Histogen (HSTO) 10-Q14 May 142014 Q1 Quarterly reportFinancial data

Company Profile

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
Document and Entity Information	Mar. 31, 2014	Apr. 30, 2014
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	31-Mar-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Trading Symbol	'CNAT	'
Entity Registrant Name	'Conatus Pharmaceuticals Inc	'
Entity Central Index Key	'0001383701	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Non-accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	15,632,000

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Mar. 31, 2014	Dec. 31, 2013
Current assets:	'	'
Cash and cash equivalents	$2,485,662	$4,158,953
Marketable securities	48,596,378	52,194,034
Prepaid and other current assets	687,164	545,504
Total current assets	51,769,204	56,898,491
Property and equipment, net	32,630	23,068
Other assets	77,376	14,395
Total assets	51,879,210	56,935,954
Current liabilities:	'	'
Accounts payable and accrued expenses	2,160,063	1,494,435
Accrued compensation	456,456	1,322,569
Total current liabilities	2,616,519	2,817,004
Note payable	1,000,000	1,000,000
Stockholders' equity:	'	'
Preferred stock, $0.0001 par value; 10,000,000 shares authorized; no shares issued and outstanding	'	'
Common stock, $0.0001 par value; 200,000,000 shares authorized; 15,632,000 shares issued and 15,424,320 shares outstanding, excluding 207,680 shares subject to repurchase, at March 31, 2014; 15,619,879 shares issued and 15,386,542 shares outstanding, excluding 233,337 shares subject to repurchase, at December 31, 2013	1,542	1,539
Additional paid-in capital	127,936,873	127,536,408
Accumulated other comprehensive (loss) income	-1,874	11,497
Deficit accumulated during the development stage	-79,673,850	-74,430,494
Total stockholders' equity	48,262,691	53,118,950
Total liabilities and stockholders' equity	$51,879,210	$56,935,954

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Statement Of Financial Position [Abstract]	'	'
Preferred stock, par value	$0.00	$0.00
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	15,632,000	15,619,879
Common stock, shares outstanding	15,424,320	15,386,542
Common stock, shares subject to repurchase	207,680	233,337

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations and Comprehensive Loss (USD $)	3 Months Ended		105 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014
Operating expenses:	'	'	'
Research and development	$3,650,598	$967,778	$51,423,185
General and administrative	1,595,247	748,796	24,362,646
Total operating expenses	5,245,845	1,716,574	75,785,831
Other income (expense):	'	'	'
Interest income	20,773	132	1,401,667
Interest expense	-17,500	-17,500	-1,254,899
Other (expense) income	-784	-15,677	239,545
Other financing expense	'	-547,164	-4,267,839
Total other income (expense)	2,489	-580,209	-3,881,526
Net loss	-5,243,356	-2,296,783	-79,667,357
Other comprehensive loss:	'	'	'
Net unrealized losses on marketable securities	-13,371	-551	-1,874
Comprehensive loss	-5,256,727	-2,297,334	-79,669,231
Reconciliation of net loss to net loss applicable to common stockholders:	'	'	'
Net loss	-5,243,356	-2,296,783	-79,667,357
Gain on extinguishment of convertible preferred stock	'	'	11,491,043
Deemed distribution from promissory note issuance	'	'	-474,561
Net loss applicable to common stockholders, basic and diluted	($5,243,356)	($2,296,783)	($68,650,875)
Net loss per share applicable to common stockholders, basic and diluted	($0.34)	($2.17)	'
Weighted average shares outstanding used in computing net loss per share applicable to common stockholders, basic and diluted	15,412,498	1,060,533	'

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Cash Flows (USD $)	3 Months Ended		105 Months Ended
Condensed Consolidated Statements of Cash Flows (USD $)	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014
Operating activities	'	'	'
Net loss	($5,243,356)	($2,296,783)	($79,667,357)
Adjustments to reconcile net loss to net cash used in operating activities:	'	'	'
Depreciation	3,356	2,698	213,068
Share-based compensation expense	379,433	21,418	1,034,266
Noncash other financing expense	'	547,164	4,846,240
Acquisition of in-process research and development	'	'	1,250,000
Share-based compensation in lieu of salaries	'	'	659,224
Noncash license expense	'	'	2,249,999
Amortization of premium on investments	195,533	8,922	273,099
Changes in operating assets and liabilities:	'	'	'
Prepaid and other current assets	-141,660	-7,148	-687,164
Other assets	-62,981	-25,901	-77,376
Accounts payable and accrued expenses	665,628	-697,169	2,160,063
Accrued compensation	-857,078	15,464	417,718
Net cash used in operating activities	-5,061,125	-2,431,335	-67,328,220
Investing activities	'	'	'
Maturities of investments	13,031,000	3,725,000	118,538,865
Purchase of investments	-9,642,248	'	-167,410,216
Cash paid to acquire in-process research and development	'	'	-250,000
Capital expenditures	-12,918	'	-245,698
Net cash provided by (used in) investing activities	3,375,834	3,725,000	-49,367,049
Financing activities	'	'	'
Issuance of promissory notes and warrants	'	'	7,201,673
Distribution to wholly owned subsidiary in connection with spin-off of Idun	'	-500,000	-500,000
Issuance of preferred stock for cash, net of offering costs	'	'	53,731,226
Issuance of common stock related to initial public offering, net of offering costs	'	'	58,608,454
Issuance of common stock for exercise of stock options and cash	12,000	10,730	139,578
Net cash provided by (used in) financing activities	12,000	-489,270	119,180,931
Net (decrease) increase in cash and cash equivalents	-1,673,291	804,395	2,485,662
Cash and cash equivalents at beginning of period	4,158,953	4,036,091	'
Cash and cash equivalents at end of period	2,485,662	4,840,486	2,485,662
Supplemental disclosure of cash flow information:	'	'	'
Cash paid for interest	17,500	17,500	275,639
Supplemental schedule of noncash investing and financing activities:	'	'	'
Conversion of notes payable for preferred stock	'	'	6,736,946
Conversion of notes payable for common stock	'	'	1,001,439
Issuance of warrants in conjunction with debt	'	'	2,361,223
Issuance of note payable related to acquisition of in-process research and development	'	'	$1,000,000

Organization_and_Basis_of_Pres

Organization and Basis of Presentation	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Organization and Basis of Presentation	'
		1	Organization and Basis of Presentation
	Conatus Pharmaceuticals Inc. (the Company) was incorporated in the state of Delaware on July 13, 2005. The Company is a biotechnology company focused on the development and commercialization of novel medicines to treat liver disease.
	As of March 31, 2014, the Company has devoted substantially all of its efforts to product development and has not realized revenues from its planned principal operations. Accordingly, the Company is considered to be in the development stage.
	The Company has a limited operating history and the sales and income potential of the Company’s business and market are unproven. The Company has experienced net losses since its inception and, as of March 31, 2014, had an accumulated deficit of $79.7 million. The Company expects to continue to incur net losses for at least the next several years. Successful transition to attaining profitable operations is dependent upon achieving a level of revenues adequate to support the Company’s cost structure. If the Company is unable to generate revenues adequate to support its cost structure, the Company may need to raise additional equity or debt financing.
	The accompanying unaudited interim condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) and the rules and regulations of the Securities and Exchange Commission (SEC) related to a quarterly report on Form 10-Q. Certain information and note disclosures normally included in annual financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to those rules and regulations. The unaudited interim condensed consolidated financial statements reflect all adjustments which, in the opinion of management, are necessary for a fair statement of the results for the periods presented. All such adjustments are of a normal and recurring nature. The operating results presented in these unaudited interim condensed consolidated financial statements are not necessarily indicative of the results that may be expected for any future periods. These unaudited interim condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the notes thereto for the year ended December 31, 2013 included in the Company’s annual report on Form 10-K filed with the SEC on March 28, 2014.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	3 Months Ended
Summary of Significant Accounting Policies	Mar. 31, 2014
Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
	2	Summary of Significant Accounting Policies
	Use of Estimates
	The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates.
	Concentrations of Credit Risk
	Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash, cash equivalents and marketable securities. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and believes it is not exposed to significant risk on its cash. Additionally, the Company established guidelines regarding approved investments and maturities of investments, which are designed to maintain safety and liquidity.

	Cash and Cash Equivalents
	The Company considers all highly liquid investments with an original maturity from the date of purchase of three months or less to be cash equivalents. Cash and cash equivalents include cash in readily available checking and money market accounts.
	Investments
	The Company classifies its investments as available-for-sale and records such assets at estimated fair value in the condensed consolidated balance sheets, with unrealized gains and losses, if any, reported as a component of other comprehensive income (loss) within the condensed consolidated statements of operations and comprehensive loss and as a separate component of stockholders’ equity. The Company invests its excess cash balances primarily in corporate debt securities and money market funds with strong credit ratings. Realized gains and losses are calculated on the specific identification method and recorded as interest income. There have been no realized gains and losses for the period ended March 31, 2014, the year ended December 31, 2013, and for the period from July 13, 2005 (inception) to March 31, 2014.
	At each balance sheet date, the Company assesses available-for-sale securities in an unrealized loss position to determine whether the unrealized loss is other-than-temporary. The Company considers factors including: the significance of the decline in value compared to the cost basis, underlying factors contributing to a decline in the prices of securities in a single asset class, the length of time the market value of the security has been less than its cost basis, the security’s relative performance versus its peers, sector or asset class, expected market volatility and the market and economy in general. When the Company determines that a decline in the fair value below its cost basis is other-than-temporary, the Company recognizes an impairment loss in the period in which the other-than-temporary decline occurred. There have been no other-than-temporary declines in the value of marketable securities, as it is more likely than not the Company will hold the securities until maturity or a recovery of the cost basis.
	Fair Value of Financial Instruments
	The carrying amounts of prepaid and other current assets, accounts payable and accrued expenses are reasonable estimates of their fair value because of the short maturity of these items.
	Property and Equipment
	Property and equipment, which consists of furniture and fixtures, computers and office equipment and leasehold improvements, are stated at cost and depreciated over the estimated useful lives of the assets (three to five years) using the straight-line method. Leasehold improvements are amortized over the shorter of their estimated useful lives or the lease term.
	Long-Lived Assets
	The Company regularly reviews the carrying value and estimated lives of all of its long-lived assets, including property and equipment, to determine whether indicators of impairment may exist which warrant adjustments to carrying values or estimated useful lives. The determinants used for this evaluation include management’s estimate of the asset’s ability to generate positive income from operations and positive cash flow in future periods, as well as the strategic significance of the assets to the Company’s business objective. Should an impairment exist, the impairment loss would be measured based on the excess of the carrying amount of the asset’s fair value. The Company has not recognized any impairment losses through March 31, 2014.
	Research and Development Expenses
	All research and development costs are expensed as incurred.

	Income Taxes
	The Company’s policy related to accounting for uncertainty in income taxes prescribes a recognition threshold and measurement attribute criteria for the financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. For those benefits to be recognized, a tax position must be more likely than not to be sustained upon examination by taxing authorities. As of December 31, 2013, there are no unrecognized tax benefits included in the condensed consolidated balance sheet that would, if recognized, affect the Company’s effective tax rate, and we have noted no material changes through March 31, 2014. The Company has not recognized interest and penalties in the condensed consolidated balance sheets or condensed consolidated statements of operations and comprehensive loss. The Company is subject to U.S. and California taxation. As of December 31, 2013, the Company’s tax years beginning 2005 to date are subject to examination by taxing authorities.
	Convertible Preferred Stock Warrant Liability
	The Company had issued freestanding warrants exercisable to purchase shares of its Series A and Series B convertible preferred stock. These warrants were classified as a liability in the accompanying condensed consolidated balance sheets prior to the completion of the Company’s initial public offering (IPO) of its common stock in July 2013, as the terms for redemption of the underlying security were outside the Company’s control. The Series A convertible preferred stock warrants were recorded at fair value using the Black-Scholes option pricing model. The Series B convertible preferred stock warrants were recorded at fair value using a Monte Carlo model. The fair value of all warrants, except as noted below, was remeasured at each financial reporting date with any changes in fair value being recognized in other financing (expense) income, a component of other (expense) income, in the accompanying condensed consolidated statements of operations and comprehensive loss. The Company ceased the remeasurement of the fair value upon exercise of the Series A warrants and the Series B warrants becoming exercisable for shares of common stock, immediately prior to the completion of the Company’s IPO in July 2013.
	Comprehensive Loss
	The Company is required to report all components of comprehensive loss, including net loss, in the condensed consolidated financial statements in the period in which they are recognized. Comprehensive loss is defined as the change in equity during a period from transactions and other events and circumstances from nonowner sources, including unrealized gains and losses on investments. Comprehensive gains (losses) have been reflected in the condensed consolidated statements of operations and comprehensive loss for all periods presented.
	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 during the period. Diluted net loss per share is computed by dividing the net loss by the weighted average number of common shares and common share equivalents outstanding for the period. Common stock equivalents are only included when their effect is dilutive. The Company’s potentially dilutive securities, which include convertible preferred stock, warrants, outstanding stock options under the stock option plan and common stock subject to repurchase by the Company, have been excluded from the computation of diluted net loss per share in the periods in which they would be anti-dilutive. For all periods presented, there is no difference in the number of shares used to compute basic and diluted shares outstanding due to the Company’s net loss position.

	The following table sets forth the computation of basic and diluted earnings per share:


			Three Months Ended March 31,
			2014			2013
	Numerator:
	Net loss attributable to common stockholders		$	(5,243,356	)	$	(2,296,783	)

	Denominator for basic and diluted net loss per share:
	Weighted average common shares outstanding, basic and diluted			15,412,498			1,060,533

	Net loss per share applicable to common stockholders:
	Basic		$	(0.34	)	$	(2.17	)
	Diluted		$	(0.34	)	$	(2.17	)
	The following table sets forth the outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share because to do so would be anti-dilutive.


			Three Months Ended March 31,
			2014			2013
	Convertible preferred stock			—			9,565,021
	Warrants to purchase preferred stock			—			280,675
	Warrants to purchase common stock			149,704			—
	Common stock options			1,615,719			593,803
	Common stock subject to repurchase			207,680			271,099

	Total			1,973,103			10,710,598

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
Fair Value Measurements	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	3	Fair Value Measurements
	The accounting guidance defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell 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 assumptions, the accounting guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows:


	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 for similar instruments in active markets, quoted prices for identical or similar instruments in markets with insufficient volume or infrequent transaction (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.

	Below is a summary of assets and liabilities measured at fair value as of March 31, 2014 and December 31, 2013.


						Fair Value Measurements Using
			March 31, 2014			Quoted Prices in		Significant		Significant
						Active Markets		Other		Unobservable
						for Identical		Observable		Inputs
						Assets (Level 1)		Inputs (Level 2)		(Level 3)
	Assets
	Money market funds		$	2,180,809		$	2,180,809	$	—	$	—
	Municipal bonds			70,000			—		70,000		—
	Corporate debt securities			48,526,378			—		48,526,378		—

	Total assets		$	50,777,187		$	2,180,809	$	48,596,378	$	—



						Fair Value Measurements Using
			December 31,			Quoted Prices in		Significant		Significant
			2013			Active Markets		Other		Unobservable
						for Identical		Observable		Inputs
						Assets (Level 1)		Inputs (Level 2)		(Level 3)
	Assets
	Money market funds		$	3,832,902		$	3,832,902	$	—	$	—
	Municipal bonds			255,000			—		255,000		—
	Corporate debt securities			50,438,149			—		50,438,149		—
	Debt securities in government sponsored entities			1,500,885			—		1,500,885		—

	Total assets		$	56,026,936		$	3,832,902	$	52,194,034	$	—

	The Company’s marketable securities, consisting principally of debt securities, are classified as available-for-sale, are stated at fair value and consist of Level 2 financial instruments in the fair value hierarchy. The Company determines the fair value of its debt security holdings based on pricing from a service provider. The service provider values the securities based on using market prices from a variety of industry-standard independent data providers. Such market prices may be quoted prices in active markets for identical assets (Level 1 inputs) or pricing determined using inputs other than quoted prices that are observable either directly or indirectly (Level 2 inputs), such as yield curve, volatility factors, credit spreads, default rates, loss severity, current market and contractual prices for the underlying instruments or debt, broker and dealer quotes, as well as other relevant economic measures.
	The fair value of the convertible preferred stock warrant liability was determined based on “Level 3” inputs and utilized the Black-Scholes option pricing model for the Series A convertible preferred stock warrants. The Series B convertible preferred stock warrants utilized a Monte Carlo model. The warrant liabilities were marked to market before converting to equity at the IPO. The following table presents activity for the convertible preferred stock warrant liability measured at fair value using significant unobservable Level 3 inputs during the year ended December 31, 2013 and the three months ended March 31, 2014.


			Fair Value
			Measurements at
			Reporting Date
			Using Significant
			Unobservable
			Inputs
			(Level 3)
	Balance at December 31, 2012		$	160,345
	Issuance of preferred stock warrants			625,679
	Changes in fair value reflected as other financing expense			3,457,184
	Conversion to equity at IPO			(4,243,208	)

	Balance at December 31, 2013			—

	Balance at March 31, 2014		$	—

	The fair value of the convertible promissory notes was determined based on “Level 3” inputs and valued the notes utilizing an estimated cost of debt from publicly available information on issuances of high yield fixed income securities issued by comparable companies. The Company concluded that a 15% discount rate was appropriate, resulting in an initial fair value for the notes of approximately $970,000. The discount was accreted to interest expense through the Company’s IPO and was accreted completely at the IPO as the notes plus accrued interest converted to common stock at the IPO. The following table presents activity for the convertible promissory notes measured at fair value using significant unobservable Level 3 inputs during the year ended December 31, 2013 and the three months ended March 31, 2014.


		Fair Value
		Measurements at
		Reporting Date
		Using Significant
		Unobservable
		Inputs
		(Level 3)
Balance at December 31, 2012		$	—
Issuance of convertible promissory notes			970,000
Accretion of debt discount to interest expense			31,439
Conversion to equity at IPO			(1,001,439	)

Balance at December 31, 2013			—

Balance at March 31, 2014		$	—

Investments

Investments	3 Months Ended
Investments	Mar. 31, 2014
Investments Schedule [Abstract]	'
Investments	'
		4	Investments
	The Company invests its excess cash in money market funds and debt instruments of financial institutions, corporations, government sponsored entities and municipalities. The following tables summarize the Company’s marketable securities:


	As of March 31, 2014		Maturity	Amortized		Unrealized		Unrealized			Estimated
	As of March 31, 2014		(in years)	Cost		Gains		Losses			Fair Value
	Corporate debt securities		1 or less	$	46,776,006	$	—	$	(766	)	$	46,775,240
	Corporate debt securities		2-Jan		1,752,246		—		(1,108	)		1,751,138
	Municipal bonds		1 or less		70,000		—		—			70,000

	Total			$	48,598,252	$	—	$	(1,874	)	$	48,596,378


	As of December 31, 2013		Maturity	Amortized		Unrealized		Unrealized			Estimated
	As of December 31, 2013		(in years)	Cost		Gains		Losses			Fair Value
	Corporate debt securities		1 or less	$	47,172,466	$	11,148	$	—		$	47,183,614
	Corporate debt securities		1 - 2		3,254,329		206		—			3,254,535
	Debt securities in government sponsored entities		1 - 2		1,500,742		143		—			1,500,885
	Municipal bonds		1 or less		255,000		—		—			255,000

	Total			$	52,182,537	$	11,497	$	—		$	52,194,034

Property_and_Equipment

Property and Equipment	3 Months Ended
Property and Equipment	Mar. 31, 2014
Property Plant And Equipment [Abstract]	'
Property and Equipment	'
		5	Property and Equipment
	Property and equipment consist of the following:


			Useful	March 31,			December 31,
			Life in	2014			2013
			Years
	Furniture and fixtures		4	$	123,685		$	115,417
	Computer equipment and office equipment		4		101,218			96,569
	Leasehold improvements		4		3,645			3,645

					228,548			215,631
	Less accumulated depreciation and amortization				(195,918	)		(192,563	)

				$	32,630		$	23,068

Note_Payable

Note Payable	3 Months Ended
	Mar. 31, 2014
Debt Disclosure [Abstract]	'
Note Payable	'
		6	Note Payable
	In July 2010, the Company entered into a $1.0 million promissory note payable to Pfizer Inc. The note bears interest at 7% per annum, which is paid quarterly, and matures on July 29, 2020. The note payable prohibits the Company from paying cash dividends and is subject to acceleration upon specified events of default as defined in the agreement including the failure to notify Pfizer of certain material adverse events. In July 2013, the note payable to Pfizer was amended to become convertible into shares of the Company’s common stock following the completion of the IPO, at the option of the holder, at a price per share equal to the fair market value of the common stock on the date of conversion.
	In May 2013, the Company entered into a note and warrant purchase agreement with certain existing investors pursuant to which it sold, in a private placement, an aggregate of $1.0 million of convertible promissory notes (the 2013 Notes), and issued warrants exercisable to purchase 1,124,026 shares of Series B Preferred Stock (the 2013 Warrants). The 2013 Notes accrued interest at a rate of 6% per annum and were due and payable on the earlier of (1) any date after November 30, 2013 upon which holders of 75% of the outstanding principal amount of all such 2013 Notes demand repayment, or (2) the occurrence of a change of control of the Company, subject in each case to their earlier conversion in the event the Company completed a qualified initial public offering or private placement of debt and/or equity. The 2013 Notes did not provide for any potential adjustments to the stated conversion rates other than in the event of stock splits, stock dividends and recapitalizations. The conversion of the 2013 Notes in the event of a qualified initial public offering or private placement of equity was deemed to be the predominant settlement mechanism. As this predominant settlement mechanism provided for the settlement of a fixed monetary amount in a variable number of equity instruments, the Company concluded that it was appropriate to recognize the 2013 Notes at fair value. The Company valued the 2013 Notes utilizing an estimated cost of debt from publicly available information on issuances of high yield fixed income securities issued by comparable companies. The Company concluded that a 15% discount rate was appropriate, resulting in an initial fair value for the 2013 Notes of approximately $970,000. Upon completion of the IPO, the 2013 Notes plus accrued interest automatically converted into 91,948 shares of common stock.
	The 2013 Warrants were exercisable for an aggregate of 1,124,026 shares of Series B Preferred Stock at an exercise price of $0.90 per share. Upon completion of the IPO, the 2013 Warrants became exercisable for an aggregate of 136,236 shares of common stock at an exercise price of $7.43 per share. The 2013 Warrants will expire on May 30, 2018. The 2013 Warrants were initially accounted for as liabilities with changes in fair value recognized within the condensed consolidated statements of operations and comprehensive loss. The Company determined that the initial value of the 2013 Warrants was $506,000. The 2013 Warrants were valued utilizing a Monte Carlo simulation of various weighted scenarios. Following the IPO, the 2013 Warrants were reclassified into equity at their fair value at the time of the completion of the IPO.
	The valuation at the issuance of the 2013 Notes and 2013 Warrants resulted in a deemed distribution in the amount of $474,561 accounted for as a reduction in net income attributable to common stockholders.

	In July 2013, the Company entered into a loan and security agreement, (the Credit Facility) with Oxford Finance LLC and Silicon Valley Bank (the Lenders). The Credit Facility provided funding for an aggregate principal amount of up to $15.0 million. The first term loan of the Credit Facility was funded in July 2013 in the amount of $1.0 million. On September 25, 2013, the Company prepaid the outstanding advances under the Credit Facility. Accordingly, the Credit Facility was terminated on September 25, 2013. In connection with the funding of the first term loan under the Credit Facility, the Company issued warrants to the Lenders to purchase up to an aggregate of 111,112 shares of Series B convertible preferred stock at an exercise price of $0.90 per share (Lender Warrants). The Lender Warrants will expire on July 3, 2023. The Lender Warrants were initially accounted for as liabilities with the changes in fair value recognized within the condensed consolidated statements of operations and comprehensive loss.
	The Lender Warrants were initially valued at $119,679, and such amount was recognized as additional expense. Upon completion of the IPO, the Lender Warrants became exercisable for an aggregate of 13,468 shares of common stock at an exercise price of $7.43 per share. Following the IPO, the Lender Warrants were reclassified into equity at their fair value at the time of the completion of the IPO.

Stockholders_Equity

Stockholders' Equity	3 Months Ended
Stockholders' Equity	Mar. 31, 2014
Equity [Abstract]	'
Stockholders' Equity	'
		7	Stockholders’ Equity
	Common Stock
	During 2005, the Company sold 727,273 shares of common stock to founders for approximately $6,000. During 2006, the Company sold 181,818 shares of common stock to founders for approximately $45,000, subject to certain restrictions that have since been released.
	In July 2013, the Company implemented a 1-for-8.25 reverse stock split of its outstanding common stock. The accompanying condensed consolidated financial statements give effect to the reverse split for all periods presented.
	In July 2013, the Company completed the IPO of 6,000,000 shares of common stock at an offering price of $11.00 per share. The Company received net proceeds of approximately $58.6 million, after deducting underwriting discounts and commissions and offering-related transaction costs.
	Warrants
	The Company issued warrants to purchase a total of 2,333,320 shares of Series A Preferred Stock in conjunction with a convertible bridge financing in 2010 and issued the 2013 Warrants and Lender Warrants in conjunction with a convertible bridge financing and the Credit Facility funding in 2013. The Company initially accounted for the warrants as liabilities because they were exercisable for shares of preferred stock that were classified outside of permanent equity. The convertible preferred stock warrant liability was required to be recorded at fair value at the grant date of the warrants and the carrying value adjusted at each reporting date. The Company revalued the warrants at July 30, 2013 (date of IPO closing) and recorded the change in the value of the warrants of approximately $3.5 million as other financing expense. The Series A warrants converted to 280,675 shares of common stock as a result of the net exercise of such warrants at the IPO. Upon the completion of the IPO, the 2013 Warrants and the Lender Warrants became exercisable for an aggregate of 149,704 shares of common stock at an exercise price of $7.43 per share. Following the IPO, the 2013 Warrants and Lender Warrants were reclassified into equity at their fair value at the time of the completion of the IPO.

	Stock Options
	The following table summarizes the Company’s stock option activity under all stock option plans for the three months ended March 31, 2014:


			Total			Weighted-
			Options			Average
						Exercise
						Price
	Balance at December 31, 2013			790,590		$	4.01
	Granted			837,250			9.21
	Exercised			(12,121	)		0.99

	Balance at March 31, 2014			1,615,719		$	6.73

	The Company recorded stock-based compensation of $379,433 and $21,418 for the three months ended March 31, 2014 and 2013, respectively.
	Common Stock Reserved for Future Issuance
	The following shares of common stock are reserved for future issuance at March 31, 2014:


	Common stock warrants			149,704
	Stock options issued and outstanding			1,615,719
	Authorized for future option grants			711,021

				2,476,444

Commitments

Commitments	3 Months Ended
	Mar. 31, 2014
Commitments And Contingencies Disclosure [Abstract]	'
Commitments	'
		8	Commitments
	The Company leases certain office space under a noncancelable operating lease with terms through June 30, 2014. Future minimum payments under this noncancelable operating lease total $29,922 at March 31, 2014. The rent expense for the three months ended March 31, 2014 and 2013 was $44,883 and $38,514, respectively.
	In February 2014, the Company entered into a noncancelable operating lease for certain office space starting in July 2014 through November 2019. Future minimum payments under this noncancelable operating lease total approximately $1.6 million at March 31, 2014.
	In July 2010, the Company entered into a stock purchase agreement with Pfizer, pursuant to which the Company acquired all of the outstanding stock of Idun Pharmaceuticals, Inc. (Idun). Under the agreement, the Company may be required to make payments to Pfizer totaling $18.0 million upon the achievement of specified regulatory milestones.

Spinoff_of_Idun_Pharmaceutical

Spin-off of Idun Pharmaceuticals, Inc.	3 Months Ended
	Mar. 31, 2014
Restructuring And Related Activities [Abstract]	'
Spin-off of Idun Pharmaceuticals, Inc.	'
		9	Spin-off of Idun Pharmaceuticals, Inc.
	In January 2013, the Company spun off its subsidiary Idun to the Company’s stockholders. Prior to the spin-off, rights relating to emricasan were distributed to the Company by Idun pursuant to a distribution agreement. The spin-off was conducted as a dividend of all of the outstanding capital stock of Idun to the Company’s stockholders. As a result, the Company no longer held any capital stock of Idun.
	In connection with the spin-off, the Company contributed $0.5 million to Idun to provide for Idun’s initial working capital requirements. The assets remaining in Idun at the time of the spin-off consisted of cash, intellectual property rights and license and collaboration agreements unrelated to emricasan. Other than the cash of $0.5 million, none of the assets held by Idun had any historical carrying value at the time of the spin-off. As a result, the Company recognized a reduction in equity as a result of the spin-off of $0.5 million, representing the carrying value of Idun in the Company’s condensed consolidated financial statements at the time of the spin-off.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	3 Months Ended
Summary of Significant Accounting Policies (Policies)	Mar. 31, 2014
Accounting Policies [Abstract]	'
Use of Estimates	'
	Use of Estimates
	The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates.
Concentrations of Credit Risk	'
	Concentrations of Credit Risk
	Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash, cash equivalents and marketable securities. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and believes it is not exposed to significant risk on its cash. Additionally, the Company established guidelines regarding approved investments and maturities of investments, which are designed to maintain safety and liquidity.
Cash and Cash Equivalents	'
	Cash and Cash Equivalents
	The Company considers all highly liquid investments with an original maturity from the date of purchase of three months or less to be cash equivalents. Cash and cash equivalents include cash in readily available checking and money market accounts.
Investments	'
	Investments
	The Company classifies its investments as available-for-sale and records such assets at estimated fair value in the condensed consolidated balance sheets, with unrealized gains and losses, if any, reported as a component of other comprehensive income (loss) within the condensed consolidated statements of operations and comprehensive loss and as a separate component of stockholders’ equity. The Company invests its excess cash balances primarily in corporate debt securities and money market funds with strong credit ratings. Realized gains and losses are calculated on the specific identification method and recorded as interest income. There have been no realized gains and losses for the period ended March 31, 2014, the year ended December 31, 2013, and for the period from July 13, 2005 (inception) to March 31, 2014.
	At each balance sheet date, the Company assesses available-for-sale securities in an unrealized loss position to determine whether the unrealized loss is other-than-temporary. The Company considers factors including: the significance of the decline in value compared to the cost basis, underlying factors contributing to a decline in the prices of securities in a single asset class, the length of time the market value of the security has been less than its cost basis, the security’s relative performance versus its peers, sector or asset class, expected market volatility and the market and economy in general. When the Company determines that a decline in the fair value below its cost basis is other-than-temporary, the Company recognizes an impairment loss in the period in which the other-than-temporary decline occurred. There have been no other-than-temporary declines in the value of marketable securities, as it is more likely than not the Company will hold the securities until maturity or a recovery of the cost basis.
Fair Value of Financial Instruments	'
	Fair Value of Financial Instruments
	The carrying amounts of prepaid and other current assets, accounts payable and accrued expenses are reasonable estimates of their fair value because of the short maturity of these items.
Property and Equipment	'
	Property and Equipment
	Property and equipment, which consists of furniture and fixtures, computers and office equipment and leasehold improvements, are stated at cost and depreciated over the estimated useful lives of the assets (three to five years) using the straight-line method. Leasehold improvements are amortized over the shorter of their estimated useful lives or the lease term.
Long-Lived Assets	'
	Long-Lived Assets
	The Company regularly reviews the carrying value and estimated lives of all of its long-lived assets, including property and equipment, to determine whether indicators of impairment may exist which warrant adjustments to carrying values or estimated useful lives. The determinants used for this evaluation include management’s estimate of the asset’s ability to generate positive income from operations and positive cash flow in future periods, as well as the strategic significance of the assets to the Company’s business objective. Should an impairment exist, the impairment loss would be measured based on the excess of the carrying amount of the asset’s fair value. The Company has not recognized any impairment losses through March 31, 2014.
Research and Development Expenses	'
	Research and Development Expenses
	All research and development costs are expensed as incurred.
Income Taxes	'
	Income Taxes
	The Company’s policy related to accounting for uncertainty in income taxes prescribes a recognition threshold and measurement attribute criteria for the financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. For those benefits to be recognized, a tax position must be more likely than not to be sustained upon examination by taxing authorities. As of December 31, 2013, there are no unrecognized tax benefits included in the condensed consolidated balance sheet that would, if recognized, affect the Company’s effective tax rate, and we have noted no material changes through March 31, 2014. The Company has not recognized interest and penalties in the condensed consolidated balance sheets or condensed consolidated statements of operations and comprehensive loss. The Company is subject to U.S. and California taxation. As of December 31, 2013, the Company’s tax years beginning 2005 to date are subject to examination by taxing authorities.
Convertible Preferred Stock Warrant Liability	'
	Convertible Preferred Stock Warrant Liability
	The Company had issued freestanding warrants exercisable to purchase shares of its Series A and Series B convertible preferred stock. These warrants were classified as a liability in the accompanying condensed consolidated balance sheets prior to the completion of the Company’s initial public offering (IPO) of its common stock in July 2013, as the terms for redemption of the underlying security were outside the Company’s control. The Series A convertible preferred stock warrants were recorded at fair value using the Black-Scholes option pricing model. The Series B convertible preferred stock warrants were recorded at fair value using a Monte Carlo model. The fair value of all warrants, except as noted below, was remeasured at each financial reporting date with any changes in fair value being recognized in other financing (expense) income, a component of other (expense) income, in the accompanying condensed consolidated statements of operations and comprehensive loss. The Company ceased the remeasurement of the fair value upon exercise of the Series A warrants and the Series B warrants becoming exercisable for shares of common stock, immediately prior to the completion of the Company’s IPO in July 2013.
Comprehensive Loss	'
	Comprehensive Loss
	The Company is required to report all components of comprehensive loss, including net loss, in the condensed consolidated financial statements in the period in which they are recognized. Comprehensive loss is defined as the change in equity during a period from transactions and other events and circumstances from nonowner sources, including unrealized gains and losses on investments. Comprehensive gains (losses) have been reflected in the condensed consolidated statements of operations and comprehensive loss for all periods presented.
Net Loss Per Share	'
	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 during the period. Diluted net loss per share is computed by dividing the net loss by the weighted average number of common shares and common share equivalents outstanding for the period. Common stock equivalents are only included when their effect is dilutive. The Company’s potentially dilutive securities, which include convertible preferred stock, warrants, outstanding stock options under the stock option plan and common stock subject to repurchase by the Company, have been excluded from the computation of diluted net loss per share in the periods in which they would be anti-dilutive. For all periods presented, there is no difference in the number of shares used to compute basic and diluted shares outstanding due to the Company’s net loss position.

	The following table sets forth the computation of basic and diluted earnings per share:


		Three Months Ended March 31,
		2014			2013
	Numerator:
	Net loss attributable to common stockholders	$	(5,243,356	)	$	(2,296,783	)

	Denominator for basic and diluted net loss per share:
	Weighted average common shares outstanding, basic and diluted		15,412,498			1,060,533

	Net loss per share applicable to common stockholders:
	Basic	$	(0.34	)	$	(2.17	)
	Diluted	$	(0.34	)	$	(2.17	)
	The following table sets forth the outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share because to do so would be anti-dilutive.


		Three Months Ended March 31,
		2014			2013
	Convertible preferred stock		—			9,565,021
	Warrants to purchase preferred stock		—			280,675
	Warrants to purchase common stock		149,704			—
	Common stock options		1,615,719			593,803
	Common stock subject to repurchase		207,680			271,099

	Total		1,973,103			10,710,598

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	3 Months Ended
Summary of Significant Accounting Policies (Tables)	Mar. 31, 2014
Accounting Policies [Abstract]	'
Schedule of Computation of Basic and Diluted Earnings Per Share	'
	The following table sets forth the computation of basic and diluted earnings per share:


		Three Months Ended March 31,
		2014			2013
	Numerator:
	Net loss attributable to common stockholders	$	(5,243,356	)	$	(2,296,783	)

	Denominator for basic and diluted net loss per share:
	Weighted average common shares outstanding, basic and diluted		15,412,498			1,060,533

	Net loss per share applicable to common stockholders:
	Basic	$	(0.34	)	$	(2.17	)
	Diluted	$	(0.34	)	$	(2.17	)
Summary of Outstanding Potentially Dilutive Securities Excluded in Calculation of Diluted Net Loss Per Share	'
	The following table sets forth the outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share because to do so would be anti-dilutive.


		Three Months Ended March 31,
		2014			2013
	Convertible preferred stock		—			9,565,021
	Warrants to purchase preferred stock		—			280,675
	Warrants to purchase common stock		149,704			—
	Common stock options		1,615,719			593,803
	Common stock subject to repurchase		207,680			271,099

	Total		1,973,103			10,710,598

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
Fair Value Measurements (Tables)	Mar. 31, 2014
Summary of Assets and Liabilities Measured at Fair Value	'
	Below is a summary of assets and liabilities measured at fair value as of March 31, 2014 and December 31, 2013.


					Fair Value Measurements Using
		March 31, 2014			Quoted Prices in		Significant		Significant
					Active Markets		Other		Unobservable
					for Identical		Observable		Inputs
					Assets (Level 1)		Inputs (Level 2)		(Level 3)
	Assets
	Money market funds	$	2,180,809		$	2,180,809	$	—	$	—
	Municipal bonds		70,000			—		70,000		—
	Corporate debt securities		48,526,378			—		48,526,378		—

	Total assets	$	50,777,187		$	2,180,809	$	48,596,378	$	—



					Fair Value Measurements Using
		December 31,			Quoted Prices in		Significant		Significant
		2013			Active Markets		Other		Unobservable
					for Identical		Observable		Inputs
					Assets (Level 1)		Inputs (Level 2)		(Level 3)
	Assets
	Money market funds	$	3,832,902		$	3,832,902	$	—	$	—
	Municipal bonds		255,000			—		255,000		—
	Corporate debt securities		50,438,149			—		50,438,149		—
	Debt securities in government sponsored entities		1,500,885			—		1,500,885		—

	Total assets	$	56,026,936		$	3,832,902	$	52,194,034	$	—

Convertible promissory notes [Member]	'
Fair Value Measurements of Using Significant Unobservable Level 3 Inputs	'
	The following table presents activity for the convertible promissory notes measured at fair value using significant unobservable Level 3 inputs during the year ended December 31, 2013 and the three months ended March 31, 2014.


		Fair Value
		Measurements at
		Reporting Date
		Using Significant
		Unobservable
		Inputs
		(Level 3)
	Balance at December 31, 2012	$	—
	Issuance of convertible promissory notes		970,000
	Accretion of debt discount to interest expense		31,439
	Conversion to equity at IPO		(1,001,439	)

	Balance at December 31, 2013		—

	Balance at March 31, 2014	$	—

Preferred stock warrant liability [Member]	'
Fair Value Measurements of Using Significant Unobservable Level 3 Inputs	'
	The following table presents activity for the convertible preferred stock warrant liability measured at fair value using significant unobservable Level 3 inputs during the year ended December 31, 2013 and the three months ended March 31, 2014.


		Fair Value
		Measurements at
		Reporting Date
		Using Significant
		Unobservable
		Inputs
		(Level 3)
	Balance at December 31, 2012	$	160,345
	Issuance of preferred stock warrants		625,679
	Changes in fair value reflected as other financing expense		3,457,184
	Conversion to equity at IPO		(4,243,208	)

	Balance at December 31, 2013		—

	Balance at March 31, 2014	$	—

Investments_Tables

Investments (Tables)	3 Months Ended
Investments (Tables)	Mar. 31, 2014
Investments Schedule [Abstract]	'
Summary of Marketable Securities	'

	The following tables summarize the Company’s marketable securities:



	As of March 31, 2014	Maturity	Amortized		Unrealized		Unrealized			Estimated
	As of March 31, 2014	(in years)	Cost		Gains		Losses			Fair Value
	Corporate debt securities	1 or less	$	46,776,006	$	—	$	(766	)	$	46,775,240
	Corporate debt securities	2-Jan		1,752,246		—		(1,108	)		1,751,138
	Municipal bonds	1 or less		70,000		—		—			70,000

	Total		$	48,598,252	$	—	$	(1,874	)	$	48,596,378


	As of December 31, 2013	Maturity	Amortized		Unrealized		Unrealized			Estimated
	As of December 31, 2013	(in years)	Cost		Gains		Losses			Fair Value
	Corporate debt securities	1 or less	$	47,172,466	$	11,148	$	—		$	47,183,614
	Corporate debt securities	1 - 2		3,254,329		206		—			3,254,535
	Debt securities in government sponsored entities	1 - 2		1,500,742		143		—			1,500,885
	Municipal bonds	1 or less		255,000		—		—			255,000

	Total		$	52,182,537	$	11,497	$	—		$	52,194,034

Property_and_Equipment_Tables

Property and Equipment (Tables)	3 Months Ended
Property and Equipment (Tables)	Mar. 31, 2014
Property Plant And Equipment [Abstract]	'
Schedule of Property and Equipment	'
	Property and equipment consist of the following:


		Useful	March 31,			December 31,
		Life in	2014			2013
		Years
	Furniture and fixtures	4	$	123,685		$	115,417
	Computer equipment and office equipment	4		101,218			96,569
	Leasehold improvements	4		3,645			3,645

				228,548			215,631
	Less accumulated depreciation and amortization			(195,918	)		(192,563	)

			$	32,630		$	23,068

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	3 Months Ended
Stockholders' Equity (Tables)	Mar. 31, 2014
Equity [Abstract]	'
Summary of Stock Option Activity	'
	The following table summarizes the Company’s stock option activity under all stock option plans for the three months ended March 31, 2014:


		Total			Weighted-
		Options			Average
					Exercise
					Price
	Balance at December 31, 2013		790,590		$	4.01
	Granted		837,250			9.21
	Exercised		(12,121	)		0.99

	Balance at March 31, 2014		1,615,719		$	6.73

Summary of Common Stock Reserved for Future Issuance	'
	The following shares of common stock are reserved for future issuance at March 31, 2014:


	Common stock warrants		149,704
	Stock options issued and outstanding		1,615,719
	Authorized for future option grants		711,021

			2,476,444

Organization_and_Basis_of_Pres1

Organization and Basis of Presentation - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Organization Consolidation And Presentation Of Financial Statements [Abstract]	'	'
Date of incorporation	13-Jul-05	'
Accumulated deficit	$79,673,850	$74,430,494

Summary_of_Significant_Account3

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended		105 Months Ended
	Mar. 31, 2014	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014
Property, Plant and Equipment [Line Items]	'	'	'	'
Realized gains and losses on investments	$0	'	$0	$0
Other-than-temporary declines in value of marketable securities	0	'	0	0
Impairment losses not recognized	0	'	'	'
Unrecognized tax benefits	'	'	0	'
Changes in unrecognized tax benefits	'	$0	'	'
Minimum [Member]	'	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'	'
Estimated useful lives of the assets	'3 years	'	'	'
Maximum [Member]	'	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'	'
Estimated useful lives of the assets	'5 years	'	'	'

Summary_of_Significant_Account4

Summary of Significant Accounting Policies - Schedule of Computation of Basic and Diluted Earnings Per Share (Detail) (USD $)	3 Months Ended		105 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014
Numerator:	'	'	'
Net loss attributable to common stockholders	($5,243,356)	($2,296,783)	($68,650,875)
Denominator for basic and diluted net loss per share:	'	'	'
Weighted average common shares outstanding, basic and diluted	15,412,498	1,060,533	'
Net loss per share applicable to common stockholders:	'	'	'
Basic	($0.34)	($2.17)	'
Diluted	($0.34)	($2.17)	'

Summary_of_Significant_Account5

Summary of Significant Accounting Policies - Summary of Outstanding Potentially Dilutive Securities Excluded in Calculation of Diluted Net Loss Per Share (Detail)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Outstanding potentially dilutive securities	1,973,103	10,710,598
Convertible preferred stock [Member]	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Outstanding potentially dilutive securities	'	9,565,021
Warrants to purchase preferred stock [Member]	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Outstanding potentially dilutive securities	'	280,675
Warrants to purchase common stock [Member]	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Outstanding potentially dilutive securities	149,704	'
Common stock options [Member]	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Outstanding potentially dilutive securities	1,615,719	593,803
Common stock subject to repurchase [Member]	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Outstanding potentially dilutive securities	207,680	271,099

Fair_Value_Measurements_Summar

Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets fair value	$50,777,187	$56,026,936
Money market funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets fair value	2,180,809	3,832,902
Municipal bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets fair value	70,000	255,000
Corporate debt securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets fair value	48,526,378	50,438,149
Debt securities in government sponsored entities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets fair value	'	1,500,885
Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets fair value	2,180,809	3,832,902
Level 1 [Member] \| Money market funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets fair value	2,180,809	3,832,902
Level 1 [Member] \| Municipal bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets fair value	'	'
Level 1 [Member] \| Corporate debt securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets fair value	'	'
Level 1 [Member] \| Debt securities in government sponsored entities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets fair value	'	'
Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets fair value	48,596,378	52,194,034
Level 2 [Member] \| Money market funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets fair value	'	'
Level 2 [Member] \| Municipal bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets fair value	70,000	255,000
Level 2 [Member] \| Corporate debt securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets fair value	48,526,378	50,438,149
Level 2 [Member] \| Debt securities in government sponsored entities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets fair value	'	1,500,885
Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets fair value	'	'
Level 3 [Member] \| Money market funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets fair value	'	'
Level 3 [Member] \| Municipal bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets fair value	'	'
Level 3 [Member] \| Corporate debt securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets fair value	'	'
Level 3 [Member] \| Debt securities in government sponsored entities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets fair value	'	'

Fair_Value_Measurements_Fair_V

Fair Value Measurements - Fair Value Measurements of Using Significant Unobservable Level 3 Inputs (Detail) (Level 3 [Member], USD $)	12 Months Ended
	Dec. 31, 2013	Mar. 31, 2014
Convertible promissory notes [Member]	'	'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'
Beginning balance	'	'
Issuance of securities	970,000	'
Accretion of debt discount to interest expense	31,439	'
Conversion to equity at IPO	-1,001,439	'
Ending balance	'	'
Preferred stock warrant liability [Member]	'	'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'
Beginning balance	160,345	'
Issuance of securities	625,679	'
Changes in fair value reflected as other financing expense	3,457,184	'
Conversion to equity at IPO	-4,243,208	'
Ending balance	'	'

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (Detail) (Convertible promissory notes [Member], USD $)	3 Months Ended
	Mar. 31, 2014
Convertible promissory notes [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Discount rate on fair value	15.00%
Initial fair value of notes	$970,000

Investments_Summary_of_Marketa

Investments - Summary of Marketable Securities (Detail) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	$48,598,252	$52,182,537
Unrealized Gains	'	11,497
Unrealized Losses	-1,874	'
Estimated Fair Value	48,596,378	52,194,034
Corporate debt securities [Member] \| 1 or less years of maturity [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Maturity (in years)	'1 or less	'1 or less
Amortized Cost	46,776,006	47,172,466
Unrealized Gains	'	11,148
Unrealized Losses	-766	'
Estimated Fair Value	46,775,240	47,183,614
Corporate debt securities [Member] \| 1 - 2 years of maturity [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Maturity (in years)	'1 - 2 Year	'1 - 2
Amortized Cost	1,752,246	3,254,329
Unrealized Gains	'	206
Unrealized Losses	-1,108	'
Estimated Fair Value	1,751,138	3,254,535
Debt securities in government sponsored entities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Maturity (in years)	'	'1 - 2
Amortized Cost	'	1,500,742
Unrealized Gains	'	143
Estimated Fair Value	'	1,500,885
Municipal bonds [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Maturity (in years)	'1 or less	'1 or less
Amortized Cost	70,000	255,000
Unrealized Gains	'	'
Unrealized Losses	'	'
Estimated Fair Value	$70,000	$255,000

Property_and_Equipment_Schedul

Property and Equipment - Schedule of Property and Equipment (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]	'	'
Property and equipment, gross	$228,548	$215,631
Less accumulated depreciation and amortization	-195,918	-192,563
Property and equipment, net	32,630	23,068
Furniture and fixtures [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property and equipment, Useful Life	'4 years	'
Property and equipment, gross	123,685	115,417
Computer equipment and office equipment [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property and equipment, Useful Life	'4 years	'
Property and equipment, gross	101,218	96,569
Leasehold improvements [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property and equipment, Useful Life	'4 years	'
Property and equipment, gross	$3,645	$3,645

Note_Payable_Additional_Inform

Note Payable - Additional Information (Detail) (USD $)

3 Months Ended

105 Months Ended

3 Months Ended

1 Months Ended

3 Months Ended

1 Months Ended

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Jul. 31, 2013

Mar. 31, 2014

31-May-13

Mar. 31, 2014

Jul. 31, 2013

Mar. 31, 2014

Jul. 31, 2010

Jul. 31, 2013

31-May-13

Jul. 31, 2013

31-May-13

Oxford Finance LLC and Silicon Valley Bank [Member]

2013 Warrants [Member]

Convertible promissory notes [Member]

Term loan one [Member]

Promissory note [Member]

Common Stock [Member]

Series B convertible preferred stock [Member]

Series B Preferred Stock [Member]

2013 Warrants [Member]

Oxford Finance LLC and Silicon Valley Bank [Member]

Pfizer Inc. [Member]

2013 Warrants [Member]

Convertible promissory notes [Member]

Term loan one [Member]

Convertible promissory notes [Member]

2013 Warrants [Member]

Short-term Debt [Line Items]

Note payable

$1,000,000

Debt instrument, interest rate

6.00%

7.00%

Debt instrument, maturity date

29-Jul-20

Convertible promissory note

1,000,000

Maturity and repayment terms

'The 2013 Notes accrued interest at a rate of 6% per annum and were due and payable on the earlier of (1) any date after November 30, 2013 upon which holders of 75% of the outstanding principal amount of all such 2013 Notes demand repayment, or (2) the occurrence of a change of control of the Company, subject in each case to their earlier conversion in the event the Company completed a qualified initial public offering or private placement of debt and/or equity.

Discount rate on fair value

15.00%

Initial fair value of notes

970,000

Conversion of notes plus accrued interest into shares of common stock

91,948

Warrant exercisable to purchase shares

13,468

136,236

1,124,026

Exercise price of warrant per share

7.43

0.9

Warrant expiration date

30-May-18

3-Jul-23

Initial value of warrants

506,000

Deemed distribution from promissory note and warrant issuance

474,561

Line of credit facility, maximum borrowing capacity

15,000,000

1,000,000

Warrant issued

111,112

Credit facility termination date

25-Sep-13

Carrying value of warrant

$119,679

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail) (USD $)

1 Months Ended

3 Months Ended

12 Months Ended

105 Months Ended

12 Months Ended

1 Months Ended

3 Months Ended

Jul. 30, 2013

Jul. 31, 2013

Mar. 31, 2014

Mar. 31, 2013

Dec. 31, 2006

Dec. 31, 2005

Mar. 31, 2014

Jul. 30, 2013

Dec. 31, 2006

Dec. 31, 2005

31-May-13

Mar. 31, 2014

Series A Warrants [Member]

Common Stock [Member]

Series A Preferred Stock [Member]

Convertible promissory notes [Member]

2013 Warrants [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Common stock, shares issued to founders

181,818

727,273

Common stock, value of shares issued to founders

$45,000

$6,000

Reverse stock split outstanding common stock

'1-for-8.25

Reverse stock split of outstanding common stock ratio

0.12

Stock issued during period, shares, new issues

6,000,000

Issuing price per share

$11

Net proceeds from the issuance of common stock

58,600,000

58,608,454

Warrant issued

2,333,320

Other financing income (expense)

3,500,000

-547,164

-4,267,839

Convertible preferred stock warrants

280,675

Warrant exercisable to purchase shares

149,704

Exercise price of warrant per share

7.43

Stock-based compensation

$379,433

$21,418

$1,034,266

Stockholders_Equity_Summary_of

Stockholders' Equity - Summary of Stock Option Activity (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Total Options, Beginning balance	790,590
Total Options, Granted	837,250
Total Options, Exercised	-12,121
Total Options, Ending balance	1,615,719
Weighted-Average Exercise Price, Beginning balance	$4.01
Weighted-Average Exercise Price, Granted	$9.21
Weighted-Average Exercise Price, Exercised	$0.99
Weighted-Average Exercise Price, Ending balance	$6.73

Stockholders_Equity_Summary_of1

Stockholders' Equity - Summary of Common Stock Reserved for Future Issuance (Detail)	Mar. 31, 2014
Common Stock Reserved For Future Issuance [Abstract]	'
Common stock warrants	149,704
Stock options issued and outstanding	1,615,719
Authorized for future option grants	711,021
Shares of common stock are reserved for future issuance	2,476,444

Commitments_Additional_Informa

Commitments - Additional Information (Detail) (USD $)	3 Months Ended
Commitments - Additional Information (Detail) (USD $)	Mar. 31, 2014	Mar. 31, 2013	Jul. 31, 2010
Operating Leased Assets [Line Items]	'	'	'
Rent expense	$44,883	$38,514	'
Stock purchase agreement, amount payable upon the achievement of specified regulatory milestone	'	'	18,000,000
Operating lease term through June 30, 2014 [Member]	'	'	'
Operating Leased Assets [Line Items]	'	'	'
Future minimum payments for noncancelable operating lease	29,922	'	'
Operating lease term July 2014 through November 2019 [Member]	'	'	'
Operating Leased Assets [Line Items]	'	'	'
Future minimum payments for noncancelable operating lease	$1,600,000	'	'

Spinoff_of_Idun_Pharmaceutical1

Spin-off of Idun Pharmaceuticals, Inc. - Additional Information (Detail) (Idun Pharmaceuticals, Inc. [Member], USD $)	1 Months Ended
In Millions, unless otherwise specified	Jan. 31, 2013
Restructuring Cost and Reserve [Line Items]	'
Change in equity as a result of spin-off	$0.50
Spin-off [Member]	'
Restructuring Cost and Reserve [Line Items]	'
Payments for restructuring	$0.50