Regulus Therapeutics (RGLS) 10-Q 12 Nov 19 2019 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Nov. 08, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Entity Registrant Name	REGULUS THERAPEUTICS INC.
Entity Central Index Key	0001505512
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		20,927,053
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Current Reporting Status	Yes
Entity Shell Company	false

CONDENSED BALANCE SHEETS

CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 14,646	$ 13,935
Contract and other receivables	699	26
Prepaid materials, net	3,826	4,194
Prepaid expenses and other current assets	358	1,140
Total current assets	19,529	19,295
Property and equipment, net	1,042	7,806
Intangibles, net	303	500
Other assets	536	326
Total assets	21,410	27,927
Current liabilities:
Accounts payable	1,521	1,714
Accrued liabilities	1,212	1,625
Accrued compensation	925	1,601
Current portion of term loan, less debt issuance costs	14,626	16,575
Current portion of contract liabilities	24	2,572
Other current liabilities	2,696	2,559
Total current liabilities	21,004	26,646
Contract liabilities, less current portion	0	6
Deferred rent, less current portion	0	6,820
Other long-term liabilities	549	309
Total liabilities	21,553	33,781
Stockholders’ equity (deficit):
Class A-1 convertible preferred stock, $0.001 par value; 415,898 shares authorized, issued and outstanding at September 30, 2019 (unaudited) and December 31, 2018, respectively	0	0
Common stock, $0.001 par value; 200,000,000 shares authorized, 20,927,053 and 8,818,019 shares issued and outstanding at September 30, 2019 (unaudited) and December 31, 2018, respectively	21	9
Additional paid-in capital	406,258	386,860
Accumulated deficit	(406,422)	(392,723)
Total stockholders’ equity (deficit)	(143)	(5,854)
Total liabilities and stockholders’ equity (deficit)	$ 21,410	$ 27,927

CONDENSED BALANCE SHEETS (Paren

CONDENSED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	20,927,053	8,818,019
Common stock, shares outstanding	20,927,053	8,818,019
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	415,898	415,898
Preferred stock, shares issued	415,898	415,898
Preferred stock, shares outstanding	415,898	415,898

CONDENSED STATEMENTS OF CHANGES

CONDENSED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Convertible Preferred Stock	Common stock	Additional paid-in capital	Accumulated other comprehensive income (loss)	Accumulated deficit
Beginning balance (in shares) at Dec. 31, 2017			8,662,435
Beginning balance at Dec. 31, 2017	$ 35,216		$ 9	$ 381,199	$ (134)	$ (345,858)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon vesting of restricted stock units (in shares)			8,660
Stock-based compensation expense	1,627			1,627
Issuance of common stock under Employee Stock Purchase Plan (in shares)			21,377
Issuance of common stock under Employee Stock Purchase Plan	207			207
Issuance of common stock upon exercise of options (in shares)			328
Issuance of common stock upon exercise of options	1			1
Unrealized gain on short-term investments	7				7
Net loss	(16,025)					(16,025)
Ending balance (in shares) at Mar. 31, 2018			8,692,800
Ending balance at Mar. 31, 2018	22,876		$ 9	383,034	(127)	(360,040)
Beginning balance (in shares) at Dec. 31, 2017			8,662,435
Beginning balance at Dec. 31, 2017	35,216		$ 9	381,199	(134)	(345,858)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(40,146)
Ending balance (in shares) at Sep. 30, 2018			8,751,298
Ending balance at Sep. 30, 2018	1,578		$ 9	385,793	(64)	(384,160)
Beginning balance (in shares) at Mar. 31, 2018			8,692,800
Beginning balance at Mar. 31, 2018	22,876		$ 9	383,034	(127)	(360,040)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon vesting of restricted stock units (in shares)			8,745
Stock-based compensation expense	1,357			1,357
Unrealized gain on short-term investments	47				47
Net loss	(13,847)					(13,847)
Ending balance (in shares) at Jun. 30, 2018			8,701,545
Ending balance at Jun. 30, 2018	10,433		$ 9	384,391	(80)	(373,887)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon vesting of restricted stock units (in shares)			44,714
Stock-based compensation expense	1,390			1,390
Issuance of common stock under Employee Stock Purchase Plan (in shares)			5,039
Issuance of common stock under Employee Stock Purchase Plan	12			12
Unrealized gain on short-term investments	16				16
Net loss	(10,273)					(10,273)
Ending balance (in shares) at Sep. 30, 2018			8,751,298
Ending balance at Sep. 30, 2018	1,578		$ 9	385,793	(64)	(384,160)
Beginning balance (in shares) at Dec. 31, 2018			8,818,019
Beginning balance at Dec. 31, 2018	(5,854)		$ 9	386,860	0	(392,723)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon vesting of restricted stock units (in shares)			93,648
Stock-based compensation expense	959			959
Issuance of common stock under Employee Stock Purchase Plan (in shares)			2,369
Issuance of common stock under Employee Stock Purchase Plan	2			2
Issuance of common stock upon sales using ATM (in shares)			1,903,880
Issuance of common stock through ATM	2,084		$ 2	2,082
Net loss	(3,260)					(3,260)
Ending balance (in shares) at Mar. 31, 2019			10,817,916
Ending balance at Mar. 31, 2019	(6,069)		$ 11	389,903	0	(395,983)
Beginning balance (in shares) at Dec. 31, 2018			8,818,019
Beginning balance at Dec. 31, 2018	(5,854)		$ 9	386,860	0	(392,723)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(13,699)
Ending balance (in shares) at Sep. 30, 2019		415,898	20,927,053
Ending balance at Sep. 30, 2019	(143)		$ 21	406,258	0	(406,422)
Beginning balance (in shares) at Mar. 31, 2019			10,817,916
Beginning balance at Mar. 31, 2019	(6,069)		$ 11	389,903	0	(395,983)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon vesting of restricted stock units (in shares)			273,438
Stock-based compensation expense	321			321
Issuance of common stock upon exercise of options (in shares)			2,500
Issuance of common stock upon exercise of options	2			2
Issuance of common stock, preferred stock and warrants from private placement, net of offering costs (in shares)		415,898	9,730,534
Issuance of common stock, preferred stock and warrants from private placement, net of offering costs	15,505		$ 10	15,495
Net loss	(5,016)					(5,016)
Ending balance (in shares) at Jun. 30, 2019		415,898	20,824,388
Ending balance at Jun. 30, 2019	4,743		$ 21	405,721	0	(400,999)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon vesting of restricted stock units (in shares)			100,749
Stock-based compensation expense	536			536
Issuance of common stock under Employee Stock Purchase Plan (in shares)			1,666
Issuance of common stock under Employee Stock Purchase Plan	1			1
Issuance of common stock upon exercise of options (in shares)			250
Issuance of common stock upon exercise of options	0			0
Net loss	(5,423)					(5,423)
Ending balance (in shares) at Sep. 30, 2019		415,898	20,927,053
Ending balance at Sep. 30, 2019	$ (143)		$ 21	$ 406,258	$ 0	$ (406,422)

CONDENSED STATEMENTS OF OPERATI

CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues:
Total revenues	$ 18	$ 18	$ 6,814	$ 54
Operating expenses:
Research and development	2,440	6,879	10,259	28,720
General and administrative	2,571	2,993	8,954	10,115
Total operating expenses	5,011	9,872	19,213	38,835
Loss from operations	(4,993)	(9,854)	(12,399)	(38,781)
Other income (expense):
Interest and other income	87	201	332	483
Interest and other expense	(517)	(620)	(1,631)	(1,848)
Loss before income taxes	(5,423)	(10,273)	(13,698)	(40,146)
Income tax expense	0	0	(1)	0
Net loss	(5,423)	(10,273)	(13,699)	(40,146)
Other comprehensive loss:
Unrealized gain on short-term investments, net	0	16	0	70
Comprehensive loss	$ (5,423)	$ (10,257)	$ (13,699)	$ (40,076)
Net loss per share, basic and diluted (in dollars per share)	$ (0.26)	$ (1.18)	$ (0.86)	$ (4.62)
Weighted average shares used to compute basic and diluted net loss per share (in shares)	20,849,083	8,703,626	16,016,515	8,688,831
Revenue under strategic alliances and collaborations
Revenues:
Total revenues	$ 18	$ 18	$ 6,814	$ 54

CONDENSED STATEMENTS OF CASH FL

CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Operating activities
Net loss	$ (13,699)	$ (40,146)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation and amortization expense	800	1,672
Stock-based compensation	1,816	4,374
Amortization of premium on investments, net	0	92
Gain on reduction of lease liability	1,839	0
Other	262	182
Change in operating assets and liabilities:
Contracts and other receivables	(673)	360
Prepaid materials	368	589
Prepaid expenses and other assets	572	1,050
Accounts payable	(193)	(4,509)
Accrued liabilities	(473)	(1,138)
Accrued compensation	(676)	(693)
Contract liabilities	(2,554)	(54)
Deferred rent	0	(933)
Other liabilities	(2,233)	(102)
Net cash used in operating activities	(14,844)	(39,256)
Investing activities
Sales and maturities of short-term investments	0	40,101
Purchases of property and equipment	(162)	(22)
Sales of property and equipment	318	0
Acquisition of intangibles	(23)	0
Net cash provided by investing activities	133	40,079
Financing activities
Proceeds from issuance of securities through private placement, net of issuance costs	15,505	0
Proceeds from issuance of common stock, net	2,087	219
Proceeds from exercise of common stock options	3	2
Principal payments on term loan	(1,977)	(833)
Proceeds from financing leases	0	492
Payments on financing leases	(196)	(138)
Net cash provided by (used in) financing activities	15,422	(258)
Net increase in cash and cash equivalents	711	565
Cash and cash equivalents at beginning of period	13,935	13,519
Cash and cash equivalents at end of period	14,646	14,084
Supplemental disclosure of cash flow information
Interest paid	(1,263)	(1,573)
Income taxes paid	(1)	(1)
Supplemental disclosure of non-cash investing and financing activities
Non-cash acquisition of property and equipment	$ 61	$ 306

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	Basis of Presentation and Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited condensed financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In management’s opinion, the accompanying financial statements reflect all adjustments, consisting of normal recurring adjustments, considered necessary for a fair presentation of the results for the interim periods presented. Interim financial results are not necessarily indicative of results anticipated for the full year. These unaudited condensed financial statements should be read in conjunction with the audited financial statements and footnotes included in our Annual Report on Form 10-K for the year ended December 31, 2018 , from which the balance sheet information herein was derived. In July 2018, we implemented a corporate restructuring to reduce operating expenses and focus our resources, which involved a reduction in our workforce. The workforce reduction was substantially completed in July 2018. As of September 30, 2019 , we had 21 employees. On October 2, 2018, we filed a Certificate of Amendment of Amended and Restated Certificate of Incorporation with the Secretary of State of the state of Delaware to effect a 1-for-12 reverse stock split of our issued and outstanding common stock. The reverse stock split became effective at 5:00 p.m. Eastern Time on October 3, 2018 and our common stock began trading on a split-adjusted basis on The Nasdaq Global Market on October 4, 2018. The accompanying condensed financial statements and notes thereto give retrospective effect to the reverse stock split for all periods presented. All issued and outstanding common stock, options exercisable for common stock, restricted stock units, and per share amounts contained in our condensed financial statements have been retrospectively adjusted. Liquidity The accompanying financial statements have been prepared on a basis which assumes we are a going concern, and does not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classifications of liabilities that may result from any uncertainty related to our ability to continue as a going concern. Through the date of the issuance of these financial statements, we have principally been financed through proceeds received from the sale of our common stock and other equity securities, debt financings, up-front payments and milestones received from collaboration agreements. As of September 30, 2019, we had approximately $14.6 million of cash and cash equivalents. Based on our operating plans, we believe our cash and cash equivalents may not be sufficient to fund our operations for the period one year following the issuance of these financial statements. As a result, there is substantial doubt about our ability to continue as a going concern. All amounts due under the Term Loan (see note 5) have been classified as a current liability as of September 30, 2019 and December 31, 2018 due to the considerations discussed above and the assessment that the material adverse change clause under the Term Loan is not within our control. We have not been notified of an event of default by the Lender as of the date of the filing of this Form 10-Q. We intend to seek additional capital through equity and/or debt financings, collaborative or other funding arrangements with partners or through other sources of financing. Should we seek additional financing from outside sources, we may not be able to raise such financing on terms acceptable to us, or at all. If we are unable to raise additional capital when required or on acceptable terms, we may be required to scale back or discontinue the advancement of product candidates, reduce headcount, file for bankruptcy, reorganize, merge with another entity, or cease operations. If we become unable to continue as a going concern, we may have to liquidate our assets, and might realize significantly less than the values at which they are carried on our financial statements, and stockholders may lose all or part of their investment in our common stock. Use of Estimates Our condensed financial statements are prepared in accordance with GAAP, which requires us to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities in our financial statements and accompanying notes. An estimated loss contingency is accrued in our financial statements if it is probable that a liability has been incurred and the amount of the loss can be reasonably estimated. Although these estimates are based on our knowledge of current events and actions we may undertake in the future, actual results may ultimately differ from these estimates and assumptions. Revenue Recognition Our revenues generally consist of upfront payments for licenses or options to obtain licenses in the future, milestone payments and payments for other research services under strategic alliances and collaboration agreements. We recognize revenue when we transfer promised goods or services to customers in an amount that reflects the consideration to which we expect to be entitled in exchange for those goods or services. To determine revenue recognition for contracts with customers we perform the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligation(s) in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligation(s) in the contract; and (v) recognize revenue when (or as) we satisfy the performance obligation(s). At contract inception, we assess the goods or services promised within each contract, assess whether each promised good or service is distinct and identify those that are performance obligations. We recognize as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. Collaborative Arrangements We enter into collaborative arrangements with partners that typically include payment to us of one of more of the following: (i) license fees; (ii) payments related to the achievement of developmental, regulatory, or commercial milestones; and (iii) royalties on net sales of licensed products. Where a portion of non-refundable up-front fees or other payments received are allocated to continuing performance obligations under the terms of a collaborative arrangement, they are recorded as contract liabilities and recognized as revenue when (or as) the underlying performance obligation is satisfied. As part of the accounting for these arrangements, we must develop estimates and assumptions that require judgment to determine the underlying stand-alone selling price for each performance obligation which determines how the transaction price is allocated among the performance obligation(s). The stand-alone selling price may include items such as forecasted revenues, development timelines, discount rates, and probabilities of technical and regulatory success. We evaluate each performance obligation to determine if it can be satisfied at a point in time, or over time. In addition, variable consideration must be evaluated to determine if it is constrained and, therefore, excluded from the transaction price. License Fees If a license to our intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, we recognize revenues from non-refundable, up-front fees allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license. For licenses that are bundled with other performance obligations, we use judgment to assess the nature of the combined performance obligation to determine whether it is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. We evaluate the measure of progress each reporting period and, if necessary, adjust the measure of performance and related revenue recognition. Milestone Payments At the inception of each arrangement that includes milestone payments (variable consideration), we evaluate whether the milestones are considered probable of being reached and estimate the amount to be included in the transaction price. If it is probable that a milestone event would occur at the inception of an arrangement, the associated milestone value is included in the transaction price. Milestone payments that are contingent upon the achievement of events that are uncertain or not controllable, such as regulatory approvals, are generally not considered probable of being achieved until those approvals are received, and therefore not included in the transaction price. The transaction price is then allocated to each performance obligation on a relative stand-alone selling price basis, for which we recognize revenue as or when the performance obligations under the contract are satisfied. At the end of each reporting period, we evaluate the probability of achievement of such milestones and any related constraint(s), and if necessary, may adjust our estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which could affect license, collaboration or other revenues and earnings in the period of adjustment. Royalties For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and for which the license is deemed to be the predominant item to which the royalties relate, we recognize revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, we have not recognized any royalty revenue resulting from any of our collaborative arrangements. Stock-Based Compensation We account for stock-based compensation expense related to stock options granted to employees and members of our board of directors by estimating the fair value of each stock option on the date of grant using the Black-Scholes option pricing model. We recognize stock-based compensation expense using the accelerated multiple-option approach. Under the accelerated multiple-option approach (also known as the graded-vesting method), we recognize compensation expense over the requisite service period for each separately vesting tranche of the award as though the award was in substance multiple awards, resulting in accelerated expense recognition over the vesting period. For performance-based awards granted to employees (i) the fair value of the award is determined on the grant date, (ii) we assess the probability of the individual milestones under the award being achieved and (iii) the fair value of the shares subject to the milestone is expensed over the implicit service period commencing once management believes the performance criteria is probable of being met. We account for restricted stock units by determining the fair value of each restricted stock unit based on the closing market price of our common stock on the date of grant. We recognize stock-based compensation expense using the accelerated multiple-option approach over the requisite service periods of the awards. Clinical Trial and Preclinical Study Accruals We make estimates of our accrued expenses for clinical trial and preclinical study activities as of each balance sheet date in our financial statements based on the facts and circumstances known to us at that time. These accruals are based upon estimates of costs incurred and fees that may be associated with services provided by clinical trial investigational sites, clinical research organizations (“CROs”) and for other clinical trial-related activities. Payments under certain contracts with such parties depend on factors such as successful enrollment of patients, site initiation and the completion of clinical trial milestones. In accruing for these services, we estimate the time period over which services will be performed and the level of effort to be expended in each period. If possible, we obtain information regarding unbilled services directly from these service providers. However, we may be required to estimate these services based on other information available to us. If we underestimate or overestimate the activities or fees associated with a study or service at a given point in time, adjustments to research and development expenses may be necessary in future periods. Historically, our estimated accrued liabilities have approximated actual expense incurred. Subsequent changes in estimates may result in a material change in our accruals. Prepaid Materials We capitalize the purchase of certain raw materials and related supplies for use in the manufacturing of drug product in our IND-enabling and clinical development programs, as we have determined that these materials have alternative future use. We can use these raw materials and related supplies in multiple clinical drug products, and therefore have future use independent of the development status of any particular drug program until it is utilized in the manufacturing process. We expense the cost of materials when used. We periodically review these capitalized materials for continued alternative future use and write down the asset to its net realizable value in the period in which an impairment is identified. Recent Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, Leases, which increases transparency and comparability among organizations by requiring recognition of lease assets and lease liabilities on the balance sheet and disclosure of key information about leasing arrangements. Since ASU 2016-02 was issued, several additional ASUs have been issued to clarify various elements of the guidance. The standard is effective for annual reporting periods beginning after December 15, 2018, including interim periods within those annual reporting periods. We adopted the new lease standard on January 1, 2019, using the alternative modified transition method provided by the standard and did not retrospectively apply to prior periods. We elected the “package of practical expedients” (excluding the hindsight practical expedient) permitted under the transition guidance which allows us not to reassess our historical assessment of whether existing contracts are or contain a lease and the classification of existing lease arrangements. As a result of the adoption of the new standard, we recognized operating lease right-of-use assets ("ROU assets") of $3.3 million and operating lease liabilities of $11.3 million on our unaudited condensed balance sheet as of January 1, 2019. Operating lease ROU assets are recorded within our unaudited condensed balance sheets as other assets and operating lease liabilities are recorded within our unaudited condensed balance sheets as other current liabilities and other non-current liabilities. There was no change upon adoption to our capital leases, referred to as finance leases under the new lease standard. Our finance lease ROU asset and liability balances were each $0.6 million as of January 1, 2019. Finance lease ROU assets are recorded in property and equipment, net and current and non-current finance lease liabilities are recorded in other current liabilities and other long-term liabilities, respectively, in our unaudited condensed balance sheets. The adoption of the new lease standard had no impact on our accumulated deficit. The adoption of the new lease standard had an immaterial impact on our results of operations and cash flows. See Note 8, Leases, for further detail. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments . The amendments in this update replace the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. Entities will apply the new guidance as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is adopted. This update is effective for annual periods beginning after December 15, 2019, and interim periods within those periods. Early adoption is permitted. The adoption of this guidance is not anticipated to have an impact on our financial statements. In June 2018, the FASB issued ASU No. 2018-07, Compensation - Stock Compensation: Improvements to Nonemployee Share-Based Payment Accounting , which aligns the measurement and classification guidance for share-based payment to non-employees with the guidance for share-based payments to employees. Under the new guidance, the measurement period for equity-classified non-employee awards will be fixed at the grant date. This update is effective for annual periods beginning after December 15, 2018, and interim periods within those periods. The adoption of this guidance had no impact on our financial statements. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement: Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement , which updates and modifies the disclosure requirements on fair value measurements in Topic 820, primarily in relation to Level 3 fair value measurements. This update is effective for annual periods beginning after December 15, 2019, and interim periods within those periods. Early adoption is permitted. The adoption of this guidance is not anticipated to have an impact on our financial statements. In November 2018, the FASB issued ASU No. 2018-18, Collaborative Arrangements , which clarifies the interaction between Topic 808 , Collaborative Arrangements and Topic 606, including clarification around certain transactions between collaborative arrangement participants and adding unit-of-account guidance to Topic 808. This update is effective for annual periods beginning after December 15, 2019, and interim periods within those periods. Early adoption is permitted. The adoption of this guidance is not anticipated to have an impact on our financial statements.

Net Loss Per Share

Net Loss Per Share	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Net Loss Per Share	Net Loss Per Share Basic net loss per share is calculated by dividing net loss by the weighted average number of common shares outstanding for the period, without consideration for common stock equivalents. Diluted net loss per share is calculated by dividing net loss by the weighted-average number of common share equivalents outstanding for the period determined using the treasury-stock method. Dilutive common stock equivalents are comprised of options outstanding under our stock option plans. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted net loss per share. Potentially dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive consisted of 4,158,980 and 2,224,216 shares attributable to convertible preferred stock for the three and nine months ended September 30, 2019 , compared to zero and 575,256 shares attributable to common stock options and restricted stock units ("RSUs") for the three and nine months ended September 30, 2018, respectively.

Investments

Investments	9 Months Ended
	Sep. 30, 2019
Debt Securities, Available-for-sale [Abstract]
Investments	Investments We have historically invested our excess cash primarily in debt instruments of financial institutions, corporations, U.S. government-sponsored agencies and the U.S. Treasury. We generally hold our investments to maturity and do not sell our investments before we have recovered our amortized cost basis. As of September 30, 2019 and December 31, 2018 , our cash balance was comprised entirely of cash and cash equivalents and there was no unrealized gain or loss in either period.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements We have certain financial assets recorded at fair value which have been classified as Level 1, 2, or 3 within the fair value hierarchy as described in the accounting standards for fair value measurements. Accounting standards define fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants as of the measurement date. Market participants are buyers and sellers in the principal market that are (i) independent, (ii) knowledgeable, (iii) able to transact, and (iv) willing to transact. The accounting standards provide an established hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available. Observable inputs are inputs that market participants would use in valuing the asset or liability and are developed based on market data obtained from independent sources. Unobservable inputs are inputs that reflect our assumptions about the factors that market participants would use in valuing the asset or liability. The accounting standards prioritize the inputs used in measuring the fair value into the following hierarchy: • Level 1 includes financial instruments for which quoted market prices for identical instruments are available in active markets. • Level 2 includes financial instruments for which there are inputs other than quoted prices included within Level 1 that are observable for the instrument such as quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets with insufficient volume or infrequent transactions (less active markets) or model-driven valuations in which significant inputs are observable or can be derived principally from, or corroborated by, observable market data. • Level 3 includes financial instruments for which fair value is derived from valuation techniques in which one or more significant inputs are unobservable, including management’s own assumptions. Financial Assets Measured at Fair Value The following table presents our fair value hierarchy for assets measured at fair value on a recurring basis as of September 30, 2019 and December 31, 2018 (in thousands): Fair value as of September 30, 2019 Total Level 1 Level 2 Level 3 Assets: Cash equivalents (money market funds) $ 14,365 $ 14,365 $ — $ — $ 14,365 $ 14,365 $ — $ — Fair value as of December 31, 2018 Total Level 1 Level 2 Level 3 Assets: Cash equivalents (money market funds) $ 11,173 $ 11,173 $ — $ — $ 11,173 $ 11,173 $ — $ — We obtain pricing information from quoted market prices or quotes from brokers/dealers. We have historically determined the fair value of our investment securities using standard observable inputs, including reported trades, broker/dealer quotes, bids and/or offers.

Term Loan

Term Loan	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Term Loan	Term Loan On June 17, 2016, we entered into a loan and security agreement ( “ Loan Agreement ” ) with Oxford Finance, LLC, ( “ Oxford ” or sometimes referred to as the “ Lender ” ), pursuant to which Oxford agreed to lend us up to $30.0 million , issuable in two separate term loans of $20.0 million (the “ Term A Loan ” ) and $10.0 million (the “ Term B Loan ” ). On June 22, 2016, we received $20.0 million in proceeds from the Term A Loan, net of debt issuance costs. The ability to borrow on the Term B Loan expired on March 31, 2017, and no amounts were borrowed under the Term B Loan. We refer to all amounts outstanding under the Loan Agreement as the Term Loan. The outstanding Term Loan will mature on May 1, 2022 (the “Maturity Date”) and bears interest at a floating per annum rate equal to (i) 8.51% plus (ii) the greater of (a) the 30 day U.S. Dollar LIBOR rate reported in The Wall Street Journal on the last business day of the month that immediately precedes the month in which the interest will accrue and (b) 0.44% . Under the original Loan Agreement, we were required to make interest-only payments through June 1, 2018, followed by 24 equal monthly payments of principal and unpaid accrued interest. In August 2018, we and Oxford entered into an amendment to our Loan Agreement, providing for a modification of the loan amortization period. Under the terms of the amendment, principal amortization and repayment was deferred between August 2018 through October 2018, and during this period, we were required to make payments of interest-only. Amortization payments recommenced in November 2018. Pursuant to the amendment, we granted the Lender a security interest in our intellectual property as additional collateral for the repayment of the Term Loan. In November 2018, and in connection with the 2018 Sanofi Amendment, we entered into a fourth amendment to the Term Loan with the Lender (the "Fourth Amendment"). Under the terms of the Fourth Amendment, the Lender consented to the 2018 Sanofi Amendment and our license, assignment and transfer to Sanofi of certain of our intellectual property, as required to be delivered to Sanofi under the 2018 Sanofi Amendment (the “Assigned Assets”), which previously served as collateral under the Loan Agreement, and released its liens in the Assigned Assets, provided that the Lender will continue to have liens on all proceeds received by us pursuant to the Sanofi License. Under the terms of the Fourth Amendment, we have the option to prepay part of the Term Loan at any time and in any amount after 10 days’ prior written notice. We are also required to prepay a portion of the Term Loan with 25% of certain payments we receive under the 2018 Sanofi Amendment, which payments consist of the Upfront Amendment Payments and the first development milestone payment in the amount of $10.0 million . In accordance with this term, we prepaid $0.6 million pursuant to our receipt of $2.5 million in Upfront Amendment Payments in November 2018. Additionally, we prepaid $0.4 million in March 2019 pursuant to our receipt of $1.8 million in Upfront Amendment Payments in March 2019. We are required to pay the applicable 5.5% final payment fee related to each such 2018 Sanofi Amendment prepayment. On January 31, 2019, we entered into a fifth amendment to the Term Loan with the Lender (the "Fifth Amendment"). Under the terms of the Fifth Amendment, our required monthly payment to the Lender for the month of February 2019 was comprised of interest only. On March 7, 2019, we entered into a sixth amendment to the Term Loan with the Lender (the "Sixth Amendment"). Under the terms of the Sixth Amendment, our required monthly payment to the Lender for the month of March 2019 was comprised of interest only. On April 9, 2019 we entered into a seventh amendment to the Term Loan with the Lender (the "Seventh Amendment"). Under the terms of the Seventh Amendment, our required monthly payments to the Lender were to be comprised of interest only through and including the payment date immediately preceding the following date (the “Second Amortization Date”): (i) April 1, 2019, if we did not receive unrestricted gross cash proceeds of not less than $10 million on or before April 30, 2019 from (a) the issuance and sale of our unsecured subordinated convertible debt and/or equity securities and/or (b) “up front” or milestone payments in connection with a joint venture, collaboration or other partnering transaction other than pursuant to our Second Amended and Restated Collaboration and License Agreement (the “2014 Sanofi Amendment”), dated February 5, 2014, with Sanofi, as amended (the receipt of such net proceeds, the “ Seventh Amendment Capital Event”), and (ii) May 1, 2019, if the Seventh Amendment Capital Event occurs. Commencing on the Second Amortization Date, and continuing on each successive payment date thereafter, we were to be required to make consecutive equal monthly payments of principal, together with applicable interest, in arrears, to the Lender; provided, however, that we were required to make the monthly principal payment due April 1, 2019 on May 1, 2019 (in addition to all other payments due on May 1, 2019) if the Seventh Amendment Capital Event did not occur. The Seventh Amendment also provided that we can irrevocably elect to increase the prepayment percentage for the funds that we are required to prepay under the Term Loan in the event we receive $10.0 million from the first development milestone under the 2018 Sanofi Amendment (the "Milestone Payment") from 25% to 75% (the “Applicable Sanofi Percentage”). Under the Seventh Amendment, we are required to maintain cash in a collateral account controlled by the Lender of (i) $10.0 million if the Applicable Sanofi Percentage is 25% and if we had not prepaid an aggregate of $5 million under the Term Loan (which amount shall not include any Sanofi License prepayments) on or before April 30, 2019 (such prepayment, the “Principal Paydown Event”), (ii) $5.0 million if the Applicable Sanofi Percentage is 75% and the Principal Paydown Event had not occurred and (iii) zero if the Principal Paydown Event had occurred. On May 3, 2019, concurrently with the Securities Purchase Agreement (the "Purchase Agreement") (as described in further detail in Note 6), we entered into an eighth amendment to the Term Loan with the Lender (the "Eighth Amendment"). Pursuant to the terms of the Eighth Amendment and as a result of the completion of the initial closing under the Purchase Agreement, our required monthly payments to the Lender will be comprised of interest only from May 2019 through and including the payment to be made in April 2020, in exchange for an interest-only period extension fee of $0.1 million . Additionally, under the Eighth Amendment, the Term Loan maturity date was extended from June 2020 to May 2022, in exchange for a maturity date extension fee of $0.7 million . Pursuant to the Eighth Amendment, if an additional $20.0 million in capital is received by us on or before December 31, 2019 (the “Eighth Amendment Capital Event”), our required monthly payments to the Lender will be comprised of interest only through and including the payment to be made in April 2021. Commencing in May 2020, or, if the Seventh Amendment Capital Event occurs, May 2021, and continuing on each successive payment date thereafter, we are required to make consecutive equal monthly payments of principal, together with applicable interest, in arrears, to the Lender. The Eighth Amendment also provides for an increase in the prepayment percentage for the funds that we are required to prepay under the Term Loan, in the event that we receive the $10.0 million Milestone Payment from 75% to 100% of the Milestone Payment. Upon payment of the Milestone Payment to the Lender, we will no longer be required to maintain cash in a collateral account controlled by Lender and the positive lien on our intellectual property will be released. We used the proceeds from the Term Loan solely for working capital and to fund our general business requirements. Our obligations under the Loan Agreement are secured by a first priority security interest in substantially all of our current and future assets, other than our intellectual property, for which Oxford currently has a positive lien, and certain assets under capital lease obligations. We have also agreed not to encumber our intellectual property assets, except as permitted by the Loan Agreement. The Loan Agreement includes customary events of default, including instances of a material adverse change in our operations, that may require prepayment of the outstanding Term Loan. All amounts due under the Term Loan have been classified as a current liability as of September 30, 2019 and December 31, 2018 due to the considerations discussed in Note 1 and the assessment that the material adverse change clause under the Term Loan is not within our control. We have not been notified of an event of default by the Lender as of the date of the filing of this Form 10-Q and as of September 30, 2019 we were in compliance with all covenants under the Loan Agreement. As of September 30, 2019 , $14.7 million was outstanding under the Term Loan, with an additional $1.9 million payable at the conclusion of the Term Loan. The Term Loan was recorded at its initial carrying value of $20.0 million , less debt issuance costs of approximately $0.2 million . In connection with the Term Loan, the debt issuance costs have been recorded as a debt discount in our consolidated balance sheets, which are being accreted to interest expense over the life of the Term Loan using an effective interest rate of 8.98% . The exit fees are being accrued over the life of the Term Loan through interest expense. As of September 30, 2019, future principal payments for the Term Loan due under the Loan Agreement are as follows (in thousands): 2019 $ — 2020 4,698 2021 7,047 2022 2,936 $ 14,681

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2019
Share-based Payment Arrangement [Abstract]
Stockholders' Equity	Stockholders’ Equity 2019 Equity Incentive Plan On June 15, 2019 the Company's board of directors approved, and on August 1, 2019 the Company's stockholders approved, the Company's 2019 Equity Incentive Plan (the "2019 Plan"). The 2019 Plan is intended as the successor to and continuation of the Company's 2012 Equity Incentive Plan (the "2012 Plan"). Subject to adjustment for certain changes in the Company’s capitalization, the aggregate number of shares of the Company’s common stock that may be issued under the 2019 Plan will not exceed 3,881,477 shares (the “Share Reserve”), which consists of (1) 2,725,773 newly reserved shares and (2) up to 1,155,704 shares consisting of (a) the number of unallocated shares remaining available for the grant of new awards under the 2012 Plan as of the effective date of the 2019 Plan and (b) the shares subject to outstanding stock awards granted under the 2009 Equity Incentive Plan (the “2009 Plan”) and the 2012 Plan (together the with 2009 Plan, the “Prior Plans”) that on or after the effective date of the 2019 Plan (i) expire or terminate for any reason prior to exercise or settlement; (ii) are forfeited because of the failure to meet a contingency or condition required to vest such shares or otherwise return to the Company, or (iii) are reacquired, withheld (or not issued) to satisfy a tax withholding obligation in connection with an award or to satisfy the purchase price or exercise price of a stock award. No further grants will be made under the Prior Plans. Private Placement of Common Stock, Non-Voting Preferred Stock and Warrants On May 3, 2019, we entered into a Purchase Agreement with certain institutional and other accredited investors, including certain directors, executive officers and employees of the Company (the “Purchasers”), pursuant to which we agreed to sell and issue shares of our common stock, shares of our newly designated non-voting convertible preferred stock, and warrants to purchase common stock, in up to two closings, in a private placement transaction (the “Private Placement”). At an initial closing under the Purchase Agreement that occurred on May 7, 2019 (the “Initial Closing”), we sold and issued to the Purchasers (i) 9,730,534 shares of common stock and accompanying warrants to purchase up to an aggregate of 9,730,534 shares of common stock at a combined purchase price of $1.205 per share, and (ii) 415,898 shares of non-voting Class A-1 convertible preferred stock, in lieu of shares of common stock, at a price of $10.80 per share, and accompanying warrants to purchase an aggregate of 4,158,980 shares of common stock at a price of $0.125 for each share of common stock underlying such warrants. Total gross proceeds from the Initial Closing were approximately $16.7 million , which does not include any proceeds that may be received upon exercise of the warrants. Each share of non-voting Class A-1 convertible preferred stock is convertible into 10 shares of Common Stock, subject to certain beneficial ownership conversion limitations. The warrants are exercisable for a period of five years following the date of issuance and have an exercise price of $1.08 per share, subject to proportional adjustments in the event of stock splits or combinations or similar events. The warrants are exercisable on a net exercise "cashless" basis. An aggregate of 526,083 shares of common stock and warrants to purchase up to 526,083 shares of common stock were purchased for $0.6 million by certain directors and executive officers of the Company. Pursuant to the Purchase Agreement, in the event our Board of Directors unanimously resolves to recommence our Phase 1 multiple ascending dose clinical trial of our RGLS4326 product candidate for the treatment of autosomal dominant polycystic kidney disease ("ADPKD") (the “Phase 1 Trial”) based on correspondence from the U.S. Food and Drug Administration’s Division of Cardiovascular and Renal Products, and thereafter but on or before December 31, 2019 we make a public announcement of our plan to recommence the Phase 1 Trial (the “Public Announcement”), we have agreed to sell and the Purchasers have agreed to purchase, at a second closing under the Purchase Agreement (“Milestone Closing”), shares of our non-voting convertible preferred stock and accompanying warrants to purchase shares of Common Stock (collectively, “Milestone Securities”) having an aggregate purchase price of approximately $25.1 million , excluding the exercise price of the warrants. The additional shares of non-voting convertible preferred stock will each be convertible into 10 shares of common stock, subject to certain beneficial ownership conversion limitations. In the event the volume-weighted average price per share of common stock on the Nasdaq Stock Market (“VWAP”) during the five full trading days following the Public Announcement is at least $1.08 , the non-voting convertible preferred stock to be sold the Milestone Closing will be Class A-1 convertible preferred stock and will be sold at a price of $10.80 per share. In the event the VWAP during the five full trading days following the Public Announcement is less than $1.08 , the sale and issuance of the Milestone Securities will be subject to stockholder approval under Nasdaq Listing Rule 5635 (“Stockholder Approval”), which must be obtained no later than March 31, 2020 (provided we shall use our best efforts to obtain the Stockholder Approval by no later than 45 days following the Public Announcement), and the non-voting preferred stock to be sold in the Milestone Closing will be newly designated Class A-2 convertible preferred stock and will have a purchase price equal to the “Alternative Milestone Price” as defined under the Purchase Agreement. The Alternative Milestone Price per share of Class A-2 convertible preferred stock will be, (a) if the Stockholder Approval is obtained prior to the Public Announcement, the VWAP over the five full trading days immediately following the Public Announcement or (b) if the Stockholder Approval is obtained after the Public Announcement, the price that is the lower of (i) the VWAP over the five full trading days immediately following the Public Announcement and (ii) the VWAP over the five full trading days immediately following the date on which the Stockholder Approval is obtained. In the event the relevant VWAP used for the Alternative Minimum Price is less than $0.50 per share, the Milestone Closing will not occur. The accompanying warrants will be sold at a price of $0.125 for each share of common stock underlying the warrants, will have an exercise price equal to 100% of the purchase price of the non-voting convertible preferred stock sold in the Milestone Closing (priced on an as-converted to common stock basis), subject to proportional adjustments in the event of stock splits or combinations or similar events, and will have an exercise term of five years from the date of issuance. The warrants will be exercisable on a net exercise "cashless" basis. We evaluated the non-voting Class A-1 convertible preferred stock and common stock warrants sold in the Initial Closing under ASC 480, Distinguishing Liabilities from Equity, and ASC 815, Derivatives and Hedging, and determined permanent equity treatment was appropriate for these freestanding financial instruments. The Initial Closing did not include any embedded features that require bifurcation. The non-voting Class A-2 convertible preferred stock and warrants issuable under the Milestone Closing are not subject to accounting recognition until the Milestone Closing occurs, as the terms of the Milestone Closing do not provide a right or an obligation on neither the Company nor the Purchasers. ATM Offering On December 12, 2018, we entered into a Common Stock Sales Agreement (the “Stock Sales Agreement”) with H.C. Wainwright & Co., LLC (“HCW”), pursuant to which we may sell and issue shares of our common stock from time to time through HCW, as our sales agent (the “ATM Offering”). We have no obligation to sell any shares of common stock in the ATM Offering, and may at any time suspend offers under the Stock Sales Agreement or terminate the Stock Sales Agreement. Subject to the terms and conditions of the Stock Sales Agreement, HCW will use its commercially reasonable efforts to sell shares of our common stock from time to time based upon our instructions (including any price, time or size limits or other parameters or conditions the we may impose). We will pay HCW a commission of 3.0% of the gross sales price of any shares sold under the Stock Sales Agreement. A total of 1,903,880 shares were sold for proceeds of $2.1 million (net of approximately $0.1 million in commissions) under the ATM Offering during the nine months ended September 30, 2019. No shares were sold during the three months ended September 30, 2019. Exchange Offer On October 15, 2018, we filed a tender offer statement on Schedule TO with the Securities and Exchange Commission related to an offer by us to certain eligible optionholders, subject to specified conditions, to exchange some or all of their outstanding options to purchase shares of our common stock for new RSUs (the "Exchange Offer"). The exchange ratio for each option eligible for exchange was determined using the Black-Scholes option pricing model and was based on, among other things, the fair market value of a share of our common stock, the volatility of our common stock, U.S. treasury rates, the exercise prices of such options, the remaining terms of such options and the term of the new RSUs. There were a total of 915,009 options eligible for exchange in the Exchange Offer by 31 eligible optionholders, all of which were exchanged for 603,058 RSUs. Of the 603,058 RSUs issued in the Exchange Offer, 514,955 contain certain performance conditions requisite for vesting commencement. Incremental stock-based compensation cost associated with the Exchange Offer was $0.4 million . Shares Reserved for Future Issuance The following shares of common stock were reserved for future issuance as of September 30, 2019 (in thousands): Class A-1 convertible preferred stock outstanding (as-converted) 4,159 Common stock options outstanding 509 RSUs outstanding 240 Warrants outstanding 13,890 Common stock available for future grant under 2019 Equity Incentive Plan 2,973 Employee Stock Purchase Plan 193 Total common shares reserved for future issuance 21,964 The following table summarizes our stock option and RSU activity (together Stock Awards) under all equity incentive plans for the nine months ended September 30, 2019 (shares in thousands): Number of options Weighted average exercise price Number of RSUs Weighted average grant date fair value Stock Awards outstanding at December 31, 2018 59 $ 45.60 606 $ 1.58 Granted 547 $ 0.85 286 $ 0.95 Exercised (options) or Vested (RSUs) (3 ) $ 0.95 (468 ) $ 1.29 Canceled/forfeited/expired (94 ) $ 11.37 (179 ) $ 1.35 Stock Awards outstanding at September 30, 2019 509 $ 4.11 245 $ 1.57 Stock-Based Compensation The following table summarizes the weighted average assumptions used to estimate the fair value of stock options and performance stock awards granted to employees under our 2012 Equity Incentive Plan, 2015 Inducement Plan and 2019 Equity Incentive Plan and the shares purchasable under our Employee Stock Purchase Plan during the periods presented: Three months ended Nine months ended 2019 2018 2019 2018 Stock options Risk-free interest rate 1.5 % 2.9 % 2.1 % 2.7 % Volatility 95.1 % 92.0 % 94.4 % 87.8 % Dividend yield — — — — Expected term (years) 6.1 6.1 6.1 6.1 Performance stock options Risk-free interest rate — — 2.6 % 2.7 % Volatility — — 93.8 % 87.4 % Dividend yield — — — — Expected term (years) 0.0 0.0 6.1 5.7 Employee stock purchase plan shares Risk-free interest rate 2.3 % 2.0 % 2.4 % 1.8 % Volatility 106.7 % 99.9 % 110.1 % 91.7 % Dividend yield — — — — Expected term (years) 0.5 0.5 0.5 0.5 The following table summarizes the allocation of our stock-based compensation expense for all stock awards during the periods presented (in thousands): Three months ended Nine months ended 2019 2018 2019 2018 Research and development $ 45 $ 491 $ 240 $ 1,745 Research and development-restructuring related adjustments — 31 — 31 General and administrative 491 883 1,576 2,613 General and administrative-restructuring related adjustments — (15 ) — (15 ) Total $ 536 $ 1,390 $ 1,816 $ 4,374

Strategic Alliances and Collabo

Strategic Alliances and Collaborations	9 Months Ended
	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Strategic Alliances and Collaborations	Strategic Alliances and Collaborations Revenue recognized from our strategic alliances and collaborations was less than $0.1 million and $6.8 million for the three and nine months ended September 30, 2019 , respectively, compared to less than $0.1 million and $0.1 million for the three and nine months ended September 30, 2018 , respectively. Sanofi In July 2012, we amended and restated our collaboration and license agreement with Sanofi to expand the potential therapeutic applications of the micro RNA alliance targets to be developed under such agreement. We determined that the elements within the strategic alliance agreement with Sanofi should be treated as a single unit of accounting because the delivered elements did not have stand-alone value to Sanofi. The following elements were delivered as part of the strategic alliance with Sanofi: (1) a license for up to four micro RNA targets; and (2) a research license under our technology alliance. In June 2013, the original research term expired, upon which we and Sanofi entered into an option agreement pursuant to which Sanofi was granted an exclusive right to negotiate the co-development and commercialization of certain of our unencumbered micro RNA programs and we were granted the exclusive right to negotiate with Sanofi for co-development and commercialization of certain miR-21 anti-miRs in oncology and Alport syndrome. In July 2013, we received an upfront payment of $2.5 million , of which $1.25 million is creditable against future amounts payable by Sanofi to us under any future co-development and commercialization agreement we enter pursuant to the option agreement. Revenue associated with the creditable portion of this option payment was deferred as of December 31, 2017 and recorded as an adjustment to accumulated deficit upon our adoption of Topic 606 on January 1, 2018. The non-creditable portion of this payment, $1.25 million , was recognized as revenue over the option period from the effective date of the option agreement in June 2013 through the expiration of the option period in January 2014. In February 2014, we and Sanofi entered into the 2014 Sanofi Amendment to renew our strategic alliance to discover, develop and commercialize micro RNA therapeutics to focus on specific orphan disease and oncology targets. Under the terms of the 2014 Sanofi Amendment, Sanofi had opt-in rights to our clinical fibrosis program targeting miR-21 for the treatment of Alport syndrome, our preclinical program targeting miR-21 for oncology indications, and our preclinical program targeting miR-221/222 for hepatocellular carcinoma (“HCC”). We were responsible for developing each of these programs to proof-of-concept, at which time Sanofi had an exclusive option on each program. If Sanofi chooses to exercise its option on any of these programs, Sanofi would reimburse us for a significant portion of our preclinical and clinical development costs and would also pay us an option exercise fee for any such program, provided that $1.25 million of the $2.5 million upfront option fee paid to us by Sanofi in connection with the June 2013 option agreement will be creditable against such option exercise fee. We are eligible to receive royalties on micro RNA therapeutic products commercialized by Sanofi and will have the right to co-promote these products relating to our preclinical program targeting miR-221/222. As indicated below, we entered into an additional amendment with Sanofi in November 2018, under which Sanofi's opt-in rights to our miR-21 programs under the 2014 Sanofi Amendment were relinquished. Sanofi's opt-in rights with regard to our miR-221/222 preclinical program under the 2014 Sanofi Amendment remained unchanged. In connection with the 2014 Sanofi Amendment, we entered into a Common Stock Purchase Agreement (the “Sanofi Purchase Agreement”), pursuant to which we sold 1,303,780 shares of our common stock to Aventisub LLC (“Aventis”), an entity affiliated with Sanofi, in a private placement at a price per share of $7.67 for an aggregate purchase price of $10.0 million . Under the terms of the Sanofi Purchase Agreement, Aventis was not permitted to sell, transfer, make any short sale of, or grant any option for the sale of any common stock for the 12 -month period following its effective date. The Sanofi Purchase Agreement and the 2014 Sanofi Amendment were negotiated concurrently and were therefore evaluated as a single agreement. Based upon restricted stock studies of similar duration and a Black-Scholes valuation to measure the discount for lack of marketability, approximately $0.4 million of the proceeds from the Sanofi Purchase Agreement was attributed to the 2014 Sanofi Amendment, and represents consideration for the value of the program targeting miR-221/222 for HCC. We are recognizing the $0.4 million allocated consideration into revenue ratably over the estimated period of performance of the miR-221/222 program. As of September 30, 2019 , contract liability associated with the Sanofi Purchase Agreement and the 2014 Sanofi Amendment was less than $0.1 million , which we are expecting to recognize over the remaining estimated period of performance of less than one year. We are eligible to receive milestone payments related to the development and commercialization of miR-221/222 for HCC of up to $38.8 million for proof-of-concept option exercise fees (net of $1.25 million creditable, as noted above), $40.0 million for clinical milestones and up to $130.0 million for regulatory and commercial milestones. In addition, we are entitled to receive royalties based on a percentage of net sales of any products from the miR-221/222 program which, in the case of sales in the United States, will be in the middle of the 10% to 20% range, and, in the case of sales outside of the United States, will range from the low end to the middle of the 10% to 20% range, depending upon the volume of sales. If we exercise our option to co-promote a miR-221/222 product, we will continue to be eligible to receive royalties on net sales of each product in the United States at the same rate, unless we elect to share a portion of Sanofi’s profits from sales of such product in the United States in lieu of royalties. In November 2018, we entered into an amendment to the 2014 Sanofi Amendment with Sanofi to modify the parties’ rights and obligations with respect to our miR-21 programs, including our RG-012 program (the “2018 Sanofi Amendment”). Under the terms of the 2018 Sanofi Amendment, we have granted Sanofi a worldwide, royalty-free, fee-bearing, exclusive license, with the right to grant sublicenses, under our know-how and patents to develop and commercialize miR-21 compounds and products for all indications, including Alport Syndrome. Sanofi will control and will assume all responsibilities and obligations for developing and commercializing each of our miR-21 programs, including our obligations regarding the administration and expense of clinical trials and all other costs, including in-license royalties and other in-license payments, related to our miR-21 programs. Under the terms of the 2018 Sanofi Amendment, we have assigned to Sanofi certain agreements, product-specific patents and all materials directed to miR-21 or to any miR-21 compound or product and are required to provide reasonable technical assistance to Sanofi for a period of 24 months after the date of the 2018 Sanofi Amendment. Under the terms of the 2018 Sanofi Amendment, we are eligible to receive approximately $6.8 million in upfront payments for the license and for miR-21 program-related materials (collectively, the “Upfront Amendment Payments”). We are also eligible to receive up to $40.0 million in development milestone payments. In addition, Sanofi has agreed to reimburse us for certain out-of-pocket transition activities and assume our upstream license royalty obligations. We and Sanofi also agreed to a general release of claims against each other for any claims that arose at any time prior to the date of the 2018 Sanofi Amendment, or that thereafter could arise based on anything that occurred prior to the date of the 2018 Sanofi Amendment. We received $2.5 million and $1.8 million in Upfront Amendment Payments under the 2018 Sanofi Amendment in November 2018 and March 2019, respectively. As the performance obligations associated with these Upfront Amendment Payments had been satisfied under Topic 606 as of March 31, 2019, both amounts were recognized as revenue in the first quarter of 2019. Additionally, we recognized an additional $2.5 million as revenue in the first quarter of 2019 for the final Upfront Amendment Payment allowable under the 2018 Sanofi Amendment, as the performance obligations associated with the final Upfront Amendment Payment were also satisfied under Topic 606 as of March 31, 2019. We received the final $2.5 million Upfront Amendment Payment in April 2019. As of September 30, 2019, the $40.0 million in development milestone payments (variable consideration) do not meet the criteria for revenue recognition.

Leases

Leases	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Leases	Leases At the inception of a contractual arrangement, we determine whether the contract contains a lease by assessing whether there is an identified asset and whether the contract conveys the right to control the use of the identified asset in exchange for consideration over a period of time. For operating leases with an initial term greater than 12 months, we recognize operating lease ROU assets and operating lease liabilities based on the present value of lease payments over the lease term at the commencement date. Operating lease ROU assets are comprised of the lease liability plus any lease payments made and excludes lease incentives. Lease terms include options to renew or terminate the lease when we are reasonably certain that the renewal option will be exercised or when it is reasonably certain that the termination option will not be exercised. For our operating leases, we generally cannot determine the interest rate implicit in the lease, in which case we use our incremental borrowing rate as the discount rate for the lease. We estimate our incremental borrowing rate for our operating leases based on what we would normally pay to borrow on a collateralized basis over a similar term for an amount equal to the lease payments. Operating lease expense is recognized on a straight-line basis over the lease term. Leases with a lease term of 12 months or less are not recorded on the unaudited condensed balance sheet. Instead, we recognize lease expense for these leases on a straight-line basis over the lease term. Our lease agreements do not contain any material variable lease payments, residual value guarantees or restrictive covenants. Certain leases require us to pay taxes, insurance, utilities, and maintenance costs for the building, which do not represent lease components. We elected to not separate lease and non-lease components. In July 2015, we entered into an operating lease agreement (the "Prior Lease") for approximately 59,248 square feet of office and laboratory facility space located at 10614 Science Center Drive, San Diego, California 92121. The lease term was 96 months from the lease commencement date, and we moved our headquarters into this facility in May 2016. In conjunction with the lease, we received $1.4 million of lease incentives and $8.2 million of tenant improvement allowance, which was to be used for non-structural leasehold improvements. The lease incentives and tenant improvement allowance were included within deferred rent. Our deferred rent balance as of December 31, 2018 was $8.0 million . The Prior Lease agreement was with ARE SD Region No. 44 LLC (“Landlord”). On February 19, 2019, we entered into an agreement, the (“Space Swap Agreement"), with Nitto Biopharma, Inc. ("Nitto"), pursuant to which we agreed, contingent upon the execution of a new lease agreement (the "February Lease") for Nitto's space with Landlord and the termination of the Prior Lease, to, among other things, (i) swap buildings with Nitto, and (ii) sell, convey and transfer all right, title and interest in certain furniture, fixtures and equipment to Nitto, as set forth in the Space Swap Agreement. Under the Space Swap Agreement, we will pay Nitto (a) a relocation assistance payment in the amount of $0.1 million ; (b) $0.2 million representing the difference between the security deposits under the Prior Lease and Nitto’s prior lease, and (c) $1.3 million as reimbursement for the six monthly installments of base monthly rent due pursuant to the new lease between Nitto and Landlord, subject to certain adjustments, which reimbursements are to be paid as rent comes due for Nitto under its new lease. On February 25, 2019, we and Landlord entered into a second amendment (the “Prior Lease Amendment”) to the Prior Lease. Under the terms of the Prior Lease Amendment, the expiration date of the Prior Lease was accelerated from April 30, 2024 to March 31, 2019 and the Prior Lease terminated on April 1, 2019. The Prior Lease Amendment eliminated all further cash payments due under the Prior Lease, including aggregate base rent over its remaining term of approximately $14.4 million . On February 25, 2019, we entered into the February Lease with Landlord, for the lease of approximately 24,562 square feet of rentable area of the building located at 10628 Science Center Drive, San Diego, California, 92121 (the "Premises"), which Premises were previously occupied by Nitto. The commencement date of the February Lease was April 1, 2019 (the “Commencement Date”). The Premises serve as our new principal executive offices and as a laboratory for research and development, manufacturing and other related uses. The term of the February Lease (“Initial Term”) was 51 months , ending June 30, 2023. The aggregate base rent due over the Initial Term was approximately $4.8 million . We were also responsible for the payment of additional rent to cover our share of the annual operating expenses, the annual tax expenses and the annual utilities costs related to the February Lease. The base rent payments due were: $0.6 million in 2019, $1.2 million in 2020, $1.2 million in 2021, $1.2 million in 2022, and $0.6 million in 2023. The execution of the February Lease and Prior Lease Amendment resulted in a modification which was not accounted for as a separate contract. Rather, we accounted for the two contracts with Landlord in combination as they were entered into at the same time and negotiated as a package to achieve the same commercial objective. The leasehold improvements under the Prior Lease were accounted for as non-cash consideration of $5.6 million paid by us upon termination of the Prior Lease to the Landlord. We accounted for a $1.3 million portion of the reduction in the lease liability for the Prior Lease as a non-cash gain in the unaudited condensed statement of operations due to the reduction in lease term and leased space with Landlord and a $0.9 million portion of the reduction of the lease liability as a deferred credit that is amortized as a reduction to rent expense over the term of the Lease. The $1.6 million obligation to reimburse Nitto for six monthly installments of base rent of the Prior Lease and certain other costs were accounted for as cost of terminating the Prior Lease in the unaudited condensed statement of operations. The net impact of the modification was a $0.4 million charge in the unaudited condensed statement of operations. As of September 30, 2019, our payment obligations to Nitto under the Space Swap Agreement were fully satisfied and no assets or liabilities remained with respect to the Prior Lease as of September 30, 2019. The commencement date of the Lease did not occur until April 1, 2019 and therefore, as of March 31, 2019, the lease liability for the February Lease was zero. On April 1, 2019, we recorded a $3.8 million lease liability for the February Lease, which was calculated as the present value of future lease payments to be made under the February Lease. A $2.9 million ROU asset was also recorded on April 1, 2019, which represents the difference between the lease liability and the $0.9 million deferred credit for the reduction of the lease liability under the Prior Lease. On June 19, 2019, we entered into a lease agreement (the “New Lease”) with Landlord for the lease of approximately 8,727 square feet of rentable area of the building located at 10628 Science Center Drive, Suite 225, San Diego, California 92121 (the “New Premises”). The commencement date of the New Lease was July 1, 2019 (the “New Commencement Date”). We are using the New Premises as our new principal executive offices and as a laboratory for research and development, manufacturing, and other related uses. The term of the New Lease (the “New Initial Term”) is two years, six months , ending December 31, 2021. The base rent payments due for the New Premises are: $0.1 million in 2019, $0.4 million in 2020 and $0.4 million in 2021, net of certain rent abatement terms. We will also be responsible for the payment of additional rent to cover our share of the annual operating expenses of the building, the annual tax expenses of the building and the annual utilities cost of the building. On June 19, 2019, we entered into a first amendment to the February Lease with Landlord (the “February Lease Amendment”). Under the terms of the February Lease Amendment, the expiration date of the February Lease was accelerated from June 30, 2023 to June 30, 2019 and the February Lease terminated upon the Commencement Date of the New Lease. The February Lease Amendment eliminated all further rents due under the February Lease, including aggregate base rent over its remaining term of approximately $4.8 million . The execution of the New Lease and February Lease Amendment resulted in a modification which was not accounted for as a separate contract. Rather, we accounted for the two contracts with Landlord in combination as they were entered into at the same time and negotiated as a package to achieve the same commercial objective. We accounted for a $0.5 million portion of the reduction in the lease liability for the February Lease as a non-cash gain in the unaudited condensed statement of operations due to the reduction in lease term and leased space with Landlord and a $0.2 million portion of the reduction of the lease liability as a deferred credit that is amortized as a reduction to rent expense over the term of the New Lease. No other assets or liabilities remained with respect to the February Lease as of September 30, 2019. The commencement date of the New Lease did not occur until July 1, 2019 and therefore, as of June 30, 2019, the lease liability for the New Lease was zero . On July 1, 2019, we recorded a $0.8 million lease liability for the New Lease, which was calculated as the present value of future lease payments to be made under the New Lease. A $0.6 million ROU asset was also recorded on July 1, 2019, which represents the difference between the lease liability and the remaining $0.2 million deferred credit for the reduction of the lease liability under the February Lease. The table below summarizes our lease liabilities and corresponding ROU assets as of September 30, 2019 (in thousands): Assets Operating $ 510 Financing 512 Total ROU assets $ 1,022 Liabilities Current: Operating $ 349 Financing 287 Long-term: Operating 512 Financing 114 Total lease liabilities $ 1,262 The table below summarizes our lease costs from our unaudited condensed statement of operations and cash payments from our unaudited condensed statement of cash flows during the three and nine months ended September 30, 2019 (in thousands): Three months ended Nine months ended Lease cost: Operating lease cost $ 70 $ 645 Finance lease cost: Amortization of right-of-use assets 46 137 Interest expense on lease liabilities 6 19 Total lease cost $ 122 $ 801 Cash payment information: Operating cash used for operating leases $ — $ 651 Operating cash used for finance leases 6 19 Financing cash used for finance leases 66 196 Total cash paid for amounts included in the measurement of lease liabilities $ 72 $ 866 The table below summarizes other non-cash information under our operating and financing lease obligations as of September 30, 2019 (in thousands, except years and rates): Supplemental non-cash information: Operating lease liabilities arising from obtaining right-of-use assets $ 861 Weighted-average remaining lease term (years) - operating leases 2.3 Weighted-average remaining lease term (years) - finance leases 1.5 Weighted-average discount rate - operating leases 10.9 % Weighted-average discount rate - finance leases 4.9 % Our future lease payments under operating and finance leases at September 30, 2019 are as follows (in thousands): Operating Leases Finance Leases Remaining 2019 $ 106 $ 72 2020 429 287 2021 442 57 Total lease payments $ 977 $ 416 Less: amount representing interest (116 ) (15 ) Present value of obligations under leases 861 401 Less: current portion (349 ) (287 ) Long-term lease obligations $ 512 $ 114
Leases	Leases At the inception of a contractual arrangement, we determine whether the contract contains a lease by assessing whether there is an identified asset and whether the contract conveys the right to control the use of the identified asset in exchange for consideration over a period of time. For operating leases with an initial term greater than 12 months, we recognize operating lease ROU assets and operating lease liabilities based on the present value of lease payments over the lease term at the commencement date. Operating lease ROU assets are comprised of the lease liability plus any lease payments made and excludes lease incentives. Lease terms include options to renew or terminate the lease when we are reasonably certain that the renewal option will be exercised or when it is reasonably certain that the termination option will not be exercised. For our operating leases, we generally cannot determine the interest rate implicit in the lease, in which case we use our incremental borrowing rate as the discount rate for the lease. We estimate our incremental borrowing rate for our operating leases based on what we would normally pay to borrow on a collateralized basis over a similar term for an amount equal to the lease payments. Operating lease expense is recognized on a straight-line basis over the lease term. Leases with a lease term of 12 months or less are not recorded on the unaudited condensed balance sheet. Instead, we recognize lease expense for these leases on a straight-line basis over the lease term. Our lease agreements do not contain any material variable lease payments, residual value guarantees or restrictive covenants. Certain leases require us to pay taxes, insurance, utilities, and maintenance costs for the building, which do not represent lease components. We elected to not separate lease and non-lease components. In July 2015, we entered into an operating lease agreement (the "Prior Lease") for approximately 59,248 square feet of office and laboratory facility space located at 10614 Science Center Drive, San Diego, California 92121. The lease term was 96 months from the lease commencement date, and we moved our headquarters into this facility in May 2016. In conjunction with the lease, we received $1.4 million of lease incentives and $8.2 million of tenant improvement allowance, which was to be used for non-structural leasehold improvements. The lease incentives and tenant improvement allowance were included within deferred rent. Our deferred rent balance as of December 31, 2018 was $8.0 million . The Prior Lease agreement was with ARE SD Region No. 44 LLC (“Landlord”). On February 19, 2019, we entered into an agreement, the (“Space Swap Agreement"), with Nitto Biopharma, Inc. ("Nitto"), pursuant to which we agreed, contingent upon the execution of a new lease agreement (the "February Lease") for Nitto's space with Landlord and the termination of the Prior Lease, to, among other things, (i) swap buildings with Nitto, and (ii) sell, convey and transfer all right, title and interest in certain furniture, fixtures and equipment to Nitto, as set forth in the Space Swap Agreement. Under the Space Swap Agreement, we will pay Nitto (a) a relocation assistance payment in the amount of $0.1 million ; (b) $0.2 million representing the difference between the security deposits under the Prior Lease and Nitto’s prior lease, and (c) $1.3 million as reimbursement for the six monthly installments of base monthly rent due pursuant to the new lease between Nitto and Landlord, subject to certain adjustments, which reimbursements are to be paid as rent comes due for Nitto under its new lease. On February 25, 2019, we and Landlord entered into a second amendment (the “Prior Lease Amendment”) to the Prior Lease. Under the terms of the Prior Lease Amendment, the expiration date of the Prior Lease was accelerated from April 30, 2024 to March 31, 2019 and the Prior Lease terminated on April 1, 2019. The Prior Lease Amendment eliminated all further cash payments due under the Prior Lease, including aggregate base rent over its remaining term of approximately $14.4 million . On February 25, 2019, we entered into the February Lease with Landlord, for the lease of approximately 24,562 square feet of rentable area of the building located at 10628 Science Center Drive, San Diego, California, 92121 (the "Premises"), which Premises were previously occupied by Nitto. The commencement date of the February Lease was April 1, 2019 (the “Commencement Date”). The Premises serve as our new principal executive offices and as a laboratory for research and development, manufacturing and other related uses. The term of the February Lease (“Initial Term”) was 51 months , ending June 30, 2023. The aggregate base rent due over the Initial Term was approximately $4.8 million . We were also responsible for the payment of additional rent to cover our share of the annual operating expenses, the annual tax expenses and the annual utilities costs related to the February Lease. The base rent payments due were: $0.6 million in 2019, $1.2 million in 2020, $1.2 million in 2021, $1.2 million in 2022, and $0.6 million in 2023. The execution of the February Lease and Prior Lease Amendment resulted in a modification which was not accounted for as a separate contract. Rather, we accounted for the two contracts with Landlord in combination as they were entered into at the same time and negotiated as a package to achieve the same commercial objective. The leasehold improvements under the Prior Lease were accounted for as non-cash consideration of $5.6 million paid by us upon termination of the Prior Lease to the Landlord. We accounted for a $1.3 million portion of the reduction in the lease liability for the Prior Lease as a non-cash gain in the unaudited condensed statement of operations due to the reduction in lease term and leased space with Landlord and a $0.9 million portion of the reduction of the lease liability as a deferred credit that is amortized as a reduction to rent expense over the term of the Lease. The $1.6 million obligation to reimburse Nitto for six monthly installments of base rent of the Prior Lease and certain other costs were accounted for as cost of terminating the Prior Lease in the unaudited condensed statement of operations. The net impact of the modification was a $0.4 million charge in the unaudited condensed statement of operations. As of September 30, 2019, our payment obligations to Nitto under the Space Swap Agreement were fully satisfied and no assets or liabilities remained with respect to the Prior Lease as of September 30, 2019. The commencement date of the Lease did not occur until April 1, 2019 and therefore, as of March 31, 2019, the lease liability for the February Lease was zero. On April 1, 2019, we recorded a $3.8 million lease liability for the February Lease, which was calculated as the present value of future lease payments to be made under the February Lease. A $2.9 million ROU asset was also recorded on April 1, 2019, which represents the difference between the lease liability and the $0.9 million deferred credit for the reduction of the lease liability under the Prior Lease. On June 19, 2019, we entered into a lease agreement (the “New Lease”) with Landlord for the lease of approximately 8,727 square feet of rentable area of the building located at 10628 Science Center Drive, Suite 225, San Diego, California 92121 (the “New Premises”). The commencement date of the New Lease was July 1, 2019 (the “New Commencement Date”). We are using the New Premises as our new principal executive offices and as a laboratory for research and development, manufacturing, and other related uses. The term of the New Lease (the “New Initial Term”) is two years, six months , ending December 31, 2021. The base rent payments due for the New Premises are: $0.1 million in 2019, $0.4 million in 2020 and $0.4 million in 2021, net of certain rent abatement terms. We will also be responsible for the payment of additional rent to cover our share of the annual operating expenses of the building, the annual tax expenses of the building and the annual utilities cost of the building. On June 19, 2019, we entered into a first amendment to the February Lease with Landlord (the “February Lease Amendment”). Under the terms of the February Lease Amendment, the expiration date of the February Lease was accelerated from June 30, 2023 to June 30, 2019 and the February Lease terminated upon the Commencement Date of the New Lease. The February Lease Amendment eliminated all further rents due under the February Lease, including aggregate base rent over its remaining term of approximately $4.8 million . The execution of the New Lease and February Lease Amendment resulted in a modification which was not accounted for as a separate contract. Rather, we accounted for the two contracts with Landlord in combination as they were entered into at the same time and negotiated as a package to achieve the same commercial objective. We accounted for a $0.5 million portion of the reduction in the lease liability for the February Lease as a non-cash gain in the unaudited condensed statement of operations due to the reduction in lease term and leased space with Landlord and a $0.2 million portion of the reduction of the lease liability as a deferred credit that is amortized as a reduction to rent expense over the term of the New Lease. No other assets or liabilities remained with respect to the February Lease as of September 30, 2019. The commencement date of the New Lease did not occur until July 1, 2019 and therefore, as of June 30, 2019, the lease liability for the New Lease was zero . On July 1, 2019, we recorded a $0.8 million lease liability for the New Lease, which was calculated as the present value of future lease payments to be made under the New Lease. A $0.6 million ROU asset was also recorded on July 1, 2019, which represents the difference between the lease liability and the remaining $0.2 million deferred credit for the reduction of the lease liability under the February Lease. The table below summarizes our lease liabilities and corresponding ROU assets as of September 30, 2019 (in thousands): Assets Operating $ 510 Financing 512 Total ROU assets $ 1,022 Liabilities Current: Operating $ 349 Financing 287 Long-term: Operating 512 Financing 114 Total lease liabilities $ 1,262 The table below summarizes our lease costs from our unaudited condensed statement of operations and cash payments from our unaudited condensed statement of cash flows during the three and nine months ended September 30, 2019 (in thousands): Three months ended Nine months ended Lease cost: Operating lease cost $ 70 $ 645 Finance lease cost: Amortization of right-of-use assets 46 137 Interest expense on lease liabilities 6 19 Total lease cost $ 122 $ 801 Cash payment information: Operating cash used for operating leases $ — $ 651 Operating cash used for finance leases 6 19 Financing cash used for finance leases 66 196 Total cash paid for amounts included in the measurement of lease liabilities $ 72 $ 866 The table below summarizes other non-cash information under our operating and financing lease obligations as of September 30, 2019 (in thousands, except years and rates): Supplemental non-cash information: Operating lease liabilities arising from obtaining right-of-use assets $ 861 Weighted-average remaining lease term (years) - operating leases 2.3 Weighted-average remaining lease term (years) - finance leases 1.5 Weighted-average discount rate - operating leases 10.9 % Weighted-average discount rate - finance leases 4.9 % Our future lease payments under operating and finance leases at September 30, 2019 are as follows (in thousands): Operating Leases Finance Leases Remaining 2019 $ 106 $ 72 2020 429 287 2021 442 57 Total lease payments $ 977 $ 416 Less: amount representing interest (116 ) (15 ) Present value of obligations under leases 861 401 Less: current portion (349 ) (287 ) Long-term lease obligations $ 512 $ 114

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Federal Securities Litigation On January 31, 2017, a putative class action complaint was filed by Baran Polat in the United States District Court for the Southern District of California (“District Court”) against the Company, its then-Chief Executive Officer Paul C. Grint, and its then-Chief Operating Officer Joseph P. Hagan (currently the Company’s Chief Executive Officer). The complaint includes claims asserted, on behalf of certain purchasers of the Company’s securities, under Sections 10(b) and 20(a) of the Securities Exchange Act of 1934, as amended. In general, the complaint alleges that, between January 21, 2016, and June 27, 2016, the defendants violated the federal securities laws by making materially false and misleading statements regarding the Company’s business and the prospects for RG-101, thereby artificially inflating the price of the Company’s securities. The plaintiff seeks unspecified monetary damages and other relief. On February 10, 2017, a second putative class action complaint was filed by Li Jin in the District Court against the Company, Mr. Hagan, Dr. Grint, and Timothy Wright, the Company’s Chief Research and Development Officer. The Complaint alleges claims similar to those asserted by Mr. Polat. The actions have been related. On February 17, 2017, the District Court entered an order stating that defendants need not answer, or otherwise respond, until the District Court enters an order appointing, pursuant to the Private Securities Litigation Reform Act of 1995, lead plaintiff and lead counsel, and the parties then submit a schedule to the District Court for the filing of an amended or consolidated complaint and the timing of defendants’ answer or response. On April 3, 2017, two motions for consolidation of the two actions, appointment of lead plaintiff, and approval of counsel were filed in the action (“Motions to Consolidate”). On October 26, 2017, the District Court entered an order consolidating the cases, appointing Mark Appel and Michael Spitters to serve as co-lead plaintiffs, and appointing Levi & Korsinsky LLP to serve as lead counsel. On December 22, 2017, lead plaintiffs filed a consolidated complaint against the Company, Dr. Grint, Mr. Hagan, and Michael Huang (the Company’s former Vice President of Clinical Development). The consolidated complaint alleges that between February 17, 2016 and June 12, 2017, the defendants violated Sections 10(b) and 20(a) of the Securities Exchange Act of 1934, as amended, by making materially false and misleading statements regarding RG-101. The consolidated complaint seeks unspecified monetary damages and an award of attorneys’ fees and costs. On February 6, 2018, the defendants filed a motion to dismiss the consolidated complaint. On March 23, 2018, lead plaintiffs filed their opposition to the motion to dismiss. On April 24, 2018, the defendants filed their reply in support of the motion to dismiss. On September 5, 2019, the court granted defendants’ motion to dismiss with leave to amend. Plaintiffs filed their amended complaint on October 1, 2019. Subsequent to the filing of the amended complaint, counsel for the parties engaged in negotiations to resolve the case. On November 4, 2019, the parties agreed in principle to settle the case for $0.9 million , with approximately $0.3 million to be paid by the Company and $0.6 million to be paid by the Company’s D&O insurance carrier. In connection with the proposed settlement and in accordance with authoritative guidance, we recorded the $0.9 million loss contingency as a current liability on our condensed balance sheet at September 30, 2019, and recorded the $0.6 million of expected insurance proceeds from our D&O insurance carrier as a current receivable on our condensed balance sheet at September 30, 2019. The $0.3 million settlement amount payable by the Company was recorded to the condensed statement of operations and comprehensive loss for the three and nine months ended September 30, 2019. The settlement is contingent upon both the parties’ entry into a definitive settlement agreement and court approval.

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In management’s opinion, the accompanying financial statements reflect all adjustments, consisting of normal recurring adjustments, considered necessary for a fair presentation of the results for the interim periods presented. Interim financial results are not necessarily indicative of results anticipated for the full year. These unaudited condensed financial statements should be read in conjunction with the audited financial statements and footnotes included in our Annual Report on Form 10-K for the year ended December 31, 2018 , from which the balance sheet information herein was derived.
Use of Estimates	Use of Estimates Our condensed financial statements are prepared in accordance with GAAP, which requires us to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities in our financial statements and accompanying notes. An estimated loss contingency is accrued in our financial statements if it is probable that a liability has been incurred and the amount of the loss can be reasonably estimated. Although these estimates are based on our knowledge of current events and actions we may undertake in the future, actual results may ultimately differ from these estimates and assumptions.
Revenue Recognition	Revenue Recognition Our revenues generally consist of upfront payments for licenses or options to obtain licenses in the future, milestone payments and payments for other research services under strategic alliances and collaboration agreements. We recognize revenue when we transfer promised goods or services to customers in an amount that reflects the consideration to which we expect to be entitled in exchange for those goods or services. To determine revenue recognition for contracts with customers we perform the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligation(s) in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligation(s) in the contract; and (v) recognize revenue when (or as) we satisfy the performance obligation(s). At contract inception, we assess the goods or services promised within each contract, assess whether each promised good or service is distinct and identify those that are performance obligations. We recognize as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. Collaborative Arrangements We enter into collaborative arrangements with partners that typically include payment to us of one of more of the following: (i) license fees; (ii) payments related to the achievement of developmental, regulatory, or commercial milestones; and (iii) royalties on net sales of licensed products. Where a portion of non-refundable up-front fees or other payments received are allocated to continuing performance obligations under the terms of a collaborative arrangement, they are recorded as contract liabilities and recognized as revenue when (or as) the underlying performance obligation is satisfied. As part of the accounting for these arrangements, we must develop estimates and assumptions that require judgment to determine the underlying stand-alone selling price for each performance obligation which determines how the transaction price is allocated among the performance obligation(s). The stand-alone selling price may include items such as forecasted revenues, development timelines, discount rates, and probabilities of technical and regulatory success. We evaluate each performance obligation to determine if it can be satisfied at a point in time, or over time. In addition, variable consideration must be evaluated to determine if it is constrained and, therefore, excluded from the transaction price. License Fees If a license to our intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, we recognize revenues from non-refundable, up-front fees allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license. For licenses that are bundled with other performance obligations, we use judgment to assess the nature of the combined performance obligation to determine whether it is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. We evaluate the measure of progress each reporting period and, if necessary, adjust the measure of performance and related revenue recognition. Milestone Payments At the inception of each arrangement that includes milestone payments (variable consideration), we evaluate whether the milestones are considered probable of being reached and estimate the amount to be included in the transaction price. If it is probable that a milestone event would occur at the inception of an arrangement, the associated milestone value is included in the transaction price. Milestone payments that are contingent upon the achievement of events that are uncertain or not controllable, such as regulatory approvals, are generally not considered probable of being achieved until those approvals are received, and therefore not included in the transaction price. The transaction price is then allocated to each performance obligation on a relative stand-alone selling price basis, for which we recognize revenue as or when the performance obligations under the contract are satisfied. At the end of each reporting period, we evaluate the probability of achievement of such milestones and any related constraint(s), and if necessary, may adjust our estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which could affect license, collaboration or other revenues and earnings in the period of adjustment. Royalties For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and for which the license is deemed to be the predominant item to which the royalties relate, we recognize revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, we have not recognized any royalty revenue resulting from any of our collaborative arrangements.
Stock-Based Compensation	Stock-Based Compensation We account for stock-based compensation expense related to stock options granted to employees and members of our board of directors by estimating the fair value of each stock option on the date of grant using the Black-Scholes option pricing model. We recognize stock-based compensation expense using the accelerated multiple-option approach. Under the accelerated multiple-option approach (also known as the graded-vesting method), we recognize compensation expense over the requisite service period for each separately vesting tranche of the award as though the award was in substance multiple awards, resulting in accelerated expense recognition over the vesting period. For performance-based awards granted to employees (i) the fair value of the award is determined on the grant date, (ii) we assess the probability of the individual milestones under the award being achieved and (iii) the fair value of the shares subject to the milestone is expensed over the implicit service period commencing once management believes the performance criteria is probable of being met. We account for restricted stock units by determining the fair value of each restricted stock unit based on the closing market price of our common stock on the date of grant. We recognize stock-based compensation expense using the accelerated multiple-option approach over the requisite service periods of the awards.
Clinical Trial and Preclinical Study Accruals	Clinical Trial and Preclinical Study Accruals We make estimates of our accrued expenses for clinical trial and preclinical study activities as of each balance sheet date in our financial statements based on the facts and circumstances known to us at that time. These accruals are based upon estimates of costs incurred and fees that may be associated with services provided by clinical trial investigational sites, clinical research organizations (“CROs”) and for other clinical trial-related activities. Payments under certain contracts with such parties depend on factors such as successful enrollment of patients, site initiation and the completion of clinical trial milestones. In accruing for these services, we estimate the time period over which services will be performed and the level of effort to be expended in each period. If possible, we obtain information regarding unbilled services directly from these service providers. However, we may be required to estimate these services based on other information available to us. If we underestimate or overestimate the activities or fees associated with a study or service at a given point in time, adjustments to research and development expenses may be necessary in future periods. Historically, our estimated accrued liabilities have approximated actual expense incurred. Subsequent changes in estimates may result in a material change in our accruals.
Prepaid Materials	Prepaid Materials We capitalize the purchase of certain raw materials and related supplies for use in the manufacturing of drug product in our IND-enabling and clinical development programs, as we have determined that these materials have alternative future use. We can use these raw materials and related supplies in multiple clinical drug products, and therefore have future use independent of the development status of any particular drug program until it is utilized in the manufacturing process. We expense the cost of materials when used. We periodically review these capitalized materials for continued alternative future use and write down the asset to its net realizable value in the period in which an impairment is identified.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, Leases, which increases transparency and comparability among organizations by requiring recognition of lease assets and lease liabilities on the balance sheet and disclosure of key information about leasing arrangements. Since ASU 2016-02 was issued, several additional ASUs have been issued to clarify various elements of the guidance. The standard is effective for annual reporting periods beginning after December 15, 2018, including interim periods within those annual reporting periods. We adopted the new lease standard on January 1, 2019, using the alternative modified transition method provided by the standard and did not retrospectively apply to prior periods. We elected the “package of practical expedients” (excluding the hindsight practical expedient) permitted under the transition guidance which allows us not to reassess our historical assessment of whether existing contracts are or contain a lease and the classification of existing lease arrangements. As a result of the adoption of the new standard, we recognized operating lease right-of-use assets ("ROU assets") of $3.3 million and operating lease liabilities of $11.3 million on our unaudited condensed balance sheet as of January 1, 2019. Operating lease ROU assets are recorded within our unaudited condensed balance sheets as other assets and operating lease liabilities are recorded within our unaudited condensed balance sheets as other current liabilities and other non-current liabilities. There was no change upon adoption to our capital leases, referred to as finance leases under the new lease standard. Our finance lease ROU asset and liability balances were each $0.6 million as of January 1, 2019. Finance lease ROU assets are recorded in property and equipment, net and current and non-current finance lease liabilities are recorded in other current liabilities and other long-term liabilities, respectively, in our unaudited condensed balance sheets. The adoption of the new lease standard had no impact on our accumulated deficit. The adoption of the new lease standard had an immaterial impact on our results of operations and cash flows. See Note 8, Leases, for further detail. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments . The amendments in this update replace the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. Entities will apply the new guidance as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is adopted. This update is effective for annual periods beginning after December 15, 2019, and interim periods within those periods. Early adoption is permitted. The adoption of this guidance is not anticipated to have an impact on our financial statements. In June 2018, the FASB issued ASU No. 2018-07, Compensation - Stock Compensation: Improvements to Nonemployee Share-Based Payment Accounting , which aligns the measurement and classification guidance for share-based payment to non-employees with the guidance for share-based payments to employees. Under the new guidance, the measurement period for equity-classified non-employee awards will be fixed at the grant date. This update is effective for annual periods beginning after December 15, 2018, and interim periods within those periods. The adoption of this guidance had no impact on our financial statements. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement: Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement , which updates and modifies the disclosure requirements on fair value measurements in Topic 820, primarily in relation to Level 3 fair value measurements. This update is effective for annual periods beginning after December 15, 2019, and interim periods within those periods. Early adoption is permitted. The adoption of this guidance is not anticipated to have an impact on our financial statements. In November 2018, the FASB issued ASU No. 2018-18, Collaborative Arrangements , which clarifies the interaction between Topic 808 , Collaborative Arrangements and Topic 606, including clarification around certain transactions between collaborative arrangement participants and adding unit-of-account guidance to Topic 808. This update is effective for annual periods beginning after December 15, 2019, and interim periods within those periods. Early adoption is permitted. The adoption of this guidance is not anticipated to have an impact on our financial statements.
Fair Value Measurement	Fair Value Measurements We have certain financial assets recorded at fair value which have been classified as Level 1, 2, or 3 within the fair value hierarchy as described in the accounting standards for fair value measurements. Accounting standards define fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants as of the measurement date. Market participants are buyers and sellers in the principal market that are (i) independent, (ii) knowledgeable, (iii) able to transact, and (iv) willing to transact. The accounting standards provide an established hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available. Observable inputs are inputs that market participants would use in valuing the asset or liability and are developed based on market data obtained from independent sources. Unobservable inputs are inputs that reflect our assumptions about the factors that market participants would use in valuing the asset or liability. The accounting standards prioritize the inputs used in measuring the fair value into the following hierarchy: • Level 1 includes financial instruments for which quoted market prices for identical instruments are available in active markets. • Level 2 includes financial instruments for which there are inputs other than quoted prices included within Level 1 that are observable for the instrument such as quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets with insufficient volume or infrequent transactions (less active markets) or model-driven valuations in which significant inputs are observable or can be derived principally from, or corroborated by, observable market data. • Level 3 includes financial instruments for which fair value is derived from valuation techniques in which one or more significant inputs are unobservable, including management’s own assumptions.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Hierarchy for Assets and Liabilities Measured at Fair Value on Recurring Basis	The following table presents our fair value hierarchy for assets measured at fair value on a recurring basis as of September 30, 2019 and December 31, 2018 (in thousands): Fair value as of September 30, 2019 Total Level 1 Level 2 Level 3 Assets: Cash equivalents (money market funds) $ 14,365 $ 14,365 $ — $ — $ 14,365 $ 14,365 $ — $ — Fair value as of December 31, 2018 Total Level 1 Level 2 Level 3 Assets: Cash equivalents (money market funds) $ 11,173 $ 11,173 $ — $ — $ 11,173 $ 11,173 $ — $ —

Term Loan (Tables)

Term Loan (Tables)	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Term Loan	As of September 30, 2019, future principal payments for the Term Loan due under the Loan Agreement are as follows (in thousands): 2019 $ — 2020 4,698 2021 7,047 2022 2,936 $ 14,681

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2019
Share-based Payment Arrangement [Abstract]
Common Stock Reserved for Future Issuance	The following shares of common stock were reserved for future issuance as of September 30, 2019 (in thousands): Class A-1 convertible preferred stock outstanding (as-converted) 4,159 Common stock options outstanding 509 RSUs outstanding 240 Warrants outstanding 13,890 Common stock available for future grant under 2019 Equity Incentive Plan 2,973 Employee Stock Purchase Plan 193 Total common shares reserved for future issuance 21,964
Stock Option Activity	The following table summarizes our stock option and RSU activity (together Stock Awards) under all equity incentive plans for the nine months ended September 30, 2019 (shares in thousands): Number of options Weighted average exercise price Number of RSUs Weighted average grant date fair value Stock Awards outstanding at December 31, 2018 59 $ 45.60 606 $ 1.58 Granted 547 $ 0.85 286 $ 0.95 Exercised (options) or Vested (RSUs) (3 ) $ 0.95 (468 ) $ 1.29 Canceled/forfeited/expired (94 ) $ 11.37 (179 ) $ 1.35 Stock Awards outstanding at September 30, 2019 509 $ 4.11 245 $ 1.57
Assumptions Used to Estimate Fair Value of Stock Options and Performance Stock and Employee Stock Purchase Plan	The following table summarizes the weighted average assumptions used to estimate the fair value of stock options and performance stock awards granted to employees under our 2012 Equity Incentive Plan, 2015 Inducement Plan and 2019 Equity Incentive Plan and the shares purchasable under our Employee Stock Purchase Plan during the periods presented: Three months ended Nine months ended 2019 2018 2019 2018 Stock options Risk-free interest rate 1.5 % 2.9 % 2.1 % 2.7 % Volatility 95.1 % 92.0 % 94.4 % 87.8 % Dividend yield — — — — Expected term (years) 6.1 6.1 6.1 6.1 Performance stock options Risk-free interest rate — — 2.6 % 2.7 % Volatility — — 93.8 % 87.4 % Dividend yield — — — — Expected term (years) 0.0 0.0 6.1 5.7 Employee stock purchase plan shares Risk-free interest rate 2.3 % 2.0 % 2.4 % 1.8 % Volatility 106.7 % 99.9 % 110.1 % 91.7 % Dividend yield — — — — Expected term (years) 0.5 0.5 0.5 0.5
Stock-Based Compensation	The following table summarizes the allocation of our stock-based compensation expense for all stock awards during the periods presented (in thousands): Three months ended Nine months ended 2019 2018 2019 2018 Research and development $ 45 $ 491 $ 240 $ 1,745 Research and development-restructuring related adjustments — 31 — 31 General and administrative 491 883 1,576 2,613 General and administrative-restructuring related adjustments — (15 ) — (15 ) Total $ 536 $ 1,390 $ 1,816 $ 4,374

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Assets And Liabilities, Lessee	The table below summarizes our lease liabilities and corresponding ROU assets as of September 30, 2019 (in thousands): Assets Operating $ 510 Financing 512 Total ROU assets $ 1,022 Liabilities Current: Operating $ 349 Financing 287 Long-term: Operating 512 Financing 114 Total lease liabilities $ 1,262
Lease, Cost	The table below summarizes our lease costs from our unaudited condensed statement of operations and cash payments from our unaudited condensed statement of cash flows during the three and nine months ended September 30, 2019 (in thousands): Three months ended Nine months ended Lease cost: Operating lease cost $ 70 $ 645 Finance lease cost: Amortization of right-of-use assets 46 137 Interest expense on lease liabilities 6 19 Total lease cost $ 122 $ 801 Cash payment information: Operating cash used for operating leases $ — $ 651 Operating cash used for finance leases 6 19 Financing cash used for finance leases 66 196 Total cash paid for amounts included in the measurement of lease liabilities $ 72 $ 866 The table below summarizes other non-cash information under our operating and financing lease obligations as of September 30, 2019 (in thousands, except years and rates): Supplemental non-cash information: Operating lease liabilities arising from obtaining right-of-use assets $ 861 Weighted-average remaining lease term (years) - operating leases 2.3 Weighted-average remaining lease term (years) - finance leases 1.5 Weighted-average discount rate - operating leases 10.9 % Weighted-average discount rate - finance leases 4.9 %
Operating Lease, Liability, Maturity	Our future lease payments under operating and finance leases at September 30, 2019 are as follows (in thousands): Operating Leases Finance Leases Remaining 2019 $ 106 $ 72 2020 429 287 2021 442 57 Total lease payments $ 977 $ 416 Less: amount representing interest (116 ) (15 ) Present value of obligations under leases 861 401 Less: current portion (349 ) (287 ) Long-term lease obligations $ 512 $ 114
Finance Lease, Liability, Maturity	future lease payments under operating and finance leases at September 30, 2019 are as follows (in thousands): Operating Leases Finance Leases Remaining 2019 $ 106 $ 72 2020 429 287 2021 442 57 Total lease payments $ 977 $ 416 Less: amount representing interest (116 ) (15 ) Present value of obligations under leases 861 401 Less: current portion (349 ) (287 ) Long-term lease obligations $ 512 $ 114

Basis of Presentation and Sum_3

Basis of Presentation and Summary of Significant Accounting Policies (Narrative) (Details) $ in Thousands	Oct. 02, 2018	Sep. 30, 2019USD ($)employee	Jan. 01, 2019USD ($)
Accounting Policies [Abstract]
Number of employees | employee		21
Conversion ratio for reverse stock split	0.0833
Cash and cash equivalents and marketable securities		$ 14,600
Operating lease, right of use asset		510	$ 3,300
Operating lease liability		861	11,300
Finance lease liability		401	600
Financing lease, right of use asset		$ 512	$ 600

Net Loss Per Share (Detail)

Net Loss Per Share (Detail) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Potentially dilutive securities not included in calculation of diluted net loss per share (in shares)	4,158,980	0	2,224,216	575,256

Fair Value Measurements (Fair V

Fair Value Measurements (Fair Value Hierarchy for Assets and Liabilities Measured at Fair Value on Recurring Basis) (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets measured at fair value on a recurring basis	$ 14,365	$ 11,173
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets measured at fair value on a recurring basis	14,365	11,173
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets measured at fair value on a recurring basis	0	0
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets measured at fair value on a recurring basis	0	0
Cash equivalents (money market funds)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets measured at fair value on a recurring basis	14,365	11,173
Cash equivalents (money market funds) | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets measured at fair value on a recurring basis	14,365	11,173
Cash equivalents (money market funds) | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets measured at fair value on a recurring basis	0	0
Cash equivalents (money market funds) | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets measured at fair value on a recurring basis	$ 0	$ 0

Term Loan (Details)

Term Loan (Details)	May 03, 2019USD ($)	Apr. 09, 2019USD ($)	Jun. 22, 2016USD ($)	Jun. 17, 2016USD ($)loan	Mar. 31, 2019USD ($)	Nov. 30, 2018USD ($)	Sep. 30, 2019USD ($)	May 07, 2019USD ($)	Nov. 05, 2018USD ($)
Debt Instrument [Line Items]
Upfront payment received					$ 1,800,000	$ 2,500,000
Debt Financing Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity				$ 30,000,000
Number of term loans | loan				2
Stated interest rate, percentage				8.51%
Long-term debt							$ 14,700,000
Debt fee							1,900,000
Long-term debt, gross							20,000,000
Debt issuance costs							$ 200,000
Debt instrument effective rate							8.98%
Debt Financing Agreement | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate, percentage				0.44%
Debt Financing Agreement Tranche A
Debt Instrument [Line Items]
Maximum borrowing capacity				$ 20,000,000
Proceeds from borrowing under term loan			$ 20,000,000
Long-term debt							$ 14,681,000
Debt Financing Agreement Tranche B
Debt Instrument [Line Items]
Maximum borrowing capacity				$ 10,000,000
Fourth Amendment
Debt Instrument [Line Items]
Prepayment requirement of loan from license fees									25.00%
Potential revenue through milestone payments									$ 10,000,000
Prepayment requirement of loan from license fees amount					$ 400,000	$ 600,000
Payment fee									5.50%
Seventh Amendment
Debt Instrument [Line Items]
Debt covenant, condition two		$ 10,000,000
Debt covenant, condition one		5,000,000
Minimum cash, debt covenant		10,000,000
Eight Amendment
Debt Instrument [Line Items]
Minimum cash, debt covenant								$ 20,000,000
Interest only payment fee	$ 100,000
Maturity extension fee	$ 700,000
Eight Amendment - Milestone Payment
Debt Instrument [Line Items]
Minimum cash, debt covenant		$ 10,000,000
Minimum | Seventh Amendment
Debt Instrument [Line Items]
Prepayment requirement of loan from license fees		25.00%
Prepayment requirement of loan from license fees amount		$ 5,000,000
Minimum | Eight Amendment
Debt Instrument [Line Items]
Prepayment requirement of loan from license fees		75.00%
Maximum | Seventh Amendment
Debt Instrument [Line Items]
Prepayment requirement of loan from license fees		75.00%
Maximum | Eight Amendment
Debt Instrument [Line Items]
Prepayment requirement of loan from license fees		100.00%

Term Loan (Future Principal Pay

Term Loan (Future Principal Payments) (Details) - Debt Financing Agreement Tranche A $ in Thousands	Sep. 30, 2019USD ($)
Debt Instrument [Line Items]
Future Repayments of Principal, 2019	$ 0
Future Repayments of Principal, 2020	4,698
Future Repayments of Principal, 2021	7,047
Future Repayments of Principal, 2022	2,936
Long-term Debt	$ 14,681

Stockholders' Equity (Narrative

Stockholders' Equity (Narrative) (Details) $ / shares in Units, $ in Thousands	May 07, 2019USD ($)$ / sharesshares	May 03, 2019USD ($)shares	Dec. 12, 2018USD ($)shares	Oct. 15, 2018USD ($)optionholdershares	Sep. 30, 2019USD ($)shares	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)shares	Sep. 30, 2018USD ($)	Aug. 01, 2019shares
Subsidiary, Sale of Stock [Line Items]
Exchange Offer share available for exchange (in shares)				915,009
Number of optionholders | optionholder				31
Restricted shares issued (in shares)				603,058
Stock-based compensation expenses | $				$ 400	$ 536	$ 1,390	$ 1,816	$ 4,374
Performance stock options
Subsidiary, Sale of Stock [Line Items]
Restricted shares issued (in shares)				514,955
Private Placement
Subsidiary, Sale of Stock [Line Items]
Share sold (in shares)		9,730,534
Warrants callable	9,730,534
Sale of stock price (usd per share) | $ / shares	$ 1.205
Consideration received | $		$ 16,700
Convertible Preferred stock into common stock	10
Warrant exercise period		5 years
Warrant exercise price (usd per share) | $ / shares	$ 1.08
Milestone Closing
Subsidiary, Sale of Stock [Line Items]
Convertible Preferred stock into common stock	10
Warrant exercise price (usd per share) | $ / shares	$ 1.08
Nonvoting convertible preferred stock, aggregate value, potential sale | $	$ 25,100
VWAP, Alternative minimum price (usd per share) | $ / shares	$ 0.50
Warrant, exercise price of purchase price	100.00%
At The Moment
Subsidiary, Sale of Stock [Line Items]
Share sold (in shares)			1,903,880
Consideration received | $			$ 2,100
Commission fee rate			3.00%
Commissions paid | $			$ 100
Shares issued (in shares)					0		0
Preferred Class A | Private Placement
Subsidiary, Sale of Stock [Line Items]
Warrants callable	4,158,980
Sale of stock price (usd per share) | $ / shares	$ 10.80
Nonvoting convertible preferred stock issued	415,898
Preferred Class A | Milestone Closing
Subsidiary, Sale of Stock [Line Items]
Sale of stock price (usd per share) | $ / shares	$ 10.80
Warrant | Milestone Closing
Subsidiary, Sale of Stock [Line Items]
Sale of stock price (usd per share) | $ / shares	0.125
Warrant | Preferred Class A | Private Placement
Subsidiary, Sale of Stock [Line Items]
Sale of stock price (usd per share) | $ / shares	$ 0.125
Directors, Executive Officers and Employees | Private Placement
Subsidiary, Sale of Stock [Line Items]
Share sold (in shares)		526,083
Directors, Executive Officers and Employees | Preferred Class A | Private Placement
Subsidiary, Sale of Stock [Line Items]
Warrants callable	526,083
Proceeds from issuance of right to purchase common shares | $	$ 600
2019 Plan
Subsidiary, Sale of Stock [Line Items]
Number of shares authorized (in shares)									2,725,773
2012 Plan
Subsidiary, Sale of Stock [Line Items]
Number of shares authorized (in shares)									1,155,704
Maximum | 2019 Plan
Subsidiary, Sale of Stock [Line Items]
Number of shares authorized (in shares)									3,881,477

Stockholders' Equity (Common St

Stockholders' Equity (Common Stock Reserved for Future Issuance) (Detail) - shares	Sep. 30, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Class A-1 convertible preferred stock outstanding (as-converted)	415,898	415,898
Common stock options outstanding (in shares)	509,000
Warrants outstanding	13,890,000
Total common shares reserved for future issuance (in shares)	21,964,000
Common stock available for future grant under 2019 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock available for future grant (in shares)	2,973,000
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock available for future grant (in shares)	193,000
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSUs outstanding (in shares)	240,000
Class A-1 Convertible Preferred Stock (As-Converted) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Class A-1 convertible preferred stock outstanding (as-converted)	4,159,000

Stockholders' Equity (Stock Opt

Stockholders' Equity (Stock Option and RSU Activity) (Detail) shares in Thousands	9 Months Ended
	Sep. 30, 2019$ / sharesshares
Number of options
Number of options, ending outstanding number (in shares)	509
Stock options
Number of options
Number of options, beginning outstanding number (in shares)	59
Number of options, Granted (in shares)	547
Number of options, Exercised (in shares)	(3)
Number of options, Canceled/forfeited/expired (in shares)	(94)
Number of options, ending outstanding number (in shares)	509
Weighted average exercise price
Weighted average exercise price, beginning balance (in dollars per share) | $ / shares	$ 45.60
Weighted average exercise price, Granted (in dollars per share) | $ / shares	0.85
Weighted average exercise price, Exercised (in dollars per share) | $ / shares	0.95
Weighted average exercise price, Canceled/forfeited/expired (in dollars per share) | $ / shares	11.37
Weighted average grant date fair value
Ending balance (usd per share) | $ / shares	$ 4.11
Restricted Stock Units (RSUs)
Number of RSUs
Shares outstanding (in shares)	606
Shares granted (in shares)	286
Shares vested in period (in shares)	(468)
Shares canceled in period (in shares)	(179)
Shares outstanding (in shares)	245
Weighted average grant date fair value
Beginning balance (usd per share) | $ / shares	$ 1.58
Granted (usd per share) | $ / shares	0.95
Exercised (usd per share) | $ / shares	1.29
Canceled/forfeited/expired (usd per share) | $ / shares	1.35
Ending balance (usd per share) | $ / shares	$ 1.57

Stockholders' Equity (Assumptio

Stockholders' Equity (Assumptions Used to Estimate Fair Value of Stock Options and Performance Stock and Employee Stock Purchase Plan) (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Employee stock purchase plan shares
Weighted average assumptions
Risk-free interest rate	2.30%	2.00%	2.40%	1.80%
Volatility	106.70%	99.90%	110.10%	91.70%
Dividend yield	0.00%	0.00%	0.00%	0.00%
Expected term (years)	6 months	6 months	6 months	6 months
Stock options
Weighted average assumptions
Risk-free interest rate	1.50%	2.90%	2.10%	2.70%
Volatility	95.10%	92.00%	94.40%	87.80%
Dividend yield	0.00%	0.00%	0.00%	0.00%
Expected term (years)	6 years 1 month 6 days	6 years 1 month 6 days	6 years 1 month 6 days	6 years 1 month 6 days
Performance stock options
Weighted average assumptions
Risk-free interest rate	0.00%	0.00%	2.60%	2.70%
Volatility	0.00%	0.00%	93.80%	87.40%
Dividend yield	0.00%	0.00%	0.00%	0.00%
Expected term (years)	0 years	0 years	6 years 1 month 6 days	5 years 7 months 25 days

Stockholders' Equity (Stock-Bas

Stockholders' Equity (Stock-Based Compensation Expense Allocation) (Detail) - USD ($) $ in Thousands	Oct. 15, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expenses	$ 400	$ 536	$ 1,390	$ 1,816	$ 4,374
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expenses		45	491	240	1,745
Research and development-restructuring related adjustments
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expenses		0	31	0	31
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expenses		491	883	1,576	2,613
General and administrative-restructuring related adjustments
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expenses		$ 0	$ (15)	$ 0	$ (15)

Strategic Alliances and Colla_2

Strategic Alliances and Collaborations (Detail)

1 Months Ended

3 Months Ended

8 Months Ended

9 Months Ended

Apr. 30, 2019USD ($)

Mar. 31, 2019USD ($)

Nov. 30, 2018USD ($)

Feb. 28, 2014USD ($)$ / sharesshares

Jul. 31, 2013USD ($)

Jul. 31, 2012target

Sep. 30, 2019USD ($)shares

Mar. 31, 2019USD ($)

Sep. 30, 2018USD ($)

Jan. 31, 2014USD ($)

Sep. 30, 2019USD ($)shares

Sep. 30, 2018USD ($)

Dec. 31, 2018USD ($)shares

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Revenues (less than for 2019)

$ 18,000

$ 18,000

$ 6,814,000

$ 54,000

Common stock, shares issued (shares) | shares

20,927,053

20,927,053

8,818,019

Common stock value

$ 21,000

$ 21,000

$ 9,000

Upfront payment received

$ 1,800,000

$ 2,500,000

Revenue under strategic alliances and collaborations

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Revenues (less than for 2019)

100,000

$ 100,000

6,800,000

$ 100,000

Sanofi

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Number of collaborative areas granted | target

4

Upfront payment non-creditable portion recognized

$ 2,500,000

Deferred revenue

$ 400,000

Potential revenue through milestone payments

$ 6,800,000

Agreement period

24 months

Upfront payment received

$ 2,500,000

$ 1,800,000

$ 2,500,000

Development milestone not achievable

40,000,000

$ 40,000,000

Sanofi | Private Placement

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Common stock, shares issued (shares) | shares

1,303,780

Price per share (in dollars per share) | $ / shares

$ 7.67

Common stock value

$ 10,000,000

Restriction period in which Alliances could not sell, transfer, make any short sale of, or grant any option for the sale of any common stock

12 months

Sanofi | Minimum | United States

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Royalties based on percentage of net sales

10.00%

Sanofi | Minimum | Outside of the United States

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Royalties based on percentage of net sales

10.00%

Sanofi | Maximum | United States

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Royalties based on percentage of net sales

20.00%

Sanofi | Maximum | Outside of the United States

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Royalties based on percentage of net sales

20.00%

Sanofi | Development Commercialization And License Agreement

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Initial upfront option payment

$ 2,500,000

Deferred revenue creditable against future milestones

$ 1,250,000

$ 1,250,000

$ 1,250,000

Upfront payment non-creditable portion recognized

$ 1,250,000

Sanofi | Common Stock Purchase Agreement

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Deferred revenue

100,000

$ 100,000

Deferred revenue recognition period (less than)

1 year

Sanofi | Proof-of-Concept Trial

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Potential revenue through milestone payments

38,800,000

$ 38,800,000

Sanofi | Regulatory and Commercialization Milestones

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Potential revenue through milestone payments

130,000,000

130,000,000

Sanofi | Clinical

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Potential revenue through milestone payments

$ 40,000,000

$ 40,000,000

Sanofi | Development Milestones

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Potential revenue through milestone payments

$ 40,000,000

Leases (Narrative) (Details)

Leases (Narrative) (Details)	Feb. 19, 2019USD ($)	Sep. 30, 2019USD ($)	Jul. 01, 2019USD ($)	Jun. 19, 2019USD ($)ft²	Apr. 01, 2019USD ($)	Feb. 25, 2019USD ($)ft²	Jan. 01, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2016USD ($)	Aug. 31, 2015USD ($)	Jul. 31, 2015ft²
Lessee, Lease, Description [Line Items]
Net rentable area | ft²											59,248
Term of contract											96 months
Incentive from lessor										$ 1,400,000
Tenant improvement allowance									$ 8,200,000
Lease liability payments eliminated						$ 14,400,000
Operating lease payments due		$ 977,000
Remaining 2019		106,000
Base rent payments due 2020		429,000
Base rent payments due 2021		442,000
Noncash leasehold improvements		5,600,000
Noncash gain due to reduction of lease liability		1,300,000
Deferred cost of liability		900,000
Operating lease liability		861,000					$ 11,300,000
Termination of lease cost		1,600,000
ROU asset		510,000					$ 3,300,000
Other Noncurrent Liabilities
Lessee, Lease, Description [Line Items]
Deferred rent credit, noncurrent								$ 8,000,000
Nitto
Lessee, Lease, Description [Line Items]
Relocation assistance payment	$ 100,000
Security deposit difference payment	200,000
Rent reimbursement	$ 1,300,000
Lease net impact of modification (less than)		400,000
Initial direct cost liability					$ 3,800,000
ROU asset					2,900,000
Deferred credit, operating lease liabilities					$ 900,000
February Lease
Lessee, Lease, Description [Line Items]
Net rentable area | ft²						24,562
Term of contract						51 months
Operating lease payments due		4,800,000				$ 4,800,000
Remaining 2019		600,000
Base rent payments due 2020		1,200,000
Base rent payments due 2021		1,200,000
Base rent payments due 2022		1,200,000
Base rent payments due 2023		600,000
New Premises
Lessee, Lease, Description [Line Items]
Net rentable area | ft²				8,727
Term of contract				2 years 6 months
Lease liability payments eliminated				$ 4,800,000
Remaining 2019		100,000
Base rent payments due 2020		400,000
Base rent payments due 2021		400,000
Noncash gain due to reduction of lease liability		500,000
Deferred cost of liability		200,000
Operating lease liability		$ 0
Initial direct cost liability			$ 800,000
ROU asset			600,000
Deferred credit, operating lease liabilities			$ 200,000

Leases (Lease Asset and Liabili

Leases (Lease Asset and Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019
Assets
Operating	$ 510	$ 3,300
Financing	512	$ 600
Total ROU assets	1,022
Liabilities
Operating, Current	349
Finance Lease, Current	287
Long-term lease obligations	512
Long-term lease obligations	114
Total lease liabilities	$ 1,262

Leases (Lease Cost) (Details)

Leases (Lease Cost) (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2019USD ($)
Leases [Abstract]
Operating lease cost	$ 70	$ 645
Finance lease cost:
Amortization of right-of-use assets	46	137
Interest expense on lease liabilities	6	19
Total lease cost	122	801
Cash payment information:
Operating cash used for operating leases	0	651
Operating cash used for finance leases	6	19
Financing cash used for finance leases	66	196
Total cash paid for amounts included in the measurement of lease liabilities	$ 72	866
Supplemental non-cash information:
Operating lease liabilities arising from obtaining right-of-use assets		$ 861
Weighted-average remaining lease term (years) - operating leases	2 years 3 months 18 days	2 years 3 months 18 days
Weighted-average remaining lease term (years) - finance leases	1 year 6 months	1 year 6 months
Weighted-average discount rate - operating leases	10.90%	10.90%
Weighted-average discount rate - finance leases	4.90%	4.90%

Leases (Operating and Finance M

Leases (Operating and Finance Maturities) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
Remaining 2019	$ 106
2020	429
2021	442
Operating lease payments due	977
Less: amount representing interest	(116)
Present value of obligations under leases	861	$ 11,300
Less: current portion	(349)
Long-term lease obligations	512
Finance Lease, Liability, Payment, Due [Abstract]
Remaining 2019	72
2020	287
2021	57
Total lease payments	416
Less: amount representing interest	(15)
Present value of obligations under leases	401	$ 600
Less: current portion	(287)
Long-term lease obligations	$ 114

Subsequent Events (Details)

Subsequent Events (Details) - Settled Litigation - USD ($) $ in Millions	Nov. 04, 2019	Sep. 30, 2019	Sep. 30, 2019
Subsequent Event [Line Items]
Litigation settlement, amount awarded to other party		$ 0.3	$ 0.3
Estimate of possible loss		0.9	0.9
Loss contingency, estimated recovery from third party for settlement		$ 0.6	$ 0.6
Subsequent Event
Subsequent Event [Line Items]
Litigation settlement, amount awarded to other party	$ 0.9
Settlement, insurance company portion	0.6
Regulus | Subsequent Event
Subsequent Event [Line Items]
Litigation settlement, amount awarded to other party	$ 0.3

Uncategorized Items - rgls-2019

Label	Element	Value
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 1,843,000
Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 1,843,000