Eloxx Pharmaceuticals (ELOX) 10-Q 10 Aug 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Aug. 03, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Trading Symbol	ELOX
Entity Registrant Name	ELOXX PHARMACEUTICALS, INC.
Entity Central Index Key	1,035,354
Current Fiscal Year End Date	--12-31
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		34,857,680

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 63,412	$ 24,049
Restricted bank deposit	100	102
Prepaid expenses and other current assets	458	355
Total current assets	63,970	24,506
Property and equipment, net	302	278
Total	64,272	24,784
Current liabilities:
Accounts payable	2,098	1,530
Accrued expenses	2,258	1,893
Total current liabilities	4,356	3,423
Stockholders’ equity:
Preferred stock, $0.01 par value per share, 5,000,000 shares authorized, no shares issued and outstanding at June 30, 2018 and December 31, 2017
Common stock, $0.01 par value per share, 500,000,000 shares authorized, 34,869,450 and 27,527,738 shares issued at June 30, 2018 and December 31, 2017, respectively	349	274
Common stock in treasury, at cost, 8,385 and 0 shares at June 30, 2018 and December 31, 2017, respectively	(83)
Additional paid in capital	120,607	60,047
Accumulated deficit	(60,957)	(38,960)
Total stockholders’ equity	59,916	21,361
Total	$ 64,272	$ 24,784

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred Stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred Stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	34,869,450	27,527,738
Common stock, shares outstanding	34,869,450	27,527,738
Common stock, treasury shares	8,385	0

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Operating expenses:
Research and development		$ 4,150	$ 2,595	$ 8,544	$ 4,950
General and administrative		9,560	584	12,953	861
Reverse merger related expenses		(167)		594
Total operating expenses		13,543	3,179	22,091	5,811
Loss from operations		(13,543)	(3,179)	(22,091)	(5,811)
Other (income) expense, net		(137)	699	(94)	745
Net loss		$ (13,406)	$ (3,878)	$ (21,997)	$ (6,556)
Basic and diluted net loss per share		$ (0.42)	$ (1.04)	$ (0.74)	$ (1.77)
Weighted average number of common shares in computing basic and diluted net loss per share	[1]	31,839,303	4,205,277	29,695,430	4,205,277
[1]	The following potentially dilutive securities have been excluded from the computation of diluted weighted average shares outstanding as their effect would be anti-dilutive: Six months ended June 30, 2018 2017 Options to purchase common stock 3,870,237 1,873,809 Restricted stock units 871,064 — Warrants 347,241 5,282,794 Preferred stock — 13,415,116 Total potential common stock equivalents 5,088,542 20,571,719

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Net loss	$ (13,406)	$ (3,878)	$ (21,997)	$ (6,556)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation			6,913	21
Depreciation	25	7	46	13
Amortization and revaluation of discount in respect to convertible loan				625
Accrued interest on convertible loan				43
Change in operating assets and liabilities:
Prepaid expenses and other current assets			(103)	701
Accounts payable			568	(1,182)
Accrued expenses			365	433
Net cash used in operating activities			(14,208)	(5,902)
Cash flows from investing activities:
Purchases of property and equipment			(101)	(96)
Net cash used in investing activities			(101)	(96)
Cash flows from financing activities:
Proceeds from convertible loan and financial derivative into Series C preferred stock				2,500
Proceeds from share based compensation arrangements			97
Net cash provided by financing activities			53,668	17,169
Effect of exchange rate on cash			2
Increase in cash and cash equivalents			39,361	11,171
Cash, cash equivalents and restricted cash, beginning of year			24,151	2,250
Cash, cash equivalents and restricted cash, end of period	63,512	13,421	63,512	13,421
Reconciliation of cash, cash equivalents and restricted cash to condensed consolidated balance sheets
Cash and cash equivalents	63,412	13,360	63,412	13,360
Restricted cash included in restricted bank deposit	100	61	100	61
Cash, cash equivalents and restricted cash, end of period	$ 63,512	$ 13,421	63,512	13,421
Supplemental disclosure of non-cash financing activities
Non-cash acquisition of treasury shares			83
Conversion of convertible loan into Series C preferred stock				3,168
Series C Preferred Stock [Member]
Cash flows from financing activities:
Proceeds from issuance of Series C preferred stock, net of issuance costs				$ 14,669
Underwritten Public Offering [Member]
Cash flows from financing activities:
Proceeds from the underwritten public offering, net of issuance costs			$ 53,571

Nature of the Business

Nature of the Business	6 Months Ended
	Jun. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of the Business	1. Nature of the Business Eloxx Pharmaceuticals, Inc., together with its wholly-owned subsidiary Eloxx Pharmaceuticals, Ltd. (collectively “we,” “our,” “us,” “Eloxx” or the “Company”), is a clinical-stage biopharmaceutical company developing novel ribonucleic acid (RNA)-modulating drug candidates (designed to be eukaryotic ribosomal selective glycosides) that are designed to treat rare and ultra-rare premature stop codon diseases. Premature stop codons are point mutations that disrupt protein synthesis from messenger RNA. As a consequence, patients with premature stop codon diseases have reduced or eliminated protein production from the mutation bearing allele accounting for some of the most severe phenotypes in these genetic diseases. These premature stop codons have been identified in over 1,800 rare and ultra-rare diseases. Read-through therapeutic development is focused on extending mRNA (messenger RNA) half-life and increasing protein synthesis by enabling the cytoplasmic ribosome to read through premature stop codons to produce full-length proteins. Eloxx’s lead investigational product candidate, ELX-02, is a small molecule drug candidate designed to restore production of full-length functional proteins. Eloxx’s preclinical candidate pool consists of a library of novel drug candidates designed to be eukaryotic ribosomal selective glycosides identified based on read-through potential. ELX-02 is in the early stages of clinical development focusing on cystic fibrosis and cystinosis. ELX-02 is an investigational drug that has not been approved by any global regulatory body. Eloxx is headquartered in Waltham, MA, with research and development operations in Rehovot, Israel. The Company’s research and development strategy is to target rare or ultra-rare diseases where a high unmet medical need, nonsense mutation bearing, patient population has been identified, there are established preclinical read-through or personalized medicine experiments that are predictive of clinical activity, and a definable path for Orphan Drug development, regulatory approval, patient access and commercialization. The Company believes patient advocacy to be an important element of patient focused drug development and seeks opportunities to collaborate with patient advocacy groups throughout the discovery and development process. The Company’s current clinical focus is on cystic fibrosis and cystinosis where the Company is advancing its lead investigational drug product candidate, ELX-02. Eloxx Pharmaceuticals Ltd. (“Eloxx Limited”) was incorporated in Israel on September 17, 2013 Reverse Merger On December 19, 2017, Sevion Therapeutics, Inc. (“Sevion”) acquired Eloxx Limited pursuant to a merger between the companies (the “Transaction” or “Reverse Merger”). Upon consummation of the Transaction (the “Closing”), Sevion adopted the business plan of Eloxx Limited and discontinued the pursuit of Sevion’s business plan. In connection with the Transaction, Sevion acquired all of the outstanding capital stock of Eloxx Limited in exchange for the issuance of an aggregate 20,316,656 shares of Sevion’s common stock, par value $0.01 per share (the “Common Stock”), after giving effect to a 1-for-20 reverse split immediately prior to the Transaction. As a result of the Transaction, Eloxx Limited became a wholly-owned subsidiary of Sevion. While Sevion was the legal acquirer in the transaction, Eloxx Limited was deemed the accounting acquirer. Immediately after giving effect to the Transaction, on December 19, 2017, Sevion changed its name to Eloxx Pharmaceuticals, Inc. These interim unaudited consolidated financial statements of the Company reflect the operations of the acquirer for accounting purposes together with a deemed issuance of shares, equivalent to the shares held by the former stockholders of the legal acquirer and a recapitalization at the equity of the accounting acquirer. The annual audited consolidated financial statements include the accounts of the Company since the effective date of the reverse capitalization and the accounts of Eloxx Limited since inception. Liquidity As reflected in the accompanying unaudited consolidated financial statements, the Company has not generated revenue from the sale of any product and does not expect to generate significant revenue unless and until obtaining marketing approval and commercialization of one of its product candidates. As of June 30, 2018, the Company had cash and cash equivalents of $63.4 million, inclusive of net proceeds of $53.6 million received upon the completion of an underwritten public offering of 5,899,500 shares of common stock of the Company at the public offering price of $9.75 per share on April 30, 2018. The Company expects that its cash and cash equivalents will fund operations to 2020 based on its current operating plans. The Company incurred a loss for the six months ended June 30, 2018 of $22.0 million and had a negative cash flow from operating activities of $14.2 million during the six months ended June 30, 2018. The accumulated deficit as of June 30, 2018 was $61.0 million. Correction of an Immaterial Error The presentation of reverse merger related expense in the Statement of Operations for the six-months ended June 30, 2018 includes the effects of the correction of an immaterial error of the amounts of functional operating expenses previously reported for the three months ended March 31, 2018. The Company assessed the materiality of these errors in accordance with the SEC’s Staff Accounting Bulletin (“SAB”) Topic 1.M, Materiality, codified in ASC Topic 250, Presentation of Financial Statements (“ASC 250”), and concluded that the previously issued unaudited condensed consolidated interim financial statements for the three months ended March 31, 2018 and 2017 were not materially misstated; however, in order to correctly reflect the adjustment as described above in the appropriate period, management has elected to correct the presentation in the Statement of Operations for the six-months ended June 30, 2018 and will revise the affected previously issued financial statements for the three-months ended March 31, 2018 when such amounts are presented as comparative prior period balances in the Form 10-Q filing for the period ending March 31, 2019. As a result, the revised consolidated financial statements for the three and six months ended June 30, 2018 reflect a $0.4 million increase to research and development expense, a $0.9 million increase in general and administrative expense, and a corresponding decrease in reverse merger related expenses of $1.3 million. The reclassification had no impact on net loss or net cash flows for the three months ended March 31, 2018 or the three and six months ended June 30, 2018, nor other prior periods presented. The impact on specific line items in the accompanying consolidated statement of operations for the three months ended March 31, 2018 is presented below (in thousands): Three Months Ended March 31, 2018 As reported Adjustments As corrected Operating expenses: Research and development $ 4,013 $ 381 $ 4,394 General and administrative 2,480 913 3,393 Reverse merger related expenses 2,055 (1,294 ) 761 Total operating expenses $ 8,548 $ — $ 8,548

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of presentation and principles of consolidation The accompanying unaudited interim consolidated financial statements have been prepared by the Company in accordance with accounting principles generally accepted in the United States (“GAAP”) as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”). Certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted, as permitted by such rules and regulations. These interim consolidated financial statements, in the opinion of management, reflect all normal recurring adjustments necessary for a fair presentation of the Company’s financial position, results of operations, and cash flows for the interim periods ended June 30, 2018 and 2017. The Unaudited Consolidated Statements of Operations includes the Company’s operating expenses related to research and development and general and administrative, along with reverse merger related expenses, which were substantially comprised of fees for professional services. The results of operations for the interim periods are not necessarily indicative of the results of operations to be expected for the full year. These interim financial statements should be read in conjunction with the audited financial statements as of and for the year ended December 31, 2017, and the notes thereto, which are included in the Company’s Annual Report on Form 10-K filed with the Securities and Exchange Commission (the “SEC”) on March 16, 2018. Summary of Accounting Policies The significant accounting policies and estimates used in the preparation of the condensed consolidated financial statements are described in the Company’s audited financial statements as of and for the year ended December 31, 2017, and the notes thereto, which are included in the Company’s Annual Report on Form 10-K. There have been no material changes in the Company’s significant accounting policies during the six months ended June 30, 2018. Recent Accounting Pronouncements adopted In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230): “Restricted Cash” (ASU 2016-18), which requires companies to include amounts generally described as restricted cash and restricted cash equivalents in cash and cash equivalents when reconciling beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The amendments in this update are effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The Company adopted the new guidance using the retrospective transition method as required with respect to each period presented. This new guidance does not have a material impact on the Company’s consolidated financial statements. In February 2016, the FASB issued ASU No. 2016-02, “Leases”. This guidance will require that lease arrangements longer than 12 months result in an entity recognizing an asset and liability equal to the present value of the lease payments in the statement of financial position. This guidance is effective for annual periods beginning after December 15, 2018, and interim periods therein. This standard requires a modified retrospective transition approach for all leases existing at, or entered into after, the date of initial application, with an option to use certain transition relief. Early adoption is permitted. The Company is currently evaluating the impact that the adoption of ASU 2016-02 will have on its financial statements and related disclosures.

Prepaids and Other Current Asse

Prepaids and Other Current Assets	6 Months Ended
	Jun. 30, 2018
Text Block [Abstract]
Prepaids and Other Current Assets	3. Prepaids and Other Current Assets Prepaids and other current assets as of June 30, 2018 and December 31, 2017 consisted of the following (in thousands): As of June 30, 2018 December 31, 2017 Prepaid insurance $ 290 $ 242 Other governmental agencies receivables — 88 Prepaid other 168 25 $ 458 $ 355

Property and Equipment, net

Property and Equipment, net	6 Months Ended
	Jun. 30, 2018
Property Plant And Equipment [Abstract]
Property and Equipment, net	4. Property and Equipment, net Property and equipment, net consisted of the following (in thousands): As of June 30, 2018 December 31, 2017 Computers and software $ 200 $ 124 Office furniture and equipment 120 118 Laboratory equipment — 37 Leasehold improvements 73 53 393 332 Less: Accumulated depreciation 91 54 Property and equipment, net $ 302 $ 278 Depreciation expense was $25,000, and $7,000 for the three months ended June 30, 2018 and 2017, respectively. Depreciation expense was $46,000, and $13,000 for the six months ended June 30, 2018, 2018 and 2017, respectively.

Accrued Expenses

Accrued Expenses	6 Months Ended
	Jun. 30, 2018
Payables And Accruals [Abstract]
Accrued Expenses	5. Accrued Expenses Accrued expenses as of June 30, 2018 and December 31, 2017 consisted of the following (in thousands): As of June 30, 2018 December 31, 2017 Accrued payroll and related expenses $ 700 $ 402 Accrued research and development expenses 712 704 Accrued professional services 846 787 $ 2,258 $ 1,893

Convertible Loan

Convertible Loan	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Convertible Loan	6. Convertible Loan On January 26, 2017 (the “Closing Date”), the Company entered into a Convertible Loan Agreement (the “Agreement”) with five of its shareholders (the “Lenders”), pursuant to which the Company raised an aggregate amount of $2.5 million (the “Convertible Loan”). The Convertible Loan included interest at an annual rate of 5%. According to the Agreement, the outstanding portion of the Convertible Loan (without accrued interest) automatically converts upon the consummation of an equity investment by a third party of an aggregate amount of at least $5.0 million (the “Qualified Equity Investment”), prior to the date that is two years from the Closing Date (the “Maturity Date”), into equity securities of the same class issued by the Company in such Qualified Equity Investment. In accordance with ASC Topic 815 “Derivatives and Hedging”, features related to convertible loans qualify as embedded derivative instruments at the date of issuance, since these are considered as stock settled debt. In determining fair value, the Company uses various valuation approaches. ASC 820 establishes a hierarchy for inputs used in measuring fair value. The embedded conversion feature is classified under level 3 in the hierarchy. The fair value assigned to the embedded conversion feature on the issuance dates amounted to $0.3 million. The embedded instruments are marked to market in each reporting period and changes are recorded in financial expenses. The discount is amortized using the effective interest over the loan period. On May 31, 2017, the Convertible Loan (without accrued interest) was converted into 825,213 shares of Series C preferred stock, according to the price per share that was paid in the 2017 Share Purchase Agreement (see Note 9). During the year ended December 31, 2017, the Company recorded $0.7 million as financial and other expenses, as a result of changes in the embedded instruments. In connection with the conversion, the embedded instrument together with all accrued interest in the amount of $0.7 million and was classified to additional paid in capital. The following table presents reconciliations for the Company’s liabilities measured and recorded at fair value on a recurring basis, using significant unobservable inputs (in thousands): Significant Unobservable Inputs (Level 3) Balance at January 26, 2017 $ (308 ) Amortization and revaluation embedded conversion feature (317 ) Conversion of convertible loan into Series C preferred stock 625 Balance at December 31, 2017 $ —

Related Parties

Related Parties	6 Months Ended
	Jun. 30, 2018
Related Party Transactions [Abstract]
Related Parties	7. Related Parties On August 29, 2013, the Company entered into an agreement (“Technion Agreement”) with TRDF, with respect to certain technology relating to aminoglycosides and the redesign of aminoglycosides for the treatment of human genetic diseases caused by premature stop mutations and further results of the research of the technology, in order to develop and commercialize products based on such technology. Under the Technion Agreement, TRDF is obligated to provide the Company with research services for an estimated annual payment of $0.1 million, the precise amount to be agreed by the parties prior to the beginning of each year of the research period. During the periods ended June 30, 2018 and 2017, the Company recorded general and administrative expenses amounting to zero and $7,000, respectively, in relation to the TRDF reimbursement for the preparation, filing, prosecution and maintenance of TRDF patents rights related to Eloxx Limited. For the periods ended June 30, 2018 and 2017 the Company did not record any research and development expenses in relation to the Technion Agreement. As of June 30, 2018 and December 31, 2017, amounts recorded in accrued expenses were $25,000 and $25,000, respectively. In addition, TRDF granted the Company a license to use, market, sell or sub-license the rights of the product developed under the TRDF research results (the “Licensed Product”), as fully defined in the Technion Agreement, for the following considerations: (a) milestone payments, to be transferred upon meeting certain milestones as defined in the Technion Agreement, up to total consideration of $6.1 million; (b) certain royalties on a low- to mid- single-digit percentage of net sales (subject to change in the case of (x) sublicensing to a big pharmaceutical or biotechnology company, or (y) payment of royalties to third parties, or (z) commercialization by a third party of an authorized generic to a licensed product), for a period until the later of (i) the expiration of a valid claim on the Licensed Product in each country the Licensed Product is sold to, or (ii) a certain amount of years from the date of the first commercial sale of the Licensed Product in such country, and (c) a low- to mid- double-digit percentage of any non-royalty sub-license income received by the Company from a sub-licensed entity. In addition, the Company will be required to pay a fee to TRDF upon an exit event as described in the Technion Agreement. On August 9, 2017 the Company received a legal claims letter from TRDF regarding TRDF’s alleged entitlement to an exit fee in accordance with the Technion Agreement. The Company recorded a $3.4 million research and development expense with an offsetting adjustment to additional paid-in capital for the year ended December 31, 2017 related to the planned issuance of those shares at fair market value on the date of the exit event. On June 13, 2018 the Company issued 569,395 shares to TRDF in satisfaction of this claim.

Legal and Other Contingencies

Legal and Other Contingencies	6 Months Ended
	Jun. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Legal and Other Contingencies	8. Legal and Other Contingencies The Company accounts for its contingent liabilities in accordance with ASC Topic 450 “Contingencies”. A provision is recorded when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated. With respect to legal matters, provisions are reviewed and adjusted to reflect the impact of negotiations, estimated settlements, legal rulings, advice of legal counsel and other information and events pertaining to a particular matter. For the periods ended June 30, 2018 and 2017, the Company was not a party to any litigation that could have a material adverse effect on the Company’s business, financial position, results of operations or cash flows. Legal costs incurred in connection with loss contingencies are expensed as incurred.

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Stockholders' Equity	9. Stockholders’ Equity For accounting purposes, all common stock, preferred stock, warrants, options to purchase common stock and loss per share amounts have been adjusted to give retroactive effect to the exchange ratio and reverse stock split for all periods presented in these condensed unaudited consolidated financial statements. Transactions related to stockholders’ equity of the Company during the six months ended June 30, 2018 were as follows (in thousands, except share amounts): Common stock Additional paid-in Accumulated Treasury stock Total stockholders' Shares Amount Capital deficit Shares Amount equity Balance at December 31, 2017 27,527,738 $ 274 $ 60,047 $ (38,960 ) — $ — $ 21,361 Issuance of common stock related to share-based compensation 808,443 8 89 — — — 97 Issuance of common stock Techion settlement 569,395 6 (6 ) — — — — Issuance of shares upon execution of warrants 64,374 1 51 — (3,385 ) (52 ) — Issuance of shares upon public offering 5,899,500 60 53,018 — — — 53,078 Equity component of deferred financing costs of shares upon public offering — — 495 — — — 495 Repurchase of Common Stock — — — — (5,000 ) (31 ) (31 ) Share-based compensation expense related to share-based award — — 6,913 — — — 6,913 Net loss — — — (21,997 ) — — (21,997 ) Balance at June 30, 2018 34,869,450 $ 349 $ 120,607 $ (60,957 ) (8,385 ) $ (83 ) $ 59,916 Preferred and Common Stock On April 30, 2018, the Company completed an underwritten public offering of 5,899,500 shares of common stock of the Company at the public offering price of $9.75 per share. The Company received net proceeds of approximately $53.6 million after deducting underwriting discounts and commissions and estimated offering expenses. On May 22, 2017, Eloxx Limited entered into a Share Purchase Agreement (the “2017 SPA”) (and subsequently joinder agreements) with certain existing and new investors, whereby, an aggregate gross amount of $21.5 million, which included the conversion of certain loans (as detailed in Note 6), was received by Eloxx Limited in exchange for the issuance of 7,136,289 shares of Series C preferred stock with a par value of $0.01 with the initial closing, of which 39,293 shares were issued as a result of the anti-dilution effect of the Reverse Merger. The related issuance costs of $0.6 million were recorded in the three and six months ended June 30, 2017. All outstanding shares of Series C preferred stock were converted to common stock upon closing of the Reverse Merger. In connection with the 2017 SPA, the Company granted 142,524 warrants to purchase 142,524 shares of Series C preferred stock to certain service providers as finder fee compensation. Upon the closing of the Reverse Merger, the Company issued 6,333,333 shares of common stock related to the closing of the 2017 SPA with a par value of $0.01 for an aggregate gross amount of $17.5 million. Additionally, Sevion raised $1.5 million prior to the Reverse Merger. The related issuance costs recorded in the three and six months ended June 30, 2018 for these transactions was $0.5 million. Warrants Transactions related to warrants to purchase the Company’s common stock during the period ended June 30, 2018, were as follows: Shares Weighted average exercise price Weighted average remaining contractual life Warrants outstanding at December 31, 2017 480,049 $ 3.97 4.24 Exercised (64,374 ) 0.08 Forfeited (68,434 ) 8.00 Warrants outstanding at June 30, 2018 347,241 $ 3.77 4.40 Warrants exercisable at June 30,2018 347,241 $ 3.77 4.40

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	10. Stock-Based Compensation Prior to April 20, 2018, the Company had two equity compensation plans; the Sevion 2008 Incentive Compensation Plan (the “2008 Plan”) and the Eloxx Limited 2013 Share Ownership and Option Plan (the “2013 Plan”). On April 20, 2018, the Company’s 2018 Equity Incentive Plan (the “2018 Plan”) became effective. All of the plans are explained in detail below. The 2018 Equity Incentive Plan On March 12, 2018, our Board of Directors (the “Board”) adopted the 2018 Plan which was subsequently approved by our stockholders on March 26, 2018. On April 20, 2018, the 2018 Plan became effective and the Company ceased granting awards under each of the 2008 Plan and the 2013 Plan (the “Prior Plans”). The purpose of the 2018 Plan is to provide a means whereby the Company can align the long-term financial interests of its employees, consultants, and directors with the financial interests of its stockholders. In addition, the Board believes that the ability to grant options and other equity-based awards will help the Company to attract, retain, and motivate employees, consultants, and directors and encourages them to devote their best efforts to the Company’s business and financial success. The 2018 Plan authorizes the grant and issuance of awards that may take the form of stock options, stock appreciation rights, restricted stock, stock units, and performance-based incentive awards. The 2018 Plan became effective on April 20, 2018, with the outstanding awards and shares available for future grants under the Prior Plans being assumed by the 2018 Plan and the total number of shares available for awards to employees, non-employee directors and other key personnel increased by 5,000,000 shares. As of June 30, 2018, there were 3,765,654 shares available for future grant under the 2018 Plan, which represents approximately 11% of the Company’s outstanding common equity. The 2008 Incentive Compensation Plan In December 2008, the Company adopted the 2008 Incentive Compensation Plan (the “2008 Plan”), which provided for the grant of stock options, stock grants and stock purchase rights to certain designated employees and certain other persons performing services for the Company, as designated by the Company’s Board of Directors. Upon effectiveness of the 2018 Plan, all outstanding awards and all shares available for issuance in the 2008 Plan were incorporated into the 2018 Plan. The 2013 Share Ownership and Option Plan In December 2013, Eloxx Limited’s Board of Directors adopted the 2013 Plan in accordance with section 102 and 3(i) of the Israeli Income Tax Ordinance (the “2013 Plan”). Under the 2013 Plan, options to purchase ordinary shares of Eloxx Limited or ordinary shares of Eloxx Limited may be granted to employees, officers, directors, service providers and consultants of Eloxx Limited. Upon effectiveness of the 2018 Plan, all outstanding awards and all shares available for issuance in the 2013 Plan were incorporated into the 2018 Plan. Summary of Option Activity Transactions related to the grant of options to employees and directors during the period ended June 30, 2018 were as follows: Shares Weighted average exercise price Weighted average remaining contractual life Aggregate intrinsic value Options outstanding at December 31, 2017 3,215,661 $ 4.91 7.70 $ 15,174,026 Granted 1,470,141 18.44 Exercised (667,130 ) 0.13 Forfeited (148,435 ) 4.69 Options outstanding at June 30, 2018 3,870,237 $ 10.66 8.70 $ 28,689,787 Options exercisable at June 30,2018 1,275,487 $ 10.72 6.90 $ 16,685,166 (1) Includes 141,389 option grant to a director at $23.27 per share which fully vested on the grant date. The aggregate intrinsic value represents the total intrinsic value (the difference between the deemed fair value of the Company’s Common Stock as of June 30, 2018, and the exercise price, multiplied by the number of in-the-money options) that would have been received by the option holders had all option holders exercised their options on June 30, 2018. This amount is impacted by the changes in the fair value of the Company’s shares. The weighted average grant date fair value of the options granted during the period ended June 30, 2018, was $11.59. Summary of Restricted Stock Unit Activity Transactions related to the grant of restricted stock units to employees and directors during the period ended June 30, 2018 were as follows: Shares Weighted average grant date fair value price Unvested at December 31, 2017 663,212 $ 8.00 Granted 207,852 15.03 Vested — — Forfeited — — Unvested at June 30, 2018 871,064 $ 9.68 The total equity-based compensation expense related to all of the Company’s equity-based awards were recognized as follows: For the Three Months Ended June 30, For the Six Months Ended June 30, 2018 2017 2018 2017 Research and development $ 329 $ 6 $ 411 $ 12 General and administrative 5,849 5 6,502 9 Total stock-based compensation expenses $ 6,178 $ 11 $ 6,913 $ 21 On January 15,2018, the Company issued an award outside of the 2008 Plan and 2013 Plan to an employee of the Company in the form of an option to purchase 69,000 shares of the Company’s common stock with an exercise price per share equal to $6.65. Subject to continued service through the vesting date, one-sixteenth of the awards will vest on each quarterly anniversary of the grant date. As of June 30, 2018, 732,212 options to purchase the Company’s stock and 663,212 restricted share units that were issued outside of the 2008 Plan and 2013 Plan were outstanding. On June 15, 2018, the Company issued a fully vested stock award to a director of 141,389 shares at $23.27.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes The United States enacted the Tax Cuts and Jobs Act (“Tax Act”) on December 22, 2017, most provisions of which took effect in years beginning after December 31, 2017. The Tax Act made substantial changes to U.S. taxation of corporations, including lowering the U.S. federal corporate income tax rate from 34% to 21%. The effect on deferred tax assets and liabilities of a change in law or tax rates is recognized in income in the period that includes the enactment date. The Tax Act also includes a provision designed to currently tax global intangible low-taxed income (“GILTI”). The Company elected to record the U.S. income tax effect of future GILTI inclusions in the period in which they arise, if ever, and the Company has estimated that there will not be a GILTI inclusion for the year ended December 31, 2018. In accordance with ASC 740-270, Income Taxes – Interim Reporting, the Company is required at the end of each interim period to determine the best estimate of its annual effective tax rate and apply that rate to year-to-date ordinary income or loss. The resulting tax expense (or benefit) is adjusted for the tax effect of specific events, if any, required to be discretely recognized in the interim period as they occur. For the six months ended June 30, 2018 and 2017, the Company recorded zero and immaterial tax expense (or benefit), respectively, attributable to the operations of a U.S. subsidiary which files income tax returns on a stand-alone basis. The Company has not recorded net deferred tax assets as of June 30, 2018, or December 31, 2017, because it maintained a full valuation allowance against all material deferred tax assets, and management has determined that it is more likely than not, that the Company will be unable to realize those future benefits. The Company’s effective tax rate differs from the statutory rates of 21% and 34% as of June 30, 2018 and 2017, respectively, due to losses for which no future benefit is expected. As of June 30, 2018, and December 31, 2017, the Company had no uncertain tax positions recorded in its consolidated balance sheets. After the enactment of the Tax Act, the SEC issued Staff Accounting Bulletin No. 118 (“SAB 118”) to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Tax Act. In our financial statements for the period ended December 31, 2017, we calculated an estimate of the impact of the Tax Act related to the remeasurement of our net U.S. deferred tax asset due to the change in U.S. federal corporate income tax rate. The provisional amount recorded was deferred tax expense of $10.2 million, but which was fully and equally offset by a deferred tax benefit related to a corresponding reduction in our valuation allowance. The Company has not adjusted the provisional amount in these financial statements for the period ended June 30, 2018, but we expect to complete this analysis within the one-year measurement period provided by SAB 118.

Net Loss Per Share

Net Loss Per Share	6 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
Net Loss Per Share	12. Net Loss Per Share The loss and the weighted average number of shares used in computing basic and diluted net loss per share for the periods, is as follows (amounts in thousands, except share numbers): Three months ended June 30, Six months ended June 30, 2018 2017 2018 2017 Numerator: Net loss $ 13,406 $ 3,878 $ 21,997 $ 6,556 Dividends accumulated for the period (1) — 483 — 867 Net loss available to stockholders of Common Stock $ 13,406 $ 4,361 $ 21,997 $ 7,423 Denominator: Shares used in computing net loss per share of Common Stock, basic and diluted (2) 31,839,303 4,205,277 29,695,430 4,205,277 Net loss per share of Common Stock, basic and diluted $ 0.42 $ 1.04 $ 0.74 $ 1.77 (1) The net loss used for the computation of basic and diluted net loss per share include 8% per share per annum compounded annually which was related to distributions for preferred stockholders of Eloxx Limited. On December 19, 2017, in conjunction with the Reverse Merger all preferred shares were converted to common shares. (2) The following potentially dilutive securities have been excluded from the computation of diluted weighted average shares outstanding as their effect would be anti-dilutive: Six months ended June 30, 2018 2017 Options to purchase common stock 3,870,237 1,873,809 Restricted stock units 871,064 — Warrants 347,241 5,282,794 Preferred stock — 13,415,116 Total potential common stock equivalents 5,088,542 20,571,719

Segment and Geographic Informat

Segment and Geographic Information	6 Months Ended
	Jun. 30, 2018
Segment Reporting [Abstract]
Segment and Geographic Information	13. Segment and Geographic Information Operating segments are defined as components of an enterprise (business activity from which it earns revenue and incurs expenses) about which discrete financial information is available and regularly reviewed by the chief operating decision maker in deciding how to allocate resources and in assessing performance. The Company’s chief operating decision maker is the Chief Executive Officer. The chief operating decision maker reviews consolidated operating results to make decisions about allocating resources and assessing performance for the entire company. The Company views its operations and manages its business as one operating segment; however, it operates in two geographic regions: United States (Waltham, MA) and Israel (Rehovot).

Summary of Significant Accoun19

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Basis of presentation and principles of consolidation	Basis of presentation and principles of consolidation The accompanying unaudited interim consolidated financial statements have been prepared by the Company in accordance with accounting principles generally accepted in the United States (“GAAP”) as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”). Certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted, as permitted by such rules and regulations. These interim consolidated financial statements, in the opinion of management, reflect all normal recurring adjustments necessary for a fair presentation of the Company’s financial position, results of operations, and cash flows for the interim periods ended June 30, 2018 and 2017. The Unaudited Consolidated Statements of Operations includes the Company’s operating expenses related to research and development and general and administrative, along with reverse merger related expenses, which were substantially comprised of fees for professional services. The results of operations for the interim periods are not necessarily indicative of the results of operations to be expected for the full year. These interim financial statements should be read in conjunction with the audited financial statements as of and for the year ended December 31, 2017, and the notes thereto, which are included in the Company’s Annual Report on Form 10-K filed with the Securities and Exchange Commission (the “SEC”) on March 16, 2018.
Summary of Accounting Policies	Summary of Accounting Policies The significant accounting policies and estimates used in the preparation of the condensed consolidated financial statements are described in the Company’s audited financial statements as of and for the year ended December 31, 2017, and the notes thereto, which are included in the Company’s Annual Report on Form 10-K. There have been no material changes in the Company’s significant accounting policies during the six months ended June 30, 2018.
Recent Accounting Pronouncements adopted	Recent Accounting Pronouncements adopted In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230): “Restricted Cash” (ASU 2016-18), which requires companies to include amounts generally described as restricted cash and restricted cash equivalents in cash and cash equivalents when reconciling beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The amendments in this update are effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The Company adopted the new guidance using the retrospective transition method as required with respect to each period presented. This new guidance does not have a material impact on the Company’s consolidated financial statements. In February 2016, the FASB issued ASU No. 2016-02, “Leases”. This guidance will require that lease arrangements longer than 12 months result in an entity recognizing an asset and liability equal to the present value of the lease payments in the statement of financial position. This guidance is effective for annual periods beginning after December 15, 2018, and interim periods therein. This standard requires a modified retrospective transition approach for all leases existing at, or entered into after, the date of initial application, with an option to use certain transition relief. Early adoption is permitted. The Company is currently evaluating the impact that the adoption of ASU 2016-02 will have on its financial statements and related disclosures.

Nature of the Business (Tables)

Nature of the Business (Tables)	6 Months Ended
	Jun. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Schedule of Impact on Specific Line Items in Accompanying Consolidated Statement of Operations	The impact on specific line items in the accompanying consolidated statement of operations for the three months ended March 31, 2018 is presented below (in thousands): Three Months Ended March 31, 2018 As reported Adjustments As corrected Operating expenses: Research and development $ 4,013 $ 381 $ 4,394 General and administrative 2,480 913 3,393 Reverse merger related expenses 2,055 (1,294 ) 761 Total operating expenses $ 8,548 $ — $ 8,548

Prepaids and Other Current As21

Prepaids and Other Current Assets (Tables)	6 Months Ended
	Jun. 30, 2018
Text Block [Abstract]
Prepaids and Other Current Assets	Prepaids and other current assets as of June 30, 2018 and December 31, 2017 consisted of the following (in thousands): As of June 30, 2018 December 31, 2017 Prepaid insurance $ 290 $ 242 Other governmental agencies receivables — 88 Prepaid other 168 25 $ 458 $ 355

Property and Equipment, net (Ta

Property and Equipment, net (Tables)	6 Months Ended
	Jun. 30, 2018
Property Plant And Equipment [Abstract]
Property and equipment, net	Property and equipment, net consisted of the following (in thousands): As of June 30, 2018 December 31, 2017 Computers and software $ 200 $ 124 Office furniture and equipment 120 118 Laboratory equipment — 37 Leasehold improvements 73 53 393 332 Less: Accumulated depreciation 91 54 Property and equipment, net $ 302 $ 278

Accrued Expenses (Tables)

Accrued Expenses (Tables)	6 Months Ended
	Jun. 30, 2018
Payables And Accruals [Abstract]
Accrued expenses	Accrued expenses as of June 30, 2018 and December 31, 2017 consisted of the following (in thousands): As of June 30, 2018 December 31, 2017 Accrued payroll and related expenses $ 700 $ 402 Accrued research and development expenses 712 704 Accrued professional services 846 787 $ 2,258 $ 1,893

Convertible Loan (Tables)

Convertible Loan (Tables)	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Reconciliations for Liabilities Measured and Recorded at Fair Value on Recurring Basis, Using Significant Unobservable Inputs	The following table presents reconciliations for the Company’s liabilities measured and recorded at fair value on a recurring basis, using significant unobservable inputs (in thousands): Significant Unobservable Inputs (Level 3) Balance at January 26, 2017 $ (308 ) Amortization and revaluation embedded conversion feature (317 ) Conversion of convertible loan into Series C preferred stock 625 Balance at December 31, 2017 $ —

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Schedule of Transactions Related to Stockholders Equity	Transactions related to stockholders’ equity of the Company during the six months ended June 30, 2018 were as follows (in thousands, except share amounts): Common stock Additional paid-in Accumulated Treasury stock Total stockholders' Shares Amount Capital deficit Shares Amount equity Balance at December 31, 2017 27,527,738 $ 274 $ 60,047 $ (38,960 ) — $ — $ 21,361 Issuance of common stock related to share-based compensation 808,443 8 89 — — — 97 Issuance of common stock Techion settlement 569,395 6 (6 ) — — — — Issuance of shares upon execution of warrants 64,374 1 51 — (3,385 ) (52 ) — Issuance of shares upon public offering 5,899,500 60 53,018 — — — 53,078 Equity component of deferred financing costs of shares upon public offering — — 495 — — — 495 Repurchase of Common Stock — — — — (5,000 ) (31 ) (31 ) Share-based compensation expense related to share-based award — — 6,913 — — — 6,913 Net loss — — — (21,997 ) — — (21,997 ) Balance at June 30, 2018 34,869,450 $ 349 $ 120,607 $ (60,957 ) (8,385 ) $ (83 ) $ 59,916
Summary of Warrants Outstanding	Transactions related to warrants to purchase the Company’s common stock during the period ended June 30, 2018, were as follows: Shares Weighted average exercise price Weighted average remaining contractual life Warrants outstanding at December 31, 2017 480,049 $ 3.97 4.24 Exercised (64,374 ) 0.08 Forfeited (68,434 ) 8.00 Warrants outstanding at June 30, 2018 347,241 $ 3.77 4.40 Warrants exercisable at June 30,2018 347,241 $ 3.77 4.40

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Transactions Related to Grant of Options to Employees and Directors	Transactions related to the grant of options to employees and directors during the period ended June 30, 2018 were as follows: Shares Weighted average exercise price Weighted average remaining contractual life Aggregate intrinsic value Options outstanding at December 31, 2017 3,215,661 $ 4.91 7.70 $ 15,174,026 Granted 1,470,141 18.44 Exercised (667,130 ) 0.13 Forfeited (148,435 ) 4.69 Options outstanding at June 30, 2018 3,870,237 $ 10.66 8.70 $ 28,689,787 Options exercisable at June 30,2018 1,275,487 $ 10.72 6.90 $ 16,685,166 (1) Includes 141,389 option grant to a director at $23.27 per share which fully vested on the grant date.
Transactions Related to Grant of Restricted Stock Units to Employees and Directors	Transactions related to the grant of restricted stock units to employees and directors during the period ended June 30, 2018 were as follows: Shares Weighted average grant date fair value price Unvested at December 31, 2017 663,212 $ 8.00 Granted 207,852 15.03 Vested — — Forfeited — — Unvested at June 30, 2018 871,064 $ 9.68
Summary of Allocated Stock-based Compensation Expense	The total equity-based compensation expense related to all of the Company’s equity-based awards were recognized as follows: For the Three Months Ended June 30, For the Six Months Ended June 30, 2018 2017 2018 2017 Research and development $ 329 $ 6 $ 411 $ 12 General and administrative 5,849 5 6,502 9 Total stock-based compensation expenses $ 6,178 $ 11 $ 6,913 $ 21

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	6 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
Schedule of Loss and Weighted Average Number of Shares Used in Computing Basic and Diluted Net Loss Per Share	The loss and the weighted average number of shares used in computing basic and diluted net loss per share for the periods, is as follows (amounts in thousands, except share numbers): Three months ended June 30, Six months ended June 30, 2018 2017 2018 2017 Numerator: Net loss $ 13,406 $ 3,878 $ 21,997 $ 6,556 Dividends accumulated for the period (1) — 483 — 867 Net loss available to stockholders of Common Stock $ 13,406 $ 4,361 $ 21,997 $ 7,423 Denominator: Shares used in computing net loss per share of Common Stock, basic and diluted (2) 31,839,303 4,205,277 29,695,430 4,205,277 Net loss per share of Common Stock, basic and diluted $ 0.42 $ 1.04 $ 0.74 $ 1.77 (1) The net loss used for the computation of basic and diluted net loss per share include 8% per share per annum compounded annually which was related to distributions for preferred stockholders of Eloxx Limited. On December 19, 2017, in conjunction with the Reverse Merger all preferred shares were converted to common shares. (2) The following potentially dilutive securities have been excluded from the computation of diluted weighted average shares outstanding as their effect would be anti-dilutive: Six months ended June 30, 2018 2017 Options to purchase common stock 3,870,237 1,873,809 Restricted stock units 871,064 — Warrants 347,241 5,282,794 Preferred stock — 13,415,116 Total potential common stock equivalents 5,088,542 20,571,719

Nature of the Business - Additi

Nature of the Business - Additional Information (Detail)	Apr. 30, 2018USD ($)$ / sharesshares	Dec. 19, 2017$ / sharesshares	Jun. 30, 2018USD ($)$ / shares	Mar. 31, 2018USD ($)	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)Disease$ / shares	Jun. 30, 2017USD ($)	Dec. 31, 2017USD ($)$ / shares
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Number of rare diseases | Disease						1,800
Common stock, par value | $ / shares			$ 0.01			$ 0.01		$ 0.01
Cash and cash equivalents			$ 63,412,000		$ 13,360,000	$ 63,412,000	$ 13,360,000	$ 24,049,000
Net loss			(13,406,000)		(3,878,000)	(21,997,000)	(6,556,000)
Net cash used in operating activities						(14,208,000)	(5,902,000)
Accumulated deficit			(60,957,000)			(60,957,000)		$ (38,960,000)
Research and development expense			4,150,000	$ 4,394,000	2,595,000	8,544,000	4,950,000
General and administrative expense			9,560,000	3,393,000	$ 584,000	12,953,000	861,000
Reverse merger related expenses				761,000
Net cash provided by (used in) operating activities						(14,208,000)	(5,902,000)
Net cash provided by (used in) investing activities						(101,000)	(96,000)
Net cash provided by (used in) financing activities						53,668,000	$ 17,169,000
Adjustment [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Net loss				0		0
Net cash used in operating activities				0		0
Research and development expense			400,000	381,000		400,000
General and administrative expense			900,000	913,000		900,000
Reverse merger related expenses			$ (1,300,000)	(1,294,000)		(1,300,000)
Net cash provided by (used in) operating activities				0		0
Net cash provided by (used in) investing activities				0		0
Net cash provided by (used in) financing activities				$ 0		0
Underwritten Public Offering [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Common stock, shares issued | shares	5,899,500
Common stock public offering price | $ / shares	$ 9.75
Net proceeds from common stock shares issued at public offering	$ 53,600,000					$ 53,571,000
Eloxx Limited [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Reverse stock split		0.05
Issuance of shares in exchange of all outstanding capital stock | shares		20,316,656
Common stock, par value | $ / shares		$ 0.01

Nature of the Business - Summar

Nature of the Business - Summary of Consolidated Statement of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Operating expenses:
Research and development	$ 4,150	$ 4,394	$ 2,595	$ 8,544	$ 4,950
General and administrative	9,560	3,393	584	12,953	861
Reverse merger related expenses		761
Total operating expenses	13,543	8,548	$ 3,179	22,091	$ 5,811
Reported [Member]
Operating expenses:
Research and development		4,013
General and administrative		2,480
Reverse merger related expenses		2,055
Total operating expenses		8,548
Adjustment [Member]
Operating expenses:
Research and development	400	381		400
General and administrative	900	913		900
Reverse merger related expenses	$ (1,300)	$ (1,294)		$ (1,300)

Prepaids and Other Current As30

Prepaids and Other Current Assets - Schedule of Other Current Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Prepaid insurance	$ 290	$ 242
Other governmental agencies receivables		88
Prepaid other	168	25
Total	$ 458	$ 355

Property and Equipment, net - P

Property and Equipment, net - Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Cost	$ 393	$ 332
Less: Accumulated depreciation	91	54
Property and equipment, net	302	278
Computers and software [Member]
Property, Plant and Equipment [Line Items]
Cost	200	124
Office furniture and equipment [Member]
Property, Plant and Equipment [Line Items]
Cost	120	118
Laboratory Equipment [Member]
Property, Plant and Equipment [Line Items]
Cost		37
Leasehold improvement [Member]
Property, Plant and Equipment [Line Items]
Cost	$ 73	$ 53

Property and Equipment, net - A

Property and Equipment, net - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Property Plant And Equipment [Abstract]
Depreciation expenses	$ 25	$ 7	$ 46	$ 13

Accrued Expenses - Accrued Expe

Accrued Expenses - Accrued Expenses (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Payables And Accruals [Abstract]
Accrued payroll and related expenses	$ 700	$ 402
Accrued research and development expenses	712	704
Accrued professional services	846	787
Total	$ 2,258	$ 1,893

Convertible Loan - Additional I

Convertible Loan - Additional Information (Detail) - Convertible Notes Payable [Member] $ in Thousands	May 31, 2017shares	Jan. 26, 2017USD ($)Lender	Jun. 30, 2018	Dec. 31, 2017USD ($)
Debt Conversion [Line Items]
Debt instrument, periodic payment, interest				$ 700
Series C Preferred Stock [Member]
Debt Conversion [Line Items]
Stock issued during period, shares, conversion of convertible securities | shares	825,213
Financial and Other Expense [Member]
Debt Conversion [Line Items]
Financial and other expenses, as a result of changes in the embedded instruments				$ 700
Fair Value, Inputs, Level 3 [Member]
Debt Conversion [Line Items]
Fair value assigned to the embedded conversion feature on the issuance dates		$ 308
Convertible loan agreement [Member]
Debt Conversion [Line Items]
Debt instrument, convertible, latest date		2 years
Debt instrument, convertible, terms of conversion feature			According to the Agreement, the outstanding portion of the Convertible Loan (without accrued interest) automatically converts upon the consummation of an equity investment by a third party of an aggregate amount of at least $5.0 million (the “Qualified Equity Investment”), prior to the date that is two years from the Closing Date (the “Maturity Date”), into equity securities of the same class issued by the Company in such Qualified Equity Investment.
Convertible loan agreement [Member] | Lenders [Member]
Debt Conversion [Line Items]
Number of shareholder as lenders | Lender		5
Debt instrument, interest rate, stated percentage		5.00%
Debt instrument, face amount		$ 2,500
Convertible loan agreement [Member] | Minimum [Member]
Debt Conversion [Line Items]
Qualified equity investment		$ 5,000

Convertible Loan - Reconciliati

Convertible Loan - Reconciliations for the Company's Liabilities Measured and Recorded at Fair Value on a Recurring Basis (Detail) - Fair Value, Inputs, Level 3 [Member] - Convertible Notes Payable [Member] $ in Thousands	11 Months Ended
	Dec. 31, 2017USD ($)
Debt Conversion [Line Items]
Beginning Balance	$ (308)
Amortization and revaluation embedded conversion feature	(317)
Series C Preferred Stock [Member]
Debt Conversion [Line Items]
Conversion of convertible loan into Series C preferred stock	$ 625

Related Parties - Additional In

Related Parties - Additional Information (Detail) - USD ($)	Jun. 13, 2018	Aug. 29, 2013	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Schedule Of Related Party Transaction Details [Line Items]
Research and development expense			$ 4,150,000	$ 4,394,000	$ 2,595,000	$ 8,544,000	$ 4,950,000
General and administrative expenses			9,560,000	$ 3,393,000	$ 584,000	12,953,000	861,000
Accrued expenses			2,258,000			2,258,000		$ 1,893,000
Technion Research and Development Foundation Ltd [Member] | Technion Agreement [Member]
Schedule Of Related Party Transaction Details [Line Items]
Research and development expense		$ 100,000				0	0	3,400,000
General and administrative expenses						0	$ 7,000
Accrued expenses			$ 25,000			25,000		$ 25,000
Aggregate milestone payment						$ 6,100,000
Shares issued	569,395

Stockholder's Equity - Schedule

Stockholder's Equity - Schedule of Transaction Related to Stockholder's Equity (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Beginning balance			$ 21,361
Issuance of common stock related to share-based compensation			97
Issuance of shares upon public offering			53,078
Equity component of deferred financing costs of shares upon public offering			495
Repurchase of Common Stock			(31)
Share-based compensation expense related to share-based award			6,913
Net loss	$ (13,406)	$ (3,878)	(21,997)	$ (6,556)
Ending balance	59,916		59,916
Common stock [Member]
Beginning balance			$ 274
Beginning balance, shares			27,527,738
Issuance of common stock related to share-based compensation			$ 8
Issuance of common stock related to share-based compensation, shares			808,443
Issuance of common stock Techion settlement			$ 6
Issuance of common stock Techion settlement, shares			569,395
Issuance of shares upon execution of warrants			$ 1
Issuance of shares upon execution of warrants, shares			64,374
Issuance of shares upon public offering			$ 60
Issuance of shares upon public offering, shares			5,899,500
Ending balance	$ 349		$ 349
Beginning balance, shares	34,869,450		34,869,450
Additional paid-in Capital [Member]
Beginning balance			$ 60,047
Issuance of common stock related to share-based compensation			89
Issuance of common stock Techion settlement			(6)
Issuance of shares upon execution of warrants			51
Issuance of shares upon public offering			53,018
Equity component of deferred financing costs of shares upon public offering			495
Share-based compensation expense related to share-based award			6,913
Ending balance	$ 120,607		120,607
Accumulated deficit [Member]
Beginning balance			(38,960)
Net loss			(21,997)
Ending balance	(60,957)		(60,957)
Treasury stock [Member]
Issuance of shares upon execution of warrants			$ (52)
Issuance of shares upon execution of warrants, shares			(3,385)
Repurchase of Common Stock			$ (31)
Repurchase of Common Stock, shares			(5,000)
Ending balance	$ (83)		$ (83)
Beginning balance, shares	(8,385)		(8,385)

Stockholder's Equity - Addition

Stockholder's Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Apr. 30, 2018	May 22, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Preferred stock, shares issued			0		0		0
Preferred stock, par value			$ 0.01		$ 0.01		$ 0.01
Common stock, shares issued			34,869,450		34,869,450		27,527,738
Common stock, par value			$ 0.01		$ 0.01		$ 0.01
Sevion Therapeutics Inc [Member]
Equity method investments			$ 1,500		$ 1,500
2017 Share Purchase Agreement [Member] | After Merger [Member]
Net proceeds from common stock shares issued at public offering					17,500
Stock issuance costs			$ 500		$ 500
Common stock, shares issued			6,333,333		6,333,333
Common stock, par value			$ 0.01		$ 0.01
Series C Preferred Stock [Member] | 2017 Share Purchase Agreement [Member]
Proceeds from issuance of preferred stock		$ 21,500
Preferred stock, shares issued		7,136,289
Preferred stock, par value		$ 0.01
Stock issuance costs				$ 600		$ 600
Series C Preferred Stock [Member] | 2017 Share Purchase Agreement [Member] | Share Based Contractor Compensation [Member]
Number of common stock in warrant			142,524		142,524
Warrant granted					142,524
Series C Preferred Stock [Member] | 2017 Share Purchase Agreement [Member] | Sevion Therapeutics Inc [Member]
Shares issued as a result of the anti-dilution effect of the Reverse Merger		39,293
Underwritten Public Offering [Member]
Common stock, shares issued	5,899,500
Common stock public offering price	$ 9.75
Net proceeds from common stock shares issued at public offering	$ 53,600				$ 53,571

Stockholder's Equity - Schedu39

Stockholder's Equity - Schedule of Transaction Related to Warrants to Purchase Common Stock (Detail) - $ / shares	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Stockholders Equity [Abstract]
Warrants outstanding beginning balance, Shares	480,049
Warrants exercised,Shares	(64,374)
Warrants forfeited, Shares	(68,434)
Warrants outstanding ending balance, Shares	347,241	480,049
Warrants exercisable, Shares	347,241
Warrants outstanding beginning balance, Weighted average exercise price	$ 3.97
Warrants exercised, Weighted average exercise price	0.08
Warrants forfeited, Weighted average exercise price	8
Warrants outstanding ending balance,Weighted average exercise price	3.77	$ 3.97
Warrants exercisable, Weighted average exercise price	$ 3.77
Warrants outstanding, Weighted average remaining contractual life	4 years 4 months 24 days	4 years 2 months 26 days
Warrants Exercisable, Weighted average remaining contractual life	4 years 4 months 24 days

Stock-based Compensation - Addi

Stock-based Compensation - Additional Information (Detail)	Jan. 15, 2018$ / sharesshares	Jun. 30, 2018$ / sharesshares	Apr. 20, 2018shares	Apr. 19, 2018CompensationPlan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity compensation plans | CompensationPlan				2
Weighted average grant date fair value of options granted | $ / shares		$ 11.59
Options to purchase common stock granted		732,212
Excercise price per share | $ / shares		$ 18.44
Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Excercise price per share | $ / shares		$ 23.27
Performance Option Awards [Member] | Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options to purchase common stock granted	69,000
Excercise price per share | $ / shares	$ 6.65
Option vesting description		Subject to continued service through the vesting date, one-sixteenth of the awards will vest on each quarterly anniversary of the grant date.
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted share units		663,212
Restricted Stock Units [Member] | Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fully vested stock award issued	141,389
Fully vested stock award issued, exercise price | $ / shares	$ 23.27
2018 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance			5,000,000
Common stock available for future grant		3,765,654
Percentage of outstanding common equity as a proportion to shares available for grant		11.00%

Stock-based Compensation - Tran

Stock-based Compensation - Transactions Related to Grant of Options to Employees and Directors (Detail) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Amount
Options outstanding at beginning of year	3,215,661
Granted	1,470,141
Exercised	(667,130)
Forfeited	(148,435)
Options outstanding at end of year	3,870,237	3,215,661
Options exercisable at end of year	1,275,487
Weighted average exercise price
Options outstanding at beginning of year	$ 4.91
Granted	18.44
Exercised	0.13
Forfeited	4.69
Options outstanding at end of year	10.66	$ 4.91
Options exercisable at end of year	$ 10.72
Weighted average remaining contractual life
Options outstanding	8 years 8 months 12 days	7 years 8 months 12 days
Options exercisable at end of year	6 years 10 months 24 days
Aggregate intrinsic value
Options outstanding at beginning of year	$ 15,174,026
Options outstanding at end of year	28,689,787	$ 15,174,026
Options exercisable at end of year	$ 16,685,166

Stock-based Compensation - Tr42

Stock-based Compensation - Transactions Related to Grant of Options to Employees and Directors (Parenthetical) (Detail)	6 Months Ended
	Jun. 30, 2018$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option granted | shares	1,470,141
Weighted average excercise price of stock option granted | $ / shares	$ 18.44
Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option granted | shares	141,389
Weighted average excercise price of stock option granted | $ / shares	$ 23.27

Stock-based Compensation - Tr43

Stock-based Compensation - Transactions Related to Grant of Restricted Stock Units to Employees and Directors (Detail) - Restricted Stock Units [Member]	6 Months Ended
	Jun. 30, 2018$ / sharesshares
Amount
Unvested at December 31, 2017 | shares	663,212
Granted | shares	207,852
Unvested at June 30, 2018 | shares	871,064
Weighted average grant date fair value price
Unvested at December 31, 2017 | $ / shares	$ 8
Granted | $ / shares	15.03
Unvested at June 30, 2018 | $ / shares	$ 9.68

Stock-based Compensation - Summ

Stock-based Compensation - Summary of Allocated Stock-based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expenses	$ 6,178	$ 11	$ 6,913	$ 21
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expenses	329	6	411	12
General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expenses	$ 5,849	$ 5	$ 6,502	$ 9

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Effective income tax rate reconciliation, at federal statutory income tax rate, percent	21.00%	34.00%	34.00%
Deferred tax assets, net	$ 0		$ 0
Liability for uncertain tax positions	0		$ 0
Income tax expense (benefit)	0
Provisional deferred tax expense	$ 10,200,000

Net Loss Per Share - Weighted A

Net Loss Per Share - Weighted Average Number of Shares Used in Computing Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Numerator:
Net loss		$ 13,406	$ 3,878	$ 21,997	$ 6,556
Dividends accumulated for the period	[1]		483		867
Net loss available to stockholders of Common Stock		$ 13,406	$ 4,361	$ 21,997	$ 7,423
Denominator:
Shares used in computing net loss per share of Common Stock, basic and diluted	[2]	31,839,303	4,205,277	29,695,430	4,205,277
Net loss per share of Common Stock, basic and diluted		$ 0.42	$ 1.04	$ 0.74	$ 1.77
[1]	The net loss used for the computation of basic and diluted net loss per share include 8% per share per annum compounded annually which was related to distributions for preferred stockholders of Eloxx Limited. On December 19, 2017, in conjunction with the Reverse Merger all preferred shares were converted to common shares.
[2]	The following potentially dilutive securities have been excluded from the computation of diluted weighted average shares outstanding as their effect would be anti-dilutive: Six months ended June 30, 2018 2017 Options to purchase common stock 3,870,237 1,873,809 Restricted stock units 871,064 — Warrants 347,241 5,282,794 Preferred stock — 13,415,116 Total potential common stock equivalents 5,088,542 20,571,719

Net Loss Per Share - Weighted47

Net Loss Per Share - Weighted Average Number of Shares Used in Computing Basic and Diluted Net Loss Per Share (Parenthetical) (Detail) - shares	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Percentage of dividend rate	8.00%
Total potential common stock equivalents	5,088,542	20,571,719
Preferred Stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total potential common stock equivalents		13,415,116
Options to Purchase Common Stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total potential common stock equivalents	3,870,237	1,873,809
Restricted Stock Units [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total potential common stock equivalents	871,064
Warrants [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total potential common stock equivalents	347,241	5,282,794

Segment and Geographic Inform48

Segment and Geographic Information - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2018SegmentRegion
Domestic And Foreign Operation [Abstract]
Number of operating segments | Segment	1
Number of geographic regions | Region	2