Dicerna Pharmaceuticals (DRNA) 10-Q 11 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	8-May-15
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Trading Symbol	DRNA
Entity Registrant Name	DICERNA PHARMACEUTICALS INC
Entity Central Index Key	1399529
Current Fiscal Year End Date	-19
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		17,826,776

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
CURRENT ASSETS:
Cash and cash equivalents	$22,635	$26,067
Held-to-maturity investments	65,035	70,055
Prepaid expenses and other current assets	1,416	1,194
Total current assets	89,086	97,316
NONCURRENT ASSETS:
Property and equipment-net	2,327	2,165
Held-to-maturity investments		2,501
Assets held in restriction	1,116	1,380
Other noncurrent assets	217	243
Total noncurrent assets	3,660	6,289
TOTAL ASSETS	92,746	103,605
CURRENT LIABILITIES:
Accounts payable	1,762	1,237
Accrued expenses and other current liabilities	4,255	3,845
Deferred rent		77
Total current liabilities	6,017	5,159
NONCURRENT LIABILITIES:
Security deposit		106
Total noncurrent liabilities		106
TOTAL LIABILITIES	6,017	5,265
STOCKHOLDERS' EQUITY
Preferred stock, $0.0001 par value-5,000,000 shares authorized at March 31, 2015 and December 31, 2014, respectively; no shares issued and outstanding at March 31, 2015 and December 31, 2014, respectively	0	0
Common stock, $0.0001 par value-150,000,000 shares authorized; 17,822,074 and 17,786,867 shares issued and outstanding at March 31, 2015 and December 31, 2014, respectively	3	3
Additional paid-in capital	234,214	231,741
Accumulated deficit	-147,488	-133,404
Total stockholders' equity	86,729	98,340
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$92,746	$103,605

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Preferred stock, par value	$0.00	$0.00
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	17,822,074	17,786,867
Common stock, shares outstanding	17,822,074	17,786,867

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Operating expenses:
Research and development	$8,692	$5,251
General and administrative	5,445	2,841
Total operating expenses	14,137	8,092
Loss from operations	-14,137	-8,092
Other income (expense):
Interest income	53	4
Interest expense		-157
Preferred stock warrant remeasurement		-2,559
Total other income (expense)	53	-2,712
Net loss	-14,084	-10,804
Less: Accretion and dividends on redeemable convertible preferred stock		204
Net loss attributable to common stockholders	($14,084)	($11,008)
Net loss per share attributable to common stockholders-basic and diluted	($0.79)	($1.02)
Weighted average shares outstanding-basic and diluted	17,815,515	10,822,325

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	($14,084)	($10,804)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	164	170
Net amortization of premium/discount on investments	21
Stock-based compensation	2,320	2,212
Increase in fair value of preferred stock warrant liability		2,559
Changes in operating assets and liabilities:
Prepaid expenses and other assets	17	-635
Accounts payable	525	-621
Accrued expenses and other liabilities	365	682
Deferred rent	25	-9
Net cash used in operating activities	-10,647	-6,446
CASH FLOWS FROM INVESTING ACTIVITIES:
Maturities of investments	7,500
Purchases of property and equipment	-434	-156
Net cash provided by (used in) investing activities	7,066	-156
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from exercised stock options	224	755
Settlement of restricted stock for tax withholding	-75
Net proceeds from initial public offering		94,148
Repayments of long-term debt principal		-1,104
Net cash provided by financing activities	149	93,799
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	-3,432	87,197
CASH AND CASH EQUIVALENTS - Beginning of period	26,067	46,595
CASH AND CASH EQUIVALENTS - End of period	22,635	133,792
SUPPLEMENTAL CASH FLOW INFORMATION:
Warrant conversion to common stock		$3,088

Description_of_Business_and_Ba

Description of Business and Basis of Presentation	3 Months Ended
	Mar. 31, 2015
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 $92,750 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.
	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 a complete set of 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 March 31, 2015 and results of operations and cash flows for the interim periods ended March 31, 2015 and 2014. 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, 2014. The results of the three months ended March 31, 2015 are not necessarily indicative of the results to be expected for the year ending December 31, 2015 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.

Net_Loss_Per_Share_Attributabl

Net Loss Per Share Attributable to Common Stockholders	3 Months Ended
	Mar. 31, 2015
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:
		Three Months Ended March 31,
		2015			2014
	Net loss	$	(14,084	)	$	(10,804	)
	Accretion of preferred stock issuance costs to redemption value		—			(204	)
	Net loss attributable to common stockholders—basic and diluted	$	(14,084	)	$	(11,008	)
	Weighted-average number of common stock outstanding—basic and diluted		17,815,515			10,822,325
	Net loss per share attributable to common stockholders—basic and diluted	$	(0.79	)	$	(1.02	)
	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 due to the losses reported:
		Three Months Ended March 31,
		2015			2014
	Options to purchase common stock		4,174,708			1,532,170
	Warrants to purchase common stock		87,901			58,785
	Warrants to purchase redeemable convertible preferred stock		—			51,762
	Redeemable convertible preferred stock		—			4,118,116
	Unvested restricted stock		84,162			64,163

Heldtomaturity_Investments

Held-to-maturity Investments	3 Months Ended
	Mar. 31, 2015
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 March 31, 2015:	Amortized		Gross		Gross			Fair
		Cost		Unrealized		Unrealized			Value
				Gains		Losses
	Held-to-maturity investments
	U.S. Government treasury and agency securities	$	65,035	$	7	$	(3	)	$	65,039
	Total held-to-maturity investments	$	65,035	$	7	$	(3	)	$	65,039
	At December 31, 2014:	Amortized		Gross		Gross			Fair
		Cost		Unrealized		Unrealized			Value
				Gains		Losses
	Held-to-maturity investments
	U.S. Government treasury and agency securities	$	72,556	$	2	$	(26	)	$	72,532
	Total held-to-maturity investments	$	72,556	$	2	$	(26	)	$	72,532
	The amortized cost and fair value of held-to-maturity investments by contractual maturities at March 31, 2015, are as follows:
		Held-to-Maturity
		Amortized		Fair
		Cost		Value
	Maturing in one year or less	$	65,035	$	65,039
	Total	$	65,035	$	65,039

Longterm_Debt

Long-term Debt	3 Months Ended
	Mar. 31, 2015
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 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 the Series A preferred stock and 26,400 shares of the 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 the 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, which was initially classified as a liability in the financial statements, was reclassified as part of shareholders’ equity upon the conversion of Series A and Series B preferred stock. 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		0.7	%
	Expected dividend yield		0	%
	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 March 31, 2015 and December 31, 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) for the three months ended March 31, 2015 and 2014, respectively.

StockBased_Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	5. Stock-Based Compensation
	Stock options granted to 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 remeasurement until the stock options vest.
	In September 2013, the Company granted stock options to purchase 132,500 shares of common stock to nonemployees with grant date fair value of $337. Based on the terms of the nonemployee stock option agreements the Company recorded a nonemployee stock-based compensation expense of $91 and $1,611 for the three month period ended March 31, 2015 and 2014, respectively. The assumptions used to estimate fair value were as follows:
		Three Months Ended	Three Months Ended
		31-Mar-15	31-Mar-14
	Stock price	$21.32 – $24.43	$28.25 – $41.12
	Expected option term (in years)	5.10 – 5.29	0.25 – 6.86
	Expected volatility	68%	56% –72 %
	Risk-free interest rate	1.20% – 1.50%	0.08% – 2.29%
	Expected dividend yield	0.00%	0.00%
	As of March 31, 2015, there were 39,375 unvested stock options held by nonemployees.
	Stock options granted to employees
	During the three month periods ended March 31, 2015 and 2014, the Company granted stock options to purchase 639,426 and 0 shares, respectively, of common stock to employees with grant-date fair values of $7.5 million and $0, respectively. The Company recorded employee stock-based compensation expense of $2,229 and $601 for the three month periods ended March 31, 2015 and 2014, respectively. The assumptions used to estimate the grant-date fair value were as follows:
		Three Months Ended
		March 31, 2015
	Stock price	$18.50 – $24.03
	Expected option term (in years)	6.25
	Expected volatility	68%
	Risk-free interest rate	1.51% – 1.58%
	Expected dividend yield	0.00%

Redeemable_Convertible_Preferr

Redeemable Convertible Preferred Stock	3 Months Ended
	Mar. 31, 2015
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 months ended March 31, 2015 and 2014, respectively.

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2015
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 unadjusted 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.
	A summary of the Company’s assets that are measured or disclosed at fair value as at March 31, 2015 and December 31, 2014 are presented below:
	Description	At March 31,			Level 1		Level 2		Level 3
		2015
	Cash equivalents
	Money market fund	$	17,980		$	17,980	$	—	$	—
	Held-to-maturity investments
	U.S. treasury securities and government agency bonds		65,039			—		65,039		—
	Assets held in restriction
	Money market fund		1,116			—		1,116		—
	Other current assets
	Certificate of deposit		264			—		264		—
	Total	$	84,399		$	17,980	$	66,419	$	—
	Description	At December 31,			Level 1		Level 2		Level 3
		2014
	Cash equivalents
	Money market fund	$	20,425		$	20,425	$	—	$	—
	Held-to-maturity investments
	U.S. treasury securities and government agency bonds		72,532			—		72,532		—
	Assets held in restriction
	Money market fund and certificate of deposit		1,380			—		1,380		—
	Total	$	94,337		$	20,425	$	73,912	$	—
	The Company’s cash equivalents, primarily money market accounts are classified within Level 1 of the fair value hierarchy because they are valued using quoted prices as of March 31, 2015 and December 31, 2014, 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 March 31, 2015 and December 31, 2014, respectively.
	The Company’s held-to-maturity investments bore interest at the prevailing market rates for instruments with similar characteristics. 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 March 31, 2015 and December 31, 2014, respectively.
	For the three month periods ended March 31, 2015 and 2014, there were no transfers between Level 1 and Level 2.
	The fair value of the preferred stock warrant liability was determined using the Black-Scholes option-pricing model until the IPO conversion date of February 4, 2014. After the closing of the IPO, the remaining preferred stock warrant liability was no longer subject to remeasurement as the warrants to purchase the Company’s preferred stock became warrants to purchase shares of the Company’s common stock. As of the IPO closing date, the fair value of the preferred stock warrants was based significantly on the fair value of the Company’s publicly traded common stock and other observable inputs and was reclassified to Level 2.
	The fair value of the preferred stock warrant prior to the closing of the IPO was based significantly on the fair value of the preferred stock, which was developed using unobservable inputs, and was classified within 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—March 31, 2014	$	—
	There were no preferred stock warrants outstanding as of March 31, 2015 and December 31, 2014.

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	8. Commitments and Contingencies
	Facility lease
	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 $9,498 over a six-year lease term. The lease commenced on December 1, 2014. As part of the lease agreement, the Company established a $1,116 letter of credit, secured by a money market account which is included in assets held in restriction at March 31, 2015 and December 31, 2014.
	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 pay an annual license maintenance fee, 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 months ended March 31, 2015 and 2014, respectively.
	Plant Bioscience Limited 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. During 2014, the Company paid $100 to PBL based on meeting a clinical milestone. In addition, PBL is entitled to receive royalties of any net sale revenue of any licensed product candidates sold by the Company. The Company did not record any research and development expense, related to this agreement, during the three months ended March 31, 2015 and 2014, respectively.
	Tekmira Pharmaceuticals Corporation license agreement
	In November 2014, the Company signed a licensing and collaboration agreement with Tekmira Pharmaceuticals Corporation (Tekmira) to license Tekmira’s LNP delivery technology for exclusive use in the Company’s primary hyperoxaluria type 1 (PH1) development program. The Company will use Tekmira’s LNP technology to deliver DCR-PH1, for the treatment of PH1. As of March 31, 2015, the Company paid $3,000 in license fees. Tekmira is entitled to receive additional payments of $22,000 in aggregate development milestones, plus a mid-single-digit royalty on future PH1 sales. This partnership also includes a supply agreement with Tekmira providing clinical drug supply and regulatory support.

Subsequent_Event

Subsequent Event	3 Months Ended
	Mar. 31, 2015
Subsequent Events [Abstract]
Subsequent Event	9. Subsequent Event
	On April 9, 2015, the Company terminated its lease and sub-lease at 480 Arsenal Street in Watertown. The transactions did not have a material impact on the Company’s financial statements. The Company expects the associated letter of credit to be cancelled during the second quarter of 2015. Assets held in restriction, in the amount of a $264 certificate of deposit, have been reclassified to other current assets as of March 31, 2015.

Description_of_Business_and_Ba1

Description of Business and Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2015
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 $92,750 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.
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 a complete set of 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 March 31, 2015 and results of operations and cash flows for the interim periods ended March 31, 2015 and 2014. 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, 2014. The results of the three months ended March 31, 2015 are not necessarily indicative of the results to be expected for the year ending December 31, 2015 or for any other interim period or for any other future year.
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.

Net_Loss_Per_Share_Attributabl1

Net Loss Per Share Attributable to Common Stockholders (Tables)	3 Months Ended
	Mar. 31, 2015
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:
		Three Months Ended March 31,
		2015			2014
	Net loss	$	(14,084	)	$	(10,804	)
	Accretion of preferred stock issuance costs to redemption value		—			(204	)
	Net loss attributable to common stockholders—basic and diluted	$	(14,084	)	$	(11,008	)
	Weighted-average number of common stock outstanding—basic and diluted		17,815,515			10,822,325
	Net loss per share attributable to common stockholders—basic and diluted	$	(0.79	)	$	(1.02	)
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 due to the losses reported:
		Three Months Ended March 31,
		2015			2014
	Options to purchase common stock		4,174,708			1,532,170
	Warrants to purchase common stock		87,901			58,785
	Warrants to purchase redeemable convertible preferred stock		—			51,762
	Redeemable convertible preferred stock		—			4,118,116
	Unvested restricted stock		84,162			64,163

Heldtomaturity_Investments_Tab

Held-to-maturity Investments (Tables)	3 Months Ended
	Mar. 31, 2015
Text Block [Abstract]
Schedule of Held-To-Maturity Investments	The following tables provide information relating to held-to-maturity investments:
	At March 31, 2015:	Amortized		Gross		Gross			Fair
		Cost		Unrealized		Unrealized			Value
				Gains		Losses
	Held-to-maturity investments
	U.S. Government treasury and agency securities	$	65,035	$	7	$	(3	)	$	65,039
	Total held-to-maturity investments	$	65,035	$	7	$	(3	)	$	65,039
	At December 31, 2014:	Amortized		Gross		Gross			Fair
		Cost		Unrealized		Unrealized			Value
				Gains		Losses
	Held-to-maturity investments
	U.S. Government treasury and agency securities	$	72,556	$	2	$	(26	)	$	72,532
	Total held-to-maturity investments	$	72,556	$	2	$	(26	)	$	72,532
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 March 31, 2015, are as follows:
		Held-to-Maturity
		Amortized		Fair
		Cost		Value
	Maturing in one year or less	$	65,035	$	65,039
	Total	$	65,035	$	65,039

Longterm_Debt_Tables

Long-term Debt (Tables)	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Summary of Estimated Fair Values of Outstanding Warrants Using 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		0.7	%
	Expected dividend yield		0	%

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2015
Stock Options Granted to Nonemployees [Member]
Schedule of Valuation Assumptions	The assumptions used to estimate fair value were as follows:
		Three Months Ended	Three Months Ended
		31-Mar-15	31-Mar-14
	Stock price	$21.32 – $24.43	$28.25 – $41.12
	Expected option term (in years)	5.10 – 5.29	0.25 – 6.86
	Expected volatility	68%	56% –72 %
	Risk-free interest rate	1.20% – 1.50%	0.08% – 2.29%
	Expected dividend yield	0.00%	0.00%
Employee Stock Option
Schedule of Valuation Assumptions	The assumptions used to estimate the grant-date fair value were as follows:
		Three Months Ended
		March 31, 2015
	Stock price	$18.50 – $24.03
	Expected option term (in years)	6.25
	Expected volatility	68%
	Risk-free interest rate	1.51% – 1.58%
	Expected dividend yield	0.00%

Redeemable_Convertible_Preferr1

Redeemable Convertible Preferred Stock (Tables) (Series C Redeemable Convertible Preferred Stock [Member])	3 Months Ended
	Mar. 31, 2015
Series C Redeemable Convertible Preferred Stock [Member]
Summary of Estimated Fair Values of Outstanding Warrants Using Black-Scholes Option-Pricing Model	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)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Schedule of Assets Measured or Disclosed at Fair Value	A summary of the Company’s assets that are measured or disclosed at fair value as at March 31, 2015 and December 31, 2014 are presented below:
	Description	At March 31,			Level 1		Level 2		Level 3
		2015
	Cash equivalents
	Money market fund	$	17,980		$	17,980	$	—	$	—
	Held-to-maturity investments
	U.S. treasury securities and government agency bonds		65,039			—		65,039		—
	Assets held in restriction
	Money market fund		1,116			—		1,116		—
	Other current assets
	Certificate of deposit		264			—		264		—
	Total	$	84,399		$	17,980	$	66,419	$	—
	Description	At December 31,			Level 1		Level 2		Level 3
		2014
	Cash equivalents
	Money market fund	$	20,425		$	20,425	$	—	$	—
	Held-to-maturity investments
	U.S. treasury securities and government agency bonds		72,532			—		72,532		—
	Assets held in restriction
	Money market fund and certificate of deposit		1,380			—		1,380		—
	Total	$	94,337		$	20,425	$	73,912	$	—
Schedule of Roll-Forward of Company's Liabilities Measured at Fair Value on Recurring Basis Using Unobservable Inputs (Level 3)	The fair value of the preferred stock warrant prior to the closing of the IPO was based significantly on the fair value of the preferred stock, which was developed using unobservable inputs, and was classified within 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—March 31, 2014	$	—

Description_of_Business_and_Ba2

Description of Business and Basis of Presentation - Additional Information (Detail) (USD $)	3 Months Ended		1 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Feb. 28, 2014
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Proceeds from issuance of common stock		$94,148
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.
IPO [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Common stock shares issued			6,900,000
Sale of stock price per share			$15
Proceeds from issuance of common stock			92,750
Underwriting discounts and commissions			7,245
Offering expenses			$3,506

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
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share [Abstract]
Net loss	($14,084)	($10,804)
Accretion of preferred stock issuance costs to redemption value		-204
Net loss attributable to common stockholders-basic and diluted	($14,084)	($11,008)
Weighted-average number of common stock outstanding-basic and diluted	17,815,515	10,822,325
Net loss per share attributable to common stockholders-basic and diluted	($0.79)	($1.02)

Net_Loss_Per_Share_Attributabl3

Net Loss Per Share Attributable to Common Stockholders - Schedule of Dilutive Securities Outstanding (Detail)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Options to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities	4,174,708	1,532,170
Hercules Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities	87,901	58,785
Warrants to Purchase Redeemable Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities		51,762
Redeemable Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities		4,118,116
Unvested Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities	84,162	64,163

HeldtoMaturity_Investments_Sch

Held-to-Maturity Investments - Schedule of Held-to-Maturity Investments (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
In Thousands, unless otherwise specified
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity investments, Amortized Cost	$65,035		$72,556
Held-to-maturity investments, Gross Unrealized Gains	7		2
Held-to-maturity investments, Gross Unrealized Losses	-3		-26
Held-to-maturity investments, Fair Value, Total	65,039		72,532
U.S. Government Treasury and Agency Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity investments, Amortized Cost	65,035		72,556
Held-to-maturity investments, Gross Unrealized Gains	7		2
Held-to-maturity investments, Gross Unrealized Losses	-3		-26
Held-to-maturity investments, Fair Value, Total	$65,039	$72,532	$72,532

HeldtoMaturityInvestments_Amor

Held-to-Maturity-Investments - Amortized Cost and Fair Value of Held-to-Maturity Investments (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
In Thousands, unless otherwise specified
Investments, Debt and Equity Securities [Abstract]
Held-to-Maturity securities, Maturing in one year or less, Amortized Cost	$65,035	$70,055
Held to Maturity, Amortized Cost, Total	65,035		72,556
Held-to-Maturity securities, Maturing in one year or less, Fair Value	65,039
Held-to-Maturity, Fair Value, Total	$65,039		$72,532

Longterm_Debt_Additional_Infor

Long-term Debt - Additional Information (Detail) (USD $)	3 Months Ended		0 Months Ended
	Mar. 31, 2014	Mar. 31, 2015	Dec. 15, 2011	Jun. 28, 2011	Apr. 07, 2014	Dec. 31, 2014	Feb. 04, 2014	Mar. 26, 2009	Dec. 31, 2013	Feb. 11, 2014
Debt Instrument [Line Items]
Loan and security agreement								$7,000,000
Estimated fair value of outstanding warrants							765,000
Common stock issued, shares		17,822,074				17,786,867
Adjustment to preferred stock warrant liability recorded in other income (expense)	-2,559,000
Hercules Warrants [Member]
Debt Instrument [Line Items]
Adjustment to preferred stock warrant liability recorded in other income (expense)	-671,000	0
Series A Warrants [Member]
Debt Instrument [Line Items]
Estimated fair value of outstanding warrants		0				0
Series B Warrants [Member]
Debt Instrument [Line Items]
Estimated fair value of outstanding warrants		0				0
Second Amendment [Member]
Debt Instrument [Line Items]
Loan and security agreement				12,000,000
Loan drew in advance			5,000,000	7,000,000
Annual interest rate									10.15%
Principal monthly installments period		April 1, 2012 through January 2, 2015
Hercules Loan [Member]
Debt Instrument [Line Items]
Repayment of debt					$3,590,000
IPO closing date		4-Feb-14
Common stock issued, shares										12,702
Hercules Loan [Member] | Series A Warrants [Member]
Debt Instrument [Line Items]
Warrants exercised, number of shares		21,000
Warrants exercised, exercise price		$25
Hercules Loan [Member] | Series B Warrants [Member]
Debt Instrument [Line Items]
Warrants exercised, number of shares		26,400
Warrants exercised, exercise price		$25

Longterm_Debt_Summary_of_Estim

Long-term Debt - Summary of Estimated Fair Values of Outstanding Warrants Using Black-Scholes Option-Pricing Model (Detail) (Hercules Warrants [Member], USD $)	0 Months Ended
	Feb. 04, 2014	Feb. 04, 2014
Hercules Warrants [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Stock price	$32.66	$32.66
Expected option term (in years)	3 years
Expected volatility	62.00%
Risk-free interest rate	0.70%
Expected dividend yield	0.00%

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013	Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$2,320	$2,212
Nonemployee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option, granted	132,500
Stock options, granted fair value	337
Stock-based compensation expense		91	1,611
Unvested stock options		39,375
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option, granted		639,426	0
Stock-based compensation expense		2,229	601
Fair value of stock options		$7,500	$0

StockBased_Compensation_Schedu

Stock-Based Compensation - Schedule of Valuation Assumptions (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Nonemployee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	68.00%
Expected dividend yield	0.00%	0.00%
Nonemployee Stock Option [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock price	21.32	28.25
Expected option term (in years)	5 years 1 month 6 days	3 months
Expected volatility		56.00%
Risk-free interest rate	1.20%	0.08%
Nonemployee Stock Option [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock price	24.43	41.12
Expected option term (in years)	5 years 3 months 15 days	6 years 10 months 10 days
Expected volatility		72.00%
Risk-free interest rate	1.50%	2.29%
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected option term (in years)	6 years 3 months
Expected volatility	68.00%
Expected dividend yield	0.00%
Employee Stock Option | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock price	18.5
Risk-free interest rate	1.51%
Employee Stock Option | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock price	24.03
Risk-free interest rate	1.58%

Redeemable_Convertible_Preferr2

Redeemable Convertible Preferred Stock - Additional Information (Detail) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2015	Dec. 31, 2014	Feb. 04, 2014
Conversion of Stock [Line Items]
Issuance of common stock		17,822,074	17,786,867
Adjustment to preferred stock warrant liability recorded in other income (expense)	($2,559)
Redeemable Convertible Preferred Stock [Member]
Conversion of Stock [Line Items]
Issuance of common stock				10,589,434
Series C Preferred Stock [Member]
Conversion of Stock [Line Items]
Fair value of preferred stock warrants				2,323
Adjustment to preferred stock warrant liability recorded in other income (expense)	($1,888)	$0

Redeemable_Convertible_Preferr3

Redeemable Convertible Preferred Stock - Summary of Estimated Fair Values of Outstanding Warrants Using Black-Scholes Option-Pricing Model (Detail) (Series C Redeemable Convertible Preferred Stock [Member], USD $)	0 Months Ended
	Feb. 04, 2014	Feb. 04, 2014
Series C Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Stock price	$32.66	$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_Schedu

Fair Value Measurements - Schedule of Assets Measured or Disclosed at Fair Value (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
In Thousands, unless otherwise specified
Held-to-maturity investments
U.S. treasury securities and government agency bonds	$65,039		$72,532
Assets held in restriction
Total	84,399	94,337
Other current assets
Total	84,399	94,337
Money Market Fund [Member]
Cash equivalents
Money market fund	17,980	20,425
Assets held in restriction
Restricted investments, at fair value	1,116
Certificate of Deposit [Member]
Other current assets
Certificate of deposit	264
Money Market Funds And Certificate Of Deposit [Member]
Assets held in restriction
Restricted investments, at fair value		1,380
U.S. Government Treasury and Agency Securities [Member]
Held-to-maturity investments
U.S. treasury securities and government agency bonds	65,039	72,532	72,532
Level 1[Member]
Assets held in restriction
Total	17,980	20,425
Other current assets
Total	17,980	20,425
Level 1[Member] | Money Market Fund [Member]
Cash equivalents
Money market fund	17,980	20,425
Level 2 [Member]
Assets held in restriction
Total	66,419	73,912
Other current assets
Total	66,419	73,912
Level 2 [Member] | Money Market Fund [Member]
Assets held in restriction
Restricted investments, at fair value	1,116
Level 2 [Member] | Certificate of Deposit [Member]
Other current assets
Certificate of deposit	264
Level 2 [Member] | Money Market Funds And Certificate Of Deposit [Member]
Assets held in restriction
Restricted investments, at fair value		1,380
Level 2 [Member] | U.S. Government Treasury and Agency Securities [Member]
Held-to-maturity investments
U.S. treasury securities and government agency bonds	$65,039	$72,532

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Debt Instrument Fair Value Carrying Value [Abstract]
Transfers between Level 1 and Level 2	$0		$0
Preferred stock conversion date	4-Feb-14
Preferred stock, warrants outstanding	0	0

Fair_Value_Measurements_Schedu1

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
In Thousands, unless otherwise specified	Mar. 31, 2014
Debt Instrument Fair Value Carrying Value [Abstract]
Balance at the beginning of the period	$529
Change in fair value of warrant liability	2,559
Transfers to Level 2	($3,088)

Commitments_and_Contingencies_

Commitments and Contingencies - Additional Information (Detail) (USD $)	3 Months Ended		0 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Jul. 11, 2014	Dec. 01, 2014
Loss Contingencies [Line Items]
Research and development expense	$8,692,000	$5,251,000
Cambridge Massachusetts , 2014 Operating Lease Agreement [Member]
Loss Contingencies [Line Items]
Operating lease future minimum payments			9,498,000
Operating lease future minimum payments term			6 years
Letter of credit				1,116,000
Deferred rent obligation			1-Dec-14
City of Hope License Agreement [Member]
Loss Contingencies [Line Items]
License agreement date	30-Sep-07
Termination of license agreement description	The Company may terminate the license agreement at any time upon 90 days written notice
City of Hope License Agreement [Member] | Minimum [Member]
Loss Contingencies [Line Items]
License fee	5,000,000
City of Hope License Agreement [Member] | Maximum [Member]
Loss Contingencies [Line Items]
License fee	10,000,000
Research and development expense	0	0
Plant Bioscience Limited License Agreement [Member]
Loss Contingencies [Line Items]
License agreement date	30-Sep-13
Research and development expense	0	0
Payments on commencement of clinical trial	100,000
Tekmira [Member]
Loss Contingencies [Line Items]
License fee	3,000,000
Aggregate development milestones and royalty	$22,000,000

Subsequent_Event_Additional_In

Subsequent Event - Additional Information (Detail) (Certificate of Deposit [Member], USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified
Certificate of Deposit [Member]
Subsequent Event [Line Items]
Other assets	$264