Dicerna Pharmaceuticals (DRNA) 10-Q7 Aug 142014 Q2 Quarterly reportFinancial data

Company Profile

Document_and_Entity_Informatio

Document and Entity Information	6 Months Ended
Document and Entity Information	Jun. 30, 2014	Aug. 05, 2014
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Jun-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q2	'
Entity Registrant Name	'DICERNA PHARMACEUTICALS INC	'
Entity Central Index Key	'0001399529	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Non-accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	17,768,771

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
CURRENT ASSETS:	'	'
Cash and cash equivalents	$77,732	$46,595
Held-to-maturity investments	22,526	'
Prepaid expenses and other current assets	1,016	2,058
Total current assets	101,274	48,653
NONCURRENT ASSETS:	'	'
Held-to-maturity investments	20,026	'
Property and equipment-net	1,473	877
Assets held in restriction	1,380	264
Total noncurrent assets	22,879	1,141
TOTAL ASSETS	124,153	49,794
CURRENT LIABILITIES:	'	'
Accounts payable	1,062	1,700
Accrued expenses and other current liabilities	2,808	1,286
Current portion of long-term debt	'	4,587
Deferred rent	88	105
Total current liabilities	3,958	7,678
NONCURRENT LIABILITIES:	'	'
Long-term debt-net of current portion	'	260
Preferred stock warrant liability	'	529
Total noncurrent liabilities	'	789
TOTAL LIABILITIES	3,958	8,467
STOCKHOLDERS' EQUITY/(DEFICIT):	'	'
Preferred stock, $0.0001 par value-5,000,000 shares and no shares authorized at June 30, 2014 and December 31, 2013, respectively; no shares issued and outstanding at June 30, 2014 and December 31, 2013, respectively	0	0
Common stock, $0.0001 par value-150,000,000 shares and 15,000,000 shares authorized at June 30, 2014 and December 31, 2013, respectively; 17,763,051 shares and 38,226 shares issued and outstanding at June 30, 2014 and December 31, 2013, respectively	2	1
Additional paid-in capital	228,007	16,545
Accumulated deficit	-107,814	-85,465
Total stockholders' equity/(deficit)	120,195	-68,919
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY / (DEFICIT)	124,153	49,794
Series A Redeemable Convertible Preferred Stock [Member]	'	'
REDEEMABLE CONVERTIBLE PREFERRED STOCK, $0.0001 PAR VALUE-NO SHARES AND 11,070,000 SHARES AUTHORIZED AT JUNE 30, 2014 AND DECEMBER 31, 2013, RESPECTIVELY; NO SHARES AND 10,589,434 SHARES ISSUED AND OUTSTANDING AT JUNE 30, 2014 AND DECEMBER 31, 2013, RESPECTIVELY:	'	'
REDEEMABLE CONVERTIBLE PREFERRED STOCK, Value	'	21,400
Series B Redeemable Convertible Preferred Stock [Member]	'	'
REDEEMABLE CONVERTIBLE PREFERRED STOCK, $0.0001 PAR VALUE-NO SHARES AND 11,070,000 SHARES AUTHORIZED AT JUNE 30, 2014 AND DECEMBER 31, 2013, RESPECTIVELY; NO SHARES AND 10,589,434 SHARES ISSUED AND OUTSTANDING AT JUNE 30, 2014 AND DECEMBER 31, 2013, RESPECTIVELY:	'	'
REDEEMABLE CONVERTIBLE PREFERRED STOCK, Value	'	29,050
Series C Redeemable Convertible Preferred Stock [Member]	'	'
REDEEMABLE CONVERTIBLE PREFERRED STOCK, $0.0001 PAR VALUE-NO SHARES AND 11,070,000 SHARES AUTHORIZED AT JUNE 30, 2014 AND DECEMBER 31, 2013, RESPECTIVELY; NO SHARES AND 10,589,434 SHARES ISSUED AND OUTSTANDING AT JUNE 30, 2014 AND DECEMBER 31, 2013, RESPECTIVELY:	'	'
REDEEMABLE CONVERTIBLE PREFERRED STOCK, Value	'	$59,796

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Jun. 30, 2014	Dec. 31, 2013
REDEEMABLE CONVERTIBLE PREFERRED STOCK, PAR VALUE	$0.00	$0.00
REDEEMABLE CONVERTIBLE PREFERRED STOCK, SHARES AUTHORIZED	0	11,070,000
REDEEMABLE CONVERTIBLE PREFERRED STOCK, SHARES ISSUED	0	10,589,434
REDEEMABLE CONVERTIBLE PREFERRED STOCK, SHARES OUTSTANDING	0	10,589,434
Preferred stock, par value	$0.00	$0.00
Preferred stock, shares authorized	5,000,000	0
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	17,763,051	38,226
Common stock, shares outstanding	17,763,051	38,226
Series A Redeemable Convertible Preferred Stock [Member]	'	'
REDEEMABLE CONVERTIBLE PREFERRED STOCK, SHARES AUTHORIZED	0	880,000
REDEEMABLE CONVERTIBLE PREFERRED STOCK, SHARES ISSUED	0	855,996
REDEEMABLE CONVERTIBLE PREFERRED STOCK, SHARES OUTSTANDING	0	855,996
REDEEMABLE CONVERTIBLE PREFERRED STOCK, Aggregate liquidation preference	$0	$21,400,000
Series B Redeemable Convertible Preferred Stock [Member]	'	'
REDEEMABLE CONVERTIBLE PREFERRED STOCK, SHARES AUTHORIZED	0	1,190,000
REDEEMABLE CONVERTIBLE PREFERRED STOCK, SHARES ISSUED	0	1,162,021
REDEEMABLE CONVERTIBLE PREFERRED STOCK, SHARES OUTSTANDING	0	1,162,021
REDEEMABLE CONVERTIBLE PREFERRED STOCK, Aggregate liquidation preference	0	29,050,000
Series C Redeemable Convertible Preferred Stock [Member]	'	'
REDEEMABLE CONVERTIBLE PREFERRED STOCK, SHARES AUTHORIZED	0	9,000,000
REDEEMABLE CONVERTIBLE PREFERRED STOCK, SHARES ISSUED	0	8,571,417
REDEEMABLE CONVERTIBLE PREFERRED STOCK, SHARES OUTSTANDING	0	8,571,417
REDEEMABLE CONVERTIBLE PREFERRED STOCK, Aggregate liquidation preference	$0	$60,000,000

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (USD $)	3 Months Ended		6 Months Ended
In Thousands, except Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Operating expenses:	'	'	'	'
Research and development	$6,806	$2,513	$12,057	$4,931
General and administrative	4,372	1,142	7,213	2,278
Total operating expenses	11,178	3,655	19,270	7,209
Loss from operations	-11,178	-3,655	-19,270	-7,209
Other income (expense):	'	'	'	'
Preferred stock warrant remeasurement	'	118	-2,559	123
Loss on extinguishment of debt	-143	'	-143	'
Interest income	8	'	12	'
Interest expense	-42	-249	-199	-519
Total other income (expense)	-177	-131	-2,889	-396
Net loss	-11,355	-3,786	-22,159	-7,605
Less: Accretion and dividends on redeemable convertible preferred stock	'	1,022	204	2,033
Net loss attributable to common stockholders	($11,355)	($4,808)	($22,363)	($9,638)
Net loss per share attributable to common stockholders-basic and diluted	($0.64)	($171.13)	($1.57)	($343.92)
Weighted average shares outstanding-basic and diluted	17,684,563	28,095	14,272,401	28,024

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Cash Flows (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
CASH FLOWS FROM OPERATING ACTIVITIES:	'	'
Net loss	($22,159)	($7,605)
Adjustments to reconcile net loss to net cash used in operating activities:	'	'
Depreciation	213	271
Stock-based compensation	4,617	60
Amortization of debt discount	48	110
Loss on extinguishment of debt	143	'
Increase (decrease) in fair value of preferred stock warrant liability	2,559	-123
Changes in operating assets and liabilities:	'	'
Research and license receivable	'	5,018
Prepaid expenses and other current assets	-944	58
Accounts payable	-272	-512
Accrued expenses and other current liabilities	1,542	35
Deferred rent	-18	-33
Net cash used in operating activities	-14,271	-2,721
CASH FLOWS FROM INVESTING ACTIVITIES:	'	'
Changes in assets held in restriction	-1,116	'
Purchases of property and equipment	-808	-3
Purchases of held-to-maturity investments	-42,552	'
Net cash used in investing activities	-44,476	-3
CASH FLOWS FROM FINANCING ACTIVITIES:	'	'
Proceeds from exercised stock options	762	11
Net proceeds from initial public offering	94,148	'
Payments of deferred stock issuance costs	'	-98
Proceeds from bridge loan financing	'	3,000
Repayments of long-term debt principal	-5,026	-2,018
Net cash provided by financing activities	89,884	895
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	31,137	-1,829
CASH AND CASH EQUIVALENTS - Beginning of period	46,595	3,670
CASH AND CASH EQUIVALENTS - End of period	77,732	1,841
NONCASH FINANCING ACTIVITIES:	'	'
Warrant conversion to common stock	$3,088	'

Description_of_Business_and_Ba

Description of Business and Basis of Presentation	6 Months Ended
Description of Business and Basis of Presentation	Jun. 30, 2014
Accounting Policies [Abstract]	'
Description of Business and Basis of Presentation	'
	1. Description of Business and Basis of Presentation
	Nature of business
	Dicerna Pharmaceuticals, Inc. and its subsidiary (the “Company”) is a biopharmaceutical company focused on the discovery and development of innovative treatments for rare inherited diseases involving the liver and for cancers that are genetically defined. The Company is using its proprietary RNA interference (RNAi) technology platform to build a broad pipeline in these therapeutic areas. The Company intends to discover, develop and commercialize novel therapeutics either on its own or in collaboration with pharmaceutical partners.
	The Company continues to be subject to a number of risks common to companies in similar stages of development. Principal among these risks are the uncertainties of technological innovations, which are particularly high in the field of drug discovery and development, dependence on key individuals, development of the same or similar technological innovations by the Company’s competitors and protection of proprietary technology. The Company’s ability to fund its planned preclinical and clinical operations, including completion of its clinical trials, is expected to depend on the amount and timing of cash receipts under its existing collaboration agreement, as well as any future collaboration or product sales and/or financing transactions.
	In February 2014, the Company completed the sale of 6,900,000 shares of common stock in an initial public offering of its common stock (the IPO) at a price to the public of $15.00 per share, resulting in proceeds to the Company of $92,749 after deducting underwriting discounts and commissions of approximately $7,245 and offering expenses paid by the Company of approximately $3,506. In connection with the close of the IPO, all of the outstanding shares of Series A mandatorily redeemable, convertible preferred stock (Series A preferred stock), Series B mandatorily redeemable, convertible preferred stock (Series B preferred stock) and Series C mandatorily redeemable, convertible preferred stock (Series C preferred stock) were converted into shares of common stock on a one-for-one basis immediately prior to the closing of the IPO. Following these transactions, the Company had a total of 17,763,051 shares of common stock issued and outstanding as of June 30, 2014. The significant increase in the shares outstanding in 2014 is expected to impact the year over year comparability of the Company’s net loss per share calculations for the full year.
	Basis of presentation and consolidation
	The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the U.S. (GAAP) and in accordance with the rules and regulations of the Securities and Exchange Commission (SEC) for interim financial information. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. The unaudited condensed consolidated interim financial statements have been prepared on the same basis as the annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary to present fairly the Company’s financial position at June 30, 2014 and results of operations and cash flows for the interim periods ended June 30, 2014 and 2013. These unaudited condensed consolidated interim financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013. The results of the three and six month periods ended June 30, 2014 are not necessarily indicative of the results to be expected for the year ending December 31, 2014 or for any other interim period or for any other future year.
	Summary of Significant Accounting Policies — There have been no material changes to the significant accounting policies previously disclosed in the Company’s Annual Report on Form 10-K, other than the held-to-maturity investments policy noted below.
	Held-to-Maturity Investments
	The Company accounts for its investments in marketable securities in accordance with FASB ASC 320, Investments – Debt and Equity Securities. The Company determines the appropriate classification of investments at the time of purchase and re-evaluates such designation as of each balance sheet date. Debt securities carried at amortized cost are classified as held-to-maturity when the Company has the positive intent and ability to hold the securities to maturity. At June 30, 2014, all of the Company’s investments are classified as held-to-maturity.

Net_Loss_Per_Share_Attributabl

Net Loss Per Share Attributable to Common Stockholders	6 Months Ended
Net Loss Per Share Attributable to Common Stockholders	Jun. 30, 2014
Earnings Per Share [Abstract]	'
Net Loss Per Share Attributable to Common Stockholders	'
	2. Net Loss Per Share Attributable to Common Stockholders
	The following table summarizes the computation of basic and diluted net loss per share attributable to common stockholders of the Company (in thousands, except share and per share data):


		Three Months Ended June 30,						Six Months Ended June 30,
		2014			2013			2014			2013
	Net loss	$	(11,355	)	$	(3,786	)	$	(22,159	)	$	(7,605	)
	Accretion of preferred stock issuance costs to redemption value		—			(15	)		(204	)		(31	)
	Accrued dividends on preferred stock		—			(1,007	)		—			(2,002	)

	Net loss attributable to common stockholders—basic and diluted	$	(11,355	)	$	(4,808	)	$	(22,363	)	$	(9,638	)

	The following potentially dilutive securities outstanding during the period, prior to the use of the treasury stock method or if-converted method, have been excluded from the computation of diluted weighted-average common stock outstanding, because such securities had an anti-dilutive impact since the Company has a net loss attributable to common stockholders:


		Three months Ended June 30,						Six months Ended June 30,
		2014			2013			2014			2013
	Options to purchase common stock		2,831,125			25,262			2,159,551			25,722
	Warrants to purchase common stock		87,901			2,198			73,424			2,198
	Warrants to purchase redeemable convertible preferred stock		—			49,294			25,738			49,294
	Redeemable convertible preferred stock		—			2,018,025			2,047,682			2,018,025
	Unvested restricted stock		109,859			10			87,141			15
	Unvested Restricted Stock
	At June 30, 2014, the Company had 113,000 shares of unvested restricted stock outstanding. The unvested restricted stock resulted from the early exercise of stock options of 73,000 and the issuance of restricted stock units of 40,000 during the six-month period ended June 30, 2014.

HeldtoMaturity_Investments

Held-to-Maturity Investments	6 Months Ended
Held-to-Maturity Investments	Jun. 30, 2014
Text Block [Abstract]	'
Held-to-Maturity Investments	'
	3. Held-to-maturity investments
	The Company invests its excess cash balances in short-term and long-term fixed-income investments. The Company determines the appropriate classification of investments at the time of purchase and re-evaluates such designation as of each balance sheet date. Debt securities carried at amortized cost are classified as held-to-maturity when the Company has the positive intent and ability to hold the securities to maturity.
	The following tables provide information relating to held-to-maturity investments at June 30, 2014 (in thousands):


		June 30, 2014
		Amortized		Gross		Gross			Fair
		Cost		Unrealized		Unrealized			Value
				Gains		Losses
	Held-to-maturity investments
	U.S. Government treasury and agency securities	$	42,552	$	7	$	(4	)	$	42,555

	Total held-to-maturity investments	$	42,552	$	7	$	(4	)	$	42,555


	The amortized cost and fair value of held-to-maturity investments by contractual maturities at June 30, 2014, are as follows (in thousands):


		Held-to-Maturity
		Amortized		Fair
		Cost		Value
	Maturing in one year or less	$	22,526	$	22,525
	Maturing after one year through two years		20,026		20,030

	Total	$	42,552	$	42,555

Longterm_Debt

Long-term Debt	6 Months Ended
	Jun. 30, 2014
Debt Disclosure [Abstract]	'
Long-term Debt	'
	4. Long-term Debt
	On March 26, 2009, the Company entered into a loan and security agreement with an independent finance company, Hercules Technology II, LP (Hercules), for up to $7,000 (Hercules loan). The Hercules loan, which has since been repaid, was collateralized by a security interest in all tangible assets. On May 28, 2010, the Company and Hercules executed an amendment to the loan and security agreement to defer $653 in principal payments originally due in June 2010 through August 2010, and amortized such deferred principal amounts equally over the remaining payment term beginning in September 2010. On June 28, 2011, the Company and Hercules executed a second amendment to the loan and security agreement, which increased the maximum loan amount to $12,000. Upon execution of the second amendment, the Company drew a $7,000 advance, a portion of which the Company used to repay the outstanding balance of principal and interest under the original loan and security agreement. On December 15, 2011, the Company drew down the remaining $5,000. Interest was payable monthly and principal was to be repaid in equal monthly installments beginning April 1, 2012 through January 2, 2015. The applicable annual interest rate was 10.15% at December 31, 2013. On April 7, 2014, the Company repaid the remaining amount of the Hercules loan in full in a total amount of $3,590.
	In connection with the Hercules loan, the Company issued warrants to Hercules for the purchase of an aggregate of 21,000 shares of Series A preferred stock and 26,400 shares of Series B preferred stock each at an exercise price of $25.00 per share. Immediately prior to the closing of the IPO on February 4, 2014, all of the outstanding shares of Series A, Series B and Series C preferred stock were automatically converted into shares of common stock on a one-for-one basis. The fair value of the warrants was classified as a liability in the accompanying balance sheet as of December 31, 2013. After the conversion of Series A and Series B preferred stock, the fair value of the warrants was reclassified as a part of stockholders’ equity. The remeasurement of the liability continued until the date of the closing of the IPO. The fair value of the outstanding Hercules warrants as of the IPO closing date was $765 and was determined using the Black-Scholes option-pricing model with the following assumptions:


		February 4,
		2014
	Stock price	$	32.66
	Expected option term (in years)		3
	Expected volatility		62	%
	Risk-free interest rate		0.69	%
	Expected dividend yield		0	%
	The estimated fair value of the outstanding Hercules warrants at December 31, 2013 was $94. On February 11, 2014, Hercules net exercised the warrants in exchange for a total of 12,702 shares of common stock. There were no Series A and Series B warrants outstanding at June 30, 2014.
	The adjustment to this preferred stock warrant liability related to the Hercules warrants was recorded in other income (expense) and amounted to $0 and $(671) the three and six month periods ended June 30, 2014, respectively, compared to $0 and $5 for the comparable periods in 2013.

StockBased_Compensation

Stock-Based Compensation	6 Months Ended
Stock-Based Compensation	Jun. 30, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Stock-Based Compensation	'
	5. Stock-Based Compensation
	Stock options granted to employees and nonemployees
	Stock-based compensation expense related to stock options granted to nonemployees is recognized as the consulting services are rendered, generally on a straight-line basis. The Company believes that the fair value of the stock options is more reliably measurable than the fair value of the services received. Compensation expense is subject to re-measurement until the options vest.

	In September 2013, the Company granted stock options to purchase 132,500 shares of common stock to nonemployees with an initial fair value of $337. During the six month period ended June 30, 2014, the services of certain nonemployees were terminated, resulting in accelerated vesting of their remaining unvested shares. Based on the terms of the nonemployee stock option agreements the Company recorded nonemployee stock-based compensation expense of $50 and $1,661 for the three and six month periods ended June 30, 2014. The assumptions used to estimate fair value were as follows:


		Three Months Ended			Six Months Ended
		June 30, 2014			June 30, 2014
	Stock price	$	16.16 – $22.57		$	16.16 – $41.12
	Expected option term (in years)		6.11 – 6.40			0.25 – 6.86
	Expected volatility		73	%		56% – 73	%
	Risk-free interest rate		2.12% – 2.27	%		0.08% – 2.29	%
	Expected dividend yield		0	%		0	%
	As of June 30, 2014, there were 61,875 unvested stock options held by nonemployees.
	During the three-month period ended June 30, 2014, the Company granted stock options to purchase 1,810,806 shares of common stock to employees with an initial fair value of $19,622. The assumptions used to estimate fair value were as follows:


		Three Months Ended
		June 30, 2014
	Stock price	$	16.30 – $18.73
	Expected option term (in years)		5.50 – 6.25
	Expected volatility		73% – 74	%
	Risk-free interest rate		1.92% – 2.00	%
	Expected dividend yield		0	%
	There were no employee options granted during the three-months ended March 31, 2014.

Redeemable_Convertible_Preferr

Redeemable Convertible Preferred Stock	6 Months Ended
	Jun. 30, 2014
Text Block [Abstract]	'
Redeemable Convertible Preferred Stock	'
	6. Redeemable Convertible Preferred Stock
	The consummation of the IPO on February 4, 2014 resulted in the conversion of all of the shares of the Company’s Series A, Series B and Series C preferred stock into shares of common stock. Each share of Series A, Series B and Series C preferred stock was automatically converted into common stock on a one-for-one basis. The conversion of Series A, Series B and Series C preferred stock resulted in the issuance of 10,589,434 shares of common stock.
	After the conversion of Series C preferred stock, the fair value of the warrants related to Series C preferred stock outstanding immediately prior to the closing of the IPO was reclassified as a part of stockholders’ equity. The remeasurement of the Series C preferred stock warrant liability continued until the closing date of the IPO. The fair value of the Series C preferred stock warrants as of the IPO closing date was $2,323 and was determined using the Black-Scholes option-pricing model with the following assumptions:


		February 4,
		2014
	Stock price	$	32.66
	Expected option term (in years)		4.39
	Expected volatility		65	%
	Risk-free interest rate		1.52	%
	Expected dividend yield		0	%
	The adjustment to the Series C preferred stock warrant liability was recorded in other income (expense) and amounted to $0 and $(1,888) for the three and six months ended June 30, 2014, respectively, and $118 for the three and six month periods ended June 30, 2013.

Fair_Value_Measurements

Fair Value Measurements	6 Months Ended
Fair Value Measurements	Jun. 30, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	7. Fair Value Measurements
	Fair value is an exit price, representing the amount that would be received from the sale of an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumption the accounting literature establishes a three-tier value hierarchy which prioritizes the inputs used in measuring fair value as follows: (Level 1) observable inputs, such as quoted prices in active markets; (Level 2) inputs other than the quoted prices in active markets that are observable either directly or indirectly; and (Level 3) unobservable inputs for which there is little or no market data, which requires the Company to develop its own assumptions. This hierarchy requires the Company to use observable market data, when available, and to minimize the use of unobservable inputs when determining fair value.
	The Company’s cash equivalents, primarily money market accounts and assets held in restriction are classified within Level 1 of the fair value hierarchy because they are valued using quoted prices as of June 30, 2014 and December 31, 2013, respectively.
	The Company’s assets held in restriction bore interest at the prevailing market rates for instruments with similar characteristics and, accordingly, the carrying value of these instruments also approximated their fair value and the financial instruments were classified within Level 2 of the fair value hierarchy because the inputs to the fair value measurement are valued using observable inputs as of June 30, 2014 and December 31, 2013, respectively.
	The Company’s held-to-maturity investments bore interest at the prevailing market rates for instruments with similar characteristics and, accordingly, the carrying value of these instruments also approximated their fair value and the financial instruments were classified within Level 2 of the fair value hierarchy because the inputs to the fair value measurement are valued using observable inputs as of June 30, 2014. The fair value of these instruments is $42,552, and the amortized cost basis is $42,555.
	The carrying value of other current assets, accounts payable, and accrued expenses approximate fair value, due to the short maturity of these instruments. The Company’s long-term debt bore an interest at the prevailing market rates for instruments with similar characteristics and, accordingly, the carrying value for these instruments also approximated their fair value and the financial measurements were also classified within Level 2 of the fair value hierarchy. There was no debt outstanding as of June 30, 2014.
	The fair value of the preferred stock warrant liability was determined using the Black-Scholes option-pricing model for the year ended December 31, 2013 and until the conversion date of February 4, 2014. After the closing of the IPO, the remaining preferred stock warrant liability was no longer subject to re-measurement as the warrants to purchase the Company’s preferred stock became warrants to purchase shares of our common stock. As of the IPO closing date, the fair value of the preferred stock warrants was based significantly on the fair value of our publicly traded common stock and other observable inputs and was reclassified to Level 2. There were no preferred stock warrants outstanding as of June 30, 2014.
	The following table provides a roll-forward of the Company’s liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3):


	BALANCE—January 1, 2014	$	529
	Change in fair value of warrant liability		2,559
	Transfers to Level 2		(3,088	)

	BALANCE— June 30, 2014	$	—
	BALANCE—January 1, 2013	$	331
	Issuance of preferred stock warrants		324
	Change in fair value of warrant liability		(123	)

	BALANCE— June 30, 2013	$	532
	BALANCE—April 1, 2013	$	326
	Issuance of preferred stock warrants		324
	Change in fair value of warrant liability		(118	)

	BALANCE— June 30, 2013	$	532

Commitments_and_Contingencies

Commitments and Contingencies	6 Months Ended
Commitments and Contingencies	Jun. 30, 2014
Commitments And Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	8. Commitments and Contingencies
	City of Hope license agreement
	In September 2007, the Company entered into a license agreement with City of Hope, an independent academic research and medical center (the Medical Center). In consideration for the right to develop, manufacture, and commercialize products based on certain of the Medical Center’s intellectual property, the Company paid a one-time, non-refundable license fee and issued shares of common stock as consideration for the license.

	The Company is required to reimburse the Medical Center for patent costs incurred, and pay an amount within the range of $5,000 to $10,000 upon the achievement of certain milestones, and royalties on future sales, if any. The license agreement will remain in effect until the expiration of the last patents or copyrights licensed under the agreement or until all obligations under the agreement with respect to payment of milestones have terminated or expired. The Company may terminate the license agreement at any time upon 90 days written notice to the Medical Center. The Company did not record any research and development expense, related to the agreement with the Medical Center during the three and six month periods ended June 30, 2014 and 2013, respectively.
	Plant Bioscience Limited (PBL) license agreement
	In September 2013, the Company entered into a commercial license agreement with Plant Bioscience Limited (PBL), pursuant to which PBL has granted to the Company a license to certain of its U.S. patents and patent applications to research, discover, develop, manufacture, sell, import and export, products incorporating one or more short RNA molecules (SRMs).
	The Company has paid PBL a one-time, non-refundable signature fee and will pay PBL a nomination fee for any additional SRMs nominated by the Company under the agreement. The Company is further obligated to pay PBL milestone payments upon achievement of certain clinical and regulatory milestones. The Company made a payment of $100 to PBL upon the commencement of its clinical trial in MYC. In addition, PBL is entitled to receive royalties of any net sale revenue of any licensed product candidates sold by the Company.

Subsequent_Event

Subsequent Event	6 Months Ended
Subsequent Event	Jun. 30, 2014
Subsequent Events [Abstract]	'
Subsequent Event	'
	9. Subsequent Event
	On July 11, 2014, the Company executed a non-cancelable operating lease for office and laboratory space in Cambridge, Massachusetts. The lease agreement obligates the Company to future minimum payments totaling $9.6 million over a six-year lease term. The lease commences on the later to occur of (i) December 1, 2014 or (ii) the date on which the landlord’s work is substantially complete. As part of the lease agreement, the Company established a $1.1 million letter of credit, secured by a certificate of deposit which is included in assets held in restriction at June 30, 2014.

Description_of_Business_and_Ba1

Description of Business and Basis of Presentation (Policies)	6 Months Ended
	Jun. 30, 2014
Accounting Policies [Abstract]	'
Nature of business	'
	Nature of business
	Dicerna Pharmaceuticals, Inc. and its subsidiary (the “Company”) is a biopharmaceutical company focused on the discovery and development of innovative treatments for rare inherited diseases involving the liver and for cancers that are genetically defined. The Company is using its proprietary RNA interference (RNAi) technology platform to build a broad pipeline in these therapeutic areas. The Company intends to discover, develop and commercialize novel therapeutics either on its own or in collaboration with pharmaceutical partners.
	The Company continues to be subject to a number of risks common to companies in similar stages of development. Principal among these risks are the uncertainties of technological innovations, which are particularly high in the field of drug discovery and development, dependence on key individuals, development of the same or similar technological innovations by the Company’s competitors and protection of proprietary technology. The Company’s ability to fund its planned preclinical and clinical operations, including completion of its clinical trials, is expected to depend on the amount and timing of cash receipts under its existing collaboration agreement, as well as any future collaboration or product sales and/or financing transactions.
	In February 2014, the Company completed the sale of 6,900,000 shares of common stock in an initial public offering of its common stock (the IPO) at a price to the public of $15.00 per share, resulting in proceeds to the Company of $92,749 after deducting underwriting discounts and commissions of approximately $7,245 and offering expenses paid by the Company of approximately $3,506. In connection with the close of the IPO, all of the outstanding shares of Series A mandatorily redeemable, convertible preferred stock (Series A preferred stock), Series B mandatorily redeemable, convertible preferred stock (Series B preferred stock) and Series C mandatorily redeemable, convertible preferred stock (Series C preferred stock) were converted into shares of common stock on a one-for-one basis immediately prior to the closing of the IPO. Following these transactions, the Company had a total of 17,763,051 shares of common stock issued and outstanding as of June 30, 2014. The significant increase in the shares outstanding in 2014 is expected to impact the year over year comparability of the Company’s net loss per share calculations for the full year.
Basis of presentation and consolidation	'
	Basis of presentation and consolidation
	The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the U.S. (GAAP) and in accordance with the rules and regulations of the Securities and Exchange Commission (SEC) for interim financial information. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. The unaudited condensed consolidated interim financial statements have been prepared on the same basis as the annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary to present fairly the Company’s financial position at June 30, 2014 and results of operations and cash flows for the interim periods ended June 30, 2014 and 2013. These unaudited condensed consolidated interim financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013. The results of the three and six month periods ended June 30, 2014 are not necessarily indicative of the results to be expected for the year ending December 31, 2014 or for any other interim period or for any other future year.
Summary of Significant Accounting Policies	'
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies — There have been no material changes to the significant accounting policies previously disclosed in the Company’s Annual Report on Form 10-K, other than the held-to-maturity investments policy noted below.
Held-to-Maturity Investments	'
	Held-to-Maturity Investments
	The Company accounts for its investments in marketable securities in accordance with FASB ASC 320, Investments – Debt and Equity Securities. The Company determines the appropriate classification of investments at the time of purchase and re-evaluates such designation as of each balance sheet date. Debt securities carried at amortized cost are classified as held-to-maturity when the Company has the positive intent and ability to hold the securities to maturity. At June 30, 2014, all of the Company’s investments are classified as held-to-maturity.

Net_Loss_Per_Share_Attributabl1

Net Loss Per Share Attributable to Common Stockholders (Tables)	6 Months Ended
	Jun. 30, 2014
Earnings Per Share [Abstract]	'
Summary of Computation of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders	'
	The following table summarizes the computation of basic and diluted net loss per share attributable to common stockholders of the Company (in thousands, except share and per share data):


		Three Months Ended June 30,						Six Months Ended June 30,
		2014			2013			2014			2013
	Net loss	$	(11,355	)	$	(3,786	)	$	(22,159	)	$	(7,605	)
	Accretion of preferred stock issuance costs to redemption value		—			(15	)		(204	)		(31	)
	Accrued dividends on preferred stock		—			(1,007	)		—			(2,002	)

	Net loss attributable to common stockholders—basic and diluted	$	(11,355	)	$	(4,808	)	$	(22,363	)	$	(9,638	)

Schedule of Dilutive Securities Outstanding	'
	The following potentially dilutive securities outstanding during the period, prior to the use of the treasury stock method or if-converted method, have been excluded from the computation of diluted weighted-average common stock outstanding, because such securities had an anti-dilutive impact since the Company has a net loss attributable to common stockholders:


		Three months Ended June 30,						Six months Ended June 30,
		2014			2013			2014			2013
	Options to purchase common stock		2,831,125			25,262			2,159,551			25,722
	Warrants to purchase common stock		87,901			2,198			73,424			2,198
	Warrants to purchase redeemable convertible preferred stock		—			49,294			25,738			49,294
	Redeemable convertible preferred stock		—			2,018,025			2,047,682			2,018,025
	Unvested restricted stock		109,859			10			87,141			15

HeldtoMaturity_Investments_Tab

Held-to-Maturity Investments (Tables)	6 Months Ended
Held-to-Maturity Investments (Tables)	Jun. 30, 2014
Text Block [Abstract]	'
Schedule of Held-To-Maturity Investments	'
	The following tables provide information relating to held-to-maturity investments at June 30, 2014 (in thousands):


		June 30, 2014
		Amortized		Gross		Gross			Fair
		Cost		Unrealized		Unrealized			Value
				Gains		Losses
	Held-to-maturity investments
	U.S. Government treasury and agency securities	$	42,552	$	7	$	(4	)	$	42,555

	Total held-to-maturity investments	$	42,552	$	7	$	(4	)	$	42,555

Amortized Cost and Fair Value of Held-To-Maturity Investments	'
	The amortized cost and fair value of held-to-maturity investments by contractual maturities at June 30, 2014, are as follows (in thousands):


		Held-to-Maturity
		Amortized		Fair
		Cost		Value
	Maturing in one year or less	$	22,526	$	22,525
	Maturing after one year through two years		20,026		20,030

	Total	$	42,552	$	42,555

Longterm_Debt_Tables

Long-term Debt (Tables)	6 Months Ended
Long-term Debt (Tables)	Jun. 30, 2014
Debt Disclosure [Abstract]	'
Summary of Assumptions Used in Black-Scholes Option-Pricing Model	'
	The fair value of the outstanding Hercules warrants as of the IPO closing date was $765 and was determined using the Black-Scholes option-pricing model with the following assumptions:


		February 4,
		2014
	Stock price	$	32.66
	Expected option term (in years)		3
	Expected volatility		62	%
	Risk-free interest rate		0.69	%
	Expected dividend yield		0	%

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	6 Months Ended
Stock-Based Compensation (Tables)	Jun. 30, 2014
Stock Options Granted to Nonemployees [Member]	'
Schedule of Valuation Assumptions	'
	The assumptions used to estimate fair value were as follows:


		Three Months Ended			Six Months Ended
		June 30, 2014			June 30, 2014
	Stock price	$	16.16 – $22.57		$	16.16 – $41.12
	Expected option term (in years)		6.11 – 6.40			0.25 – 6.86
	Expected volatility		73	%		56% – 73	%
	Risk-free interest rate		2.12% – 2.27	%		0.08% – 2.29	%
	Expected dividend yield		0	%		0	%
Stock Options Granted to Employees [Member]	'
Schedule of Valuation Assumptions	'
	The assumptions used to estimate fair value were as follows:


		Three Months Ended
		June 30, 2014
	Stock price	$	16.30 – $18.73
	Expected option term (in years)		5.50 – 6.25
	Expected volatility		73% – 74	%
	Risk-free interest rate		1.92% – 2.00	%
	Expected dividend yield		0	%

Redeemable_Convertible_Preferr1

Redeemable Convertible Preferred Stock (Tables) (Series C Redeemable Convertible Preferred Stock [Member])	6 Months Ended
	Jun. 30, 2014
Series C Redeemable Convertible Preferred Stock [Member]	'
Schedule of Valuation Assumptions	'
	The fair value of the Series C preferred stock warrants as of the IPO closing date was $2,323 and was determined using the Black-Scholes option-pricing model with the following assumptions:


		February 4,
		2014
	Stock price	$	32.66
	Expected option term (in years)		4.39
	Expected volatility		65	%
	Risk-free interest rate		1.52	%
	Expected dividend yield		0	%

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	6 Months Ended
Fair Value Measurements (Tables)	Jun. 30, 2014
Fair Value Disclosures [Abstract]	'
Schedule of Roll-Forward of Company's Liabilities Measured at Fair Value on Recurring Basis Using Unobservable Inputs (Level 3)	'
	The following table provides a roll-forward of the Company’s liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3):


	BALANCE—January 1, 2014	$	529
	Change in fair value of warrant liability		2,559
	Transfers to Level 2		(3,088	)

	BALANCE— June 30, 2014	$	—
	BALANCE—January 1, 2013	$	331
	Issuance of preferred stock warrants		324
	Change in fair value of warrant liability		(123	)

	BALANCE— June 30, 2013	$	532
	BALANCE—April 1, 2013	$	326
	Issuance of preferred stock warrants		324
	Change in fair value of warrant liability		(118	)

	BALANCE— June 30, 2013	$	532

Description_of_Business_and_Ba2

Description of Business and Basis of Presentation - Additional Information (Detail) (USD $)	6 Months Ended				1 Months Ended
In Thousands, except Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Feb. 04, 2014	Dec. 31, 2013	Feb. 28, 2014
	Jun. 30, 2014	Jun. 30, 2013	Feb. 04, 2014	Dec. 31, 2013	IPO [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]	'	'	'	'	'
Common stock shares issued	'	'	'	'	6,900,000
Sale of stock price per share	'	'	$32.66	'	$15
Proceeds from issuance of common stock	$94,148	'	'	'	$92,749
Underwriting discounts and commissions	'	98	'	'	7,245
Offering expenses	'	'	'	'	$3,506
Preferred stock conversion basis	'In connection with the close of the IPO, all of the outstanding shares of Series A mandatorily redeemable, convertible preferred stock (Series A preferred stock), Series B mandatorily redeemable, convertible preferred stock (Series B preferred stock) and Series C mandatorily redeemable, convertible preferred stock (Series C preferred stock) were converted into shares of common stock on a one-for-one basis immediately prior to the closing of the IPO.	'	'	'	'
Common stock, shares issued	17,763,051	'	'	38,226	'
Common stock, shares outstanding	17,763,051	'	'	38,226	'

Net_Loss_Per_Share_Attributabl2

Net Loss Per Share Attributable to Common Stockholders - Summary of Computation of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders (Detail) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Earnings Per Share [Abstract]	'	'	'	'
Net loss	($11,355)	($3,786)	($22,159)	($7,605)
Accretion of preferred stock issuance costs to redemption value	'	-15	-204	-31
Accrued dividends on preferred stock	'	-1,007	'	-2,002
Net loss attributable to common stockholders-basic and diluted	($11,355)	($4,808)	($22,363)	($9,638)

Net_Loss_Per_Share_Attributabl3

Net Loss Per Share Attributable to Common Stockholders - Schedule of Dilutive Securities Outstanding (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Options to Purchase Common Stock [Member]	'	'	'	'
Dilutive Securities Included And Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Anti-dilutive securities	2,831,125	25,262	2,159,551	25,722
Warrants to Purchase Common Stock [Member]	'	'	'	'
Dilutive Securities Included And Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Anti-dilutive securities	87,901	2,198	73,424	2,198
Warrants to Purchase Redeemable Convertible Preferred Stock [Member]	'	'	'	'
Dilutive Securities Included And Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Anti-dilutive securities	'	49,294	25,738	49,294
Redeemable Convertible Preferred Stock [Member]	'	'	'	'
Dilutive Securities Included And Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Anti-dilutive securities	'	2,018,025	2,047,682	2,018,025
Unvested Restricted Stock [Member]	'	'	'	'
Dilutive Securities Included And Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Anti-dilutive securities	109,859	10	87,141	15

Net_Loss_Per_Share_Attributabl4

Net Loss Per Share Attributable to Common Shareholders - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2014
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]	'
Unvested restricted exercise stock options	73,000
Restricted Stock [Member]	'
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]	'
Unvested restricted stock outstanding	113,000
Issuance of restricted stock units	40,000

HeldtoMaturity_Investments_Sch

Held-to-Maturity Investments - Schedule of Held-to-Maturity Investments (Detail) (USD $)	Jun. 30, 2014
In Thousands, unless otherwise specified	Jun. 30, 2014
Schedule of Held-to-maturity Securities [Line Items]	'
Held-to-maturity investments, Amortized Cost	$42,552
Held-to-maturity investments, Gross Unrealized Gains	7
Held-to-maturity investments, Gross Unrealized Losses	-4
Held-to-maturity investments,Fair Value,Total	42,555
U.S. Government Treasury and Agency Securities [Member]	'
Schedule of Held-to-maturity Securities [Line Items]	'
Held-to-maturity investments, Amortized Cost	42,552
Held-to-maturity investments, Gross Unrealized Gains	7
Held-to-maturity investments, Gross Unrealized Losses	-4
Held-to-maturity investments,Fair Value,Total	$42,555

HeldtoMaturityInvestments_Amor

Held-to-Maturity-Investments - Amortized Cost and Fair Value of Held-to-Maturity Investments (Detail) (USD $)	Jun. 30, 2014
In Thousands, unless otherwise specified	Jun. 30, 2014
Investments Debt And Equity Securities [Abstract]	'
Held-to-Maturity securities, Maturing in one year or less, Amortized Cost	$22,526
Held-to-Maturity securities, Maturing after one year through two years, Amortized Cost	20,026
Held to Maturity, Amortized Cost, Total	42,552
Held-to-Maturity securities, Maturing in one year or less, Fair Value	22,525
Held-to-Maturity securities, Maturing after one year through two years, Fair Value	20,030
Held-to-maturity investments,Fair Value,Total	$42,555

Longterm_Debt_Additional_Infor

Long-term Debt - Additional Information (Detail) (USD $)

0 Months Ended

3 Months Ended

6 Months Ended

0 Months Ended

6 Months Ended

0 Months Ended

6 Months Ended

In Thousands, except Share data, unless otherwise specified

28-May-10

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2013

Feb. 04, 2014

Dec. 31, 2013

Mar. 26, 2009

Jun. 30, 2014

Dec. 15, 2011

Jun. 28, 2011

Jun. 30, 2014

Dec. 31, 2013

Jun. 28, 2011

Apr. 07, 2014

Jun. 30, 2014

Feb. 11, 2014

Jun. 30, 2014

Series A Warrants [Member]

Series B Warrants [Member]

Second Amendment [Member]

Hercules Loan [Member]

Series A Warrants [Member]

Series B Warrants [Member]

Debt Instrument [Line Items]

Loan and security agreement

$7,000

$12,000

Loan and security agreement, principal payments

653

Principal payments due

'June 2010 through August 2010

Loan drew in advance

5,000

7,000

Annual interest rate

10.15%

Principal monthly installments period

'April 1, 2012 through January 2, 2015

Repayment of debt

3,590

Warrants exercised, Number of shares

21,000

26,400

Warrants exercised, Exercise price

IPO closing date

4-Feb-14

Estimated fair value of outstanding warrants

765

Common stock issued, shares

17,763,051

38,226

12,702

Adjustment to preferred stock warrant liability recorded in other income (expense)

$118

($2,559)

$123

Longterm_Debt_Summary_of_Assum

Long-term Debt - Summary of Assumptions Used in Black-Scholes Option-Pricing Model (Detail) (USD $)	0 Months Ended
	Feb. 04, 2014	Feb. 04, 2014
Long Term Debt [Abstract]	'	'
Stock price	'	$32.66
Expected option term (in years)	'3 years	'
Expected volatility	62.00%	'
Risk-free interest rate	0.69%	'
Expected dividend yield	0.00%	'

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)	6 Months Ended		3 Months Ended	6 Months Ended	9 Months Ended	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2014	Sep. 30, 2013	Jun. 30, 2014	Mar. 31, 2014
	Jun. 30, 2014	Jun. 30, 2013	Stock Options Granted to Nonemployees [Member]	Stock Options Granted to Nonemployees [Member]	Stock Options Granted to Nonemployees [Member]	Stock Options Granted to Employees [Member]	Stock Options Granted to Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'	'
Stock option, granted	'	'	'	'	132,500	1,810,806	0
Common stock fair value	'	'	'	'	$337	'	'
Stock-based compensation expense	4,617	60	50	1,661	'	'	'
Unvested stock options	'	'	61,875	61,875	'	'	'
Common stock fair value	'	'	'	'	'	$19,622	'

StockBased_Compensation_Schedu

Stock-Based Compensation - Schedule of Valuation Assumptions (Detail) (USD $)	3 Months Ended	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2014
Stock Options Granted to Employees [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Expected dividend yield	0.00%	'
Stock Options Granted to Employees [Member] \| Minimum [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Stock price	$16.30	'
Expected option term (in years)	'5 years 6 months	'
Expected volatility	73.00%	'
Risk-free interest rate	1.92%	'
Stock Options Granted to Employees [Member] \| Maximum [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Stock price	$18.73	'
Expected option term (in years)	'6 years 3 months	'
Expected volatility	74.00%	'
Risk-free interest rate	2.00%	'
Stock Options Granted to Nonemployees [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Expected volatility	73.00%	'
Stock Options Granted to Nonemployees [Member] \| Minimum [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Stock price	$16.16	$16.16
Expected option term (in years)	'6 years 1 month 10 days	'3 months
Expected volatility	'	56.00%
Risk-free interest rate	2.12%	0.08%
Expected dividend yield	0.00%	0.00%
Stock Options Granted to Nonemployees [Member] \| Maximum [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Stock price	$22.57	$41.12
Expected option term (in years)	'6 years 4 months 24 days	'6 years 10 months 10 days
Expected volatility	'	73.00%
Risk-free interest rate	2.27%	2.29%

Redeemable_Convertible_Preferr2

Redeemable Convertible Preferred Stock - Additional Information (Detail) (USD $)	3 Months Ended	6 Months Ended				3 Months Ended		6 Months Ended
In Thousands, except Share data, unless otherwise specified	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Feb. 04, 2014	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Feb. 04, 2014
	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Redeemable Convertible Preferred Stock [Member]	Series C Preferred Stock [Member]	Series C Preferred Stock [Member]	Series C Preferred Stock [Member]	Series C Preferred Stock [Member]	Series C Preferred Stock [Member]
Conversion of Stock [Line Items]	'	'	'	'	'	'	'	'	'	'
Issuance of common stock	'	17,763,051	'	38,226	10,589,434	'	'	'	'	'
Fair value of preferred stock warrants	'	'	'	'	'	'	'	'	'	$2,323
Adjustment to preferred stock warrant liability recorded in other income (expense)	($118)	$2,559	($123)	'	'	$0	$118	($1,888)	$118	'

Redeemable_Convertible_Preferr3

Redeemable Convertible Preferred Stock - Schedule of Valuation Assumptions (Detail) (USD $)	0 Months Ended
	Feb. 04, 2014	Feb. 04, 2014
Temporary Equity [Line Items]	'	'
Stock price	$32.66	$32.66
Series C Redeemable Convertible Preferred Stock [Member]	'	'
Temporary Equity [Line Items]	'	'
Stock price	'	$32.66
Expected option term (in years)	'4 years 4 months 21 days	'
Expected volatility	65.00%	'
Risk-free interest rate	1.52%	'
Expected dividend yield	0.00%	'

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (Detail) (USD $)	6 Months Ended
	Jun. 30, 2014
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'
Held-to-maturity, Fair value	$42,555,000
Held-to-maturity, Amortized cost	42,552,000
Debt outstanding	0
Preferred stock conversion date	4-Feb-14
Preferred stock, warrants outstanding	0
Level 2 [Member]	'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'
Held-to-maturity, Fair value	42,555,000
Held-to-maturity, Amortized cost	$42,552,000

Fair_Value_Measurements_Schedu

Fair Value Measurements - Schedule of Roll-Forward of Company's Liabilities Measured at Fair Value on Recurring Basis Using Unobservable Inputs (Level 3) (Detail) (USD $)	3 Months Ended	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Debt Instrument Fair Value Carrying Value [Abstract]	'	'	'
Balance at the beginning of the period	$326	$529	$331
Issuance of preferred stock warrants	324	'	324
Change in fair value of warrant liability	-118	2,559	-123
Transfers to Level 2	'	-3,088	'
Balance at the end of the period	$532	$0	$532

Commitments_and_Contingencies_

Commitments and Contingencies - Additional Information (Detail)	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2014	Jun. 30, 2014
	USD ($)	USD ($)	USD ($)	USD ($)	City of Hope License Agreement [Member]	City of Hope License Agreement [Member]	City of Hope License Agreement [Member]	City of Hope License Agreement [Member]	City of Hope License Agreement [Member]	City of Hope License Agreement [Member]	Plant Bioscience Limited License Agreement [Member]
					USD ($)	UAH	USD ($)	USD ($)	Minimum [Member]	Maximum [Member]	USD ($)
									USD ($)	USD ($)
Loss Contingencies [Line Items]	'	'	'	'	'	'	'	'	'	'	'
License agreement date	'	'	'	'	'	'	30-Sep-07	'	'	'	30-Sep-13
Annual license maintenance fee and patent costs	'	'	'	'	'	'	'	'	$5,000	$10,000	'
License agreement termination notice period	'	'	'	'	'	'	'90 days	'	'	'	'
License agreement termination description	'	'	'	'	'	'	'The Company may terminate the license agreement at any time upon 90 days written notice to the Medical Center.	'	'	'	'
Research and development expense, related to the agreement	6,806	2,513	12,057	4,931	0	0	0	0	'	'	'
Payments on commencement of clinical trial	'	'	'	'	'	'	'	'	'	'	$100

Subsequent_Event_Additional_In

Subsequent Event - Additional Information (Detail) (Subsequent Event [Member], USD $)	0 Months Ended
	Jul. 11, 2014	Jul. 11, 2014
Subsequent Event [Member]	'	'
Subsequent Event [Line Items]	'	'
Operating lease future minimum payments	'	$9,600,000
Operating lease future minimum payments term	'6 years	'
Letter of credit	'	$1,100,000