Dicerna Pharmaceuticals (DRNA) 10-Q 8 May 17 2017 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2017	May 05, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q1
Trading Symbol	DRNA
Entity Registrant Name	DICERNA PHARMACEUTICALS INC
Entity Central Index Key	1,399,529
Current Fiscal Year End Date	--12-31
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		20,794,193

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
CURRENT ASSETS:
Cash and cash equivalents	$ 22,873	$ 20,865
Held-to-maturity investments (Note 3)	10,002	25,009
Prepaid expenses and other current assets	2,708	1,952
Deferred financing costs	620
Total current assets	36,203	47,826
NONCURRENT ASSETS:
Property and equipment-net	2,042	2,234
Restricted cash equivalents	1,116	1,116
Other noncurrent assets	75	76
Total noncurrent assets	3,233	3,426
TOTAL ASSETS	39,436	51,252
CURRENT LIABILITIES:
Accounts payable	4,085	4,318
Accrued expenses and other current liabilities	6,262	5,726
Total current liabilities	10,347	10,044
TOTAL LIABILITIES	10,347	10,044
COMMITMENTS AND CONTINGENCIES (Note 7)
STOCKHOLDERS' EQUITY:
Preferred stock, $0.0001 par value-5,000,000 shares authorized; no shares issued or outstanding at March 31, 2017 or December 31, 2016 (Notes 4 and 8)
Common stock, $0.0001 par value-150,000,000 shares authorized; 20,794,193 and 20,753,001 shares issued and outstanding at March 31, 2017 and December 31, 2016, respectively	2	2
Additional paid-in capital	299,044	296,962
Accumulated deficit	(269,957)	(255,756)
Total stockholders' equity	29,089	41,208
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 39,436	$ 51,252

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	20,794,193	20,753,001
Common stock, shares outstanding	20,794,193	20,753,001

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Revenue	$ 133
Operating expenses:
Research and development	8,876	$ 11,264
General and administrative	5,496	4,484
Total operating expenses	14,372	15,748
Loss from operations	(14,239)	(15,748)
Interest income	38	55
Net loss	$ (14,201)	$ (15,693)
Net loss per share-basic and diluted	$ (0.68)	$ (0.76)
Weighted average shares outstanding-basic and diluted	20,791,644	20,646,793

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (14,201)	$ (15,693)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	158	207
Loss on disposal of property and equipment	51
Net amortization of premium/discount on investments	7	36
Stock-based compensation	2,007	2,385
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(755)	367
Accounts payable	(192)	(227)
Accrued expenses and other liabilities	(84)	(1,342)
Net cash used in operating activities	(13,009)	(14,267)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(58)	(127)
Maturities of held-to-maturity investments	15,000	5,500
Purchases of held-to-maturity investments		(20,016)
Net cash provided by (used in) investing activities	14,942	(14,643)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from stock option exercises and issuances under Employee Stock Purchase Plan	86	493
Settlement of restricted stock for tax withholding	(11)	(27)
Net cash provided by financing activities	75	466
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	2,008	(28,444)
CASH AND CASH EQUIVALENTS - Beginning of period	20,865	56,058
CASH AND CASH EQUIVALENTS - End of period	22,873	27,614
NONCASH FINANCING ACTIVITIES:
Deferred financing costs included in accrued expenses and other liabilities	620
NONCASH INVESTING ACTIVITIES:
Property and equipment purchases included in accounts payable and accrued expenses	$ 12	$ 44

Description of Business and Bas

Description of Business and Basis of Presentation	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Description of Business and Basis of Presentation	1. Description of Business and Basis of Presentation Business Dicerna Pharmaceuticals, Inc. (the “Company”) is a biopharmaceutical company focused on the discovery and development of innovative subcutaneously delivered ribonucleic acid interference (“RNAi”)-based pharmaceuticals using its GalXC TM Basis of presentation These condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and in accordance with the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim financial information. Accordingly, these condensed consolidated financial statements do not include all of the information and notes required by GAAP to constitute a complete set of financial statements. These condensed consolidated financial statements have been prepared on the same basis as the Company’s annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary to present fairly the Company’s financial position at March 31, 2017 and results of operations and cash flows for the interim periods ended March 31, 2017 and 2016. These unaudited condensed consolidated interim financial statements should be read in conjunction with the Company’s audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016, as amended. The results of the three months ended March 31, 2017 are not necessarily indicative of the results to be expected for the year ending December 31, 2017 or for any other interim period or for any other future year. Significant judgments and estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements, as well as the revenues and expenses incurred during the reporting periods. On an ongoing basis, the Company evaluates judgments and estimates, including those related to accrued expenses and stock-based compensation. The Company bases its estimates on historical experience and on various other factors that the Company believes are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not apparent from other sources. Changes in estimates are reflected in reported results for the period in which they become known. Actual results could differ materially from those estimates. Liquidity risk Based on the Company’s current operating plan and liquidity, including the receipt of gross proceeds of $70.0 million from the issuance of the Company’s Redeemable Convertible Preferred Stock on April 11, 2017 (see Notes 4 and 8), management believes that available cash, cash equivalents and held-to-maturity investments will be sufficient to fund the Company’s planned level of operations for at least the 12-month period following May 8, 2017, which is the date that these condensed consolidated financial statements have been issued. Notwithstanding the availability of current liquidity, the Company’s ability to fund its current and planned preclinical and clinical operations, including completion of its clinical trials, will depend on its ability to raise additional capital through a combination of public or private equity offerings, debt financings, and research collaborations and license agreements. If the Company is unable to generate funding from one or more of these sources within a reasonable timeframe, it may have to delay, reduce or terminate its research and development programs, preclinical or clinical trials or undergo reductions in its workforce or other corporate restructuring activities. Summary of Significant Accounting Policies 10-K, Recent Accounting Pronouncements Adopted in 2017 Stock-based compensation In March 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting 2016-09”), 2016-09 2016-09. Not yet adopted Revenue recognition In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), Revenue Recognition Revenue from Contracts with Customers Income taxes In October 2016, the FASB issued ASU No. 2016-16, Accounting for Income Taxes: Intra-Entity Asset Transfers of Assets Other than Inventory 2016-16”), 2016-16 pre-tax 2016-16 Leases In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) 2016-02”), which 2016-02 2016-02 2016-02 Statement of cash flows In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230) 2016-15”), 2016-15 2016-15 2016-15 In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash 2016-18”), 2016-18 2016-18

Net Loss Per Share Attributable

Net Loss Per Share Attributable to Common Stockholders	3 Months Ended
	Mar. 31, 2017
Earnings Per Share [Abstract]
Net Loss Per Share Attributable to Common Stockholders	2. Net Loss Per Share Attributable to Common Stockholders The following potentially dilutive securities outstanding during the periods presented have been excluded from the computation of diluted weighted-average common shares outstanding, because such securities had an anti-dilutive impact and because the Company has a net loss: As of March 31, 2017 2016 Options to purchase common stock 6,049,346 4,888,522 Warrants to purchase common stock 87,901 87,901 Unvested restricted stock 10,000 29,156

Held-to-maturity Investments

Held-to-maturity Investments	3 Months Ended
	Mar. 31, 2017
Text Block [Abstract]
Held-to-maturity Investments	3. Held-to-maturity The following tables provide information relating to the Company’s held-to-maturity As of March 31, 2017: Amortized Gross Gross Fair Held-to-maturity U.S. treasury securities maturing in one year or less $ 10,002 $ — $ (4 ) $ 9,998 As of December 31, 2016: Amortized Gross Gross Fair Held-to-maturity U.S. treasury securities maturing in one year or less $ 25,009 $ — $ (5 ) $ 25,004

Redeemable Convertible Preferre

Redeemable Convertible Preferred Stock	3 Months Ended
	Mar. 31, 2017
Text Block [Abstract]
Redeemable Convertible Preferred Stock	4. Redeemable Convertible Preferred Stock On March 30, 2017, the Company entered into a redeemable convertible preferred stock purchase agreement (“SPA”) with seven institutional investors (“Investors”), led by funds advised by Bain Capital Life Sciences L.P. (“Lead Investor”), pursuant to which the Company agreed to issue and sell in a private placement 700,000 shares of its newly designated Redeemable Convertible Preferred Stock, par value $0.0001 per share (“Redeemable Convertible Preferred”), at a purchase price of $100.00 per share, for total gross proceeds of $70.0 million (“Private Placement”). See also Note 8. The Company has filed a Certificate of Designation of Redeemable Convertible Preferred Stock (“Certificate of Designation”) with the Secretary of State of the State of Delaware establishing that each share of Redeemable Convertible Preferred will have a stated value of $100.00 (“Stated Value”). Pursuant to the Certificate of Designation, the Company shall have the right to require the Investors to convert the Redeemable Convertible Preferred into common stock (“Mandatory Conversion”), at any time following the earlier of (i) the second anniversary of the closing of the Private Placement or (ii) the occurrence of both of the following: (a) (1) the date that the Company first administers, after the issue date, a dose of a pharmaceutical product candidate (which such product candidate shall be one of the following candidates, or a variation thereof: DCR-PHXC, DCR-PCSK9 or the undisclosed rare disease program currently in pre-clinical development (each, a “Product Candidate”)) to a human being pursuant to an IND filed by the Company with the Food and Drug Administration (“FDA”); or (2) after the Company has first administered, after the issue date, a dose of a Product Candidate to a human being pursuant to a clinical trial authorization with the Medicine and Healthcare Products Regulatory Agency in the European Union (“EU”) and an IND relating to such Product Candidate has become effective; and (b) the date the Company enters into a partnership or license agreement with a major company in the pharmaceutical or biotechnology industry relating to a non-Product Candidate, pursuant to which such company provides the Company with an up-front cash payment of a minimum amount agreed upon by the Company and the Lead Investor and agrees to customary future milestone and royalty payments, provided, that, in each case ((i) and (ii)), the trading price of the Company’s common stock exceeds 200% of the Conversion Price, as defined below, for 45 out of the 60 most recent trading days. The Company’s ability to require conversion shall be subject to (i) a 19.99% blocker provision to comply with NASDAQ Listing Rules (“19.99% Conversion Blocker”), (ii) if so elected by an investor, a 9.99% blocker provision (9.99% Conversion Blocker) that will prohibit beneficial ownership of more than 9.99% of the outstanding shares of the Company’s common stock or voting power at any time, and (iii) applicable regulatory restrictions. The 19.99% Conversion Blocker and the 9.99% Conversion Blocker are hereinafter referred to as the “Conversion Blockers.” “Conversion Price” shall mean an initial price of $3.19 per share, subject to proportionate adjustment for any stock split, stock dividend, combination or other similar recapitalization event. Following the date of a Mandatory Conversion, any shares of Redeemable Convertible Preferred that are not converted as a result of the Conversion Blockers or applicable regulatory restrictions shall continue to be entitled to all of the rights of the holders of Redeemable Convertible Preferred except that they will no longer be entitled to further accrual of dividends, priority distribution of assets upon consummation of a change of control or a liquidation event and certain special voting provisions. On or at any time following the seventh anniversary of the closing of the Private Placement, (i) the Company shall also have the right to redeem the Redeemable Convertible Preferred for a cash consideration equal to the sum of the Accrued Value, as of the date of redemption, plus an amount equal to all accrued or declared and unpaid dividends on the Redeemable Convertible Preferred that have not previously been added to the Accrued Value, and (ii) the holders of a majority of the Redeemable Convertible Preferred shall also have the right to cause the Company to redeem the Redeemable Convertible Preferred at the same price. “Accrued Value” means, with respect to each share of Redeemable Convertible Preferred, the sum of (i) the Stated Value plus (ii) on each quarterly dividend date, an additional amount equal to the dollar value of any dividends on a share of Redeemable Convertible Preferred which have accrued on any dividend payment date and have not previously been added to such Accrued Value. At any time and from time to time at their election, the holders of Redeemable Convertible Preferred will have the option to convert the Redeemable Convertible Preferred into shares of the Company’s common stock by dividing (i) the sum of the Accrued Value plus an amount equal to all accrued or declared and unpaid dividends on the Redeemable Convertible Preferred that have not previously been added to the Accrued Value by (ii) the Conversion Price in effect at the time of such conversion. The conversion of shares of Redeemable Convertible Preferred into shares of common stock is subject to the Conversion Blockers. In the event of the Company’s liquidation, dissolution or winding up, the holder of each share of Redeemable Convertible Preferred will be entitled to receive, in preference to the holders of the common stock and any junior preferred stock, an amount per share equal to the greater of (i) the sum of the Accrued Value plus an amount equal to all accrued or declared and unpaid dividends on the Redeemable Convertible Preferred that have not previously been added to the Accrued Value, or (ii) the amount that such shares would have been entitled to receive if they had converted into common stock immediately prior to such liquidation, dissolution or winding up. Upon consummation of a specified change of control transaction, each holder of Redeemable Convertible Preferred will be entitled to receive in preference to the holders of common stock and any junior preferred stock, an amount equal to the greater of (i) 101% of the sum of the Accrued Value plus an amount equal to all accrued or declared and unpaid dividends on the Redeemable Convertible Preferred that have not previously been added to the Accrued Value, or (ii) the amount that such shares would have been entitled to receive if they had converted into common stock immediately prior to such event. In addition, for so long as any shares of Redeemable Convertible Preferred remain outstanding, without the approval of holders of a majority of the Redeemable Convertible Preferred, the Company may not, among other things, (i) amend, modify or fail to give effect to any right of holders of the Redeemable Convertible Preferred, (ii) change the authorized number of Redeemable Convertible Preferred or issue additional Redeemable Convertible Preferred or create a new class or series of equity securities or securities convertible into equity securities with equal or superior rights, preferences or privileges to those of the Redeemable Convertible Preferred in terms of liquidation preference, dividend rights or certain governance rights, (iii) issue shares of common stock or securities convertible into common stock while the Company has insufficient shares to effect the conversion of the Redeemable Convertible Preferred into common stock, (iv) declare or pay dividends or redeem or repurchase any capital stock (other than certain repurchases from employees, directors, advisors or consultants upon termination of service) or (v) incur certain indebtedness in excess of $10 million. Except as set forth above or as otherwise required by law, holders of shares of Redeemable Convertible Preferred are entitled to vote together with shares of common stock (based on one vote per share of common stock into which the shares of Redeemable Convertible Preferred are convertible on the applicable record date) on any matter on which the holders of common stock are entitled to vote. Per the Certificate of Designation, each holder of Redeemable Convertible Preferred is entitled to receive cumulative dividends on the Accrued Value of each share of Redeemable Convertible Preferred at an initial rate of 12% per annum, compounded quarterly and subject to two rate reductions, of 4% each, upon the occurrence of certain agreed-upon milestone events. Dividends on the Redeemable Convertible Preferred are payable in kind and will accrue on the Accrued Value of each share of Redeemable Convertible Preferred until the earlier of conversion, redemption, consummation of a change of control, a liquidation event, or upon failure to mandatorily convert due to the Conversion Blockers or applicable regulatory restrictions. In accordance with the terms of the SPA, on March 28, 2017, the Company’s board of directors voted to increase the size of the board from eight directors to nine directors and appointed Adam M. Koppel, M.D., Ph.D., a managing director of the Lead Investor, as a director of the Company, effective immediately following the closing of the Private Placement, to fill the resulting vacancy. To the extent such director is not reelected at any time and, so long as the Lead Investor owns at least 25% of the Redeemable Convertible Preferred (or underlying common stock) owned by it at the closing of the Private Placement, it shall have the right to designate a board observer. The Company also entered into an amended and restated registration rights agreement, by and among the Company and the Investors (“Registration Rights Agreement”). Pursuant to the Registration Rights Agreement, the Investors will be entitled to certain demand, shelf and “piggyback” registration rights with respect to the shares of common stock issuable upon conversion of the Redeemable Convertible Preferred, subject to the limitations set forth in the Registration Rights Agreement. The shares of Redeemable Convertible Preferred and the shares of common stock issuable upon conversion of the Redeemable Convertible Preferred were offered and sold by the Company pursuant to an exemption from the registration requirements of the Securities Act provided by Section 4(a)(2) thereunder.

Stock Option Plan and Stock-Bas

Stock Option Plan and Stock-Based Compensation	3 Months Ended
	Mar. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Option Plan and Stock-Based Compensation	5. Stock Option Plan and Stock-Based Compensation During the three month periods ended March 31, 2017 and 2016, the Company granted stock options to purchase 978,497 and 927,775 shares, respectively, of common stock to employees with aggregate grant-date fair values of $2.0 million and $5.2 million, respectively. The fair value of each stock option award was estimated on the date of grant using the Black-Scholes option-pricing model that uses the assumptions noted in the table below. Expected volatility for the Company’s common stock was determined based on an average of the historical volatility of a peer group of similar companies due to limited historical volatility of the Company’s own common stock. The Company also has limited stock option exercise information, and as such, the expected term of stock options granted was calculated using the simplified method, which represents the average of the contractual term of the stock option and the weighted-average vesting period of the stock option. The assumed dividend yield was based upon the Company’s expectation of not paying dividends in the foreseeable future. The risk-free interest rate for periods within the expected life of the stock option was based upon the U.S. Treasury yield curve in effect at the time of grant. The assumptions used to estimate the grant-date fair value were as follows: Three Months Ended March 31, 2017 Three Months Ended March 31, 2016 Stock price $2.49 – $2.97 $5.26 – $9.09 Expected option term (in years) 6.25 6.25 Expected volatility 79.4% – 80.0% 70.9% – 71.3% Risk-free interest rate 2.04% – 2.07% 1.44% – 1.71% Expected dividend yield 0.00% 0.00% The Company recorded stock-based compensation expense of $2.0 million and $2.4 million for the three month periods ended March 31, 2017 and 2016, respectively, classified in the Company’s condensed consolidated statements of operations as follows: Three Months Ended March 31, 2017 2016 Research and development expenses $ 944 $ 1,175 General and administrative expenses 1,063 1,210 Total $ 2,007 $ 2,385

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	6. Fair Value Measurements A summary of the Company’s financial assets that are measured or disclosed at fair value on a recurring basis as of March 31, 2017 and December 31, 2016 are presented below: Description At March 31, Level 1 Level 2 Level 3 Cash equivalents Money market fund $ 15,847 $ 15,847 $ — $ — Held-to-maturity U.S. treasury securities 9,998 — 9,998 — Restricted cash equivalents Money market fund 1,116 — 1,116 — Total $ 26,961 $ 15,847 $ 11,114 $ — Description At December 31, Level 1 Level 2 Level 3 Cash equivalents Money market fund $ 12,853 $ 12,853 $ — $ — Held-to-maturity U.S. treasury securities 25,004 — 25,004 — Restricted cash equivalents Money market fund 1,116 — 1,116 — Total $ 38,973 $ 12,853 $ 26,120 $ — The Company’s cash equivalents, which are in money market funds, are classified within Level 1 of the fair value hierarchy because they are valued using quoted prices as of March 31, 2017 and December 31, 2016. The Company’s restricted cash equivalents bore interest at the prevailing market rates for instruments with similar characteristics and, accordingly, the carrying value of these instruments also approximated their fair value. These financial instruments were classified within Level 2 of the fair value hierarchy, because the inputs to the fair value measurement are valued using observable inputs as of March 31, 2017 and December 31, 2016. The Company’s held-to-maturity As of March 31, 2017 and December 31, 2016, the carrying amounts of accounts payable and accrued expenses approximated their estimated fair values because of the short-term nature of these financial instruments. For the three month periods ended March 31, 2017 and 2016, there were no transfers between Level 1 and Level 2.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. Commitments and Contingencies Facility lease Future minimum lease payments on the Company’s non-cancelable Period Ending March 31, Operating 2018 $ 1,594 2019 1,641 2020 1,691 2021 1,150 Total $ 6,076 Litigation On June 10, 2015, Alnylam Pharmaceuticals, Inc. (“Alnylam”) filed a complaint against the Company in the Superior Court of Middlesex County, Massachusetts (the “Court”). The complaint alleges misappropriation of confidential, proprietary, and trade secret information, as well as other related claims, in connection with the Company’s hiring of a number of former employees of Merck and its discussions with Merck regarding the acquisition of its subsidiary, Sirna Therapeutics, Inc., which was subsequently acquired by Alnylam. The complaint seeks among other things, unspecified damages, attorneys’ fees, and an order permanently enjoining the Company from disclosing or using any of Alnylam’s confidential information or trade secrets. The Court has set a trial date of February 7, 2018. The Company believes that these allegations lack merit, has filed an answer denying all liability and intends to continue to vigorously defend all claims asserted. At this time, the Company has not recorded a liability in connection with these matters because management believes that any potential loss is neither probable nor reasonably estimable. From time to time, the Company may be subject to various claims and legal proceedings. If the potential loss from any claim, asserted or unasserted, or legal proceeding is considered probable and the amount is reasonably estimable, the Company will accrue a liability for the estimated loss. There were no litigation liabilities as of March 31, 2017 or December 31, 2016.

Subsequent Event

Subsequent Event	3 Months Ended
	Mar. 31, 2017
Subsequent Events [Abstract]
Subsequent Event	8. Subsequent Event On April 11, 2017, the Company closed the Private Placement and issued an aggregate of 700,000 shares of Redeemable Convertible Preferred. Aggregate gross proceeds received in connection with the Private Placement totaled $70.0 million, less related transaction costs of approximately $0.6 million. As of the date of closing of the Private Placement, the Lead Investor, which appointed one of its managing directors to the Company’s board of directors, owned approximately 19% of the Company on an as-converted basis. Other investors who participated in the Private Placement included Domain Associates, RA Capital and Skyline Ventures, which are entities that are affiliated or formerly were affiliated with certain members of the Company’s board of directors. See also Note 4.

Description of Business and B14

Description of Business and Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Business	Business Dicerna Pharmaceuticals, Inc. (the “Company”) is a biopharmaceutical company focused on the discovery and development of innovative subcutaneously delivered ribonucleic acid interference (“RNAi”)-based pharmaceuticals using its GalXC TM
Basis of presentation	Basis of presentation These condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and in accordance with the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim financial information. Accordingly, these condensed consolidated financial statements do not include all of the information and notes required by GAAP to constitute a complete set of financial statements. These condensed consolidated financial statements have been prepared on the same basis as the Company’s annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary to present fairly the Company’s financial position at March 31, 2017 and results of operations and cash flows for the interim periods ended March 31, 2017 and 2016. These unaudited condensed consolidated interim financial statements should be read in conjunction with the Company’s audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016, as amended. The results of the three months ended March 31, 2017 are not necessarily indicative of the results to be expected for the year ending December 31, 2017 or for any other interim period or for any other future year.
Significant judgments and estimates	Significant judgments and estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements, as well as the revenues and expenses incurred during the reporting periods. On an ongoing basis, the Company evaluates judgments and estimates, including those related to accrued expenses and stock-based compensation. The Company bases its estimates on historical experience and on various other factors that the Company believes are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not apparent from other sources. Changes in estimates are reflected in reported results for the period in which they become known. Actual results could differ materially from those estimates.
Liquidity risk	Liquidity risk Based on the Company’s current operating plan and liquidity, including the receipt of gross proceeds of $70.0 million from the issuance of the Company’s Redeemable Convertible Preferred Stock on April 11, 2017 (see Notes 4 and 8), management believes that available cash, cash equivalents and held-to-maturity investments will be sufficient to fund the Company’s planned level of operations for at least the 12-month period following May 8, 2017, which is the date that these condensed consolidated financial statements have been issued. Notwithstanding the availability of current liquidity, the Company’s ability to fund its current and planned preclinical and clinical operations, including completion of its clinical trials, will depend on its ability to raise additional capital through a combination of public or private equity offerings, debt financings, and research collaborations and license agreements. If the Company is unable to generate funding from one or more of these sources within a reasonable timeframe, it may have to delay, reduce or terminate its research and development programs, preclinical or clinical trials or undergo reductions in its workforce or other corporate restructuring activities.
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies 10-K,
Recent Accounting Pronouncements	Recent Accounting Pronouncements Adopted in 2017 Stock-based compensation In March 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting 2016-09”), 2016-09 2016-09. Not yet adopted Revenue recognition In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), Revenue Recognition Revenue from Contracts with Customers Income taxes In October 2016, the FASB issued ASU No. 2016-16, Accounting for Income Taxes: Intra-Entity Asset Transfers of Assets Other than Inventory 2016-16”), 2016-16 pre-tax 2016-16 Leases In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) 2016-02”), which 2016-02 2016-02 2016-02 Statement of cash flows In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230) 2016-15”), 2016-15 2016-15 2016-15 In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash 2016-18”), 2016-18 2016-18

Net Loss Per Share Attributab15

Net Loss Per Share Attributable to Common Stockholders (Tables)	3 Months Ended
	Mar. 31, 2017
Earnings Per Share [Abstract]
Schedule of Dilutive Securities Outstanding	The following potentially dilutive securities outstanding during the periods presented have been excluded from the computation of diluted weighted-average common shares outstanding, because such securities had an anti-dilutive impact and because the Company has a net loss: As of March 31, 2017 2016 Options to purchase common stock 6,049,346 4,888,522 Warrants to purchase common stock 87,901 87,901 Unvested restricted stock 10,000 29,156

Held-to-maturity Investments (T

Held-to-maturity Investments (Tables)	3 Months Ended
	Mar. 31, 2017
Text Block [Abstract]
Schedule of Held-To-Maturity Investments	The following tables provide information relating to the Company’s held-to-maturity As of March 31, 2017: Amortized Gross Gross Fair Held-to-maturity U.S. treasury securities maturing in one year or less $ 10,002 $ — $ (4 ) $ 9,998 As of December 31, 2016: Amortized Gross Gross Fair Held-to-maturity U.S. treasury securities maturing in one year or less $ 25,009 $ — $ (5 ) $ 25,004

Stock Option Plan and Stock-B17

Stock Option Plan and Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2017
Stock-Based Compensation Expense	The Company recorded stock-based compensation expense of $2.0 million and $2.4 million for the three month periods ended March 31, 2017 and 2016, respectively, classified in the Company’s condensed consolidated statements of operations as follows: Three Months Ended March 31, 2017 2016 Research and development expenses $ 944 $ 1,175 General and administrative expenses 1,063 1,210 Total $ 2,007 $ 2,385
Stock Options Granted to Non-Employees [Member]
Schedule of Valuation Assumptions	The assumptions used to estimate the grant-date fair value were as follows: Three Months Ended March 31, 2017 Three Months Ended March 31, 2016 Stock price $2.49 – $2.97 $5.26 – $9.09 Expected option term (in years) 6.25 6.25 Expected volatility 79.4% – 80.0% 70.9% – 71.3% Risk-free interest rate 2.04% – 2.07% 1.44% – 1.71% Expected dividend yield 0.00% 0.00%

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Schedule of Financial Assets Measured or Disclosed at Fair Value on Recurring Basis	A summary of the Company’s financial assets that are measured or disclosed at fair value on a recurring basis as of March 31, 2017 and December 31, 2016 are presented below: Description At March 31, Level 1 Level 2 Level 3 Cash equivalents Money market fund $ 15,847 $ 15,847 $ — $ — Held-to-maturity U.S. treasury securities 9,998 — 9,998 — Restricted cash equivalents Money market fund 1,116 — 1,116 — Total $ 26,961 $ 15,847 $ 11,114 $ — Description At December 31, Level 1 Level 2 Level 3 Cash equivalents Money market fund $ 12,853 $ 12,853 $ — $ — Held-to-maturity U.S. treasury securities 25,004 — 25,004 — Restricted cash equivalents Money market fund 1,116 — 1,116 — Total $ 38,973 $ 12,853 $ 26,120 $ —

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Summary of Future Minimum Lease Payments on Company's Non-cancelable Operating Lease	Future minimum lease payments on the Company’s non-cancelable Period Ending March 31, Operating 2018 $ 1,594 2019 1,641 2020 1,691 2021 1,150 Total $ 6,076

Description of Business and B20

Description of Business and Basis of Presentation - Additional Information (Detail) - USD ($) $ in Millions	Apr. 11, 2017	Mar. 30, 2017
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Proceeds from private placement		$ 70
Subsequent Event [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Proceeds from private placement	$ 70

Net Loss Per Share Attributab21

Net Loss Per Share Attributable to Common Stockholders - Schedule of Dilutive Securities Outstanding (Detail) - shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Employee Stock Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities	6,049,346	4,888,522
Hercules Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities	87,901	87,901
Unvested Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities	10,000	29,156

Held-to-maturity Investments -

Held-to-maturity Investments - Schedule of Held-To-Maturity Investments (Detail) - US Treasury Securities [Member] - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity investments, Amortized Cost	$ 10,002	$ 25,009
Held-to-maturity investments, Gross Unrealized Gains	0	0
Held-to-maturity investments, Gross Unrealized Losses	(4)	(5)
Held-to-maturity investments, Fair Value, Total	$ 9,998	$ 25,004

Redeemable convertible Prefer23

Redeemable convertible Preferred Stock - Additional Information (Detail)	Mar. 30, 2017USD ($)d$ / sharesshares	Mar. 28, 2017Director	Mar. 31, 2017
Temporary Equity [Line Items]
Redeemable convertible preferred stock, issued | shares	700,000
Redeemable convertible preferred stock, par value	$ 0.0001
Redeemable convertible preferred stock, price per share	$ 100
Proceeds from private placement | $	$ 70,000,000
Initial conversion price	$ 3.19
Redeemable convertible preferred stock, terms of conversion			The Company's ability to require conversion shall be subject to (i) a 19.99% blocker provision to comply with NASDAQ Listing Rules ("19.99% Conversion Blocker"), (ii) if so elected by an investor, a 9.99% blocker provision (9.99% Conversion Blocker) that will prohibit beneficial ownership of more than 9.99% of the outstanding shares of the Company's common stock or voting power at any time, and (iii) applicable regulatory restrictions.
Percentage of redeemable convertible preferred stock conversion blocker provision	19.99%
Percentage of redeemable convertible preferred stock ownership limit conversion blocker provision	9.99%
Conversion price percentage of company's common stock	200.00%
Number of trading days | d	45
Number of consecutive trading days applicable conversion price	60 days
Liquidation preference percentage	101.00%
Maximum borrowings under securitization facility | $	$ 10,000,000
Cumulative dividends rate	12.00%
Percentage of rate reduction	4.00%
Number of interest rate reductions	2
Existing number of directors | Director		8
Increased number of directors | Director		9
Director [Member]
Temporary Equity [Line Items]
Minimum required ownership percentage		25.00%

Stock Option Plan and Stock-B24

Stock Option Plan and Stock-Based Compensation - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 2,007	$ 2,385
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option, granted	978,497	927,775
Fair value of stock options	$ 2,000	$ 5,200
Stock-based compensation expense	$ 2,000	$ 2,400

Stock Option Plan and Stock-B25

Stock Option Plan and Stock-Based Compensation - Schedule of Valuation Assumptions (Detail) - Employee Stock Option [Member] - $ / shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected option term (in years)	6 years 3 months	6 years 3 months
Expected dividend yield	0.00%	0.00%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock price	$ 2.49	$ 5.26
Expected volatility	79.40%	70.90%
Risk-free interest rate	2.04%	1.44%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock price	$ 2.97	$ 9.09
Expected volatility	80.00%	71.30%
Risk-free interest rate	2.07%	1.71%

Stock Option Plan and Stock-B26

Stock Option Plan and Stock-Based Compensation - Classification of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	$ 2,007	$ 2,385
Research and Development Expenses [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	944	1,175
General and Administrative Expenses [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	$ 1,063	$ 1,210

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Assets Measured or Disclosed at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Restricted cash equivalents
Total	$ 26,961	$ 38,973
Money Market Fund [Member]
Cash equivalents
Money market fund	15,847	12,853
Restricted cash equivalents
Restricted investments, at fair value	1,116	1,116
US Treasury Securities [Member]
Held-to-maturity investments
U.S. treasury securities	9,998	25,004
Level 1 [Member]
Restricted cash equivalents
Total	15,847	12,853
Level 1 [Member] | Money Market Fund [Member]
Cash equivalents
Money market fund	15,847	12,853
Level 2 [Member]
Restricted cash equivalents
Total	11,114	26,120
Level 2 [Member] | Money Market Fund [Member]
Restricted cash equivalents
Restricted investments, at fair value	1,116	1,116
Level 2 [Member] | US Treasury Securities [Member]
Held-to-maturity investments
U.S. treasury securities	$ 9,998	$ 25,004

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	Mar. 31, 2017	Mar. 31, 2016
Debt Instrument Fair Value Carrying Value [Abstract]
Transfers between Level 1 and Level 2	$ 0	$ 0

Commitments and Contingencies -

Commitments and Contingencies - Summary of Future Minimum Lease Payments on Company's Non-cancelable Operating Lease (Detail) $ in Thousands	Mar. 31, 2017USD ($)
Commitments and Contingencies Disclosure [Abstract]
2,018	$ 1,594
2,019	1,641
2,020	1,691
2,021	1,150
Total	$ 6,076

Commitments and Contingencies30

Commitments and Contingencies - Additional Information (Detail) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Outstanding litigation liabilities	$ 0	$ 0

Subsequent Event - Additional I

Subsequent Event - Additional Information (Detail) - USD ($) $ in Millions	Apr. 11, 2017	Mar. 30, 2017
Subsequent Event [Line Items]
Redeemable convertible preferred stock, issued		700,000
Proceeds from private placement		$ 70
Subsequent Event [Member]
Subsequent Event [Line Items]
Redeemable convertible preferred stock, issued	700,000
Proceeds from private placement	$ 70
Transaction costs related to private placement	$ 0.6
Director [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Ownership interest held by investor on converted basis	19.00%