Regulus Therapeutics (RGLS) 10-Q 14 Nov 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2013	Nov. 08, 2013
Document Information [Line Items]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-13	'
Document Fiscal Year Focus	'2013	'
Document Fiscal Period Focus	'Q3	'
Trading Symbol	'RGLS	'
Entity Registrant Name	'REGULUS THERAPEUTICS INC.	'
Entity Central Index Key	'0001505512	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Smaller Reporting Company	'
Entity Common Stock, Shares Outstanding	'	41,777,326

Condensed_Balance_Sheets

Condensed Balance Sheets (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$33,490	$40,552
Short-term investments	90,413	57,548
Contracts and other receivables	95	'
Prepaid and other current assets	1,288	829
Total current assets	125,286	98,929
Property and equipment, net	3,981	3,310
Intangibles, net	1,145	1,154
Other assets	178	125
Total assets	130,590	103,518
Current liabilities:	'	'
Accounts payable	1,140	311
Accrued liabilities	1,705	658
Accrued compensation	1,228	1,348
Current portion of deferred revenue	9,454	10,451
Total current liabilities	13,527	12,768
Convertible notes payable, at fair value	13,921	10,134
Deferred revenue, less current portion	7,138	17,756
Other long-term liabilities	1,558	767
Total liabilities	36,144	41,425
Stockholders' equity:	'	'
Common stock, $0.001 par value; 200,000,000 shares authorized, 41,774,442 and 35,831,808 shares issued and outstanding at September 30, 2013 (unaudited) and December 31, 2012, respectively	42	36
Additional paid-in capital	171,608	122,528
Accumulated other comprehensive loss	-44	-52
Accumulated deficit	-77,160	-60,419
Total stockholders' equity	94,446	62,093
Total liabilities and stockholders' equity	$130,590	$103,518

Condensed_Balance_Sheets_Paren

Condensed Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	41,774,442	35,831,808
Common stock, shares outstanding	41,774,442	35,831,808

Condensed_Statements_of_Operat

Condensed Statements of Operations and Comprehensive Loss (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues:	'	'	'	'
Total revenues	$6,118	$2,809	$14,115	$9,462
Operating expenses:	'	'	'	'
Research and development	7,106	5,248	21,710	14,735
General and administrative	1,917	1,093	5,545	2,998
Total operating expenses	9,023	6,341	27,255	17,733
Loss from operations	-2,905	-3,532	-13,140	-8,271
Other income (expense):	'	'	'	'
Interest and other income	72	20	207	74
Interest expense	-7	-110	-25	-294
Loss on extinguishment of debt	'	-1,738	'	-1,738
Gain (loss) from changes in valuation of convertible note payable	671	-331	-3,787	-331
Loss before income taxes	-2,169	-5,691	-16,745	-10,560
Income tax benefit	-5	-6	-4	-28
Net loss	-2,164	-5,685	-16,741	-10,532
Other comprehensive loss:	'	'	'	'
Unrealized gain on short-term investments, net	37	10	8	44
Comprehensive loss	-2,127	-5,675	-16,733	-10,488
Net loss per share:	'	'	'	'
Basic	($0.05)	($15.98)	($0.45)	($41.03)
Diluted	($0.07)	($15.98)	($0.45)	($41.03)
Weighted average shares used to compute net loss per share:	'	'	'	'
Basic	40,154,812	355,735	37,367,368	256,682
Diluted	41,555,660	355,735	37,367,368	256,682
Strategic Alliances and Collaborations	'	'	'	'
Revenues:	'	'	'	'
Total revenues	$6,118	$2,809	$14,115	$9,462

Condensed_Statements_of_Cash_F

Condensed Statements of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Operating activities	'	'
Net loss	($16,741)	($10,532)
Adjustments to reconcile net loss to net cash used in operating activities	'	'
Depreciation and amortization expense	996	741
Loss on extinguishment of debt	'	1,738
Loss from valuation of convertible note payable	3,787	331
Stock-based compensation	2,524	732
Amortization of premium on investments, net	1,018	311
Gain on investments	-6	'
Change in operating assets and liabilities:	'	'
Contracts and other receivables	-95	-3,000
Prepaid and other assets	-512	56
Accounts payable	829	148
Accrued liabilities	851	73
Accrued compensation	-120	302
Deferred revenue	-11,615	-527
Deferred rent and other liabilities	68	55
Net cash used in operating activities	-19,016	-9,572
Investing activities	'	'
Purchases of short-term investments	-50,390	-9,287
Maturities and sales of short-term investments	16,520	24,550
Purchases of property and equipment	-608	-724
Acquisition of intangibles	-46	-185
Net cash (used in) provided by investing activities	-34,524	14,354
Financing activities	'	'
Proceeds from issuance of common stock, net	46,562	102
Proceeds from issuance of convertible notes payable	'	5,000
Principal payments on other long-term obligations	-84	-326
Costs paid in connection with initial public offering	'	-1,307
Net cash provided by financing activities	46,478	3,469
Net (decrease) increase in cash and cash equivalents	-7,062	8,251
Cash and cash equivalents at beginning of period	40,552	9,175
Cash and cash equivalents at end of period	33,490	17,426
Supplemental disclosure of cash flow information	'	'
Interest paid	'	32
Income taxes paid	1	207
Supplemental disclosure of non-cash investing and financing activities	'	'
Amounts accrued for property and equipment, net	57	'
Amounts accrued for patent expenditures, net	'	$10

Basis_of_Presentation_and_Summ

Basis of Presentation and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2013
Basis of Presentation and Summary of Significant Accounting Policies	'
	1. Basis of Presentation and Summary of Significant Accounting Policies
	Basis of Presentation
	The accompanying unaudited condensed financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In management’s opinion, the accompanying financial statements reflect all adjustments, consisting of normal recurring adjustments, considered necessary for a fair presentation of the results for the interim periods presented.
	Interim financial results are not necessarily indicative of results anticipated for the full year. These unaudited condensed financial statements should be read in conjunction with the audited financial statements and footnotes included in the Annual Report on Form 10-K for the year ended December 31, 2012 for Regulus Therapeutics Inc. (“we,” “us,” “our,” or the “Company”), from which the balance sheet information herein for the year ended December 31, 2012 was derived.
	On September 7, 2012, our board of directors approved a one-for-two reverse stock split of our common stock. The accompanying condensed financial statements and notes to the condensed financial statements give retroactive effect to the reverse split for all periods presented. No further splits (or reverse splits) of our common stock have been contemplated as of September 30, 2013.
	In October 2012, we completed an initial public offering and concurrent private placement of 18,980,982 shares of common stock at an offering price of $4.00 per share. In addition, principal and interest of $10.8 million from convertible notes outstanding were automatically converted upon the closing of the initial public offering into an aggregate of 2,703,269 shares of our common stock. We raised a total of $70.0 million in net proceeds from our initial public offering and concurrent private placement, after deducting underwriter discounts, commissions and other offering expenses.
	In July 2013, we completed a public offering of 5,175,000 shares of common stock at an offering price of $9.50 per share. The shares were registered pursuant to a registration statement on Form S-1. We raised a total of $45.8 million in net proceeds, after deducting underwriting discounts, commissions and other offering expenses.
	Use of Estimates
	Our financial statements are prepared in accordance with GAAP. The preparation of our financial statements requires us to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities in our financial statements and accompanying notes. Although these estimates are based on our knowledge of current events and actions we may undertake in the future, actual results may ultimately differ from these estimates and assumptions.
	Revenue Recognition
	As of September 30, 2013, we have ongoing strategic alliance agreements and collaborations with GlaxoSmithKline plc (“GSK”), Sanofi, AstraZeneca AB (“AstraZeneca”) and Biogen Idec MA Inc. (“Biogen Idec”). Our revenues generally consist of upfront payments for licenses or options to obtain licenses in the future, research and development funding and milestone payments. We recognize revenues when all four of the following criteria are met: (1) persuasive evidence that an arrangement exists; (2) delivery of the products and/or services has occurred; (3) the selling price is fixed or determinable; and (4) collectability is reasonably assured.
	For these multiple element arrangements, deliverables under our agreements are accounted for as separate units of accounting provided that (i) a delivered item has value to the customer on a stand-alone basis; and (ii) if the agreement includes a general right of return relative to the delivered item, delivery or performance of the undelivered item is considered probable and substantially in the control of the vendor. The allocation of consideration amongst the units of accounting under our strategic alliance agreements and collaborations are derived using a “best estimate of selling price” if vendor specific objective evidence and third-party evidence of fair value is not available.
	Milestones
	We recognize revenue from milestone payments when earned, provided that (i) the milestone event is substantive in that it can only be achieved based in whole or in part on either our performance or on the occurrence of a specific outcome resulting from our performance and its achievability was not reasonably assured at the inception of the agreement; (ii) we do not have ongoing performance obligations related to the achievement of the milestone; and (iii) it would result in the receipt of additional payments. A milestone payment is considered substantive if all of the following conditions are met: (i) the milestone payment is non-refundable; (ii) achievement of the milestone was not reasonably assured at the inception of the arrangement; (iii) substantive effort is involved to achieve the milestone; and (iv) the amount of the milestone payments appears reasonable in relation to the effort expended, the other milestones in the arrangement and the related risk associated with the achievement of the milestone. Any amounts received under the agreements in advance of performance, if deemed substantive, are recorded as deferred revenue and recognized as revenue as we complete our performance obligations.
	Generally, the milestone events contained in our strategic alliance agreements and collaborations coincide with the progression of our product candidates from target selection, to clinical candidate selection, to clinical trial, to regulatory approval and then to commercialization. The process of successfully discovering a new development candidate, having it approved and ultimately sold for a profit is highly uncertain. As such, the milestone payments we may earn from our partners involve a significant degree of risk to achieve. Therefore, as a product candidate progresses through the stages of its life-cycle, the value of the product candidate generally increases.
	Deferred Revenue
	Amounts received prior to satisfying the above revenue recognition criteria are recorded as deferred revenue in the accompanying condensed balance sheets. Amounts not expected to be recognized within the next 12 months are classified as non-current deferred revenue.
	Stock-Based Compensation
	We account for stock-based compensation expense related to stock options granted to employees and members of our board of directors by estimating the fair value of each stock option on the date of grant using the Black-Scholes model. We recognize stock-based compensation expense using the accelerated multiple-option approach. Under the accelerated multiple-option approach (also known as the graded-vesting method), we recognize compensation expense over the requisite service period for each separately vesting tranche of the award as though the award was in substance multiple awards, resulting in accelerated expense recognition over the vesting period.
	We account for stock options granted to non-employees other than members of our board of directors, which primarily consist of members of our scientific advisory board, using the fair value approach. Stock options granted to non-employees are subject to periodic revaluation over their vesting terms.
	Fair Value Option
	Applicable accounting guidance permits entities to choose, at specified election dates, to measure specified items at fair value if the decision about the election is: 1) applied instrument by instrument, 2) irrevocable, and 3) applied to an entire instrument.
	In July 2012, we amended and restated our $5.0 million convertible promissory note originally issued in February 2010 to GSK (“2010 GSK Note”), which was accounted for as a debt extinguishment of the original note. We elected to measure the 2010 GSK Note under the fair value option. Upon initial measurement, the difference between the carrying value of the original note and the fair value of the 2010 GSK Note was recorded as a loss on extinguishment of debt to non-operating earnings. Thereafter, any change to the fair value of the 2010 GSK Note is recorded as a gain (loss) from valuation of convertible note payable to non-operating earnings.
	Recent Accounting Pronouncements
	In February 2013, the FASB issued Accounting Standards Update No. 2013-02, Comprehensive Income (Topic 220): Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income (“ASU 2013-02”). This update will require companies to present information about amounts reclassified out of accumulated other comprehensive income and their corresponding effect on net income in one place and reference the amounts to the related footnote disclosures. Current accounting standards present this information in different places throughout the financial statements. ASU 2013-02 was effective for us for the nine months ended September 30, 2013. The adoption of ASU 2013-02 had no impact on our financial condition, results of operations, or cash flows.
	In July 2013, the FASB issued Accounting Standards Update No. 2013-11, Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists (“ASU 2013-11”). This update provides explicit guidance on the financial statement presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. This guidance is effective prospectively for fiscal years, and interim periods within those years, beginning after December 15, 2013, with an option for early adoption. We intend to adopt this guidance in 2014, and do not believe the adoption of this standard will have a material impact on our financial condition, results of operations or related financial statement disclosures.

Net_Loss_Per_Share

Net Loss Per Share	9 Months Ended
	Sep. 30, 2013
Net Loss Per Share	'
	2. Net Loss Per Share
	Basic net loss per share is calculated by dividing the net loss by the weighted average number of common shares outstanding for the period, without consideration for common stock equivalents. Diluted net loss per share is calculated by dividing the net loss by the weighted average number of common stock equivalents outstanding for the period determined using the treasury-stock method. Dilutive common stock equivalents are comprised of convertible preferred stock, options outstanding under our stock option plan and convertible notes payable. Applicable accounting guidance provides that a contract that is reported as an asset or liability for accounting purposes may require an adjustment to the numerator of the diluted earnings per share calculation for any changes in income or loss that would result if the contract had been reported as an equity instrument for accounting purposes during the period. Securities are assumed to be converted at the beginning of the period, and the resulting common shares are included in the denominator of the diluted earnings per share calculation for the entire period presented. Adding back the gain from the change in valuation of the convertible note payable for the three months ended September 30, 2013 to the numerator and adding the number of shares to be issued upon conversion of the convertible note payable into the denominator of the diluted earnings per share calculation resulted in an increase to the loss per share for the period. The convertible note payable was anti-dilutive for the nine months ended September 30, 2013.
	The following table summarizes the adjustment to net loss for the diluted net loss per share calculation for the three months ended September 30, 2013 (in thousands):
	Net loss	$	(2,164	)
	Less: gain from change in valuation of note payable		671
	Net loss used to compute diluted net loss per share	$	(2,835	)
	Potentially dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive are as follows (in common equivalent shares):
		Three months ended					Nine months ended
		September 30,					September 30,
		2013			2012		2013		2012
	Convertible preferred stock outstanding		—			13,699,999		—		13,699,999
	Common stock options		3,041,033			2,845,675		2,474,614		2,823,463
	Convertible note payable		—			—		1,400,848		—
	Total		3,041,033			16,545,674		3,875,462		16,523,462
	In October 2012, all convertible preferred stock converted into common stock in conjunction with our initial public offering. As of September 30, 2013 we had a convertible note payable outstanding with a principal balance of $5.4 million that was convertible into common shares at $4.00 per share, at the option of the note holder.

Investments

Investments	9 Months Ended
	Sep. 30, 2013
Investments	'
	3. Investments
	We invest our excess cash in commercial paper and debt instruments of financial institutions, corporations, U.S. government-sponsored agencies, and the U.S. Treasury. For investments in debt securities with unrealized losses, we do not intend to sell these investments, nor is it more than likely that we will be required to do so, prior to the recovery of their amortized cost basis, which may be their maturity. As of September 30, 2013, our short-term investments had a weighted average maturity of less than two years.
	The following tables summarize our short-term investments (dollars in thousands):
		Maturity		Amortized		Unrealized					Estimated
		(in years)		cost		Gains		Losses			fair value
	As of September 30, 2013
	Corporate debt securities		2 or less	$	68,649	$	18	$	(50	)	$	68,617
	Commercial paper		1 or less		999		—		—			999
	Certificates of deposit		2 or less		13,770		—		—			13,770
	Debt securities of U.S. government-sponsored agencies		1 or less		7,025		2		—			7,027
	Total			$	90,443	$	20	$	(50	)	$	90,413
		Maturity		Amortized		Unrealized					Estimated
		(in years)		cost		Gains		Losses			fair value
	As of December 31, 2012
	Corporate debt securities		2 or less	$	44,898	$	7	$	(49	)	$	44,856
	Commercial paper		2 or less		6,492		—		—			6,492
	Certificates of deposit		1 or less		6,200		—		—			6,200
	Total			$	57,590	$	7	$	(49	)	$	57,548

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2013
Fair Value Measurements	'
	4. Fair Value Measurements
	We have certain financial assets and liabilities recorded at fair value which have been classified as Level 1, 2 or 3 within the fair value hierarchy as described in the accounting standards for fair value measurements.
	Applicable accounting guidance defines fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants as of the measurement date. Market participants are buyers and sellers in the principal market that are (i) independent, (ii) knowledgeable, (iii) able to transact, and (iv) willing to transact. The guidance provides an established hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available. Observable inputs are inputs that market participants would use in valuing the asset or liability and are developed based on market data obtained from independent sources. Unobservable inputs are inputs that reflect our assumptions about the factors that market participants would use in valuing the asset or liability. The guidance prioritizes the inputs used in measuring the fair value into the following hierarchy:
		•		Level 1 includes financial instruments for which quoted market prices for identical instruments are available in active markets.
		•		Level 2 includes financial instruments for which there are inputs other than quoted prices included within Level 1 that are observable for the instrument such as quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets with insufficient volume or infrequent transactions (less active markets) or model-driven valuations in which significant inputs are observable or can be derived principally from, or corroborated by, observable market data.
		•		Level 3 includes financial instruments for which fair value is derived from valuation techniques in which one or more significant inputs are unobservable, including management’s own assumptions.
	The following table presents our fair value hierarchy for assets and liabilities measured at fair value on a recurring basis at September 30, 2013 and December 31, 2012 (in thousands):
			Fair value as of September 30, 2013
			Total		Level 1		Level 2		Level 3
	Assets:
	Cash equivalents		$	33,377	$	33,377	$	—	$	—
	Corporate debt securities			68,617		—		68,617		—
	Commercial paper			999		—		999		—
	Certificates of deposit			13,770		—		13,770		—
	Debt securities of U.S. government-sponsored agencies			7,027		—		7,027		—
			$	123,790	$	33,377	$	90,413	$	—
	Liabilities:
	Convertible notes payable		$	13,921	$	—	$	—	$	13,921
			Fair value as of December 31, 2012
			Total		Level 1		Level 2		Level 3
	Assets:
	Cash equivalents		$	39,363	$	39,363	$	—	$	—
	Corporate debt securities			44,856		—		44,856		—
	Commercial paper			6,492		—		6,492		—
	Certificates of deposit			6,200		—		6,200		—
			$	96,911	$	39,363	$	57,548	$	—
	Liabilities:
	Convertible notes payable		$	10,134	$	—	$	—	$	10,134
	Changes in the estimated fair value of convertible notes payable from December 31, 2012 through September 30, 2013 are as follows (in thousands):
			Fair Value Measurements
			Using Significant
			Unobservable Inputs
			(Level 3)
	Balance at December 31, 2012		$	10,134
	Change in estimated fair value of convertible notes payable			3,787
	Balance at September 30, 2013		$	13,921
	We obtain pricing information from quoted market prices or quotes from brokers/dealers. We generally determine the fair value of our investment securities using standard observable inputs, including reported trades, broker/dealer quotes, bids and/or offers.
	In July 2012, we amended and restated the 2010 GSK Note, which resulted in a debt extinguishment for accounting purposes. Concurrently with the debt extinguishment, we elected the fair value option for the 2010 GSK Note. The amended and restated 2010 GSK Note provided for a rollover of the 2010 GSK Note into a new promissory note effective as of the closing date of a qualifying initial public offering (“Post-IPO GSK Note”). We used a third party valuation firm to value the Post-IPO GSK Note at September 30, 2013 and recorded a gain from the change in valuation of the Post-IPO GSK Note of $0.7 million for the three months ended September 30, 2013 and a loss of $3.8 million for the nine months ended September 30, 2013 on the condensed statements of operations and comprehensive loss for the respective periods. The gain from the change in valuation of the Post-IPO GSK Note for the three months ended September 30, 2013 was principally driven by a reduction in our stock price to $9.43 as of September 30, 2013, compared to $9.81 as of June 30, 2013.
	The third-party valuation firm used an income approach in the form of a convertible bond valuation model to value the Post-IPO GSK Note. The convertible bond model considered the debt and option characteristics of the Post-IPO GSK Note. The key inputs to the model as of September 30, 2013 were stock price, volatility (65%), risk-free rate (0.32%), and credit spread (8.5%). The volatility inputs were based on historical and implied volatility of peer companies. Peer companies were materially consistent with those used previously in our 409A analyses and in previous valuations of this instrument. The risk-free rate inputs were based on the yield of U.S. Treasury Strips as of each date. The credit spread inputs were based on a creditworthiness analysis of the Company and market rates for comparable straight debt instruments.

Convertible_Notes_Payable

Convertible Notes Payable	9 Months Ended
	Sep. 30, 2013
Convertible Notes Payable	'
	5. Convertible Notes Payable
	2012 Amendment of the 2010 GSK Note
	In July 2012, we amended and restated our 2010 GSK Note. In October 2012, in conjunction with our initial public offering, we issued the Post-IPO GSK Note in the principal amount of $5.4 million, which was equivalent to the original principal amount of $5.0 million plus accrued but unpaid interest of approximately $0.4 million. The amended and restated 2010 GSK Note was then simultaneously cancelled and our obligations thereunder terminated. The Post-IPO GSK Note has a maturity date of October 9, 2015. At GSK’s option, the Post-IPO GSK Note may be converted into shares of our common stock at any time prior to the maturity at a conversion price per share equal to the initial public offering price of $4.00, subject to complying with certain threshold ownership percentage limitations set forth in the Post-IPO GSK Note. At September 30, 2013, the fair value of the Post-IPO GSK Note is $13.9 million and is classified as “Convertible note payable, at fair value” on the condensed balance sheet.

Stockholders_Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2013
Stockholders' Equity	'
	6. Stockholders’ Equity
	Shares Reserved for Future Issuance
	The following shares of common stock are reserved for future issuance at September 30, 2013:
			September 30,			December 31,
			2013			2012
	Common stock options outstanding			4,160,215			4,661,549
	Common stock options available for future grant			2,161,410			946,403
	Employee Stock Purchase Plan			460,283			150,000
	Convertible note payable			1,400,848			1,366,787
	Total common shares reserved for future issuance			8,182,756			7,124,739
	The following table summarizes our stock option activity under all stock option plans for the nine months ended September 30, 2013 (in thousands):
			Number of			Weighted
			options			average
						exercise
						price
	Options outstanding at December 31, 2012			4,720		$	2.11
	Granted			361		$	7.91
	Exercised			(720	)	$	0.8
	Canceled/forfeited/expired			(201	)	$	3.44
	Options outstanding at September 30, 2013			4,160		$	2.78
	Stock-Based Compensation
	The following table summarizes the weighted average assumptions we used in our Black-Scholes calculations:
			Three months ended					Nine months ended
			September 30,					September 30,
			2013			2012		2013			2012
	Employee Stock Options:
	Risk-free interest rate			1.7	%		*		1.4	%		1.1	%
	Expected dividend yield			0	%		*		0	%		0	%
	Expected volatility			72.7	%		*		67.8	%		71	%
	Expected term (years)			6.1			*		6.1			6.1
	*	No stock options were granted during the three months ended September 30, 2012.
	The following table summarizes the allocation of our stock compensation expense (in thousands):
			Three months ended					Nine months ended
			September 30,					September 30,
			2013			2012		2013			2012
	Research and development		$	594		$	278	$	1,664		$	461
	General and administrative			384			136		860			271
	Total		$	978		$	414	$	2,524		$	732

Strategic_Alliances_and_Collab

Strategic Alliances and Collaborations	9 Months Ended
	Sep. 30, 2013
Strategic Alliances and Collaborations	'
	7. Strategic Alliances and Collaborations
	The following table summarizes the amounts included in our revenues which resulted from our strategic alliances and collaborations (in thousands):
		Three months ended				Nine months ended
		September 30,				September 30,
		2013		2012		2013		2012
	Sanofi	$	5,422	$	2,500	$	10,828	$	7,530
	GSK		144		186		1,634		1,809
	AstraZeneca		465		94		1,394		94
	Biogen Idec		87		29		259		29
	Total	$	6,118	$	2,809	$	14,115	$	9,462
	Sanofi
	In July 2012, we amended and restated our collaboration and license agreement with Sanofi to expand the potential therapeutic applications of the microRNA alliance targets to be developed under such agreement. The modification made to the agreement was considered a material modification, which required the application of the new authoritative guidance adopted by us in January 2011 for multiple element arrangements. We determined that the elements within the strategic alliance agreement with Sanofi should be treated as a single unit of accounting because the delivered elements did not have stand-alone value to Sanofi. The following elements were delivered as part of the strategic alliance with Sanofi: (1) a license for up to four microRNA targets; and (2) a research license under our technology alliance.
	In June 2013, the original research term expired, upon which we and Sanofi entered into an option agreement pursuant to which we granted Sanofi an exclusive right to negotiate the co-development and commercialization of certain of our unencumbered microRNA programs and we were granted the exclusive right to negotiate with Sanofi for co-development and commercialization of certain miR-21 anti-miRs in oncology and Alport’s Syndrome. These options expire in December 2013, subject to a 30-day extension in certain circumstances. In July 2013, we received an upfront payment of $2.5 million, of which $1.25 million is creditable against future amounts payable by Sanofi to us under any future co-development and commercialization agreement we enter pursuant to the option agreement. The non-creditable portion of this payment, $1.25 million, will be recognized as revenue over the option period from the effective date of the option agreement in June 2013 until the expiration of the option period in December 2013. Revenue associated with the creditable portion of this option payment will be deferred until the option period expires, or is re-evaluated in connection with a creditable transaction. In addition, we agreed to continue specified research on the miR-21 programs during the option period. As a result of the expiration of the original research term and subsequent option agreement, we re-evaluated our estimated period of performance and are now amortizing the remaining deferred revenue of $10.1 million associated with the initial upfront payment of $25.0 million ratably from June 2013 until the expiration of the option period in December 2013.
	We have evaluated the remaining contingent event-based payments under our strategic alliance agreement with Sanofi and determined that the preclinical payments meet the definition of a substantive milestone because they are related to events: (i) that can be achieved based in whole or in part on our performance or on the occurrence of a specific outcome resulting from our performance, (ii) for which there was substantive uncertainty at the date the agreement was entered into that the event would be achieved, and (iii) that would result in additional payments being due to us. Accordingly, revenue for these achievements will be recognized in its entirety in the period when the milestone is achieved and collectability is reasonably assured. Other contingent event-based payments under the strategic alliance agreement for which payment is contingent upon the results of Sanofi’s performance will not be accounted for using the milestone method. Such payments will be recognized as revenue over the remaining estimated period of performance, if any, and when collectability is reasonably assured. As of the expiration of the research term in June 2013, Sanofi no longer has rights to select additional microRNA targets. As such, we can earn a preclinical milestone of $15.0 million upon the filing of an Investigational New Drug application (“IND”) for the selected microRNA target. We can also receive milestone payments of up to $33.0 million for clinical milestones and up to $165.0 million for regulatory and commercial milestones. In addition, we are entitled to receive royalties based on a percentage of net sales which will range from 8 to 12%, depending upon the volume of sales.
	GSK
	In April 2008, we entered into a strategic alliance with GSK to discover, develop and commercialize novel microRNA-targeted therapeutics to treat inflammatory diseases (the “immuno-inflammatory alliance”). In February 2010, we and GSK expanded the strategic alliance to include hepatitis C virus infection (“HCV”) to discover, develop and commercialize microRNA therapeutics targeting miR-122 for the treatment of HCV (the “HCV alliance”). In June 2012, we amended our product development and commercialization agreement with GSK to extend the target selection period for the fourth collaboration target under the agreement. The modification made to the agreement was considered a material modification, which required the application of the new authoritative guidance adopted by us in January 2011 for multiple element arrangements. We determined that the elements within the strategic alliance should be treated as a single unit of accounting because the delivered elements, the opt-in licenses for microRNA product candidates, did not have stand-alone value to GSK. As a result of the extension of the target selection period, we extended the amortization period for the remaining deferred revenue to approximately eight years, which represented our new estimated performance period under the amended agreement. As of September 30, 2013, deferred revenue associated with the product development and commercialization agreement was $3.7 million.
	In June 2013, the product development and commercialization agreement with GSK was amended to state that RG-101, and other formulations thereof, will be developed by us independently of our alliance with GSK for the treatment of chronic HCV infection. This amendment removed any further milestone or royalty obligations owed by GSK to us as it relates to RG-101. Concurrent with the amendment, we accelerated the remaining unamortized $1.1 million in deferred revenue associated with the upfront payment from the February 2010 amendment that expanded our agreement with GSK to include potential microRNA therapeutics for the treatment of HCV, which represents that our estimated performance period under the amended agreement is complete.
	HCV Alliance
	Notwithstanding the foregoing, GSK has retained its interest in the miR-122 program in HCV, and miR-122 remains a collaboration target under the alliance. If the HCV program is successful, we could receive contractual milestone payments up to $144.5 million, including up to $5.5 million for preclinical milestones, up to $29.0 million for clinical milestones, up to $50.0 million for regulatory milestones and up to $60.0 million for commercialization milestones. In addition, we will receive tiered royalties which can increase up to the low end of the 10 to 20% range on sales from any product that GSK successfully commercializes under this alliance.
	We have evaluated the remaining contingent event-based payments under our strategic alliance agreement with GSK and determined that the preclinical and clinical payments meet the definition of a substantive milestone because they are related to events: (i) that can be achieved based in whole or in part on our performance or on the occurrence of a specific outcome resulting from our performance, (ii) for which there was substantive uncertainty at the date the agreement was entered into that the event would be achieved, and (iii) that would result in additional payments being due to us. Accordingly, revenue for these achievements will be recognized in its entirety in the period when the milestone is achieved and collectability is reasonably assured. Other contingent event-based payments under the strategic alliance agreement for which payment is contingent upon the results of GSK’s performance will not be accounted for using the milestone method. Such payments will be recognized as revenue over the remaining estimated period of performance, if any, and when collectability is reasonably assured. We can earn a preclinical milestone of $5.5 million upon the selection of a development candidate. We can also earn the following clinical milestones: $4.0 million for initiation of a Phase 1 clinical trial; $5.0 million for the initiation of a Phase 2 clinical trial; and $20.0 million if GSK chooses to opt-in to the program following the completion of a proof-of-concept trial.
	Immuno-Inflammatory Alliance
	The immuno-inflammatory alliance with GSK includes contractual milestones. If all the product candidates are successfully developed and commercialized through pre-agreed sales targets we could receive milestone payments up to $432.5 million, including up to $15.5 million for preclinical milestones, up to $87.0 million for clinical milestones, up to $150.0 million for regulatory milestones and up to $180.0 million for commercialization milestones. We are also entitled to receive tiered royalties as a percentage of annual sales which can increase up to the low end of the 10 to 20% range.
	We have evaluated the remaining contingent event-based payments under our strategic alliance agreement with GSK and determined that the preclinical and clinical payments meet the definition of a substantive milestone because they are related to events: (i) that can be achieved based in whole or in part on our performance or on the occurrence of a specific outcome resulting from our performance, (ii) for which there was substantive uncertainty at the date the agreement was entered into that the event would be achieved, and (iii) that would result in additional payments being due to us. Accordingly, revenue for these achievements will be recognized in its entirety in the period when the milestone is achieved and collectability is reasonably assured. Other contingent event-based payments under the strategic alliance agreement for which payment is contingent upon the results of GSK’s performance will not be accounted for using the milestone method. Such payments will be recognized as revenue over the remaining estimated period of performance, if any, and when collectability is reasonably assured. We can earn the following preclinical milestones: $0.5 million upon the selection of a fourth microRNA target and $5.0 million upon the selection of a development candidate for each of the selected three targets. We can also earn the following clinical milestones for each of the selected three targets: $4.0 million for the initiation of a Phase 1 clinical trial; $5.0 million for the initiation of a Phase 2 clinical trial; and $20.0 million if GSK chooses to opt-in to the program following the completion of a proof-of-concept trial.
	AstraZeneca
	In August 2012, we entered into a collaboration and license agreement with AstraZeneca. Under the terms of the agreement, we have agreed to collaborate with AstraZeneca to identify, research and develop compounds targeting three microRNA alliance targets primarily in the fields of cardiovascular diseases, metabolic diseases and oncology. Pursuant to the agreement, we granted AstraZeneca an exclusive, worldwide license to thereafter develop, manufacture and commercialize lead compounds designated by AstraZeneca in the course of the collaboration activities against the alliance targets for all human therapeutic uses. Under the terms of the agreement we are required to use commercially reasonable efforts to perform all research, development and manufacturing activities described in the research plan, at our cost, until the acceptance of an IND or the end of the research term, which extends until the fourth anniversary of the date of the agreement, and may be extended only by mutual written agreement of us and AstraZeneca. Following the earlier to occur of the acceptance of an IND in a major market or the end of the research term, AstraZeneca will assume all costs, responsibilities and obligations for further development, manufacture and commercialization of alliance product candidates.
	Under the terms of the agreement, we received an upfront payment of $3.0 million in October 2012. We determined the elements within the strategic alliance agreement should be treated as a single unit of accounting because the delivered element, the license, does not have stand-alone value. As a result, we are recognizing revenue related to the upfront payment on a straight-line basis over our estimated period of performance, which is four years based on the expected term of the research and development plan. If all three targets are successfully developed and commercialized through pre-agreed sales targets, we could receive milestone payments up to $498.0 million, including up to $5.0 million for preclinical milestones, up to $123.0 million for clinical milestones, and up to $370.0 million for commercialization milestones. In addition, we are entitled to receive royalties based on a percentage of net sales which will range from the mid-single digits to the low end of 10 to 20%, depending upon the product and the volume of sales, which royalties may be reduced in certain, limited circumstances.
	We have evaluated the contingent event-based payments under our strategic alliance agreement with AstraZeneca and determined that the preclinical payments meet the definition of substantive milestones because they are related to events: (i) that can be achieved based in whole or in part on our performance or on the occurrence of a specific outcome resulting from our performance, (ii) for which there was substantive uncertainty at the date the agreement was entered into that the event would be achieved, and (iii) that would result in additional payments being due to us. Accordingly, revenue for these achievements will be recognized in its entirety in the period when the milestone is achieved and collectability is reasonably assured. Other contingent event-based payments under the strategic alliance agreement for which payment is contingent upon the results of AstraZeneca’s performance will not be accounted for using the milestone method. Such payments will be recognized as revenue over the remaining estimated period of performance, if any, and when collectability is reasonably assured.
	Concurrently with the collaboration and license agreement, we entered into a Common Stock Purchase Agreement (“CSPA”) with AstraZeneca, pursuant to which we agreed to sell to AstraZeneca an aggregate of $25.0 million of our common stock in a private placement concurrently with our initial public offering, at a price per share equal to the initial public offering price. In October 2012, in accordance with the CSPA, we sold AstraZeneca 6,250,000 shares of our common stock at a price per share of $4.00. Further, the CSPA stipulated that AstraZeneca could not sell, transfer, make any short sale of, or grant any option for the sale of any common stock for a 365-day period following the effective date of our initial public offering. Accounting guidance for multiple element arrangements contains a presumption that separate contracts negotiated and/or entered into at or near the same time with the same entity were negotiated as a package and should be evaluated as a single agreement. We valued the discount applied to the shares of common stock due to the one-year restriction. Based upon restricted stock studies of similar duration and a Black-Scholes valuation to measure the lack of marketability discount, $4.3 million was attributed to the collaboration and license agreement. We continue to recognize the $4.3 million into revenue ratably over the estimated period of performance of the collaboration.
	Biogen Idec
	In August 2012, we entered into a collaboration and license agreement with Biogen Idec pursuant to which we and Biogen Idec have agreed to collaborate on microRNA biomarkers for multiple sclerosis (“MS”). Under the terms of the agreement, we granted Biogen Idec an exclusive, royalty free, worldwide license to our interest in the collaboration intellectual property for the purpose of commercializing non-microRNA products for the treatment, diagnosis and prevention of MS and non-MS diseases and disorders. We also granted Biogen Idec an exclusive, royalty-free, worldwide license, with the right to sublicense, to our interest in the collaboration intellectual property (and a non-exclusive license to our background intellectual property) for the purpose of commercializing products for the diagnosis of MS. We also granted Biogen Idec a right of first negotiation on certain commercial transactions relating to microRNA products which utilize intellectual property developed during the collaboration. Pursuant to the terms of the agreement, in August 2012 we received an upfront payment of $0.8 million. We are also eligible to receive research milestone payments up to an aggregate of $1.3 million. We considered the elements within the collaboration and license agreement as a single unit of accounting because the delivered element, the license, does not have stand-alone value. As a result, we are recognizing revenue relating to the upfront payment of $0.8 million on a straight-line basis over our estimated period of performance, which is approximately two years based on the expected term of the research and development plan.
	In June 2013, we amended the collaboration and license agreement with Biogen Idec to provide for revised terms with respect to phase 1 of the research plan under the Biogen Idec agreement and revised payment provisions relating to the phase 1 milestones. The Biogen Idec amendment does not modify the maximum dollar amount we were originally eligible to receive in connection with phase 1 milestones under the Biogen Idec agreement, or our estimated period of performance.
	We have evaluated the contingent event-based payments under our collaboration and license agreement with Biogen Idec and determined that the research payments meet the definition of substantive milestones because they are related to events: (i) that can be achieved based in whole or in part on our performance or on the occurrence of a specific outcome resulting from our performance, (ii) for which there was substantive uncertainty at the date the agreement was entered into that the event would be achieved, and (iii) that would result in additional payments being due to us. Accordingly, revenue for these achievements will be recognized in its entirety in the period when the milestone is achieved and collectability is reasonably assured. We can earn the following research milestones: $0.25 million for identification of a microRNA biomarker; $0.5 million for validation of the microRNA biomarker in a second independent sample set; and $0.5 million upon the refinement of the microRNA biomarker signature from a longitudinal study of patient samples on MS therapy.
	Concurrently with the collaboration and license agreement, we entered into a note purchase agreement with Biogen Idec, pursuant to which we issued Biogen Idec a convertible promissory note in the principal amount of $5.0 million. The $5.0 million note plus accrued interest converted into 1,256,232 shares of our common stock upon the closing of our initial public offering in October 2012 at a conversion price of $4.00 per share.

Related_Party_Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2013
Related Party Transactions	'
	8. Related Party Transactions
	We have entered into several agreements with related parties in the ordinary course of business to license intellectual property and to procure administrative and research and development support services. These agreements include a Services Agreement with our founding companies Isis Pharmaceuticals, Inc. (“Isis”) and Alnylam Pharmaceuticals, Inc. (“Alnylam”). Total costs incurred from services provided from Alnylam under the Services Agreement were $0.1 million and $0.5 million for the three and nine months ended September 30, 2013, respectively. Activities under the Services Agreement for the nine months ended September 30, 2012 were immaterial.
	In August, 2013, we entered into an amendment to the Amended and Restated License and Collaboration Agreement with Isis and Alnylam dated January 1, 2009, as amended in June 2010 and October 2011 (as amended, the “Amendment”). Under the terms of the Amendment, the parties agreed to our use of certain Alnylam-controlled intellectual property concerning the use and manufacture of GalNAc conjugates (“GalNAc Process Technology”) on a non-exclusive basis. We will generally not be permitted to sublicense or otherwise transfer the GalNAc Process Technology and other Alnylam licensed intellectual property rights relating to GalNAc conjugate technology without the prior written consent of Alnylam, subject to certain limited exceptions for sublicenses to third party collaboration partners. There were no financial terms related to this Amendment.

Subsequent_Events

Subsequent Events	9 Months Ended
	Sep. 30, 2013
Subsequent Events	'
	9. Subsequent Events
	In October 2013, we received a payment of $0.1 million from Biogen Idec for work performed pursuant to the terms of our collaboration and license agreement based on our research to discover microRNAs as biomarkers for MS.

Basis_of_Presentation_and_Summ1

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2013
Basis of Presentation	'
	Basis of Presentation
	The accompanying unaudited condensed financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In management’s opinion, the accompanying financial statements reflect all adjustments, consisting of normal recurring adjustments, considered necessary for a fair presentation of the results for the interim periods presented.
	Interim financial results are not necessarily indicative of results anticipated for the full year. These unaudited condensed financial statements should be read in conjunction with the audited financial statements and footnotes included in the Annual Report on Form 10-K for the year ended December 31, 2012 for Regulus Therapeutics Inc. (“we,” “us,” “our,” or the “Company”), from which the balance sheet information herein for the year ended December 31, 2012 was derived.
	On September 7, 2012, our board of directors approved a one-for-two reverse stock split of our common stock. The accompanying condensed financial statements and notes to the condensed financial statements give retroactive effect to the reverse split for all periods presented. No further splits (or reverse splits) of our common stock have been contemplated as of September 30, 2013.
	In October 2012, we completed an initial public offering and concurrent private placement of 18,980,982 shares of common stock at an offering price of $4.00 per share. In addition, principal and interest of $10.8 million from convertible notes outstanding were automatically converted upon the closing of the initial public offering into an aggregate of 2,703,269 shares of our common stock. We raised a total of $70.0 million in net proceeds from our initial public offering and concurrent private placement, after deducting underwriter discounts, commissions and other offering expenses.
	In July 2013, we completed a public offering of 5,175,000 shares of common stock at an offering price of $9.50 per share. The shares were registered pursuant to a registration statement on Form S-1. We raised a total of $45.8 million in net proceeds, after deducting underwriting discounts, commissions and other offering expenses.
Use of Estimates	'
	Use of Estimates
	Our financial statements are prepared in accordance with GAAP. The preparation of our financial statements requires us to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities in our financial statements and accompanying notes. Although these estimates are based on our knowledge of current events and actions we may undertake in the future, actual results may ultimately differ from these estimates and assumptions.
Revenue Recognition	'
	Revenue Recognition
	As of September 30, 2013, we have ongoing strategic alliance agreements and collaborations with GlaxoSmithKline plc (“GSK”), Sanofi, AstraZeneca AB (“AstraZeneca”) and Biogen Idec MA Inc. (“Biogen Idec”). Our revenues generally consist of upfront payments for licenses or options to obtain licenses in the future, research and development funding and milestone payments. We recognize revenues when all four of the following criteria are met: (1) persuasive evidence that an arrangement exists; (2) delivery of the products and/or services has occurred; (3) the selling price is fixed or determinable; and (4) collectability is reasonably assured.
	For these multiple element arrangements, deliverables under our agreements are accounted for as separate units of accounting provided that (i) a delivered item has value to the customer on a stand-alone basis; and (ii) if the agreement includes a general right of return relative to the delivered item, delivery or performance of the undelivered item is considered probable and substantially in the control of the vendor. The allocation of consideration amongst the units of accounting under our strategic alliance agreements and collaborations are derived using a “best estimate of selling price” if vendor specific objective evidence and third-party evidence of fair value is not available.
	Milestones
	We recognize revenue from milestone payments when earned, provided that (i) the milestone event is substantive in that it can only be achieved based in whole or in part on either our performance or on the occurrence of a specific outcome resulting from our performance and its achievability was not reasonably assured at the inception of the agreement; (ii) we do not have ongoing performance obligations related to the achievement of the milestone; and (iii) it would result in the receipt of additional payments. A milestone payment is considered substantive if all of the following conditions are met: (i) the milestone payment is non-refundable; (ii) achievement of the milestone was not reasonably assured at the inception of the arrangement; (iii) substantive effort is involved to achieve the milestone; and (iv) the amount of the milestone payments appears reasonable in relation to the effort expended, the other milestones in the arrangement and the related risk associated with the achievement of the milestone. Any amounts received under the agreements in advance of performance, if deemed substantive, are recorded as deferred revenue and recognized as revenue as we complete our performance obligations.
	Generally, the milestone events contained in our strategic alliance agreements and collaborations coincide with the progression of our product candidates from target selection, to clinical candidate selection, to clinical trial, to regulatory approval and then to commercialization. The process of successfully discovering a new development candidate, having it approved and ultimately sold for a profit is highly uncertain. As such, the milestone payments we may earn from our partners involve a significant degree of risk to achieve. Therefore, as a product candidate progresses through the stages of its life-cycle, the value of the product candidate generally increases.
Deferred Revenue	'
	Deferred Revenue
	Amounts received prior to satisfying the above revenue recognition criteria are recorded as deferred revenue in the accompanying condensed balance sheets. Amounts not expected to be recognized within the next 12 months are classified as non-current deferred revenue.
Stock-Based Compensation	'
	Stock-Based Compensation
	We account for stock-based compensation expense related to stock options granted to employees and members of our board of directors by estimating the fair value of each stock option on the date of grant using the Black-Scholes model. We recognize stock-based compensation expense using the accelerated multiple-option approach. Under the accelerated multiple-option approach (also known as the graded-vesting method), we recognize compensation expense over the requisite service period for each separately vesting tranche of the award as though the award was in substance multiple awards, resulting in accelerated expense recognition over the vesting period.
	We account for stock options granted to non-employees other than members of our board of directors, which primarily consist of members of our scientific advisory board, using the fair value approach. Stock options granted to non-employees are subject to periodic revaluation over their vesting terms.
Fair Value Option	'
	Fair Value Option
	Applicable accounting guidance permits entities to choose, at specified election dates, to measure specified items at fair value if the decision about the election is: 1) applied instrument by instrument, 2) irrevocable, and 3) applied to an entire instrument.
	In July 2012, we amended and restated our $5.0 million convertible promissory note originally issued in February 2010 to GSK (“2010 GSK Note”), which was accounted for as a debt extinguishment of the original note. We elected to measure the 2010 GSK Note under the fair value option. Upon initial measurement, the difference between the carrying value of the original note and the fair value of the 2010 GSK Note was recorded as a loss on extinguishment of debt to non-operating earnings. Thereafter, any change to the fair value of the 2010 GSK Note is recorded as a gain (loss) from valuation of convertible note payable to non-operating earnings.
Recent Accounting Pronouncements	'
	Recent Accounting Pronouncements
	In February 2013, the FASB issued Accounting Standards Update No. 2013-02, Comprehensive Income (Topic 220): Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income (“ASU 2013-02”). This update will require companies to present information about amounts reclassified out of accumulated other comprehensive income and their corresponding effect on net income in one place and reference the amounts to the related footnote disclosures. Current accounting standards present this information in different places throughout the financial statements. ASU 2013-02 was effective for us for the nine months ended September 30, 2013. The adoption of ASU 2013-02 had no impact on our financial condition, results of operations, or cash flows.
	In July 2013, the FASB issued Accounting Standards Update No. 2013-11, Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists (“ASU 2013-11”). This update provides explicit guidance on the financial statement presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. This guidance is effective prospectively for fiscal years, and interim periods within those years, beginning after December 15, 2013, with an option for early adoption. We intend to adopt this guidance in 2014, and do not believe the adoption of this standard will have a material impact on our financial condition, results of operations or related financial statement disclosures.

Net_Loss_Per_Share_Tables

Net Loss Per Share (Tables)	9 Months Ended
	Sep. 30, 2013
Summary of Adjustment for Net Loss for Diluted Net Loss per Share Calculation	'
	The following table summarizes the adjustment to net loss for the diluted net loss per share calculation for the three months ended September 30, 2013 (in thousands):
	Net loss	$	(2,164	)
	Less: gain from change in valuation of note payable		671
	Net loss used to compute diluted net loss per share	$	(2,835	)
Potentially Dilutive Securities Not Included in Calculation of Diluted Net Loss per Share	'
	Potentially dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive are as follows (in common equivalent shares):
		Three months ended					Nine months ended
		September 30,					September 30,
		2013			2012		2013		2012
	Convertible preferred stock outstanding		—			13,699,999		—		13,699,999
	Common stock options		3,041,033			2,845,675		2,474,614		2,823,463
	Convertible note payable		—			—		1,400,848		—
	Total		3,041,033			16,545,674		3,875,462		16,523,462

Investments_Tables

Investments (Tables)	9 Months Ended
	Sep. 30, 2013
Summary of Short-Term Investments	'
	The following tables summarize our short-term investments (dollars in thousands):
		Maturity		Amortized		Unrealized					Estimated
		(in years)		cost		Gains		Losses			fair value
	As of September 30, 2013
	Corporate debt securities		2 or less	$	68,649	$	18	$	(50	)	$	68,617
	Commercial paper		1 or less		999		—		—			999
	Certificates of deposit		2 or less		13,770		—		—			13,770
	Debt securities of U.S. government-sponsored agencies		1 or less		7,025		2		—			7,027
	Total			$	90,443	$	20	$	(50	)	$	90,413
		Maturity		Amortized		Unrealized					Estimated
		(in years)		cost		Gains		Losses			fair value
	As of December 31, 2012
	Corporate debt securities		2 or less	$	44,898	$	7	$	(49	)	$	44,856
	Commercial paper		2 or less		6,492		—		—			6,492
	Certificates of deposit		1 or less		6,200		—		—			6,200
	Total			$	57,590	$	7	$	(49	)	$	57,548

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2013
Fair Value Hierarchy for Assets and Liabilities Measured at Fair Value on Recurring Basis	'
	The following table presents our fair value hierarchy for assets and liabilities measured at fair value on a recurring basis at September 30, 2013 and December 31, 2012 (in thousands):
		Fair value as of September 30, 2013
		Total		Level 1		Level 2		Level 3
	Assets:
	Cash equivalents	$	33,377	$	33,377	$	—	$	—
	Corporate debt securities		68,617		—		68,617		—
	Commercial paper		999		—		999		—
	Certificates of deposit		13,770		—		13,770		—
	Debt securities of U.S. government-sponsored agencies		7,027		—		7,027		—
		$	123,790	$	33,377	$	90,413	$	—
	Liabilities:
	Convertible notes payable	$	13,921	$	—	$	—	$	13,921
		Fair value as of December 31, 2012
		Total		Level 1		Level 2		Level 3
	Assets:
	Cash equivalents	$	39,363	$	39,363	$	—	$	—
	Corporate debt securities		44,856		—		44,856		—
	Commercial paper		6,492		—		6,492		—
	Certificates of deposit		6,200		—		6,200		—
		$	96,911	$	39,363	$	57,548	$	—
	Liabilities:
	Convertible notes payable	$	10,134	$	—	$	—	$	10,134
Changes in Estimated Fair Value of Convertible Notes Payable	'
	Changes in the estimated fair value of convertible notes payable from December 31, 2012 through September 30, 2013 are as follows (in thousands):
		Fair Value Measurements
		Using Significant
		Unobservable Inputs
		(Level 3)
	Balance at December 31, 2012	$	10,134
	Change in estimated fair value of convertible notes payable		3,787
	Balance at September 30, 2013	$	13,921

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2013
Common Stock Reserved for Future Issuance	'
	The following shares of common stock are reserved for future issuance at September 30, 2013:
			September 30,			December 31,
			2013			2012
	Common stock options outstanding			4,160,215			4,661,549
	Common stock options available for future grant			2,161,410			946,403
	Employee Stock Purchase Plan			460,283			150,000
	Convertible note payable			1,400,848			1,366,787
	Total common shares reserved for future issuance			8,182,756			7,124,739
Stock Option Activity	'
	The following table summarizes our stock option activity under all stock option plans for the nine months ended September 30, 2013 (in thousands):
			Number of			Weighted
			options			average
						exercise
						price
	Options outstanding at December 31, 2012			4,720		$	2.11
	Granted			361		$	7.91
	Exercised			(720	)	$	0.8
	Canceled/forfeited/expired			(201	)	$	3.44
	Options outstanding at September 30, 2013			4,160		$	2.78
Assumptions Used to Estimate Fair Value of Stock Options Using Black-Scholes Option Pricing Model	'
	Stock-Based Compensation
	The following table summarizes the weighted average assumptions we used in our Black-Scholes calculations:
			Three months ended					Nine months ended
			September 30,					September 30,
			2013			2012		2013			2012
	Employee Stock Options:
	Risk-free interest rate			1.7	%		*		1.4	%		1.1	%
	Expected dividend yield			0	%		*		0	%		0	%
	Expected volatility			72.7	%		*		67.8	%		71	%
	Expected term (years)			6.1			*		6.1			6.1
	*	No stock options were granted during the three months ended September 30, 2012.
Stock-Based Compensation	'
	The following table summarizes the allocation of our stock compensation expense (in thousands):
			Three months ended					Nine months ended
			September 30,					September 30,
			2013			2012		2013			2012
	Research and development		$	594		$	278	$	1,664		$	461
	General and administrative			384			136		860			271
	Total		$	978		$	414	$	2,524		$	732

Strategic_Alliances_and_Collab1

Strategic Alliances and Collaborations (Tables)	9 Months Ended
	Sep. 30, 2013
Revenue from Strategic Alliance	'
	The following table summarizes the amounts included in our revenues which resulted from our strategic alliances and collaborations (in thousands):
		Three months ended				Nine months ended
		September 30,				September 30,
		2013		2012		2013		2012
	Sanofi	$	5,422	$	2,500	$	10,828	$	7,530
	GSK		144		186		1,634		1,809
	AstraZeneca		465		94		1,394		94
	Biogen Idec		87		29		259		29
	Total	$	6,118	$	2,809	$	14,115	$	9,462

Business_Basis_of_Presentation

Business, Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	1 Months Ended	9 Months Ended				1 Months Ended
	Jul. 31, 2013	Sep. 30, 2013	Sep. 30, 2012	Oct. 30, 2012	Jul. 31, 2012	Oct. 30, 2012	Oct. 30, 2012
						Convertible Notes	Initial Public Offering
Organization And Summary Of Significant Accounting Policies [Line Items]	'	'	'	'	'	'	'
Common stock shares, issued	5,175,000	'	'	'	'	'	18,980,982
Common stock shares, par value	$9.50	'	'	'	'	'	$4
Outstanding principal amount	'	'	'	$10,800,000	$5,000,000	'	'
Conversion of convertible notes into common stock shares	'	1,256,232	'	'	'	2,703,269	'
Proceeds from issuance of common stock	$45,800,000	$46,562,000	$102,000	'	'	'	$70,000,000

Summary_of_Adjustment_for_Net_

Summary of Adjustment for Net Loss for Diluted Net Loss per Share Calculation (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Dilutive Securities Included In Computation Of Earnings Per Share [Line Items]	'	'	'	'
Net loss	($2,164)	($5,685)	($16,741)	($10,532)
Less: gain from change in valuation of note payable	671	-331	-3,787	-331
Net loss used to compute diluted net loss per share	($2,835)	'	'	'

Potentially_Dilutive_Securitie

Potentially Dilutive Securities Not Included in Calculation of Diluted Net Loss per Share (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Potentially dilutive securities not included in calculation of diluted net loss per share	3,041,033	16,545,674	3,875,462	16,523,462
Convertible Preferred Stock	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Potentially dilutive securities not included in calculation of diluted net loss per share	'	13,699,999	'	13,699,999
Common stock options	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Potentially dilutive securities not included in calculation of diluted net loss per share	3,041,033	2,845,675	2,474,614	2,823,463
Convertible Notes Payable	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Potentially dilutive securities not included in calculation of diluted net loss per share	'	'	1,400,848	'

Net_Loss_Per_Share_Additional_

Net Loss Per Share - Additional Information (Detail) (USD $)	Sep. 30, 2013
In Millions, except Per Share data, unless otherwise specified
Schedule Of Earnings Per Share Basic And Diluted [Line Items]	'
Convertible notes payable	$5.40
Conversion price per share of convertible notes payable	$4

Summary_of_ShortTerm_Investmen

Summary of Short-Term Investments (Detail) (USD $)	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Investment [Line Items]	'	'
Amortized cost	$90,443	$57,590
Unrealized Gains	20	7
Unrealized Losses	-50	-49
Estimated fair value	90,413	57,548
Corporate Debt Securities	'	'
Investment [Line Items]	'	'
Maturity	'2 or less	'2 or less
Amortized cost	68,649	44,898
Unrealized Gains	18	7
Unrealized Losses	-50	-49
Estimated fair value	68,617	44,856
Commercial Paper	'	'
Investment [Line Items]	'	'
Maturity	'1 or less	'2 or less
Amortized cost	999	6,492
Estimated fair value	999	6,492
Certificates of Deposit	'	'
Investment [Line Items]	'	'
Maturity	'2 or less	'1 or less
Amortized cost	13,770	6,200
Estimated fair value	13,770	6,200
US Government-Sponsored Agencies Debt Securities	'	'
Investment [Line Items]	'	'
Maturity	'1 or less	'
Amortized cost	7,025	'
Unrealized Gains	2	'
Estimated fair value	$7,027	'

Fair_Value_Hierarchy_for_Asset

Fair Value Hierarchy for Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Assets measured at fair value on a recurring basis	$123,790	$96,911
Convertible Notes Payable	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Liabilities measured at fair value on a recurring basis	13,921	10,134
Cash Equivalents	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Assets measured at fair value on a recurring basis	33,377	39,363
Corporate Debt Securities	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Assets measured at fair value on a recurring basis	68,617	44,856
Commercial Paper	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Assets measured at fair value on a recurring basis	999	6,492
Certificates of Deposit	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Assets measured at fair value on a recurring basis	13,770	6,200
US Government-Sponsored Agencies Debt Securities	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Assets measured at fair value on a recurring basis	7,027	'
Fair Value, Inputs, Level 1	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Assets measured at fair value on a recurring basis	33,377	39,363
Fair Value, Inputs, Level 1 | Cash Equivalents	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Assets measured at fair value on a recurring basis	33,377	39,363
Fair Value, Inputs, Level 2	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Assets measured at fair value on a recurring basis	90,413	57,548
Fair Value, Inputs, Level 2 | Corporate Debt Securities	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Assets measured at fair value on a recurring basis	68,617	44,856
Fair Value, Inputs, Level 2 | Commercial Paper	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Assets measured at fair value on a recurring basis	999	6,492
Fair Value, Inputs, Level 2 | Certificates of Deposit	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Assets measured at fair value on a recurring basis	13,770	6,200
Fair Value, Inputs, Level 2 | US Government-Sponsored Agencies Debt Securities	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Assets measured at fair value on a recurring basis	7,027	'
Fair Value, Inputs, Level 3 | Convertible Notes Payable	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Liabilities measured at fair value on a recurring basis	$13,921	$10,134

Changes_in_Estimated_Fair_Valu

Changes in Estimated Fair Value of Convertible Notes Payable (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'	'	'
Change in estimated fair value of convertible notes payable	$671	($331)	($3,787)	($331)
Fair Value, Inputs, Level 3	'	'	'	'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'	'	'
Beginning Balance	'	'	10,134	'
Change in estimated fair value of convertible notes payable	'	'	3,787	'
Ending Balance	$13,921	'	$13,921	'

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Jun. 30, 2013
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'	'	'	'	'
Gain (Loss) from valuation of convertible notes payable	$671	($331)	($3,787)	($331)	'
Stock price	$9.43	'	$9.43	'	$9.81
Fair value assumption, volatility rate	'	'	65.00%	'	'
Fair value assumption, risk free rate	'	'	0.32%	'	'
Fair value assumption, credit spread	'	'	8.50%	'	'

Convertible_Notes_Payable_Addi

Convertible Notes Payable - Additional Information (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Oct. 30, 2012	Jul. 31, 2012	Oct. 31, 2012	Oct. 31, 2012
					Oct-12	Oct-12
						Convertible Debt
						GSK
Debt Instrument [Line Items]	'	'	'	'	'	'
Convertible notes issued	'	'	'	'	'	$5,400,000
Outstanding principal amount	'	'	10,800,000	5,000,000	5,000,000	'
Accrued interest on convertible notes	'	'	'	'	400,000	'
Conversion rate	'	'	'	'	9-Oct-15	'
Conversion price per shares	$4	'	'	'	$4	'
Convertible note payable, at fair value	$13,921,000	$10,134,000	'	'	'	'

Common_Stock_Reserved_for_Futu

Common Stock Reserved for Future Issuance (Detail)	Sep. 30, 2013	Dec. 31, 2012
Equity [Line Items]	'	'
Common stock options outstanding	4,160,000	4,720,000
Total common shares reserved for future issuance	8,182,756	7,124,739
Common Stock	'	'
Equity [Line Items]	'	'
Common stock options outstanding	4,160,215	4,661,549
Common stock shares available for future grant	2,161,410	946,403
Employee Stock Purchase Plan	'	'
Equity [Line Items]	'	'
Common stock shares available for future grant	460,283	150,000
Convertible Notes Payable	'	'
Equity [Line Items]	'	'
Total common shares reserved for future issuance	1,400,848	1,366,787

Stock_Option_Activity_Detail

Stock Option Activity (Detail) (USD $)	9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013
Number of options	'
Options outstanding at December 31, 2012	4,720
Granted	361
Exercised	-720
Canceled/forfeited/expired	-201
Options outstanding at September 30, 2013	4,160
Weighted average exercise price	'
Options outstanding at December 31, 2012	$2.11
Granted	$7.91
Exercised	$0.80
Canceled/forfeited/expired	$3.44
Options outstanding at September 30, 2013	$2.78

Assumptions_Used_to_Estimate_F

Assumptions Used to Estimate Fair Value of Stock Options Using Black-Scholes Option Pricing Model (Detail) (Common stock options)	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2012
Common stock options	'	'	'
Employee Stock Options:	'	'	'
Risk-free interest rate	1.70%	1.40%	1.10%
Expected dividend yield	0.00%	0.00%	0.00%
Expected volatility	72.70%	67.80%	71.00%
Expected term (years)	'6 years 1 month 6 days	'6 years 1 month 6 days	'6 years 1 month 6 days

StockBased_Compensation_Detail

Stock-Based Compensation (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Stock-based compensation expenses	$978	$414	$2,524	$732
Research and development	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Stock-based compensation expenses	594	278	1,664	461
General and administrative	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Stock-based compensation expenses	$384	$136	$860	$271

Revenue_from_Strategic_Allianc

Revenue from Strategic Alliance (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenue from External Customer [Line Items]	'	'	'	'
Total revenues	$6,118	$2,809	$14,115	$9,462
Strategic Alliances and Collaborations	'	'	'	'
Revenue from External Customer [Line Items]	'	'	'	'
Total revenues	6,118	2,809	14,115	9,462
Strategic Alliances and Collaborations | Sanofi	'	'	'	'
Revenue from External Customer [Line Items]	'	'	'	'
Total revenues	5,422	2,500	10,828	7,530
Strategic Alliances and Collaborations | GSK	'	'	'	'
Revenue from External Customer [Line Items]	'	'	'	'
Total revenues	144	186	1,634	1,809
Strategic Alliances and Collaborations | Astra Zeneca	'	'	'	'
Revenue from External Customer [Line Items]	'	'	'	'
Total revenues	465	94	1,394	94
Strategic Alliances and Collaborations | Biogen Idec	'	'	'	'
Revenue from External Customer [Line Items]	'	'	'	'
Total revenues	$87	$29	$259	$29

Strategic_Alliances_and_Collab2

Strategic Alliances and Collaborations - Additional Information (Detail) (USD $)

1 Months Ended

9 Months Ended

9 Months Ended

9 Months Ended

1 Months Ended

1 Months Ended

9 Months Ended

1 Months Ended

9 Months Ended

9 Months Ended

Jul. 31, 2013

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Jun. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Jul. 31, 2013

Jul. 31, 2013

Sep. 30, 2013

Sep. 30, 2013

Oct. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

GSK

GSK

GSK

GSK

GSK

GSK

GSK

GSK

GSK

GSK

GSK

GSK

GSK

GSK

GSK

GSK

GSK

GSK

GSK

GSK

GSK

GSK

GSK

GSK

Sanofi

Sanofi

Sanofi

Sanofi

Sanofi

Sanofi

Sanofi

Sanofi

Astra Zeneca

Astra Zeneca

Astra Zeneca

Astra Zeneca

Astra Zeneca

Astra Zeneca

Astra Zeneca

Biogen Idec

Biogen Idec

Biogen Idec

Biogen Idec

Biogen Idec

Immuno-Inflammatory Alliance

HCV Alliance

Preclinical

Preclinical

Clinical

Clinical

Regulatory

Regulatory

Commercialization

Fourth Micro RNA Targets

Development Candidate

Phase One Clinical Trial

Phase One Clinical Trial

Phase Two Clinical Trial

Phase Two Clinical Trial

Proof-of-Concept Trial

Proof-of-Concept Trial

Commercialization Milestones

Development Commercialization And License Agreement

Minimum

Minimum

Maximum

Maximum

HCV Alliance

Preclinical

Clinical

Development Commercialization And License Agreement

Research and Development

Minimum

Maximum

Agreement

Preclinical

Clinical

Commercialization

Minimum

Maximum

Research Tax Credit Carryforward

Identification Of Micro Rna Biomarker

Validation Of Micro Rna Biomarker

Longitudinal Study Of Patient Samples On Ms Therapy

Immuno-Inflammatory Alliance

HCV Alliance

Immuno-Inflammatory Alliance

HCV Alliance

Immuno-Inflammatory Alliance

HCV Alliance

Immuno-Inflammatory Alliance

Immuno-Inflammatory Alliance

Immuno-Inflammatory Alliance

Immuno-Inflammatory Alliance

HCV Alliance

Immuno-Inflammatory Alliance

HCV Alliance

Immuno-Inflammatory Alliance

HCV Alliance

HCV Alliance

Immuno-Inflammatory Alliance

HCV Alliance

Immuno-Inflammatory Alliance

HCV Alliance

HCV Alliance

HCV Alliance

HCV Alliance

HCV Alliance

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Option expiry date

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'2013-12

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Option extension period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'30 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Initial upfront option payment

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$2,500,000

$25,000,000

'

'

'

$3,000,000

'

'

'

'

'

$800,000

'

'

'

'

Upfront payment creditable against future accounts receivables

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,250,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Upfront payment non-creditable portion recognized

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,250,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Deferred revenue

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3,700,000

'

'

'

'

'

'

'

'

'

10,100,000

'

'

'

4,300,000

'

'

'

'

'

'

'

'

'

'

Revenue through milestone payments

'

'

'

'

432,500,000

144,500,000

15,500,000

5,500,000

87,000,000

29,000,000

150,000,000

50,000,000

180,000,000

500,000

5,000,000

4,000,000

4,000,000

5,000,000

5,000,000

20,000,000

20,000,000

60,000,000

'

'

'

'

'

'

165,000,000

15,000,000

33,000,000

'

'

'

'

'

498,000,000

5,000,000

123,000,000

370,000,000

'

'

'

1,300,000

250,000

500,000

500,000

Royalties based on percentage of net sales

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

10.00%

10.00%

20.00%

20.00%

'

'

'

'

'

'

8.00%

12.00%

'

'

'

'

'

10.00%

20.00%

'

'

'

'

'

Deferred revenue recognition period

'

'

'

'8 years

'

'

'

'

'

'

'

'

'

'

'

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'

'

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'

'

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'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Acceleration of remaining amortization of upfront payment

'

'

'

1,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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'

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'

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'

'

'

'

'

'

'

'

'

'

Number of collaborative areas granted

'

'

'

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'

'

'

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'

'

'

'

'

'

'

'

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'

'

'

'

'

'

'

'

'

'

'

3

'

'

'

'

'

'

'

'

'

'

Collaboration and license agreement date

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'August 2012

'

'

'

'

'

'August 2012

'

'

'

'

Expected term of research and development plan

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'4 years

'

'

'

'

'

'

'

'

'

'

'

Common stock issue

'

42,000

36,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

25,000,000

'

'

'

'

'

'

'

'

'

'

Common stock issued

'

41,774,442

35,831,808

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

6,250,000

'

'

'

'

'

'

'

'

'

'

Price per share

$9.50

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$4

'

'

'

'

'

'

'

'

'

'

Number of days during which AstraZeneca could not sell, transfer, make any short sale of, or grant any option for the sale of any common stock

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'365 days

'

'

'

'

'

'

'

'

'

'

Restricting common stock valuation measurement period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'1 year

'

'

'

'

'

'

'

'

'

'

Revenue recognition period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'2 years

'

'

'

'

Issued promissory note

'

$5,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Conversion to common stock

'

1,256,232

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Conversion rate

'

$4

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Related_Party_Transactions_Add

Related Party Transactions - Additional Information (Detail) (Alnylam, USD $)	3 Months Ended	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2013
Alnylam	'	'
Related Party Transaction [Line Items]	'	'
Service agreement	$0.10	$0.50

Subsequent_Events_Additional_I

Subsequent Events - Additional Information (Detail) (Biogen Idec, USD $)	9 Months Ended	1 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Oct. 31, 2013
		Subsequent Event
Subsequent Event [Line Items]	'	'
Payment received pursuant to the terms of collaboration and license agreement	$0.80	$0.10