Dicerna Pharmaceuticals (DRNA) 10-Q 9 Aug 21 2021 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	6 Months Ended
	Jun. 30, 2021	Aug. 02, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2021
Document Transition Report	false
Entity File Number	001-36281
Entity Registrant Name	DICERNA PHARMACEUTICALS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-5993609
Entity Address, Address Line One	75 Hayden Avenue
Entity Address, City or Town	Lexington
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02421
City Area Code	617
Local Phone Number	621-8097
Title of each class	Common Stock, $0.0001 Par Value
Trading Symbol(s)	DRNA
Name of each exchange on which registered	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		77,734,172
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Entity Central Index Key	0001399529
Current Fiscal Year End Date	--12-31

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
CURRENT ASSETS:
Cash and cash equivalents	$ 221,210	$ 126,023
Held-to-maturity investments, current	371,755	442,820
Restricted cash equivalents, current	0	744
Contract receivables	3,147	34,713
Prepaid expenses and other current assets	20,380	14,403
Total current assets	616,492	618,703
NONCURRENT ASSETS:
Property and equipment, net	23,593	17,546
Right-of-use operating assets, net	74,400	60,843
Restricted cash equivalents, noncurrent	5,618	5,618
Held-to-maturity investments, noncurrent	116,599	0
Other noncurrent assets	1,790	5,136
Total noncurrent assets	222,000	89,143
TOTAL ASSETS	838,492	707,846
CURRENT LIABILITIES:
Accounts payable	12,829	7,901
Accrued expenses and other current liabilities	29,577	28,061
Lease liability, current	3,946	3,439
Deferred revenue, current	160,200	138,537
Deferred income, current	1,098	0
Total current liabilities	207,650	177,938
NONCURRENT LIABILITIES:
Lease liability, noncurrent	61,203	48,744
Deferred revenue, noncurrent	268,606	336,236
Deferred income, noncurrent	178,708	0
Derivative liability	7,750	6,000
Other noncurrent liabilities	3,501	1,174
Total noncurrent liabilities	519,768	392,154
TOTAL LIABILITIES	727,418	570,092
COMMITMENTS AND CONTINGENCIES (NOTE 11)
STOCKHOLDERS’ EQUITY:
Preferred stock, $0.0001 par value – 5,000,000 shares authorized; no shares issued or outstanding at June 30, 2021 or December 31, 2020	0	0
Common stock, $0.0001 par value – 150,000,000 shares authorized; 77,601,552 and 75,757,213 shares issued and outstanding at June 30, 2021 and December 31, 2020, respectively	8	8
Additional paid-in capital	819,909	775,809
Accumulated deficit	(708,843)	(638,063)
Total stockholders’ equity	111,074	137,754
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 838,492	$ 707,846

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2021	Dec. 31, 2020
STOCKHOLDERS’ EQUITY:
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	150,000,000	150,000,000
Common stock, shares issued (in shares)	77,601,552	75,757,213
Common stock, shares outstanding (in shares)	77,601,552	75,757,213

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Statement [Abstract]
Revenue	$ 41,337	$ 40,448	$ 88,940	$ 74,476
Operating expenses:
Research and development	56,119	53,376	112,157	96,547
General and administrative	25,462	20,565	46,134	36,588
Total operating expenses	81,581	73,941	158,291	133,135
Loss from operations	(40,244)	(33,493)	(69,351)	(58,659)
Other income (expense):
Interest income	111	1,729	391	4,342
Interest expense	(4)	(6)	(8)	(10)
Other (expense) income	(132)	(50)	(1,266)	15
Total other (expense) income	(25)	1,673	(883)	4,347
Loss before income taxes	(40,269)	(31,820)	(70,234)	(54,312)
Provision for income taxes	(546)	0	(546)	0
Net loss	$ (40,815)	$ (31,820)	$ (70,780)	$ (54,312)
Net loss per share – diluted (in dollars per share)	$ (0.53)	$ (0.43)	$ (0.92)	$ (0.74)
Net loss per share – basic (in dollars per share)	$ (0.53)	$ (0.43)	$ (0.92)	$ (0.74)
Weighted average common shares outstanding – diluted (in shares)	77,029,763	74,001,126	76,644,786	73,460,252
Weighted average common shares outstanding – basic (in shares)	77,029,763	74,001,126	76,644,786	73,460,252

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	COMMON STOCK	ADDITIONAL PAID-IN CAPITAL	ACCUMULATED DEFICIT
Balance at beginning of period (in shares) at Dec. 31, 2019		71,573,196
Balance at beginning of period at Dec. 31, 2019	$ 152,195	$ 7	$ 677,504	$ (525,316)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercises of common stock options (in shares)		128,373
Exercises of common stock options	588		588
Stock-based compensation expense	8,527		8,527
Proceeds from issuance of common stock from public offering, net of underwriting fees and issuance costs (in shares)		2,077,500
Proceeds from issuance of common stock, net of commissions and offering costs of $904	39,088		39,088
Net loss	(22,492)			(22,492)
Balance at end of period (in shares) at Mar. 31, 2020		73,779,069
Balance at end of period at Mar. 31, 2020	177,906	$ 7	725,707	(547,808)
Balance at beginning of period (in shares) at Dec. 31, 2019		71,573,196
Balance at beginning of period at Dec. 31, 2019	152,195	$ 7	677,504	(525,316)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(54,312)
Balance at end of period (in shares) at Jun. 30, 2020		74,321,325
Balance at end of period at Jun. 30, 2020	162,168	$ 7	741,789	(579,628)
Balance at beginning of period (in shares) at Mar. 31, 2020		73,779,069
Balance at beginning of period at Mar. 31, 2020	177,906	$ 7	725,707	(547,808)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercises of common stock options and sales of common stock under Employee Stock Purchase Plan (in shares)		542,256
Exercises of common stock options and sales of common stock under Employee Stock Purchase Plan	5,876		5,876
Stock-based compensation expense	10,206		10,206
Net loss	(31,820)			(31,820)
Balance at end of period (in shares) at Jun. 30, 2020		74,321,325
Balance at end of period at Jun. 30, 2020	162,168	$ 7	741,789	(579,628)
Balance at beginning of period (in shares) at Dec. 31, 2020		75,757,213
Balance at beginning of period at Dec. 31, 2020	137,754	$ 8	775,809	(638,063)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercises of common stock options (in shares)		707,723
Exercises of common stock options	7,616		7,616
Vesting of restricted common stock units (in shares)		177,950
Shares withheld to cover taxes upon restricted stock unit vesting (in shares)		(59,012)
Shares withheld to cover taxes upon restricted stock unit vesting	(1,414)		(1,414)
Stock-based compensation expense	12,413		12,413
Net loss	(29,965)			(29,965)
Balance at end of period (in shares) at Mar. 31, 2021		76,583,874
Balance at end of period at Mar. 31, 2021	126,404	$ 8	794,424	(668,028)
Balance at beginning of period (in shares) at Dec. 31, 2020		75,757,213
Balance at beginning of period at Dec. 31, 2020	137,754	$ 8	775,809	(638,063)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(70,780)
Balance at end of period (in shares) at Jun. 30, 2021		77,601,552
Balance at end of period at Jun. 30, 2021	111,074	$ 8	819,909	(708,843)
Balance at beginning of period (in shares) at Mar. 31, 2021		76,583,874
Balance at beginning of period at Mar. 31, 2021	126,404	$ 8	794,424	(668,028)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercises of common stock options and sales of common stock under Employee Stock Purchase Plan (in shares)		957,564
Exercises of common stock options and sales of common stock under Employee Stock Purchase Plan	12,314		12,314
Vesting of restricted common stock units (in shares)		73,073
Shares withheld to cover taxes upon restricted stock unit vesting (in shares)		(12,959)
Shares withheld to cover taxes upon restricted stock unit vesting	(462)		(462)
Stock-based compensation expense	13,633		13,633
Net loss	(40,815)			(40,815)
Balance at end of period (in shares) at Jun. 30, 2021		77,601,552
Balance at end of period at Jun. 30, 2021	$ 111,074	$ 8	$ 819,909	$ (708,843)

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (Parenthetical) $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)
Statement of Stockholders' Equity [Abstract]
Commissions and offering costs	$ 904

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (70,780)	$ (54,312)
Adjustments to reconcile net loss to net cash provided by operating activities:
Stock-based compensation expense	26,046	18,733
Change in fair value of derivative liability	1,750	0
Depreciation and amortization expense	2,487	1,066
Accretion (amortization) of premium on investments	1,965	(302)
Non-cash lease expense	5,550	3,640
Other	42	(5)
Changes in operating assets and liabilities:
Deferred revenue	(45,967)	117,243
Deferred income	179,806	0
Prepaid expenses and other assets	(4,481)	(11,988)
Accounts payable	4,810	2,035
Contract receivables	31,566	200,342
Accrued expenses and other liabilities	3,525	7,536
Lease liability	(4,182)	(4,564)
Net cash provided by operating activities	132,137	279,424
CASH FLOWS FROM INVESTING ACTIVITIES:
Maturities of held-to-maturity investments	344,000	254,000
Purchases of held-to-maturity investments	(391,498)	(529,041)
Purchases of property and equipment	(8,223)	(3,358)
Other	0	15
Net cash used in investing activities	(55,721)	(278,384)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock, net of placement agent commissions	0	39,192
Payments of common stock offering costs	0	(104)
Payments for minimum statutory tax withholding related to net share settlement of equity awards	(1,876)	0
Proceeds from exercises of stock options	19,925	6,550
Other	(22)	(24)
Net cash provided by financing activities	18,027	45,614
NET INCREASE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH EQUIVALENTS	94,443	46,654
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH EQUIVALENTS – Beginning of period	132,385	156,710
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH EQUIVALENTS – End of period	226,828	203,364
NONCASH OPERATING ACTIVITIES
Right-of-use assets acquired through operating leases	15,302	1,101
NONCASH INVESTING ACTIVITIES
Property and equipment purchases included in accounts payable and accrued expenses	177	446
NONCASH FINANCING ACTIVITIES
Right-of-use assets acquired through financing leases	0	48
Reconciliation of Cash, Cash Equivalents, and Restricted Cash Equivalents
Cash and cash equivalents	221,210	197,801
Restricted cash equivalents, noncurrent	5,618	5,563
Total cash, cash equivalents, and restricted cash equivalents shown in the condensed consolidated statements of cash flows	$ 226,828	$ 203,364

DESCRIPTION OF BUSINESS AND BAS

DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION	6 Months Ended
	Jun. 30, 2021
Accounting Policies [Abstract]
DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION	DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION Business Dicerna Pharmaceuticals, Inc. (the “Company” or “Dicerna”) is a biopharmaceutical company focused on discovering, developing, and commercializing medicines that are designed to leverage ribonucleic acid interference (“RNAi”) to silence selectively genes that cause or contribute to disease. Using the Company’s proprietary GalXC™ and GalXC-Plus™ RNAi technologies, Dicerna is committed to developing RNAi-based therapies with the potential to treat both rare and more prevalent diseases. By silencing disease-causing genes, Dicerna’s GalXC platform has the potential to address conditions that are difficult to treat with other modalities. Initially focused on disease-causing genes in the liver, Dicerna has continued to innovate and is exploring new applications of its RNAi technology with GalXC-Plus, which expands the functionality and application of the Company’s flagship liver-based GalXC technology to tissues and cell types outside the liver and has the potential to treat diseases across multiple therapeutic areas. In addition to the Company’s own pipeline of core discovery and clinical candidates, Dicerna has established collaborative relationships with some of the world’s leading pharmaceutical companies, including Novo Nordisk A/S (“Novo”), Roche, Eli Lilly and Company (“Lilly”), Alexion Pharmaceuticals, Inc. (together with its affiliates, “Alexion”), Boehringer Ingelheim International GmbH (“BI”), and Alnylam Pharmaceuticals, Inc. (“Alnylam”). Between Dicerna and its collaborative partners, the Company currently has more than 20 active discovery, preclinical, or clinical programs focused on cardiometabolic, viral, chronic liver, and complement-mediated diseases, as well as neurodegenerative diseases and pain. COVID-19 On March 11, 2020, the World Health Organization declared the spread of the novel coronavirus (“COVID-19”) a pandemic. The global spread of COVID-19 has created significant volatility, uncertainty, and economic disruption worldwide. Governments in affected regions have implemented, and may continue to implement, safety precautions which include quarantines, travel restrictions, business closures, and other public health safety measures. Throughout 2020 and into 2021, Dicerna was impacted by mandatory work from home edicts directed by local governments in the jurisdictions in which the Company operates. However, essential work exemptions continued to permit critical research and development and laboratory activities for limited personnel. Those exemptions enabled some continued discovery research and activities supporting the Company’s collaborative agreements and its own programs. Externally, the COVID-19 pandemic has resulted in some challenges in reserving slots for preclinical studies and accessing non-human primates for such studies, as well as slower enrollment in the Company’s clinical trials. Dicerna has undertaken efforts to mitigate potential impacts to our business including those related to conducting clinical trials and managing our supply chain. The Company continues to be alert to the potential for disruptions that could arise from COVID-19 or its variants and monitors the Food and Drug Administration’s (“FDA”) and other health authorities’ guidance for the conduct of clinical trials during this time. Current supply of Dicerna’s investigational medicines is sufficient to support ongoing and planned clinical trials. Based on current evaluations, Dicerna’s supply chains continue to appear intact to meet at least the next 18 months of clinical, nonclinical, commercial, and chemistry, manufacturing, and control (“CMC”) supply demands across all programs. The Company has undertaken efforts to mitigate potential future impacts to the supply chain by increasing its stock of critical starting materials required to meet its needs and its collaborative partners’ needs through 2022 and by identifying and engaging alternative suppliers. The Company continues to be alert to the potential for disruptions that could arise from COVID-19 or its variants, including on account of United States (“U.S.”) government utilization of its Defense Production Act authorities, and remains in close contact with suppliers. It is difficult to predict what the lasting impact of the pandemic will be, and what the impact might be if the Company or any of the third parties with whom it engages were to experience additional shutdowns or other prolonged business disruptions. The Company’s ability to conduct its business in the manner and on the timelines presently planned could have a material adverse impact on the Company’s business, results of operations, and financial condition. In addition, depending on the duration and impact of the recurrence or resurgence of COVID-19 cases or continued evolution of further strains of COVID-19 or its variants, and depending on where the infection rates are highest, and including the ability of regulators to continue ensuring the timely review and approval of applications, the Company’s business, results of operations, and financial condition may be negatively impacted. The Company will continue to monitor developments as it deals with the disruptions and uncertainties relating to the COVID-19 pandemic. 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”) along with the rules and regulations of the Securities and Exchange Commission for interim financial information, and include the accounts of Dicerna Pharmaceuticals, Inc. and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. The year-end condensed consolidated balance sheet data were derived from audited financial statements but do not include all disclosures 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 for a fair statement of the Company’s financial position at June 30, 2021 and its results of operations, changes in stockholders’ equity, and cash flows for the interim periods ended June 30, 2021 and 2020. 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, 2020. The results of operations for the three and six months ended June 30, 2021 are not necessarily indicative of the results to be expected for the year ending December 31, 2021, for any other interim period, or for any other future year. Significant judgments and estimates The preparation of condensed 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 Company’s condensed 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 revenue recognition, deferred income, stock-based compensation, the derivative liability, and accrued expenses. 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 values 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. Recent accounting pronouncements In December 2019, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2019-12, Simplifying the Accounting for Income Taxes , amending accounting guidance that simplifies the accounting for income taxes as part of its initiative to reduce complexity in the accounting standards. The amendments eliminate certain exceptions related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period, and the recognition of deferred tax liabilities for outside basis differences. The amendments also clarify and simplify other aspects of the accounting for income taxes. For public business entities, ASU 2019-12 is required to be adopted effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. The Company adopted ASU 2019-12 on January 1, 2021 and it did not have a material impact on its financial statements or related disclosures. Summary of significant accounting policies There have been no changes to the significant accounting policies disclosed in the Company’s most recent Annual Report on Form 10-K.

NET LOSS PER SHARE

NET LOSS PER SHARE	6 Months Ended
	Jun. 30, 2021
Earnings Per Share [Abstract]
NET LOSS PER SHARE	NET LOSS PER SHARE The Company computes basic net loss per common share by dividing net loss by the weighted average number of common shares outstanding. In periods of net income, the Company’s accounting policy includes allocating a proportional share of net income to participating securities, as determined by dividing total weighted average participating securities by the sum of the total weighted average common shares and participating securities (the “two-class method”). Participating securities have the effect of diluting both basic and diluted earnings per share during periods of income. During periods when the Company incurs a net loss, the Company does not allocate a loss to participating securities because they have no contractual obligation to share in the losses of the Company. The Company computes diluted net loss per common share after giving consideration to the dilutive effect of stock options and nonvested restricted stock units that are outstanding during the period, except where such non-participating securities would be anti-dilutive. The outstanding securities presented below were excluded from the calculation of net loss per share because such securities would have been anti-dilutive due to the Company’s net loss per share during the periods ending on the dates presented: JUNE 30, JUNE 30, Options to purchase common stock 14,307,555 15,109,939 Nonvested restricted stock units 1,221,426 887,355 Total 15,528,981 15,997,294

HELD-TO-MATURITY INVESTMENTS

HELD-TO-MATURITY INVESTMENTS	6 Months Ended
	Jun. 30, 2021
Investments, Debt and Equity Securities [Abstract]
HELD-TO-MATURITY INVESTMENTS	HELD-TO-MATURITY INVESTMENTS A summary of the Company’s held-to-maturity investments is presented below: JUNE 30, 2021 DESCRIPTION AMORTIZED COST GROSS UNREALIZED HOLDING GAINS GROSS UNREALIZED HOLDING LOSSES FAIR VALUE U.S. Treasury securities maturing in one year or less $ 371,755 $ 39 $ (13) $ 371,781 U.S. Treasury securities maturing in greater than one year 116,599 — (34) 116,565 Total $ 488,354 $ 39 $ (47) $ 488,346 DECEMBER 31, 2020 DESCRIPTION AMORTIZED COST GROSS UNREALIZED HOLDING GAINS GROSS UNREALIZED HOLDING LOSSES FAIR VALUE U.S. Treasury securities maturing in one year or less $ 442,820 $ 163 $ (12) $ 442,971 The Company’s policy is not to measure an allowance for credit losses for interest receivable and to write off any uncollectible interest receivable as a reversal of interest income in the period in which it determines the interest will not be collected. The Company did not write off any interest receivable during the three and six months ended June 30, 2021 and 2020.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS A summary of the Company’s assets and liabilities that are measured or disclosed at fair value on a recurring basis is presented below: JUNE 30, 2021 DESCRIPTION TOTAL FAIR VALUE LEVEL 1 LEVEL 2 LEVEL 3 Financial assets Cash equivalents Money market funds $ 220,835 $ 220,835 $ — $ — Held-to-maturity investments U.S. Treasury securities 488,346 — 488,346 — Restricted cash equivalents Money market funds 5,618 5,618 — — Total financial assets $ 714,799 $ 226,453 $ 488,346 $ — Financial liabilities Derivative liability $ 7,750 $ — $ — $ 7,750 Total financial liabilities $ 7,750 $ — $ — $ 7,750 DECEMBER 31, 2020 DESCRIPTION TOTAL FAIR VALUE LEVEL 1 LEVEL 2 LEVEL 3 Financial assets Cash equivalents Money market funds $ 126,006 $ 126,006 $ — $ — Held-to-maturity investments U.S. Treasury securities 442,971 — 442,971 — Restricted cash equivalents Money market funds 6,362 6,362 — — Total financial assets $ 575,339 $ 132,368 $ 442,971 $ — Financial liabilities Derivative liability $ 6,000 $ — $ — $ 6,000 Total financial liabilities $ 6,000 $ — $ — $ 6,000 The Company’s cash equivalents and restricted cash equivalents, which are held in money market funds, are classified within Level 1 of the fair value hierarchy because they are valued using quoted prices in active markets as of June 30, 2021 and December 31, 2020. Restricted cash equivalents represent money market investments which secure letters of credit established in connection with the Company’s facility leases. The Company’s held-to-maturity investments bore interest at the prevailing market rates for instruments with similar characteristics and therefore the amortized cost approximated fair value. These financial instruments were classified within Level 2 of the fair value hierarchy because the inputs to the fair value measurements were valued using observable inputs as of June 30, 2021 and December 31, 2020. The Company does not enter into derivative financial instruments for speculative or trading purposes. The Company has a derivative liability associated with certain contingent payments under our collaboration agreement with Alnylam, which is classified within Level 3 of the fair value hierarchy because the fair value utilizes unobservable inputs for which there is no market data and therefore requires the Company to develop its own assumptions. Such assumptions include the probability of success of development, the probability that Alnylam exercises its commercialization option, the timing of regulatory approval and the first commercial sale, and the volume of sales. The following table presents a rollforward of activity associated with the derivative liability during the six months ended June 30, 2021: CONTINGENT PAYMENT DERIVATIVE LIABILITY Balance, January 1, 2021 $ (6,000) Expense recognized in other (expense) income due to remeasurement of fair value of the liability (1,500) Balance, March 31, 2021 (7,500) Expense recognized in other (expense) income due to remeasurement of fair value of the liability (250) Balance, June 30, 2021 $ (7,750) It is our policy to recognize transfers between levels of the fair value hierarchy, if any, at the end of the reporting period; however, there have been no such transfers during the periods presented. As of June 30, 2021 and December 31, 2020, the Company’s contract receivables, accounts payable, and accrued expenses approximated their estimated fair values because of the short-term nature of these financial instruments.

PREPAID EXPENSES AND OTHER CURR

PREPAID EXPENSES AND OTHER CURRENT ASSETS	6 Months Ended
	Jun. 30, 2021
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
PREPAID EXPENSES AND OTHER CURRENT ASSETS	PREPAID EXPENSES AND OTHER CURRENT ASSETS Prepaid expenses and other current assets consist of the following: JUNE 30, DECEMBER 31, 2020 Prepaid clinical, contract research, and manufacturing costs $ 11,107 $ 9,651 Interest receivable 1,868 1,345 Prepaid insurance 1,749 817 Other prepaid expenses and other current assets 5,656 2,590 Prepaid expenses and other current assets $ 20,380 $ 14,403

COLLABORATIVE RESEARCH AND LICE

COLLABORATIVE RESEARCH AND LICENSE AGREEMENTS	6 Months Ended
	Jun. 30, 2021
Revenue from Contract with Customer [Abstract]
COLLABORATIVE RESEARCH AND LICENSE AGREEMENTS	COLLABORATIVE RESEARCH AND LICENSE AGREEMENTS Alnylam collaboration and patent cross-license agreements Background On April 3, 2020, the Company and Alnylam (collectively, the “parties”) entered into a Collaboration and License Agreement (the “A1AT Agreement”) and a Patent Cross License Agreement (the “PH Agreement”). Pursuant to the A1AT Agreement, Dicerna will lead efforts on investigational RNAi therapeutics for the treatment of alpha-1 antitrypsin (“AAT”) deficiency (“AATD”)-associated liver disease (“AATLD”). Pursuant to the PH Agreement, the parties completed a cross-license of their respective intellectual property for Alnylam’s lumasiran and Dicerna’s nedosiran investigational programs for the treatment of primary hyperoxaluria (“PH”). No upfront cash consideration was exchanged in either transaction. Pursuant to the A1AT Agreement, Alnylam’s AAT product (ALN-AAT02, or the “Alnylam Product”) and Dicerna’s AAT product (belcesiran, or the “Dicerna Product”) were to be explored for the treatment of AATLD. Under the A1AT Agreement, the Company obtained an exclusive worldwide license to Alnylam’s intellectual property to exploit the Alnylam Product. Dicerna assumed responsibility for the development of both the Alnylam Product and the Dicerna Product at its cost. Dicerna selected belcesiran to advance in development for the treatment of patients with AATLD. At the completion of Phase 3, Alnylam has the no-cost opportunity to opt-in to commercialize belcesiran in countries outside the U.S. where it already has a commercialization infrastructure in place (the “Commercialization Option”). If Alnylam exercises its Commercialization Option, the parties will share future development costs. Further, each party will pay tiered royalties to the other party based on a percentage of net product sales generated in its territory ranging from low single-digits to high teens. In the event Alnylam waives its Commercialization Option, the Company will retain worldwide rights to commercialize belcesiran in exchange for payments upon the satisfaction of certain milestones, up to an aggregate of $45.0 million, and royalties will be payable to Alnylam based on net product sales in the low to mid-single-digits. As a result of these uncertain payments the Company may owe to Alnylam, the Company has recorded a derivative liability on the condensed consolidated balance sheets as of June 30, 2021 and December 31, 2020. The A1AT Agreement is subject to customary termination provisions, and the Company may terminate the A1AT Agreement at any time without cause following the notice period described in the A1AT Agreement. Pursuant to the PH Agreement, the parties granted to each other a perpetual non-exclusive cross-license to their respective intellectual property related to their respective PH treatment investigational programs to ensure that each party has the freedom to develop and commercialize its respective product with Alnylam’s lumasiran targeting glycolate oxidase (“GO”) for the treatment of PH type 1 and Dicerna’s nedosiran targeting lactate dehydrogenase A (“LDHA”) for the treatment of PH types 1, 2, and 3. Each party will have sole discretion concerning the research and development of its products in the field. In exchange for the license, Alnylam is required to pay mid- to high-single-digit royalties to Dicerna based on global net sales of lumasiran and Dicerna is required to pay low-single-digit royalties to Alnylam on global net sales of nedosiran. The PH Agreement cannot be terminated by either party for the other party’s breach. However, either party may terminate the PH Agreement or may reduce the royalty payable to the other party upon a patent-related challenge by the other party unless the challenge is withdrawn and no longer pending within the time periods specified in the PH Agreement. Further, the PH Agreement will terminate upon the expiration of the last-to-expire patent rights licensed thereunder. In April 2021, pursuant to an agreement with Royalty Pharma plc (“Royalty Pharma”), the Company received a $180.0 million upfront payment from the sale of Dicerna’s royalty interest in Alnylam’s net sales of OXLUMO (lumasiran). The upfront payment was recorded as deferred income upon receipt. Under this agreement, the Company is also eligible to receive up to $60.0 million in contingent sales-based milestone payments. Refer to Note 7 - Royalty Pharma Financing for further details. Accounting Analysis The Company determined that the A1AT Agreement and the PH Agreement represent separate agreements for accounting purposes, as the transactions have different commercial objectives, the consideration under each contract is not dependent upon the price or performance of the other contract, and the goods or services under each contract are separate performance obligations. A1AT Agreement The Company concluded that the A1AT Agreement was within the scope of Accounting Standards Codification (“ASC”) 606, Revenue from Contracts with Customers , as the provision of research and development services is considered an output of the entity’s ordinary activities in exchange for consideration. The Company identified a single performance obligation under the A1AT Agreement, which consists of the provision of certain nonclinical and clinical services through the completion of the Phase 1 clinical trial for any product. The Company determined that the transaction price at inception of the A1AT Agreement consists of non-cash consideration in the form of the license received from Alnylam. The Company determined that the fair value of the non-cash consideration (the license received from Alnylam) is insignificant given the early-stage development status of the Alnylam Product and the related risks associated with developing a commercial product. The sales-based royalties that Dicerna may be entitled to receive in the event that Alnylam exercises its Commercialization Option have been excluded from the transaction price and will be recognized only if Alnylam exercises its Commercialization Option and the related sales occur. As described above, Dicerna may be required to pay contingent milestones and royalties to compensate Alnylam for the license provided under the agreement. Given the uncertainty associated with these contingent payments, the Company established a derivative liability for these payments and recognized $6.0 million of other expense in the period ended December 31, 2020. In the six months ended June 30, 2021, the Company recognized an additional $1.75 million of other expense associated with this liability. The Company has recorded development costs incurred under the A1AT Agreement as research and development expenses in the Company’s condensed consolidated statement of operations. PH Agreement The Company concluded that the PH Agreement is within the scope of ASC 610, Other Income – Gains and Losses from the Derecognition of Nonfinancial Assets , as the exchange of non-exclusive licenses is considered an exchange of non-financial assets outside the ordinary scope of business. Pursuant to ASC 610-20, the Company applied the guidance in ASC 606 to determine if a contract exists, identify the distinct non-financial assets, and determine when control transfers and, therefore, when to derecognize the asset. Additionally, the Company applied the measurement principles of ASC 606 to determine the amount of consideration, if any, to include in the calculation of the gain or loss for the non-financial asset. The Company determined that it transferred control of a non-financial asset (the non-exclusive license granted to Alnylam) at contract inception. Applying the non-cash consideration guidance in ASC 606, the Company further determined that the fair value of the non-financial asset received (the non-exclusive license from Alnylam) was insignificant. Therefore, the Company concluded that no gain or loss would be recorded related to the PH Agreement at contract inception. The Company has recorded costs related to its PH program as research and development expenses in the Company’s condensed consolidated statement of operations. Novo collaboration and share purchase agreements Background On November 15, 2019, Dicerna and Novo entered into a Collaboration and License Agreement (the “Novo Collaboration Agreement”). Under the terms of the Novo Collaboration Agreement, the Company and Novo seek to use GalXC to explore more than 30 gene targets associated with liver disease with the goal of delivering multiple clinical candidates for disorders including chronic liver disease, non-alcoholic steatohepatitis (“NASH”), type 2 diabetes, obesity, and rare diseases. The Company will conduct and fund discovery and preclinical development to clinical candidate selection for each liver cell target. Novo will be responsible for all further development and the commercialization of each candidate selected for development, with the Company manufacturing clinical candidates selected for Phase 1-related clinical development, subject to reimbursement for its manufacturing costs. In addition, the Company will assist Novo with the Investigational New Drug (“IND”) filing for the first development candidate. The Company also retains the ability to opt in to co-development of a total of two programs during clinical development in Phases 1-3, subject to limitations in the event of a change in control. If the Company exercises a co-development option, it also has an option to co-promote the product in the United States, subject to limitations in the event of a change in control of the Company. Additionally, the Company may lead the development and commercialization of two programs targeting orphan liver diseases, with Novo retaining the ability to opt in to both programs in Phases 1-3. The Company and Novo will share in profits and losses for the Company’s orphan liver and Novo products should both parties elect to co-develop. The Company is working exclusively with Novo during the research collaboration period on the discovery, research, development, and commercialization of hepatocyte targets subject to certain exclusions including those targets subject to the Company’s existing partnerships, and Novo is, during a specified discovery period, working exclusively with the Company in any new research and development of compounds and products directed to collaboration targets using small interfering RNA (“siRNA”) conjugated to the sugar N-acetyl-D-galactosamine (“GalNAc”) to reduce the expression of specific target genes in the liver. Under the Novo Collaboration Agreement, the Company is providing Novo with exclusive and non-exclusive licenses and manufacturing support to enable Novo to commercialize products derived from or containing compounds developed pursuant to such agreement. Under the terms of the Novo Collaboration Agreement, Novo paid the Company an upfront payment of $175.0 million, which was subject to delivery of target information, in January 2020. The Company is also eligible to receive an additional $75.0 million ($25.0 million at the end of each of the first three years of the Novo Collaboration Agreement), contingent upon the Company delivering GalXC molecules for a defined number of targets, and additional payments totaling up to approximately $357.5 million per target upon achievement of specified development, regulatory, and commercial milestones. In addition, Novo will pay the Company mid-single-digits to mid-teens royalties on product sales on a country-by-country and product-by-product basis until the later of 10 years after the date of first commercial sale of each product in such country, expiration of specified patent rights in such country, or the expiration of specified regulatory exclusivity in such country for GalXC products, subject to royalty step-down provisions set forth in the agreement. In connection with the Novo Collaboration Agreement, the Company and Novo entered into the Novo Share Issuance Agreement on November 15, 2019, pursuant to which Novo purchased 2,279,982 shares (the “Novo Shares”) of the Company’s common stock, par value $0.0001 per share (“Common Stock”), at a purchase price of $21.93 per share, for an aggregate purchase price of approximately $50.0 million. During the fourth quarter of 2020, Novo nominated its first candidate under the Novo Collaboration Agreement. Pursuant to the agreement, upon achievement of proof of principle of the first nominated candidate, Dicerna earned a $2.5 million milestone, which the Company received in February 2021. Also during the fourth quarter of 2020, Novo confirmed that Dicerna met its annual obligation to deliver GalXC molecules for a defined number of targets for the first year of the Novo Collaboration Agreement, entitling the Company to a $25.0 million payment, which the Company received in February 2021. Accounting Analysis The Novo Collaboration Agreement and the Novo Share Issuance Agreement (collectively, “the Novo Agreements”) were executed on the same date and negotiated as a package. Management therefore concluded that the Novo Agreements are to be combined for accounting purposes and concluded that Novo is a customer in this arrangement pursuant to the revenue recognition guidance. The Company identified contract promises under the agreement for the license of intellectual property and know-how rights for selected gene targets and research and development services to develop a clinical candidate for each selected gene target, including manufacturing activities. The Company may also be required to provide research and development services for an unspecified number of targets, with the goal of the collaboration being to develop clinical candidates for each of the selected gene targets. The Company determined that the license and research and development services were not capable of being distinct or distinct within the context of the contract. The research and development services to be provided by Dicerna are specialized in nature, specifically with respect to the Company’s therapeutic expertise related to RNAi and the Company’s GalXC conjugates. In addition, there is an interdependent relationship between the contract promises. As such, the Company concluded that there is a single identified combined performance obligation consisting of a license and research and development services. The Company may be required to perform certain additional services after Novo’s nomination of a development candidate. These services include Phase 1-related activities, such as manufacturing through the approval of an IND application for a development candidate, research and development activities to support the filing of an IND application for the first development candidate, and other development services to support Novo’s development activities related to any development candidates. The Company will be reimbursed by Novo for these additional services. Because the provision of these additional goods and services are conditional on Novo electing to nominate a development candidate, the Company has concluded that these goods and services represent customer options and are not considered performance obligations. The total transaction price for the Novo Agreements is $256.7 million, consisting of the total $175.0 million upfront compensation, the $75.0 million additional aggregate payments described above (payable in equal annual payments of $25.0 million), a $4.2 million premium on the sale of shares under the Novo Share Issuance Agreement, and a $2.5 million milestone earned in the fourth quarter of 2020 for achieving proof of principle for the first candidate. The Company applied equity accounting guidance to measure the $45.8 million recorded in equity upon the issuance of the shares. The upfront payment of $175.0 million was payable to the Company upon the delivery of a bioinformatics package and mapping plan for at least one of the initial targets selected by Novo and was paid in January 2020. If the Novo Collaboration Agreement is terminated prior to the third anniversary of its effective date, the Company is entitled to 80% of the outstanding and unearned annual payments. The Company assumed that the mapped targets will be delivered and that the contract will not be canceled. The Company has experience with mapping targets, and therefore, concluded that such amount does not need to be constrained. Accordingly, the Company included the $75.0 million of additional payments in the transaction price. The Company used the most likely amount method to estimate variable consideration and estimated that the most likely amount for each potential future preclinical, development, and regulatory variable consideration milestone payment under this agreement was zero, as the achievement of those milestones is uncertain and highly susceptible to factors outside of the Company’s control. Accordingly, all potential future milestones were excluded from the transaction price. Management reevaluates the transaction price at the end of each reporting period and as uncertain events are resolved or other changes in circumstances occur and adjusts the transaction price as necessary. Sales-based royalties, including milestone payments based on the level of sales, were also excluded from the transaction price, as the license is deemed to be the predominant item to which the royalties relate. The Company will recognize such 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). Revenue associated with the performance obligation is being recognized as services are provided using a cost-to-cost measure of progress method. The transfer of control occurs over time, as the Company’s performance does not create an asset with alternative use, and the Company has an enforceable right to payment for performance completed to date. In management’s judgment, this input method is the best measure of progress towards satisfying the performance obligation and reflects a faithful depiction of the transfer of goods and services. The aggregate amount of the transaction price allocated to the Company’s unsatisfied or partially unsatisfied performance obligations under the Novo Collaboration Agreement at June 30, 2021 was $229.6 million. As of June 30, 2021, the Company expected to recognize the balance of deferred revenue over the remaining portion of the five-year research term, or four years, which may be extended for up to two years. Roche collaboration agreement Background On October 30, 2019, the Company and Roche entered into a Collaboration and License Agreement (the “Roche Collaboration Agreement”). Under the terms of the Roche Collaboration Agreement, the Company and Roche seek to progress RG6346, the companies’ investigational therapy in clinical development, toward worldwide development and commercialization. The Roche Collaboration Agreement also provides an option for the companies to collaborate in the discovery, development, and commercialization of oligonucleotide therapeutics intended for the treatment of hepatitis B virus (“HBV”). The Roche Collaboration Agreement requires that Dicerna complete the ongoing Phase 1 clinical trial, including additional Phase 1 cohorts that were requested by Roche for which Roche will reimburse the Company for the cost of the additional cohorts. Roche will lead the post-Phase 1 development and commercialization of the RG6346 program. Roche also had until receipt of interim Phase 1 data from the RG6346 Phase 1 study (but no later than December 31, 2020) to initiate a research and development collaboration with the Company to pursue up to five targets selected by Roche, (each a “Selected Target”), which are intended primarily to treat HBV. Under an amendment to the Roche Collaboration Agreement in June 2020, Roche and Dicerna agreed to extend the date for nomination of targets from December 31, 2020 to January 15, 2021, subject to further potential extension by the parties due to the COVID-19 global pandemic shutdowns. Under an additional amendment to the Roche Collaboration Agreement in May 2021, Roche and Dicerna further agreed to extend the date for nomination of the targets to June 15, 2021. In April 2020, Roche nominated the first target, and as of the three months ended June 30, 2021, Roche had nominated three of the up to five targets under the research and development portion of the Roche Collaboration Agreement. Under the terms of the Roche Collaboration Agreement, the goal of such research and development collaboration will be to select compounds developed by the Company or Roche for Roche’s continued development and commercialization. The Company’s and Roche’s research and early development organizations will work exclusively with each other during the research and development collaboration period on the discovery, research, and development of such targets selected by Roche, which includes the performance of certain services by Dicerna. Under the Roche Collaboration Agreement, the Company is providing Roche with exclusive and non-exclusive licenses to support Roche’s activities and to enable Roche to commercialize products derived from or containing compounds developed pursuant to such agreement. Under the terms of the Roche Collaboration Agreement, Roche paid the Company a non-refundable upfront payment of $200.0 million in January 2020. The Company is also eligible to receive additional payments totaling up to approximately $1.47 billion, which includes payments upon achievement of specified development, regulatory, and commercial milestones. In addition, Roche will pay the Company up to mid-teens percent royalties on worldwide product sales. Royalties are payable until the later of 10 years after first commercial sale of each product in a country, expiration of patent rights in a country, or for products containing RG6346 in a given country, the expiration of data or regulatory exclusivity, subject to certain royalty step-down provisions set forth in the agreement. In addition, the Company has an option to co-fund the development of products under the agreement and, if exercised, receive high-twenties to mid-thirties royalty rates on net sales of products in the U.S. If the Company exercises the co-funding option, it also has an option to co-promote products containing RG6346 in the U.S. Accounting Analysis The Company concluded that Roche is a customer in this arrangement pursuant to the revenue recognition guidance. The Company identified contract promises under the agreement for (i) the license of intellectual property and know-how rights related to the lead compound, (ii) research and development services to complete the Phase 1 study associated with the lead compound, (iii) lead compound transfer activities, (iv) manufacturing of clinical supply for the lead compound Phase 1 study, and (v) Roche’s option to receive additional goods and services related to the research and development collaboration. The Company determined that the Roche Collaboration Agreement contains two performance obligations consisting of: (i) a combined performance obligation that includes a license, related development and manufacturing services to complete the Phase 1 study, and manufacturing obligations through the completion of the Phase 1 study related to the lead compound (the “RG6346 Performance Obligation”), and (ii) a material right to enter into a research and development collaboration to develop additional targets. While evaluating contract promises to determine whether each was capable of being distinct and distinct within the context of the contract, management considered the specialized nature of the services to be provided by Dicerna, specifically with respect to the Company’s therapeutic expertise related to RNAi and the Company’s GalXC conjugates and the interdependent relationship between the contract promises. As such, the Company concluded that the promises of the license and research and development services related to the lead compound were not distinct from each other. Accordingly, these promises were combined into one performance obligation, the RG6346 Performance Obligation. Upon Roche’s exercise of its option to enter into the research and development collaboration for which no additional consideration was received, Roche had the right to nominate up to five additional targets. For each target nominated, Roche received a license to the Selected Target, for which the Company will perform research services through clinical candidate selection. The Company concluded that, upon Roche’s nomination of a target, the license and related research services through clinical candidate selection for each Selected Target represents a combined performance obligation, which is separate from the RG6346 Performance Obligation. The Company is not required to perform services on more than three Selected Targets at any time. Roche also had the right to replace up to three Selected Targets if a clinical candidate could not be identified during the research term. The total transaction price for the Roche Collaboration Agreement is $232.1 million, consisting of the $200.0 million upfront payment, a $25.0 million milestone payment associated with Roche’s initiation of RG6346 in a Phase 2 combination trial, and the estimated reimbursement from Roche related to the additional cohorts. The Company used the most likely amount method to estimate the amount of reimbursement, which was considered variable consideration. As reimbursement will be made as the Company performs the related services, the Company concluded that such amount does not need to be constrained, and therefore, included the full amount of the estimated reimbursement by Roche in the transaction price. The Company also estimated that the most likely amount for each potential future development and regulatory variable consideration milestone payment under this agreement was zero at contract inception, as the achievement of those milestones was uncertain and highly susceptible to factors outside of the Company’s control. Accordingly, all potential future milestones were initially excluded from the transaction price. Management reevaluates the transaction price at the end of each reporting period and as uncertain events are resolved or other changes in circumstances occur and adjusts the transaction price as necessary. Sales-based royalties, including milestone payments based on the level of sales, were also excluded from the transaction price, as the license is deemed to be the predominant item to which the royalties relate. The Company will recognize such 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). The Company allocated the current $232.1 million transaction price to the performance obligations on a relative standalone selling price basis. The Company estimated the standalone selling price for the lead compound performance obligation using the adjusted market assessment approach, whereby the Company adjusted comparable third-party transactions to reflect the stage of development of the Company’s asset. To determine the estimated standalone selling price of the material right, the Company estimated the standalone selling price of the underlying performance obligations included in the material right and estimated the probability of Roche exercising such underlying performance obligations. The Company concluded that the research and development collaboration material right contained (i) five material rights to receive a selected target license and related research and development services, and (ii) three material rights to receive a replacement selected target license and related research and development services. Upon the nomination of a target, the Selected Target license and related research services through clinical candidate selection are accounted for as a combined performance obligation. The value of the material right related to the Selected Target is included in the transaction price for the combined performance obligation. The variable consideration related to the reimbursement from Roche for the additional Phase 1 cohorts and any milestones and royalties that are achieved will be allocated specifically to the lead compound performance obligation, as this variable consideration relates specifically to the Company’s satisfaction of the lead compound performance obligation and such allocation has been determined to be consistent with the allocation objective of the revenue recognition guidance. Revenue associated with the lead compound performance obligation is recognized as services are provided using a cost-to-cost measure of progress method. The transfer of control occurs over time, as the Company’s performance does not create an asset with alternative use, and the Company has an enforceable right to payment for performance completed to date. In management’s judgment, this input method is the best measure of progress towards satisfying the performance obligation and reflects a faithful depiction of the transfer of goods and services. The transaction price allocated to the research and development collaboration material right is recognized based on the timing of recognition of the underlying performance obligations that comprise the material right, or upon expiry of the material right if such right is not exercised. The aggregate amount of the transaction price allocated to the Company’s unsatisfied or partially unsatisfied performance obligations under the Roche Collaboration Agreement at June 30, 2021 was $122.1 million. As of June 30, 2021, the Company expects to recognize the balance of deferred revenue during the research term of up to five years. Lilly collaboration and share purchase agreements Background On October 25, 2018, the Company entered into a Collaboration and License Agreement with Lilly (the “Lilly Collaboration Agreement”) for the discovery, development, and commercialization of potential new medicines in the areas of cardiometabolic disease, neurodegenerative diseases, and pain. Under the terms of the Lilly Collaboration Agreement, the Company and Lilly will use the Company’s proprietary GalXC RNAi technology to progress new drug targets toward clinical development and commercialization. In addition, the Company and Lilly will collaborate on non-liver (i.e., extrahepatic) tissues, including neural tissues. The Company will work exclusively with Lilly in the neurodegenerative disease and pain fields, with the exception of mutually agreed upon orphan indications. Additionally, the Company will work exclusively with Lilly on select targets in the cardiometabolic field. Under the Lilly Collaboration Agreement, the Company will provide Lilly with exclusive and non-exclusive licenses to support the companies’ activities and to enable Lilly to commercialize products derived from or containing compounds developed pursuant to such agreement. The Lilly Collaboration Agreement provides for three initially named hepatocyte targets, and the Company and Lilly developed research programs with the goal of researching and developing multiple lead candidates directed to each of these initial targets. The Lilly Collaboration Agreement contemplates in excess of ten targets. Lilly paid the Company a non-refundable upfront payment of $100.0 million. The Company is also eligible to receive up to $350.0 million per target in development and commercialization milestones, in addition to a $5.0 million payment, which will become due for each of the extrahepatic targets when a product candidate achieves proof of principle in an animal model. In addition, the Company is eligible to earn mid-single- to low-double-digit royalties on product sales on a country-by-country and product-by-product basis until the later of expiration of patent rights in a country, the expiration of data or regulatory exclusivity in such country, or 10 years after the first product sale in such country, subject to certain royalty step-down provisions set forth in the agreement. Simultaneously with the entry into the Lilly Collaboration Agreement, the Company and Lilly entered into a Share Purchase Agreement (the “Lilly Share Issuance Agreement”), pursuant to which Lilly purchased 5,414,185 shares of the Company’s common stock at $18.47 per share, for an aggregate purchase price of $100.0 million. The Lilly Share Issuance Agreement is to be combined with the Lilly Collaboratio

ROYALTY PHARMA FINANCING

ROYALTY PHARMA FINANCING	6 Months Ended
	Jun. 30, 2021
Deferred Income Disclosure [Abstract]
ROYALTY PHARMA FINANCING	ROYALTY PHARMA FINANCINGPursuant to the PH Agreement between Dicerna and Alnylam that was signed in 2020, Dicerna became entitled to royalties on worldwide net product sales of Alnylam’s PH product, OXLUMO™ (lumasiran). Under the terms of the PH Agreement, Dicerna was entitled to royalties in the mid- to high-single-digits based on OXLUMO global net sales. Refer to Note 6 – Collaborative Research And License Agreements for further information.In April 2021, the Company sold its right to receive royalties from sales of OXLUMO to Royalty Pharma plc for an upfront cash payment of $180.0 million and up to $60.0 million in contingent sales-based milestone payments. The Company evaluated the arrangement to determine whether the upfront payment should be accounted for as debt or deferred income and determined that, as none of the criteria for classification as debt had been met, the proceeds from the upfront payment should be recorded as deferred income on the condensed consolidated balance sheets. The Company applies the “units-of-revenue” method of recognition of this income in the condensed consolidated statements of operations, and such amounts are recorded in other (expense) income.

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	6 Months Ended
	Jun. 30, 2021
Share-based Payment Arrangement [Abstract]
STOCK-BASED COMPENSATION	STOCK-BASED COMPENSATION The Company has classified stock-based compensation in its condensed consolidated statements of operations as follows: THREE MONTHS ENDED SIX MONTHS ENDED 2021 2020 2021 2020 Research and development expenses $ 7,143 $ 4,578 $ 13,577 $ 8,881 General and administrative expenses 6,490 5,628 12,469 9,852 Total $ 13,633 $ 10,206 $ 26,046 $ 18,733 During the three and six months ended June 30, 2021, the Company granted stock options to purchase 285,375 and 2,254,022 shares of common stock with aggregate grant date fair values of $5.6 million and $37.4 million, respectively, compared to stock options to purchase 701,925 and 3,608,225 shares of common stock granted with aggregate grant date fair values of $9.5 million and $53.8 million during the three and six months ended June 30, 2020, respectively. The assumptions used to estimate the grant date fair value using the Black-Scholes option pricing model were as follows: THREE MONTHS ENDED SIX MONTHS ENDED 2021 2020 2021 2020 Common stock price $25.76 - $30.71 $17.33 - $21.61 $22.07 - $30.71 $15.61 - $22.58 Expected option term (in years) 5.27 - 6.08 5.50 - 6.08 5.27 - 6.08 5.50 - 6.08 Expected volatility 77.72% - 79.16% 78.33% - 80.45% 77.72% - 79.16% 78.33% - 80.45% Risk-free interest rate 0.90% - 1.15% —% - 0.42% 0.51% - 1.15% —% - 1.71% Expected dividend yield —% —% —% —%

INCOME TAXES

INCOME TAXES	6 Months Ended
	Jun. 30, 2021
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXESDuring the three months ended June 30, 2021, the Company recorded an income tax provision of $0.5 million, resulting in an effective tax rate of approximately 0.79% for the six months ended June 30, 2021. The difference between the effective tax rate and the federal statutory tax rate primarily relates to changes in the valuation allowance on net deferred tax assets. The tax expense largely relates to federal tax payable that is not expected to be fully offset by any tax attributes.

LEASES

LEASES	6 Months Ended
	Jun. 30, 2021
Leases [Abstract]
LEASES	LEASES On January 14, 2020, the Company entered into a non-cancelable real property lease agreement for 61,282 square feet of laboratory and office space at 75 Hayden Avenue in Lexington, Massachusetts (the “75 Hayden Avenue” lease). The original term commenced during the fourth quarter of 2020 and is for 125 months with options to extend for two additional successive periods of five years thereafter. On July 1, 2020, the Company entered into an amendment to the 75 Hayden Avenue lease (the “75 Hayden Amendment”). The 75 Hayden Amendment expanded the square footage leased under the 75 Hayden Avenue lease by 30,446 square feet to contain a total of  91,728 rentable square feet and increased the monthly base rent by an average of $0.2 million per month. The term for the additional space under the 75 Hayden Amendment commenced for accounting purposes during the second quarter of 2021 and is for 118.5 months with options to extend for two additional successive periods of five years thereafter. Payments for the extensions are not included in measurement of the right-of-use (“ROU”) asset and lease liability, as it is not reasonably certain that the Company will exercise its options to extend the lease term. The aggregate total fixed rent for the 75 Hayden Amendment is approximately $21.3 million with the annual fixed rental payments increasing from $1.9 million to $2.6 million during the amended term. T he Company recognized an ROU asset and a lease liability of approximately $17.2 million and $15.3 million, respectively, in the three months ended June 30, 2021 related to the 75 Hayden Amendment.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	6 Months Ended
	Jun. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES From time to time, the Company may be subject to various claims and legal proceedings in the ordinary course of business. 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 contingent liabilities recorded as of June 30, 2021.

DESCRIPTION OF BUSINESS AND B_2

DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (Policies)	6 Months Ended
	Jun. 30, 2021
Accounting Policies [Abstract]
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”) along with the rules and regulations of the Securities and Exchange Commission for interim financial information, and include the accounts of Dicerna Pharmaceuticals, Inc. and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. The year-end condensed consolidated balance sheet data were derived from audited financial statements but do not include all disclosures 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 for a fair statement of the Company’s financial position at June 30, 2021 and its results of operations, changes in stockholders’ equity, and cash flows for the interim periods ended June 30, 2021 and 2020. 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, 2020. The results of operations for the three and six months ended June 30, 2021 are not necessarily indicative of the results to be expected for the year ending December 31, 2021, for any other interim period, or for any other future year.
Significant judgments and estimates	Significant judgments and estimates The preparation of condensed 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 Company’s condensed 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 revenue recognition, deferred income, stock-based compensation, the derivative liability, and accrued expenses. 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 values 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.
Recent accounting pronouncement and summary of significant accounting policies	Recent accounting pronouncements In December 2019, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2019-12, Simplifying the Accounting for Income Taxes , amending accounting guidance that simplifies the accounting for income taxes as part of its initiative to reduce complexity in the accounting standards. The amendments eliminate certain exceptions related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period, and the recognition of deferred tax liabilities for outside basis differences. The amendments also clarify and simplify other aspects of the accounting for income taxes. For public business entities, ASU 2019-12 is required to be adopted effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. The Company adopted ASU 2019-12 on January 1, 2021 and it did not have a material impact on its financial statements or related disclosures. Summary of significant accounting policies There have been no changes to the significant accounting policies disclosed in the Company’s most recent Annual Report on Form 10-K.
Net loss per share	NET LOSS PER SHARE The Company computes basic net loss per common share by dividing net loss by the weighted average number of common shares outstanding. In periods of net income, the Company’s accounting policy includes allocating a proportional share of net income to participating securities, as determined by dividing total weighted average participating securities by the sum of the total weighted average common shares and participating securities (the “two-class method”). Participating securities have the effect of diluting both basic and diluted earnings per share during periods of income. During periods when the Company incurs a net loss, the Company does not allocate a loss to participating securities because they have no contractual obligation to share in the losses of the Company. The Company computes diluted net loss per common share after giving consideration to the dilutive effect of stock options and nonvested restricted stock units that are outstanding during the period, except where such non-participating securities would be anti-dilutive.
Commitments and contingencies	COMMITMENTS AND CONTINGENCIES From time to time, the Company may be subject to various claims and legal proceedings in the ordinary course of business. 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.

NET LOSS PER SHARE (Tables)

NET LOSS PER SHARE (Tables)	6 Months Ended
	Jun. 30, 2021
Earnings Per Share [Abstract]
Outstanding Securities excluded from Calculation of Net Loss Per Share	The outstanding securities presented below were excluded from the calculation of net loss per share because such securities would have been anti-dilutive due to the Company’s net loss per share during the periods ending on the dates presented: JUNE 30, JUNE 30, Options to purchase common stock 14,307,555 15,109,939 Nonvested restricted stock units 1,221,426 887,355 Total 15,528,981 15,997,294

HELD-TO-MATURITY INVESTMENTS (T

HELD-TO-MATURITY INVESTMENTS (Tables)	6 Months Ended
	Jun. 30, 2021
Investments, Debt and Equity Securities [Abstract]
Schedule of Held-To-Maturity Investments	A summary of the Company’s held-to-maturity investments is presented below: JUNE 30, 2021 DESCRIPTION AMORTIZED COST GROSS UNREALIZED HOLDING GAINS GROSS UNREALIZED HOLDING LOSSES FAIR VALUE U.S. Treasury securities maturing in one year or less $ 371,755 $ 39 $ (13) $ 371,781 U.S. Treasury securities maturing in greater than one year 116,599 — (34) 116,565 Total $ 488,354 $ 39 $ (47) $ 488,346 DECEMBER 31, 2020 DESCRIPTION AMORTIZED COST GROSS UNREALIZED HOLDING GAINS GROSS UNREALIZED HOLDING LOSSES FAIR VALUE U.S. Treasury securities maturing in one year or less $ 442,820 $ 163 $ (12) $ 442,971

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
Schedule of Assets Measured or Disclosed at Fair Value	A summary of the Company’s assets and liabilities that are measured or disclosed at fair value on a recurring basis is presented below: JUNE 30, 2021 DESCRIPTION TOTAL FAIR VALUE LEVEL 1 LEVEL 2 LEVEL 3 Financial assets Cash equivalents Money market funds $ 220,835 $ 220,835 $ — $ — Held-to-maturity investments U.S. Treasury securities 488,346 — 488,346 — Restricted cash equivalents Money market funds 5,618 5,618 — — Total financial assets $ 714,799 $ 226,453 $ 488,346 $ — Financial liabilities Derivative liability $ 7,750 $ — $ — $ 7,750 Total financial liabilities $ 7,750 $ — $ — $ 7,750 DECEMBER 31, 2020 DESCRIPTION TOTAL FAIR VALUE LEVEL 1 LEVEL 2 LEVEL 3 Financial assets Cash equivalents Money market funds $ 126,006 $ 126,006 $ — $ — Held-to-maturity investments U.S. Treasury securities 442,971 — 442,971 — Restricted cash equivalents Money market funds 6,362 6,362 — — Total financial assets $ 575,339 $ 132,368 $ 442,971 $ — Financial liabilities Derivative liability $ 6,000 $ — $ — $ 6,000 Total financial liabilities $ 6,000 $ — $ — $ 6,000
Schedule of Liabilities Measured or Disclosed at Fair Value	A summary of the Company’s assets and liabilities that are measured or disclosed at fair value on a recurring basis is presented below: JUNE 30, 2021 DESCRIPTION TOTAL FAIR VALUE LEVEL 1 LEVEL 2 LEVEL 3 Financial assets Cash equivalents Money market funds $ 220,835 $ 220,835 $ — $ — Held-to-maturity investments U.S. Treasury securities 488,346 — 488,346 — Restricted cash equivalents Money market funds 5,618 5,618 — — Total financial assets $ 714,799 $ 226,453 $ 488,346 $ — Financial liabilities Derivative liability $ 7,750 $ — $ — $ 7,750 Total financial liabilities $ 7,750 $ — $ — $ 7,750 DECEMBER 31, 2020 DESCRIPTION TOTAL FAIR VALUE LEVEL 1 LEVEL 2 LEVEL 3 Financial assets Cash equivalents Money market funds $ 126,006 $ 126,006 $ — $ — Held-to-maturity investments U.S. Treasury securities 442,971 — 442,971 — Restricted cash equivalents Money market funds 6,362 6,362 — — Total financial assets $ 575,339 $ 132,368 $ 442,971 $ — Financial liabilities Derivative liability $ 6,000 $ — $ — $ 6,000 Total financial liabilities $ 6,000 $ — $ — $ 6,000
Schedule of Derivative Liabilities at Fair Value	The following table presents a rollforward of activity associated with the derivative liability during the six months ended June 30, 2021: CONTINGENT PAYMENT DERIVATIVE LIABILITY Balance, January 1, 2021 $ (6,000) Expense recognized in other (expense) income due to remeasurement of fair value of the liability (1,500) Balance, March 31, 2021 (7,500) Expense recognized in other (expense) income due to remeasurement of fair value of the liability (250) Balance, June 30, 2021 $ (7,750)

PREPAID EXPENSES AND OTHER CU_2

PREPAID EXPENSES AND OTHER CURRENT ASSETS (Tables)	6 Months Ended
	Jun. 30, 2021
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Summary of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consist of the following: JUNE 30, DECEMBER 31, 2020 Prepaid clinical, contract research, and manufacturing costs $ 11,107 $ 9,651 Interest receivable 1,868 1,345 Prepaid insurance 1,749 817 Other prepaid expenses and other current assets 5,656 2,590 Prepaid expenses and other current assets $ 20,380 $ 14,403

COLLABORATIVE RESEARCH AND LI_2

COLLABORATIVE RESEARCH AND LICENSE AGREEMENTS (Tables)	6 Months Ended
	Jun. 30, 2021
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following table provides a summary of revenue recognized for the Alexion Agreement and the Alexion Amendment: THREE MONTHS ENDED SIX MONTHS ENDED 2021 2020 2021 2020 Alexion Agreement $ 2,316 $ 5,792 9,505 $ 7,914 Alexion Amendment 171 1,271 799 1,911 Total $ 2,487 $ 7,063 $ 10,304 $ 9,825 The following table provides a summary of revenue recognized: THREE MONTHS ENDED SIX MONTHS ENDED 2021 2020 2021 2020 Novo $ 6,700 $ 2,447 $ 13,312 $ 4,052 Roche 14,234 20,677 39,845 39,984 Lilly 14,735 9,487 22,298 19,069 Alexion 2,487 7,063 10,304 9,825 BI 3,181 774 3,181 1,546 Total $ 41,337 $ 40,448 $ 88,940 $ 74,476
Contract with Customer, Asset and Liability	The following tables provide a summary of deferred revenue balances for the Alexion Agreement and the Alexion Amendment: JUNE 30, 2021 CURRENT NONCURRENT TOTAL Alexion Agreement $ 6,951 $ 3,166 $ 10,117 Alexion Amendment 1,303 27,736 29,039 Total $ 8,254 $ 30,902 $ 39,156 DECEMBER 31, 2020 CURRENT NONCURRENT TOTAL Alexion Agreement $ 9,216 $ 7,528 $ 16,744 Alexion Amendment 9,464 20,323 29,787 Total $ 18,680 $ 27,851 $ 46,531 The following tables provide a summary of deferred revenue balances: JUNE 30, 2021 CURRENT NONCURRENT TOTAL Novo $ 36,829 $ 142,795 $ 179,624 Roche 62,022 55,019 117,041 Lilly 53,095 39,890 92,985 Alexion 8,254 30,902 39,156 Total $ 160,200 $ 268,606 $ 428,806 DECEMBER 31, 2020 CURRENT NONCURRENT TOTAL Novo $ 30,169 $ 162,630 $ 192,799 Roche 49,493 81,273 130,766 Lilly 40,195 64,482 104,677 Alexion 18,680 27,851 46,531 Total $ 138,537 $ 336,236 $ 474,773 The Company recognized the following revenues as a result of changes in contract liability balances: THREE MONTHS ENDED SIX MONTHS ENDED 2021 2020 2021 2020 Amounts included in deferred revenue at the beginning of the period (1) $ 31,947 $ 38,595 $ 60,260 $ 65,278 Performance obligations satisfied (or partially satisfied) in previous reporting periods (2) $ 6,431 $ 1,011 $ 20,188 $ 2,004 (1) The Company determines the revenue recognized in each period from contract liabilities by first attributing revenue to the individual contract liability balance outstanding at the beginning of the period. If additional consideration is received on those contracts in subsequent periods, we assume all revenue recognized in the reporting period first applies to the beginning contract liability as opposed to the new consideration for the period. (2) Relates to changes in estimated costs for the Company’s future performance obligations and estimated variable consideration

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	6 Months Ended
	Jun. 30, 2021
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation Expense	The Company has classified stock-based compensation in its condensed consolidated statements of operations as follows: THREE MONTHS ENDED SIX MONTHS ENDED 2021 2020 2021 2020 Research and development expenses $ 7,143 $ 4,578 $ 13,577 $ 8,881 General and administrative expenses 6,490 5,628 12,469 9,852 Total $ 13,633 $ 10,206 $ 26,046 $ 18,733
Schedule of Valuation Assumptions	The assumptions used to estimate the grant date fair value using the Black-Scholes option pricing model were as follows: THREE MONTHS ENDED SIX MONTHS ENDED 2021 2020 2021 2020 Common stock price $25.76 - $30.71 $17.33 - $21.61 $22.07 - $30.71 $15.61 - $22.58 Expected option term (in years) 5.27 - 6.08 5.50 - 6.08 5.27 - 6.08 5.50 - 6.08 Expected volatility 77.72% - 79.16% 78.33% - 80.45% 77.72% - 79.16% 78.33% - 80.45% Risk-free interest rate 0.90% - 1.15% —% - 0.42% 0.51% - 1.15% —% - 1.71% Expected dividend yield —% —% —% —%

DESCRIPTION OF BUSINESS AND B_3

DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (Details)	Jun. 30, 2021program
Accounting Policies [Abstract]
Number of programs	20

NET LOSS PER SHARE (Details)

NET LOSS PER SHARE (Details) - shares	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	15,528,981	15,997,294
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	14,307,555	15,109,939
Nonvested restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	1,221,426	887,355

HELD-TO-MATURITY INVESTMENTS -

HELD-TO-MATURITY INVESTMENTS - Schedule of Held-To-Maturity Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
U.S. Treasury securities maturing in one year or less
AMORTIZED COST	$ 371,755	$ 442,820
U.S. Treasury securities maturing in greater than one year
AMORTIZED COST	116,599	0
US Treasury securities
U.S. Treasury securities maturing in one year or less
AMORTIZED COST	371,755
GROSS UNREALIZED HOLDING GAINS	39
GROSS UNREALIZED HOLDING LOSSES	(13)
FAIR VALUE	371,781
U.S. Treasury securities maturing in greater than one year
AMORTIZED COST	116,599
GROSS UNREALIZED HOLDING GAINS	0
GROSS UNREALIZED HOLDING LOSSES	(34)
FAIR VALUE	116,565
AMORTIZED COST	488,354	442,820
GROSS UNREALIZED HOLDING GAINS	39	163
GROSS UNREALIZED HOLDING LOSSES	(47)	(12)
FAIR VALUE	$ 488,346	$ 442,971

HELD-TO-MATURITY INVESTMENTS _2

HELD-TO-MATURITY INVESTMENTS - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Investments, Debt and Equity Securities [Abstract]
Accrued interest receivable	$ 0	$ 0	$ 0	$ 0

FAIR VALUE MEASUREMENTS - Summa

FAIR VALUE MEASUREMENTS - Summary of Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Restricted cash equivalents
Total financial assets	$ 714,799	$ 575,339
Financial liabilities
Derivative liability	7,750	6,000
Total financial liabilities	7,750	6,000
U.S. Treasury securities
Held-to-maturity investments
U.S. Treasury securities	488,346	442,971
Money market funds
Cash equivalents
Money market funds	220,835	126,006
Restricted cash equivalents
Money market funds	5,618	6,362
LEVEL 1
Restricted cash equivalents
Total financial assets	226,453	132,368
Financial liabilities
Derivative liability	0	0
Total financial liabilities	0	0
LEVEL 1 | U.S. Treasury securities
Held-to-maturity investments
U.S. Treasury securities	0	0
LEVEL 1 | Money market funds
Cash equivalents
Money market funds	220,835	126,006
Restricted cash equivalents
Money market funds	5,618	6,362
LEVEL 2
Restricted cash equivalents
Total financial assets	488,346	442,971
Financial liabilities
Derivative liability	0	0
Total financial liabilities	0	0
LEVEL 2 | U.S. Treasury securities
Held-to-maturity investments
U.S. Treasury securities	488,346	442,971
LEVEL 2 | Money market funds
Cash equivalents
Money market funds	0	0
Restricted cash equivalents
Money market funds	0	0
LEVEL 3
Restricted cash equivalents
Total financial assets	0	0
Financial liabilities
Derivative liability	7,750	6,000
Total financial liabilities	7,750	6,000
LEVEL 3 | U.S. Treasury securities
Held-to-maturity investments
U.S. Treasury securities	0	0
LEVEL 3 | Money market funds
Cash equivalents
Money market funds	0	0
Restricted cash equivalents
Money market funds	$ 0	$ 0

FAIR VALUE MEASUREMENTS - Fair

FAIR VALUE MEASUREMENTS - Fair Value Roll Forward (Details) - CONTINGENT PAYMENT DERIVATIVE LIABILITY - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2021
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ (7,500)	$ (6,000)	$ (6,000)
Expense recognized in other (expense) income due to remeasurement of fair value of the liability	(250)	(1,500)	(1,750)
Ending balance	$ (7,750)	$ (7,500)	$ (7,750)

PREPAID EXPENSES AND OTHER CU_3

PREPAID EXPENSES AND OTHER CURRENT ASSETS (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid clinical, contract research, and manufacturing costs	$ 11,107	$ 9,651
Interest receivable	1,868	1,345
Prepaid insurance	1,749	817
Other prepaid expenses and other current assets	5,656	2,590
Prepaid expenses and other current assets	$ 20,380	$ 14,403

COLLABORATIVE RESEARCH AND LI_3

COLLABORATIVE RESEARCH AND LICENSE AGREEMENTS - Alnylam (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended	12 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2021	Dec. 31, 2020	Apr. 03, 2020
CONTINGENT PAYMENT DERIVATIVE LIABILITY
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Other expense associated with liability	$ 250	$ 1,500	$ 1,750
A1AT Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Aggregate milestone receivable expense				$ 6,000
A1AT Agreement | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Aggregate sales milestones receivable					$ 45,000

COLLABORATIVE RESEARCH AND LI_4

COLLABORATIVE RESEARCH AND LICENSE AGREEMENTS - Novo Collaboration Agreement and Novo Share Issuance Agreement (Details)	Nov. 15, 2019USD ($)targetprogram$ / sharesshares	Dec. 31, 2020USD ($)$ / shares	Jun. 30, 2021USD ($)$ / shares
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common stock, par value (in dollars per share) | $ / shares		$ 0.0001	$ 0.0001
Novo Agreements
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Transaction price allocated to revenue arrangement	$ 256,700,000
Premium on sale of shares	4,200,000
Proceeds from equity upon issuance	$ 45,800,000
Percent of outstanding and unearned annual payments	80.00%
Variable consideration	$ 0
Novo Collaboration Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of gene targets | target	30
Number of programs | program	2
Non-refundable upfront payment	$ 175,000,000
Development and commercialization milestones receivable, year one	25,000,000
Development and commercialization milestones receivable, year two	25,000,000
Development and commercialization milestones receivable, year three	$ 25,000,000
Development and commercialization milestones receivable, term	3 years
Payment due on specified development, regulatory, and commercial milestones	$ 357,500,000
Collaborative arrangement term	10 years		5 years
Milestone amount earned		$ 2,500,000
Targets delivered, milestone amount earned		$ 25,000,000
Transaction price allocated to revenue arrangement			$ 229,600,000
Collaborative arrangement term, other option			4 years
Extension term			2 years
Novo Collaboration Agreement | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Development and commercialization milestones receivable	$ 75,000,000
Novo Share Issuance Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of shares issuable (in shares) | shares	2,279,982
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001
Sale of stock (in dollars per share) | $ / shares	$ 21.93
Expected proceeds from issuance of common stock	$ 50,000,000

COLLABORATIVE RESEARCH AND LI_5

COLLABORATIVE RESEARCH AND LICENSE AGREEMENTS - Roche Collaboration Agreement (Details) - Roche Collaboration Agreement	Oct. 30, 2019USD ($)target	Jun. 30, 2021USD ($)	Jan. 31, 2020USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of targets | target	5
Number of targets nominated | target	3
Non-refundable upfront payment	$ 200,000,000		$ 200,000,000
Collaborative arrangement term	10 years
Number of additional targets | target	5
Transaction price allocated to revenue arrangement	$ 232,100,000	$ 122,100,000
Milestone payment	25,000,000
Variable consideration	0
Extension term		5 years
Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Development and commercialization milestones receivable	$ 1,470,000,000
Number of replaced targets | target	3

COLLABORATIVE RESEARCH AND LI_6

COLLABORATIVE RESEARCH AND LICENSE AGREEMENTS - Lilly Collaboration and Share Purchase Agreements (Details)	Oct. 25, 2018USD ($)target$ / sharesshares	Feb. 28, 2021extensionOption	Jun. 30, 2021USD ($)	Dec. 31, 2020USD ($)
Disaggregation of Revenue [Line Items]
Deferred revenue			$ 428,806,000	$ 474,773,000
Lilly Collaboration And License Agreement
Disaggregation of Revenue [Line Items]
Number of hepatocyte targets | target	3
Number of targets in excess to contemplate agreement | target	10
Initial non-creditable upfront payment	$ 100,000,000
Payment due on first non-hepatocyte target achievement	$ 5,000,000
Collaborative arrangement term	10 years	3 years
Number of extension options | extensionOption		3
Extension term		1 year
Deferred revenue			92,985,000	104,677,000
Lilly Collaboration And License Agreement | Maximum
Disaggregation of Revenue [Line Items]
Development and commercialization milestones receivable	$ 350,000,000
Lilly Share Issuance Agreement
Disaggregation of Revenue [Line Items]
Initial non-creditable upfront payment	$ 100,000,000
Number of shares sold (in shares) | shares	5,414,185
Price per share (in dollars per share) | $ / shares	$ 18.47
Milestone amount earned	$ 10,000,000		$ 10,000,000	$ 10,000,000
Transaction price allocated to revenue arrangement	168,700,000
Premium on sale of shares	48,700,000
Proceeds from equity upon issuance	51,300,000
Variable consideration	$ 0

COLLABORATIVE RESEARCH AND LI_7

COLLABORATIVE RESEARCH AND LICENSE AGREEMENTS - Alexion Collaboration and Equity Agreements (Details)	Oct. 22, 2018USD ($)candidatetarget$ / sharesshares	Dec. 31, 2019USD ($)target	Jun. 30, 2021USD ($)	Dec. 31, 2020USD ($)
Disaggregation of Revenue [Line Items]
Deferred revenue			$ 428,806,000	$ 474,773,000
Alexion Agreements
Disaggregation of Revenue [Line Items]
Deferred revenue			39,200,000
Alexion Agreement
Disaggregation of Revenue [Line Items]
Number of treatment candidates | candidate	2
Initial non-creditable upfront payment	$ 22,000,000
Collaborative arrangement option exercise fee for each of candidates selected	$ 10,000,000
Collaborative arrangement term	10 years
Transaction price allocated to revenue arrangement	$ 5,900,000
Number of pathway targets | target	2
Transaction price	$ 51,100,000
Aggregate contingent milestone payments	19,500,000
Variable consideration	3,700,000
Variable consideration beyond initial milestones	0
Deferred revenue			10,117,000	16,744,000
Alexion Agreement | Maximum
Disaggregation of Revenue [Line Items]
Additional payment receivable	600,000,000
Option exercise fee	20,000,000
Development milestones receivable for each product	105,000,000
Aggregate sales milestones receivable	$ 160,000,000
Alexion Share Issuance Agreement
Disaggregation of Revenue [Line Items]
Number of shares issuable (in shares) | shares	835,834
Price per share (in dollars per share) | $ / shares	$ 17.95
Expected proceeds from issuance of common stock	$ 15,000,000
Share purchase price allocated to equity	9,100,000
Transaction price allocated to revenue arrangement	5,900,000
Alexion Amendment
Disaggregation of Revenue [Line Items]
Option exercise fee	$ 20,000,000	$ 20,000,000
Collaborative arrangement option exercise fee for each of candidates selected		$ 10,000,000
Number of pathway targets | target	2	4
Transaction price	$ 35,000,000
Aggregate contingent milestone payments	$ 15,000,000
Number of additional pathway targets | target	2
Deferred revenue			$ 29,039,000	$ 29,787,000

COLLABORATIVE RESEARCH AND LI_8

COLLABORATIVE RESEARCH AND LICENSE AGREEMENTS - Alexion Summary of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue	$ 41,337	$ 40,448	$ 88,940	$ 74,476
Total
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue	2,487	7,063	10,304	9,825
Alexion Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue	2,316	5,792	9,505	7,914
Alexion Amendment
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue	$ 171	$ 1,271	$ 799	$ 1,911

COLLABORATIVE RESEARCH AND LI_9

COLLABORATIVE RESEARCH AND LICENSE AGREEMENTS - Alexion Deferred Revenue (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
CURRENT	$ 160,200	$ 138,537
NONCURRENT	268,606	336,236
TOTAL	428,806	474,773
Total
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
CURRENT	8,254	18,680
NONCURRENT	30,902	27,851
TOTAL	39,156	46,531
Alexion
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
CURRENT	6,951	9,216
NONCURRENT	3,166	7,528
TOTAL	10,117	16,744
Alexion Amendment
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
CURRENT	1,303	9,464
NONCURRENT	27,736	20,323
TOTAL	$ 29,039	$ 29,787

COLLABORATIVE RESEARCH AND L_10

COLLABORATIVE RESEARCH AND LICENSE AGREEMENTS - BI Agreement and Related Amendments (Details) - USD ($)	Oct. 27, 2017	Jan. 31, 2019	Oct. 31, 2018
Boehringer Ingelheim Agreement
Disaggregation of Revenue [Line Items]
Non-refundable upfront payment	$ 10,000,000
Reimbursable third-party expenses	300,000
Boehringer Ingelheim Agreement | Transferred over Time
Disaggregation of Revenue [Line Items]
Transaction price recognized	10,300,000
Additional Target Agreement
Disaggregation of Revenue [Line Items]
Non-refundable upfront payment			$ 5,000,000
Option exercise fee	$ 5,000,000
Reimbursable expense			700,000
Transaction price allocated to revenue arrangement		$ 5,700,000
Additional Target Agreement | Maximum
Disaggregation of Revenue [Line Items]
Consideration receivable upon potential development and commercial milestones			$ 170,000,000

COLLABORATIVE RESEARCH AND L_11

COLLABORATIVE RESEARCH AND LICENSE AGREEMENTS - Summary of Revenue Recognized (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Revenue	$ 41,337	$ 40,448	$ 88,940	$ 74,476
Novo
Disaggregation of Revenue [Line Items]
Revenue	6,700	2,447	13,312	4,052
Roche
Disaggregation of Revenue [Line Items]
Revenue	14,234	20,677	39,845	39,984
Lilly
Disaggregation of Revenue [Line Items]
Revenue	14,735	9,487	22,298	19,069
Alexion
Disaggregation of Revenue [Line Items]
Revenue	2,487	7,063	10,304	9,825
BI
Disaggregation of Revenue [Line Items]
Revenue	$ 3,181	$ 774	$ 3,181	$ 1,546

COLLABORATIVE RESEARCH AND L_12

COLLABORATIVE RESEARCH AND LICENSE AGREEMENTS - Summary of Deferred Revenue Balances (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
CURRENT	$ 160,200	$ 138,537
NONCURRENT	268,606	336,236
TOTAL	428,806	474,773
Novo
Disaggregation of Revenue [Line Items]
CURRENT	36,829	30,169
NONCURRENT	142,795	162,630
TOTAL	179,624	192,799
Roche
Disaggregation of Revenue [Line Items]
CURRENT	62,022	49,493
NONCURRENT	55,019	81,273
TOTAL	117,041	130,766
Lilly
Disaggregation of Revenue [Line Items]
CURRENT	53,095	40,195
NONCURRENT	39,890	64,482
TOTAL	92,985	104,677
Alexion
Disaggregation of Revenue [Line Items]
CURRENT	8,254	18,680
NONCURRENT	30,902	27,851
TOTAL	$ 39,156	$ 46,531

COLLABORATIVE RESEARCH AND L_13

COLLABORATIVE RESEARCH AND LICENSE AGREEMENTS - Revenues as a Result of Changes in Contract Liability (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue from Contract with Customer [Abstract]
Amounts included in deferred revenue at the beginning of the period	$ 31,947	$ 38,595	$ 60,260	$ 65,278
Performance obligations satisfied (or partially satisfied) in previous reporting periods	$ 6,431	$ 1,011	$ 20,188	$ 2,004

ROYALTY PHARMA FINANCING (Detai

ROYALTY PHARMA FINANCING (Details) $ in Millions	1 Months Ended
	Apr. 30, 2021USD ($)
Deferred Income Disclosure [Abstract]
Upfront cash payment	$ 180
Contingent sales-based milestone payments	$ 60

STOCK-BASED COMPENSATION - Clas

STOCK-BASED COMPENSATION - Classification of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 13,633	$ 10,206	$ 26,046	$ 18,733
Research and development expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	7,143	4,578	13,577	8,881
General and administrative expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 6,490	$ 5,628	$ 12,469	$ 9,852

STOCK-BASED COMPENSATION - Narr

STOCK-BASED COMPENSATION - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock options granted (in shares)	285,375	701,925	2,254,022	3,608,225
Aggregate grant date fair value	$ 5.6	$ 9.5	$ 37.4	$ 53.8
Nonvested restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units granted (in shares)	63,489	189,455	502,799	910,055
Grant date fair value of units	$ 1.9	$ 3.8	$ 12.4	$ 19.8

STOCK-BASED COMPENSATION - Sche

STOCK-BASED COMPENSATION - Schedule of Valuation Assumptions (Details) - Employee Stock Option - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock price (in dollars per share)	$ 25.76	$ 17.33	$ 22.07	$ 15.61
Expected option term (in years)	5 years 3 months 7 days	5 years 6 months	5 years 3 months 7 days	5 years 6 months
Expected volatility	77.72%	78.33%	77.72%	78.33%
Risk-free interest rate	0.90%	0.00%	0.51%	0.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock price (in dollars per share)	$ 30.71	$ 21.61	$ 30.71	$ 22.58
Expected option term (in years)	6 years 29 days	6 years 29 days	6 years 29 days	6 years 29 days
Expected volatility	79.16%	80.45%	79.16%	80.45%
Risk-free interest rate	1.15%	0.42%	1.15%	1.71%

INCOME TAXES (Details)

INCOME TAXES (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 546	$ 0	$ 546	$ 0
Effective tax rate			0.79%

LEASES (Details)

LEASES (Details) $ in Thousands	Jul. 01, 2020USD ($)ft²	Jan. 14, 2020ft²renewalOption	Jun. 30, 2021USD ($)renewalOption	Dec. 31, 2020USD ($)
Lessee, Lease, Description [Line Items]
Lease not yet commenced, lease term	118 months 15 days
Right-of-use operating assets, net			$ 74,400	$ 60,843
75 Hayden Avenue
Lessee, Lease, Description [Line Items]
Area of real estate property | ft²	91,728	61,282
Lease not yet commenced, lease term				125 months
Number of renewal options | renewalOption		2	2
Renewal term		5 years
Extension term			5 years
Increase in monthly base rent	$ 200
Additional area of lease | ft²	30,446
Aggregate total fixed rent			$ 21,300
Right-of-use operating assets, net			17,200
Operating lease liability			15,300
Minimum | 75 Hayden Avenue
Lessee, Lease, Description [Line Items]
Annual fixed rental payments			1,900
Maximum | 75 Hayden Avenue
Lessee, Lease, Description [Line Items]
Annual fixed rental payments			$ 2,600

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Details)	Jun. 30, 2021USD ($)
Commitments and Contingencies Disclosure [Abstract]
Contingent liabilities	$ 0