature of Operations	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations	1. Nature of Operations RXi Pharmaceuticals Corporation is a biotechnology company focused on discovering and developing immuno-oncology therapeutics to treat cancer based on its self-delivering RNAi (“ sd-rxRNA ® sd-rxRNA Prior to RXi’s acquisition of MirImmune Inc. (“ MirImmune sd-rxRNA On January 3, 2018, the Board of Directors of the Company approved a 1-for-10 paid-in

Liquidity and Going Concern

Liquidity and Going Concern	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Liquidity and Going Concern	2. Liquidity and Going Concern The Company has limited cash resources, certain limitations under the purchase agreement with Lincoln Park Capital Fund, LLC (“ LPC

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	3. Summary of Significant Accounting Policies Basis of Presentation The accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“ GAAP Principles of Consolidation The consolidated financial statements include the accounts of RXi and its wholly owned subsidiary. All material intercompany accounts have been eliminated in consolidation. Uses of Estimates in Preparation of Financial Statements The preparation of financial statements in accordance with GAAP requires management to make estimates and assumptions that 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. Actual results could differ materially from these estimates. Cash, Cash Equivalents and Restricted Cash The Company considers all highly liquid instruments with an original maturity of three months or less to be cash equivalents. Restricted cash consists of certificates of deposit held by financial institutions as collateral for the Company’s corporate credit cards. The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheet that sum to the total of the same such amounts shown in the statement of cash flows (in thousands): December 31, December 31, 2017 2016 Cash and cash equivalents $ 3,581 $ 12,906 Restricted cash 50 50 Cash, cash equivalents and restricted cash shown in the statement of cash flows $ 3,631 $ 12,956 Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash. The Company maintains cash balances in several accounts with one bank, which at times are in excess of federally insured limits. The Company has established guidelines related to credit ratings and maturities intended to safeguard principal balances and maintain liquidity. The Company’s investments are maintained in accordance with the Company’s investment policy, which defines allowable investments, specifies credit quality standards and limits the exposure of any single issuer. Property and Equipment Property and equipment are stated at cost and depreciated using the straight-line method based on the estimated useful lives of the related assets. The Company provides for depreciation over the assets’ estimated useful lives as follows: Computer equipment 3 years Machinery & equipment 5 years Furniture & fixtures 5 years Leasehold improvements 5 years Depreciation and amortization expense for the years ended December 31, 2017 and 2016 was approximately $70,000 and $53,000, respectively. Derivative Financial Instruments The Company follows the provisions of the Financial Accounting Standards Board (“ FASB ASC Derivatives and Hedging ASC 815 Fair Value of Financial Instruments The carrying amounts reported in the balance sheet for cash equivalents, restricted cash, notes receivable and accounts payable approximate their fair values due to their short-term nature. Impairment of Long-Lived Assets The Company reviews long-lived assets for impairment on an interim basis if an event occurs that might reduce the fair value of such assets below their carrying values. An impairment loss would be recognized based on the difference between the carrying value of the asset and its estimated fair value, which would be determined based on either discounted future cash flows or other appropriate fair value methods. The Company fully impaired its non-marketable Revenue Recognition Revenue is recognized when there is persuasive evidence of an arrangement, the fee is fixed or determinable, delivery has occurred or services have been rendered and collection of the related receivable is reasonably assured. The Company may generate revenue from product sales, license agreements, collaborative research and development arrangements and government grants. Payments received prior to the recognition of revenue are recorded as deferred revenue. Research and Development Expenses Research and development costs relate to salaries, employee benefits, facility-related expenses, supplies, stock-based compensation related to employees and non-employees Preclinical and clinical trial expenses relate to estimates of costs incurred and fees connected with clinical trial sites, third-party clinical research organizations and other preclinical and clinical related activities and include such items as subject-related fees, laboratory work, investigator fees and analysis costs. Costs associated with these expenses are generally payable on the passage of time or when certain milestones are achieved. Expense is recorded during the period incurred or in the period in which a milestone is achieved. In order to ensure that the Company has adequately provided for preclinical and clinical expenses during the proper period, the Company maintains an accrual to cover these expenses. These accruals are assessed on a quarterly basis and are based on such assumptions as expected total cost, the length of the study, timing of subject visits and other information available to us. Actual results may differ from these estimates and could have a material impact on the Company’s reported results. The Company’s historical accrual estimates have not been materially different from its actual costs. Patents and Patent Application Costs Although the Company believes that its patents and underlying technology have continuing value, the amount of future benefits to be derived from the patents is uncertain. Patent costs are, therefore, expensed as research and development costs as incurred. Acquired In-process Assets purchased in asset acquisition transactions are expensed as in-process in-process Stock-based Compensation The Company follows the provisions of the FASB ASC Topic 718, “ Compensation — Stock Compensation ASC 718 non-employee For stock options granted as consideration for services rendered by non-employees, 505-50, Equity Based Payments to Non-Employees Non-employee re-measured non-cash non-employees re-measurements Income Taxes The Company recognizes assets or liabilities for the deferred tax consequences of temporary differences between the tax basis of assets or liabilities and their reported amounts in the financial statements in accordance with the FASB ASC Topic 740, “Accounting for Income Taxes” ASC 740 . Comprehensive Loss The Company’s comprehensive loss is equal to its net loss for all periods presented. Net Loss per Share The Company accounts for and discloses net loss per share attributable to common stockholders in accordance with the FASB ASC Topic 260, “ Earnings per Share.”

Recent Accounting Pronouncement

Recent Accounting Pronouncements	12 Months Ended
	Dec. 31, 2017
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	4. Recent Accounting Pronouncements In May 2014, the FASB issued Accounting Standards Update (“ ASU 2014-09, “Revenue from Contracts with Customers (Topic 606) ” 2014-09 2016-08, “Revenue from Contracts with Customers (Topic 606) – Principal Versus Agent Considerations,” which improves the operability and understandability of the implementation guidance on principal versus agent considerations. In April 2016, the FASB issued ASU 2016-10, 2016-12, In February 2016, the FASB issued ASU 2016-02, right-of-use In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230) — Classification of Certain Cash Receipts and Cash Payments 2016-15 2016-15 In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230) — Restricted Cash,” 2016-18 In January 2017, the FASB issued ASU 2017-01, Business Combinations (Topic 805) — Clarifying the Definition of a Business 2017-01 In May 2017, the FASB issued ASU 2017-09, Compensation — Stock Compensation (Topic 718) — Scope of Modification Accounting 2017-09

MirImmune Inc. Acquisition

MirImmune Inc. Acquisition	12 Months Ended
	Dec. 31, 2017
Research and Development [Abstract]
MirImmune Inc. Acquisition	5. MirImmune Inc. Acquisition In January 2017, the Company entered into a Stock Purchase Agreement (the “ Stock Purchase Agreement RXi Merger Sub Series C Convertible Preferred Stock Upon the closing of the acquisition, the notes receivable from MirImmune outstanding on the Company’s balance sheet as of December 31, 2016 were cancelled. The Company assessed the acquisition of MirImmune under the FASB ASC Topic 805, “ Business Combinations ASC 805 in-process Additionally, the Company assessed the MirImmune acquisition under ASC Topic 740, “ Income Taxes ASC 740 During the year ended December 31, 2017, the Company recorded $4,696,000 in in-process The Company was restricted from converting any of the Series C Convertible Preferred Stock into common stock to the extent that such conversion was not approved by the Company’s stockholders in accordance with the stockholder approval requirements of Nasdaq Marketplace Rule 5635. On June 9, 2017, with the approval of the Company’s stockholders in accordance with the Nasdaq stockholder approval requirements, every ten shares of the Series C Convertible Preferred Stock outstanding were automatically converted into one share of common stock, such that there were no shares of Series C Convertible Preferred Stock issued or outstanding after the conversion. On November 7, 2017, the Company filed a Certificate Eliminating the Series C Convertible Preferred Stock from the Certificate of Incorporation of the Company with the Secretary of State of the State of Delaware. Under the terms of the Stock Purchase Agreement, if certain development or commercial milestones are achieved within two years, the Company will be required to either (i) issue a number of shares of common stock (the “ Milestone Shares The Company assessed the Milestone Shares under the FASB ASC Topic 480, “ Distinguishing Liabilities from Equity ASC 480 in-process

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2017
Payables and Accruals [Abstract]
Accrued Expenses	6. Accrued Expenses Accrued expenses consist of the following, in thousands: December 31, 2017 2016 Compensation and benefits $ 735 $ 745 Clinical development expenses 261 490 Professional fees 167 104 Research and development costs 583 276 Other 8 10 Total accrued expenses $ 1,754 $ 1,625

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. Commitments and Contingencies License Commitments The Company acquires assets under development and enters into research and development arrangements with third parties that often require milestone and royalty payments based on the progress of the asset through development stages. Milestone payments may be required, for example, upon approval of the product for marketing by a regulatory agency. In certain agreements, the Company is required to make royalty payments based upon a percentage of the sales of the products licensed pursuant to such agreements. Because of the contingent nature of these payments, they are not included in the table of contractual obligations shown below (see also Note 12). These arrangements may be material individually, and in the unlikely event that milestones for multiple products covered by these arrangements were reached in the same period, the aggregate charge to expense could be material to the results of operations. In addition, these arrangements often give the Company the discretion to unilaterally terminate development of the product, which would allow the Company to avoid making the contingent payments; however, the Company is unlikely to cease development if the compound successfully achieves clinical testing objectives. The Company’s contractual license obligations that will require future cash payments as of December 31, 2017 are as follows, in thousands: Year Ending December 31, 2018 $ 200 2019 165 2020 165 2021 165 2022 100 Thereafter 700 Total $ 1,495 Operating Leases The Company leases office and laboratory space for its corporate headquarters and primary research facility in Marlborough, Massachusetts. The lease for the office and lab space will expire in March 2019. Monthly rental expense is approximately $9,500, which includes the Company’s pro rata share of annual real estate taxes and operating expenses. Total rent expense under the Company’s operating lease was $115,000 and $117,000 for the years ended December 31, 2017 and 2016, respectively. At December 31, 2017, the Company’s future minimum payments required under operating leases are as follows, in thousands: Year Ending December 31, 2018 $ 120 2019 30 Total $ 150 The Company applies the disclosure provisions of FASB ASC Topic 460, “ Guarantor’s Accounting and Disclosure Requirements for Guarantees, Including Indirect Guarantees of Indebtedness of Others ASC 460

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Stockholders' Equity	8. Stockholders’ Equity Series B Convertible Preferred Stock — Series B Convertible Preferred Stock Series C Convertible Preferred Stock — Series C Convertible Preferred Stock Certificate of Designation as-converted Upon its issuance, the Series C Convertible Preferred Stock was assessed under ASC 480. The Company determined that the Series C Convertible Preferred Stock was not within the scope of ASC 480 and therefore, the Series C Convertible Preferred Stock was not considered a liability. The Series C Convertible Preferred Stock was recorded in permanent equity on the Company’s balance sheet. The Series C Convertible Preferred Stock was then assessed under the FASB ASC 815, “ Derivatives and Hedging ASC 815 Pursuant to the Stock Purchase Agreement, the Company acquired all of the issued and outstanding shares of capital stock of MirImmune for an aggregate of 275,036 shares of common stock of the Company and an aggregate of 1,118,224 shares of Series C Convertible Preferred Stock. The Company was restricted from converting any of the Series C Convertible Preferred Stock into common stock to the extent that such conversion was not approved by the Company’s stockholders in accordance with the stockholder approval requirements of Nasdaq Marketplace Rule 5635. On June 9, 2017, with the approval of the Company’s stockholders in accordance with the Nasdaq stockholder approval requirements, every ten shares of the Series C Convertible Preferred Stock outstanding were automatically converted into one share of common stock. Please refer to Note 5 for further details on the acquisition of MirImmune. On November 7, 2017, the Company filed a Certificate Eliminating the Series B Convertible Preferred Stock from the Certificate of Incorporation of the Company and a Certificate Eliminating the Series C Convertible Preferred Stock from the Certificate of Incorporation of the Company (together, the “ Certificates of Elimination Lincoln Park Capital Fund, LLC — 2014 Purchase Agreement On August 8, 2017, the Company entered into a purchase agreement (the “ 2017 Purchase Agreement Warrants The following table summarizes the Company’s outstanding warrants at December 31, 2017: Exercise prices Number of Shares Expiration $52.00 130,007 June 2, 2020 $9.00 1,277,993 December 21, 2021 Total warrants outstanding 1,408,000 During the year ended December 31, 2017, outstanding warrants for the purchase of 46 shares of the Company’s common stock with an exercise price of $390.00 expired. No warrants were exercised during the years ended December 31, 2017 or 2016.

Net Loss per Share Attributable

Net Loss per Share Attributable to Common Stockholders	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Net Loss per Share Attributable to Common Stockholders	9. Net Loss per Share Attributable to Common Stockholders The following table sets forth the potential common shares excluded from the calculation of net loss per common share attributable to common stockholders because their inclusion would be anti-dilutive: December 31, 2017 2016 Options to purchase common stock 50,156 37,444 Common stock underlying Series B Convertible Preferred Stock — 637,444 Warrants to purchase common stock 1,408,000 1,408,046 Total 1,458,156 2,082,934

Stock-based Compensation

Stock-based Compensation	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-based Compensation	10. Stock-based Compensation Stock Plans On January 23, 2012, the Company’s Board of Directors and sole stockholder adopted the RXi Pharmaceuticals Corporation 2012 Long-Term Incentive Plan (the “ 2012 Incentive Plan As of December 31, 2017, an aggregate of 125,000 shares of common stock were reserved for issuance under the Company’s 2012 Incentive Plan, including 50,156 shares subject to outstanding common stock options granted under the 2012 Incentive Plan and 74,824 shares available for future grants. Stock options granted by the Company to employees may have different vesting parameters, but generally vest within 4 years after the option grant date and expire within ten years of issuance. Stock-based Compensation The Company uses the Black-Scholes option-pricing model to determine the fair value of all its option grants. For valuing options granted during the years ended December 31, 2017 and 2016, the following assumptions were used: December 31, 2017 2016 Risk-free interest rate 1.73 – 2.49 % 1.18 – 2.02 % Expected volatility 82.99 – 123.01 % 79.42 – 116.88 % Weighted average expected volatility 84.65 % 89.12 % Expected lives (in years) 5.20 – 10.00 5.20 – 10.00 Expected dividend yield 0.00 % 0.00 % The weighted-average fair value of options granted during the years ended December 31, 2017 and 2016 was $4.90 and $21.50 per share, respectively. The risk-free interest rate used for each grant was based upon the yield on zero-coupon non-employees The following table summarizes the activity of the Company’s stock option plan for the year ended December 31, 2017: Total Number Weighted- Weighted- Aggregate Balance at December 31, 2016 37,444 $ 272.90 Granted 33,038 6.90 Exercised — — Cancelled (20,326 ) 39.50 Balance at December 31, 2017 50,156 $ 192.30 6.62 years $ — Exercisable at December 31, 2017 33,913 $ 275.30 5.53 years $ — The Company recorded stock-based compensation expense in the consolidated statement of operations for the years ended December 31, 2017 and 2016 as follows, in thousands: December 31, 2017 2016 Research and development $ 89 $ 243 General and administrative 225 513 Total stock-based compensation $ 314 $ 756 Stock-based compensation expense for the year ended December 31, 2017 includes $22,000, recorded in research and development expense, related to stock option modifications in connection with the retirement of the Company’s former Chief Development Officer. There is no income tax benefit as the Company is currently operating at a loss and an actual income tax benefit may not be realized. As of December 31, 2017, the compensation expense for all unvested stock options in the amount of approximately $157,000 will be recognized in the Company’s results of operations over a weighted average period of 1.70 years.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes For the years ended December 31, 2017 and 2016, all of the Company’s loss before income taxes was generated in the United States. On December 22, 2017, the President of the United States signed into law the Tax Cuts and Jobs Act tax reform legislation. This legislation makes significant changes in U.S. tax law including a reduction in the corporate tax rates, changes to net operating loss carryforwards and carrybacks, and a repeal of the corporate alternative minimum tax. The legislation reduced the U.S. corporate tax rate from the current rate of 34% to 21%. As a result of the enacted law, the Company was required to revalue deferred tax assets and liabilities at the enacted rate. This revaluation resulted in a decrease in net deferred tax asset of approximately $8,800,000 and a corresponding reduction in the valuation allowance against these assets. There is no impact to income tax expense. The other provisions of the Tax Cuts and Jobs Act did not have a material impact on the 2017 consolidated financial statements. The components of federal and state income tax expense/(benefit) are as follows (in thousands): December 31, 2017 2016 Current Federal $ — $ — State — — Total current — — Deferred Federal 2,945 (2,892 ) State (1,568 ) (741 ) Total deferred 1,377 (3,633 ) Valuation allowance (2,998 ) 3,633 Total income tax benefit $ (1,621 ) $ — The Company’s acquisition of MirImmune resulted in an income tax benefit of $1,621,000 and a corresponding increase to acquired in-process research and development expense resulting from the reduction in the Company’s valuation allowance due to the deferred tax liability created as a result of the book and tax basis difference. Refer to footnote 5 for further details of the MirImmune acquisition. The differences between the income taxes expected at the Federal statutory income tax rate and the reported income tax (benefit) expense is as follows: 2017 2016 Federal statutory rate (34.0 )% (34.0 )% State income taxes, net of federal benefit (6.5 ) (4.6 ) Non-deductible 0.5 1.7 Income tax credits (2.5 ) (3.5 ) Deferred rate change 62.5 — Valuation allowance (31.5 ) 40.4 Effective tax rate (11.5 )% 0.0 % The components of net deferred tax assets are as follows (in thousands): December 31, 2017 2016 Net operating loss carryforwards $ 14,681 $ 17,245 Tax credit carryforwards 1,322 745 Stock-based compensation 1,336 1,891 Licensing deduction deferral 3,393 5,385 Other timing differences 175 262 Gross deferred tax assets 20,907 25,528 Valuation allowance (20,907 ) (25,528 ) Net deferred tax asset $ — $ — The Company’s deferred tax assets at December 31, 2017 and 2016 consisted primarily of its net operating loss carryforwards, deferred compensation, tax credit carryforwards, intangible assets capitalized for federal income tax purposes and certain accruals that for tax purposes are not deductible until future payment is made. The valuation allowance decreased $4,621,000 and increased $3,633,000 for the years ended December 31, 2017 and 2016, respectively, and is primarily attributable to the deferred tax rate change in 2017. The Company has incurred net operating losses since inception. At December 31, 2017, the Company had federal and state net operating loss carryforwards of approximately $55,000,000 and $48,000,000, respectively, which are available to reduce future taxable income through 2037. In addition, the Company has federal and state research credits of $937,000 and $488,000, respectively, to offset future tax expense through 2037. Based on an assessment of all available evidence including, but not limited to the Company’s limited operating history in its core business and lack of profitability, uncertainties of the commercial viability of its technology, the impact of government regulation and healthcare reform initiatives, and other risks normally associated with biotechnology companies, the Company has concluded that it is more likely than not that these net operating loss carryforwards and credits will not be realized and, as a result, a full deferred income tax valuation allowance has been recorded against these assets. Under the provisions of the Internal Revenue Code, certain substantial changes in the Company’s ownership may result in a limitation on the amount of net operating loss carryforwards and research and development credit carryforwards which could be utilized annually to offset future taxable income and taxes payable. The Company does not believe any substantial changes in ownership have occurred, however a detailed analysis would need to be conducted in order to be certain. The Company files income tax returns in the United States, Massachusetts and New Jersey. The Company is subject to tax examinations for federal and state purposes for tax years 2012 through 2017. The Company has not recorded any uncertain tax positions as of December 31, 2017 or 2016. The Company does not believe there will be any material changes in its unrecognized tax positions over the next 12 months. The Company has not incurred any interest or penalties. In the event that the Company is assessed interest or penalties at some point in the future, they will be classified in the financial statements as general and administrative expenses.

License Agreements

License Agreements	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
License Agreements	12. License Agreements As part of its business, the Company enters into licensing agreements with third parties that often require milestone and royalty payments based on the progress of the asset through development stages. Milestone payments may be required, for example, upon approval of the product for marketing by a regulatory agency. In certain agreements, the Company is required to make royalty payments based upon a percentage of the sales of the products licensed pursuant to such agreements. The expenditures required under these arrangements may be material individually in the event that the Company develops product candidates covered by the intellectual property licensed under any such arrangement, and in the unlikely event that milestones for multiple products covered by these arrangements were reached in the same period, the aggregate charge to expense could be material to the results of operations. In addition, these arrangements often give the Company discretion to unilaterally terminate development of the product, which would allow the Company to avoid making the contingent payments; however, the Company is unlikely to cease development if the compound successfully achieves clinical testing objectives. Advirna LLC. Advirna sd-rxRNA Our rights under the Advirna agreement will expire upon the later of: (i) the expiration of the last-to-expire last-to-be Hapten Pharmaceuticals, LLC Assignment and License Agreement Hapten We have certain customary diligence obligations under the Assignment and License Agreement requiring us to use commercially reasonable efforts to develop and commercialize one or more products covered by the Assignment and License Agreement, which obligations, if not performed, could result in rights assigned or licensed to us reverting back to Hapten.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2017
Subsequent Events [Abstract]
Subsequent Events	13. Subsequent Events Subsequent to the balance sheet date, the Company sold 225,000 shares of common stock to LPC for net proceeds of approximately $788,000.

Summary of Significant Accoun21

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“ GAAP
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of RXi and its wholly owned subsidiary. All material intercompany accounts have been eliminated in consolidation.
Uses of Estimates in Preparation of Financial Statements	Uses of Estimates in Preparation of Financial Statements The preparation of financial statements in accordance with GAAP requires management to make estimates and assumptions that 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. Actual results could differ materially from these estimates.
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted Cash The Company considers all highly liquid instruments with an original maturity of three months or less to be cash equivalents. Restricted cash consists of certificates of deposit held by financial institutions as collateral for the Company’s corporate credit cards. The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheet that sum to the total of the same such amounts shown in the statement of cash flows (in thousands): December 31, December 31, 2017 2016 Cash and cash equivalents $ 3,581 $ 12,906 Restricted cash 50 50 Cash, cash equivalents and restricted cash shown in the statement of cash flows $ 3,631 $ 12,956
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash. The Company maintains cash balances in several accounts with one bank, which at times are in excess of federally insured limits. The Company has established guidelines related to credit ratings and maturities intended to safeguard principal balances and maintain liquidity. The Company’s investments are maintained in accordance with the Company’s investment policy, which defines allowable investments, specifies credit quality standards and limits the exposure of any single issuer.
Property and Equipment	Property and Equipment Property and equipment are stated at cost and depreciated using the straight-line method based on the estimated useful lives of the related assets. The Company provides for depreciation over the assets’ estimated useful lives as follows: Computer equipment 3 years Machinery & equipment 5 years Furniture & fixtures 5 years Leasehold improvements 5 years Depreciation and amortization expense for the years ended December 31, 2017 and 2016 was approximately $70,000 and $53,000, respectively.
Derivative Financial Instruments	Derivative Financial Instruments The Company follows the provisions of the Financial Accounting Standards Board (“ FASB ASC Derivatives and Hedging ASC 815
Fair Value of Financial Instruments	Fair Value of Financial Instruments The carrying amounts reported in the balance sheet for cash equivalents, restricted cash, notes receivable and accounts payable approximate their fair values due to their short-term nature.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company reviews long-lived assets for impairment on an interim basis if an event occurs that might reduce the fair value of such assets below their carrying values. An impairment loss would be recognized based on the difference between the carrying value of the asset and its estimated fair value, which would be determined based on either discounted future cash flows or other appropriate fair value methods. The Company fully impaired its non-marketable
Revenue Recognition	Revenue Recognition Revenue is recognized when there is persuasive evidence of an arrangement, the fee is fixed or determinable, delivery has occurred or services have been rendered and collection of the related receivable is reasonably assured. The Company may generate revenue from product sales, license agreements, collaborative research and development arrangements and government grants. Payments received prior to the recognition of revenue are recorded as deferred revenue.
Research and Development Expenses	Research and Development Expenses Research and development costs relate to salaries, employee benefits, facility-related expenses, supplies, stock-based compensation related to employees and non-employees Preclinical and clinical trial expenses relate to estimates of costs incurred and fees connected with clinical trial sites, third-party clinical research organizations and other preclinical and clinical related activities and include such items as subject-related fees, laboratory work, investigator fees and analysis costs. Costs associated with these expenses are generally payable on the passage of time or when certain milestones are achieved. Expense is recorded during the period incurred or in the period in which a milestone is achieved. In order to ensure that the Company has adequately provided for preclinical and clinical expenses during the proper period, the Company maintains an accrual to cover these expenses. These accruals are assessed on a quarterly basis and are based on such assumptions as expected total cost, the length of the study, timing of subject visits and other information available to us. Actual results may differ from these estimates and could have a material impact on the Company’s reported results. The Company’s historical accrual estimates have not been materially different from its actual costs.
Patents and Patent Application Costs	Patents and Patent Application Costs Although the Company believes that its patents and underlying technology have continuing value, the amount of future benefits to be derived from the patents is uncertain. Patent costs are, therefore, expensed as research and development costs as incurred.
Acquired In-process Research and Development	Acquired In-process Assets purchased in asset acquisition transactions are expensed as in-process in-process
Stock-based Compensation	Stock-based Compensation The Company follows the provisions of the FASB ASC Topic 718, “ Compensation — Stock Compensation ASC 718 non-employee For stock options granted as consideration for services rendered by non-employees, 505-50, Equity Based Payments to Non-Employees Non-employee re-measured non-cash non-employees re-measurements
Income Taxes	Income Taxes The Company recognizes assets or liabilities for the deferred tax consequences of temporary differences between the tax basis of assets or liabilities and their reported amounts in the financial statements in accordance with the FASB ASC Topic 740, “Accounting for Income Taxes” ASC 740 .
Comprehensive Loss	Comprehensive Loss The Company’s comprehensive loss is equal to its net loss for all periods presented.
Net Loss per Share	Net Loss per Share The Company accounts for and discloses net loss per share attributable to common stockholders in accordance with the FASB ASC Topic 260, “ Earnings per Share.”

Summary of Significant Accoun22

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Schedule of Reconciliation of Cash, Cash Equivalents, and Restricted Cash Reported Within Balance Sheet	The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheet that sum to the total of the same such amounts shown in the statement of cash flows (in thousands): December 31, December 31, 2017 2016 Cash and cash equivalents $ 3,581 $ 12,906 Restricted cash 50 50 Cash, cash equivalents and restricted cash shown in the statement of cash flows $ 3,631 $ 12,956
Summary of Depreciation Over Assets' Estimated Useful Lives	The Company provides for depreciation over the assets’ estimated useful lives as follows: Computer equipment 3 years Machinery & equipment 5 years Furniture & fixtures 5 years Leasehold improvements 5 years

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2017
Payables and Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consist of the following, in thousands: December 31, 2017 2016 Compensation and benefits $ 735 $ 745 Clinical development expenses 261 490 Professional fees 167 104 Research and development costs 583 276 Other 8 10 Total accrued expenses $ 1,754 $ 1,625

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Future Cash Payments Under Contractual License Obligations	The Company’s contractual license obligations that will require future cash payments as of December 31, 2017 are as follows, in thousands: Year Ending December 31, 2018 $ 200 2019 165 2020 165 2021 165 2022 100 Thereafter 700 Total $ 1,495
Future Minimum Payments Under Operating Leases	At December 31, 2017, the Company’s future minimum payments required under operating leases are as follows, in thousands: Year Ending December 31, 2018 $ 120 2019 30 Total $ 150

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Summary of Warrants Outstanding	The following table summarizes the Company’s outstanding warrants at December 31, 2017: Exercise prices Number of Shares Expiration $52.00 130,007 June 2, 2020 $9.00 1,277,993 December 21, 2021 Total warrants outstanding 1,408,000

Net Loss per Share Attributab26

Net Loss per Share Attributable to Common Stockholders (Tables)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Common Shares Excluded from the Calculation of Net Loss per Common Share Attributable to Common Stockholders	The following table sets forth the potential common shares excluded from the calculation of net loss per common share attributable to common stockholders because their inclusion would be anti-dilutive: December 31, 2017 2016 Options to purchase common stock 50,156 37,444 Common stock underlying Series B Convertible Preferred Stock — 637,444 Warrants to purchase common stock 1,408,000 1,408,046 Total 1,458,156 2,082,934

Stock-based Compensation (Table

Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Assumptions Used to Determine Fair Value of Option Grants	The Company uses the Black-Scholes option-pricing model to determine the fair value of all its option grants. For valuing options granted during the years ended December 31, 2017 and 2016, the following assumptions were used: December 31, 2017 2016 Risk-free interest rate 1.73 – 2.49 % 1.18 – 2.02 % Expected volatility 82.99 – 123.01 % 79.42 – 116.88 % Weighted average expected volatility 84.65 % 89.12 % Expected lives (in years) 5.20 – 10.00 5.20 – 10.00 Expected dividend yield 0.00 % 0.00 %
Summary of Stock Option Activity	The following table summarizes the activity of the Company’s stock option plan for the year ended December 31, 2017: Total Number Weighted- Weighted- Aggregate Balance at December 31, 2016 37,444 $ 272.90 Granted 33,038 6.90 Exercised — — Cancelled (20,326 ) 39.50 Balance at December 31, 2017 50,156 $ 192.30 6.62 years $ — Exercisable at December 31, 2017 33,913 $ 275.30 5.53 years $ —
Details of Stock-based Compensation Expense Recorded	The Company recorded stock-based compensation expense in the consolidated statement of operations for the years ended December 31, 2017 and 2016 as follows, in thousands: December 31, 2017 2016 Research and development $ 89 $ 243 General and administrative 225 513 Total stock-based compensation $ 314 $ 756

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Components of Federal and State Income Tax Expense	The components of federal and state income tax expense/(benefit) are as follows (in thousands): December 31, 2017 2016 Current Federal $ — $ — State — — Total current — — Deferred Federal 2,945 (2,892 ) State (1,568 ) (741 ) Total deferred 1,377 (3,633 ) Valuation allowance (2,998 ) 3,633 Total income tax benefit $ (1,621 ) $ —
Effect Income Tax Rate Reconciliation	The differences between the income taxes expected at the Federal statutory income tax rate and the reported income tax (benefit) expense is as follows: 2017 2016 Federal statutory rate (34.0 )% (34.0 )% State income taxes, net of federal benefit (6.5 ) (4.6 ) Non-deductible 0.5 1.7 Income tax credits (2.5 ) (3.5 ) Deferred rate change 62.5 — Valuation allowance (31.5 ) 40.4 Effective tax rate (11.5 )% 0.0 %
Components of Net Deferred Tax Assets	The components of net deferred tax assets are as follows (in thousands): December 31, 2017 2016 Net operating loss carryforwards $ 14,681 $ 17,245 Tax credit carryforwards 1,322 745 Stock-based compensation 1,336 1,891 Licensing deduction deferral 3,393 5,385 Other timing differences 175 262 Gross deferred tax assets 20,907 25,528 Valuation allowance (20,907 ) (25,528 ) Net deferred tax asset $ — $ —

Nature of Operations - Addition

Nature of Operations - Additional Information (Detail) - Subsequent Events [Member]	Jan. 03, 2018
Nature of Operations [Line Items]
Stock split description	Company approved a 1-for-10 reverse stock split of the Company's outstanding common stock, which was effected on January 8, 2018.
Reverse stock split ratio	0.001

Summary of Significant Accoun30

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
Liquid instrument maturity period	Three months or less
Depreciation and amortization	$ 70,000	$ 53,000
Impairment recognized on investment included in other assets		$ 0
Other (Expense) Income, Net [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairment recognized on investment included in other assets	$ 9,000

Summary of Significant Accoun31

Summary of Significant Accounting Policies - Schedule of Reconciliation of Cash, Cash Equivalents, and Restricted Cash Reported Within Balance Sheet (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Cash and cash equivalents	$ 3,581	$ 12,906
Restricted cash	50	50
Cash, cash equivalents and restricted cash shown in the statement of cash flows	$ 3,631	$ 12,956	$ 5,167

Summary of Significant Accoun32

Summary of Significant Accounting Policies - Summary of Depreciation Over Assets Estimated Useful Lives (Detail)	12 Months Ended
	Dec. 31, 2017
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life of assets	3 years
Machinery & Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life of assets	5 years
Furniture & Fixtures [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life of assets	5 years
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life of assets	5 years

MirImmune Inc. Acquisition - Ad

MirImmune Inc. Acquisition - Additional Information (Detail) - USD ($)	Jan. 06, 2017	Dec. 31, 2017	Nov. 07, 2017	Jun. 09, 2017
Research and Development Assets Acquired Other than Through Business Combination [Line Items]
Number of shares issued in connection with the acquisition of MirImmune Inc.	275,036	275,036
Holdback of aggregate closing consideration, percentage	3.00%
Income tax expense (benefit)		$ 1,621,000
Acquired in-process research and development		4,696,000
Shares of common stock to be issued upon milestone	251,909
Additional number of common stock to be issued upon milestone percentage	13.00%
MirImmune, Inc. [Member]
Research and Development Assets Acquired Other than Through Business Combination [Line Items]
Income tax expense (benefit)		$ 1,621,000
Series C Convertible Preferred Stock [Member]
Research and Development Assets Acquired Other than Through Business Combination [Line Items]
Number of shares issued in connection with the acquisition of MirImmune Inc.	1,118,224	1,118,224
Terms of stock conversion ratio		Every ten shares of the Series C Convertible Preferred Stock outstanding were automatically converted into one share of common stock
Stock conversion ratio		1		1
Preferred Stock, shares issued			0
Preferred Stock, shares outstanding			0

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accrued Liabilities and Other Liabilities [Abstract]
Compensation and benefits	$ 735	$ 745
Clinical development expenses	261	490
Professional fees	167	104
Research and development costs	583	276
Other	8	10
Total accrued expenses	$ 1,754	$ 1,625

Commitments and Contingencies -

Commitments and Contingencies - Future Cash Payments Under Contractual License Obligations (Detail) $ in Thousands	Dec. 31, 2017USD ($)
Commitments and Contingencies Disclosure [Abstract]
2,018	$ 200
2,019	165
2,020	165
2,021	165
2,022	100
Thereafter	700
Total	$ 1,495

Commitments and Contingencies36

Commitments and Contingencies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Lease agreement maturity date	Mar. 31, 2019
Monthly rental expense	$ 9,500
Operating lease expenses	$ 115,000	$ 117,000

Commitments and Contingencies37

Commitments and Contingencies - Future Minimum Payments Under Operating Leases (Detail) $ in Thousands	Dec. 31, 2017USD ($)
Commitments and Contingencies Disclosure [Abstract]
2,018	$ 120
2,019	30
Total	$ 150

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)	Aug. 08, 2017	Jan. 06, 2017	Dec. 31, 2017	Dec. 31, 2016	Nov. 07, 2017	Jun. 09, 2017	Jan. 05, 2017	Dec. 18, 2014
Class of Stock [Line Items]
Number of common stock issued upon conversion of convertible instrument			0	0
Preferred stock, shares authorized			10,000,000	10,000,000
Number of shares issued in connection with the acquisition of MirImmune Inc.		275,036	275,036
Net proceeds from the issuance of common stock			$ 290,000	$ 10,203,000
Number of common stock, outstanding warrants			1,408,000
Series B Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Number of common stock issued upon conversion of convertible instrument			(5,737)	(2,345)
Conversion of preferred stock into common shares			5,737	2,345
Preferred stock, shares authorized			0	8,100	8,100
Series C Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Number of common stock issued upon conversion of convertible instrument			(1,118,224)
Preferred stock, shares authorized					1,800,000		1,800,000
Number of shares issued in connection with the acquisition of MirImmune Inc.		1,118,224	1,118,224
Terms of stock conversion ratio			Every ten shares of the Series C Convertible Preferred Stock outstanding were automatically converted into one share of common stock
Shares issued upon conversion			1			1
Common Stock [Member]
Class of Stock [Line Items]
Number of common stock issued upon conversion of convertible instrument				260,556
Number of shares issued in connection with the acquisition of MirImmune Inc.			275,036
Common stock, shares issued			105,000	6,500
Common Stock [Member] | Lincoln Park Capital Fund, LLC [Member]
Class of Stock [Line Items]
Common stock, shares issued	45,000		60,000	6,500
Net proceeds from the issuance of common stock			$ 290,000	$ 152,000
Cost of capital, value per share	$ 5.80
Common Stock [Member] | Lincoln Park Capital Fund, LLC [Member] | Maximum [Member]
Class of Stock [Line Items]
Potential consideration under purchase agreement	15,000,000							10,800,000
Common Stock [Member] | Series B Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Number of common stock issued upon conversion of convertible instrument			637,445	260,555
Common Stock [Member] | Series C Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Number of common stock issued upon conversion of convertible instrument			111,822
Warrants With Exercise Price $390.00 [Member]
Class of Stock [Line Items]
Exercise prices			$ 390
Number of common stock, outstanding warrants			46

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Warrants Outstanding (Detail)	12 Months Ended
	Dec. 31, 2017$ / sharesshares
Class of Warrant or Right [Line Items]
Number of Shares Underlying Warrants	1,408,000
Warrants With Exercise Price $52.00 [Member]
Class of Warrant or Right [Line Items]
Exercise prices | $ / shares	$ 52
Number of Shares Underlying Warrants	130,007
Expiration	Jun. 2, 2020
2016 Warrants With Exercise Price $9.00 [Member]
Class of Warrant or Right [Line Items]
Exercise prices | $ / shares	$ 9
Number of Shares Underlying Warrants	1,277,993
Expiration	Dec. 21, 2021

Net Loss per Share Attributab40

Net Loss per Share Attributable to Common Stockholders - Common Shares Excluded from the Calculation of Net Loss per Common Share Attributable to Common Stockholders (Detail) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total amount of anti-dilutive securities excluded from computation of earnings per share	1,458,156	2,082,934
Series B Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total amount of anti-dilutive securities excluded from computation of earnings per share	0	637,444
Options to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total amount of anti-dilutive securities excluded from computation of earnings per share	50,156	37,444
Warrants to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total amount of anti-dilutive securities excluded from computation of earnings per share	1,408,000	1,408,046

Stock-based Compensation - Addi

Stock-based Compensation - Additional Information (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Shares reserved for issuance	125,000	125,000
Purchase of common stock	50,156	50,156	37,444
Shares of common stock available for future grants	74,824	74,824
Expiration period of Option		10 years
Vesting period of option		4 years
Weighted average grant date fair value per share of options granted		$ 4.90	$ 21.50
Stock-based compensation expense		$ 22,000
Stock-based compensation expense tax benefit		0
Unrecognized share based compensation expense on unvested stock option	$ 157,000	$ 157,000
Unrecognized share based compensation expense on unvested stock option period of recognition	1 year 8 months 12 days

Stock-based Compensation - Sche

Stock-based Compensation - Schedule of Assumptions Used to Determine Fair Value of Option Grants (Detail)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, Minimum	1.73%	1.18%
Risk-free interest rate, Maximum	2.49%	2.02%
Expected volatility, Minimum	82.99%	79.42%
Expected volatility, Maximum	123.01%	116.88%
Weighted average expected volatility	84.65%	89.12%
Expected dividend yield	0.00%	0.00%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected lives (in years)	5 years 2 months 12 days	5 years 2 months 12 days
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected lives (in years)	10 years	10 years

Stock-based Compensation - Summ

Stock-based Compensation - Summary of Stock Option Activity (Detail)	12 Months Ended
	Dec. 31, 2017USD ($)$ / sharesshares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Total Number of Shares, Beginning Balance | shares	37,444
Total Number of Shares, Granted | shares	33,038
Total Number of Shares, Exercised | shares	0
Total Number of Shares, Cancelled | shares	(20,326)
Total Number of Shares, Ending Balance | shares	50,156
Total Number of Shares, Exercisable | shares	33,913
Weighted-Average Exercise Price Per Share, Beginning Balance | $ / shares	$ 272.90
Weighted-Average Exercise Price Per Share, Granted | $ / shares	6.90
Weighted-Average Exercise Price Per Share, Exercised | $ / shares	0
Weighted-Average Exercise Price Per Share, Cancelled | $ / shares	39.50
Weighted-Average Exercise Price Per Share, Ending Balance | $ / shares	192.30
Weighted-Average Exercise Price Per Share, Exercisable | $ / shares	$ 275.30
Weighted-Average Remaining Contractual Term, Ending Balance	6 years 7 months 13 days
Weighted-Average Remaining Contractual Term, Exercisable	5 years 6 months 10 days
Aggregate Intrinsic Value, Ending Balance | $	$ 0
Aggregate Intrinsic Value, Exercisable | $	$ 0

Stock-based Compensation - Deta

Stock-based Compensation - Details of Stock-based Compensation Expense Recorded (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 314	$ 756
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	89	243
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 225	$ 513

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Line Items]
Federal statutory rate		34.00%	34.00%
Decrease in deferred tax assets due to change in tax act		$ 8,800,000
Income tax benefit		1,621,000
Increase (decrease) in valuation allowance due to tax rate change in 2017		$ 4,621,000	$ (3,633,000)
Expiration of carry forwards loss		2,037
Research tax credit expiration period		2,037
Liability for uncertain tax positions		$ 0	$ 0
MirImmune, Inc. [Member]
Income Tax Disclosure [Line Items]
Income tax benefit		1,621,000
Scenario, Forecast [Member]
Income Tax Disclosure [Line Items]
Federal statutory rate	21.00%
Federal Income Tax [Member]
Income Tax Disclosure [Line Items]
Net operating loss carryforwards		55,000,000
Research tax credit		937,000
State Income Tax [Member]
Income Tax Disclosure [Line Items]
Net operating loss carryforwards		48,000,000
Research tax credit		$ 488,000
Earliest Tax Year [Member]
Income Tax Disclosure [Line Items]
Open tax year subject to tax examination		2,012
Latest Tax Year [Member]
Income Tax Disclosure [Line Items]
Open tax year subject to tax examination		2,017

Income Taxes - Components of Fe

Income Taxes - Components of Federal and State Income Tax Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Current
Federal	$ 0	$ 0
State	0	0
Total current	0	0
Deferred
Federal	2,945	(2,892)
State	(1,568)	(741)
Total deferred	1,377	(3,633)
Valuation allowance	(2,998)	$ 3,633
Total income tax benefit	$ (1,621)

Income Taxes - Effect Income Ta

Income Taxes - Effect Income Tax Rate Reconciliation (Detail)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Federal statutory rate	(34.00%)	(34.00%)
State income taxes, net of federal benefit	(6.50%)	(4.60%)
Non-deductible expenses	0.50%	1.70%
Income tax credits	(2.50%)	(3.50%)
Deferred rate change	62.50%
Valuation allowance	(31.50%)	40.40%
Effective tax rate	(11.50%)	0.00%

Income Taxes - Components of Ne

Income Taxes - Components of Net Deferred Tax Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Net operating loss carryforwards	$ 14,681	$ 17,245
Tax credit carryforwards	1,322	745
Stock-based compensation	1,336	1,891
Licensing deduction deferral	3,393	5,385
Other timing differences	175	262
Gross deferred tax assets	20,907	25,528
Valuation allowance	(20,907)	(25,528)
Net deferred tax asset	$ 0	$ 0

License Agreements - Additional

License Agreements - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2017
Advirna LLC [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty percentage on future licensing revenue	1.00%

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($)	Jan. 01, 2018	Aug. 08, 2017	Dec. 31, 2017	Dec. 31, 2016
Subsequent Event [Line Items]
Net proceeds from the issuance of common stock			$ 290,000	$ 10,203,000
Common Stock [Member]
Subsequent Event [Line Items]
Common stock, shares issued			105,000	6,500
Common Stock [Member] | Lincoln Park Capital Fund, LLC [Member]
Subsequent Event [Line Items]
Common stock, shares issued		45,000	60,000	6,500
Net proceeds from the issuance of common stock			$ 290,000	$ 152,000
Subsequent Events [Member] | Common Stock [Member] | Lincoln Park Capital Fund, LLC [Member]
Subsequent Event [Line Items]
Common stock, shares issued	225,000
Net proceeds from the issuance of common stock	$ 788,000