Histogen (HSTO) 10-Q 8 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	1-May-15
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Trading Symbol	CNAT
Entity Registrant Name	Conatus Pharmaceuticals Inc.
Entity Central Index Key	1383701
Current Fiscal Year End Date	-19
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		19,737,407

Condensed_Balance_Sheets

Condensed Balance Sheets (USD $)	Mar. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$8,302,715	$9,912,674
Marketable securities	22,700,616	27,159,272
Prepaid and other current assets	541,111	796,818
Total current assets	31,544,442	37,868,764
Property and equipment, net	219,970	237,066
Other assets	558,704	342,051
Total assets	32,323,116	38,447,881
Current liabilities:
Accounts payable and accrued expenses	2,249,497	3,003,612
Accrued compensation	875,533	1,171,621
Total current liabilities	3,125,030	4,175,233
Note payable	1,000,000	1,000,000
Deferred rent	93,994	58,699
Stockholders' equity:
Preferred stock, $0.0001 par value; 10,000,000 shares authorized; no shares issued and outstanding	0	0
Common stock, $0.0001 par value; 200,000,000 shares authorized; 15,712,407 shares issued and 15,609,230 shares outstanding, excluding 103,177 shares subject to repurchase, at March 31, 2015; 15,695,834 shares issued and 15,560,614 shares outstanding, excluding 135,220 shares subject to repurchase, at December 31, 2014	1,561	1,556
Additional paid-in capital	130,835,119	129,976,075
Accumulated other comprehensive loss	-2,539	-13,297
Accumulated deficit	-102,730,049	-96,750,385
Total stockholders' equity	28,104,092	33,213,949
Total liabilities and stockholders' equity	$32,323,116	$38,447,881

Condensed_Balance_Sheets_Paren

Condensed Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Preferred stock, par value	$0.00	$0.00
Preferred stock, shares authorized	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	15,712,407	15,695,834
Common stock, shares outstanding	15,609,230	15,560,614
Common stock, shares subject to repurchase	103,177	135,220

Condensed_Statements_of_Operat

Condensed Statements of Operations and Comprehensive Loss (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Operating expenses:
Research and development	$3,883,613	$3,650,598
General and administrative	2,081,309	1,595,247
Total operating expenses	5,964,922	5,245,845
Other income (expense):
Interest income	11,419	20,773
Interest expense	-17,500	-17,500
Other expense	-8,661	-784
Total other (expense) income	-14,742	2,489
Net loss	-5,979,664	-5,243,356
Other comprehensive income (loss):
Net unrealized gains (losses) on marketable securities	10,758	-13,371
Comprehensive loss	($5,968,906)	($5,256,727)
Net loss per share, basic and diluted	($0.38)	($0.34)
Weighted average shares outstanding used in computing net loss per share, basic and diluted	15,581,886	15,412,498

Condensed_Statements_of_Cash_F

Condensed Statements of Cash Flows (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Operating activities
Net loss	($5,979,664)	($5,243,356)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	17,096	3,356
Stock-based compensation expense	821,672	379,433
Amortization of premium on marketable securities	102,775	195,533
Changes in operating assets and liabilities:
Prepaid and other current assets	272,957	-141,660
Other assets		-62,981
Accounts payable and accrued expenses	-939,801	665,628
Accrued compensation	-278,069	-857,078
Deferred rent	35,295
Net cash used in operating activities	-5,947,739	-5,061,125
Investing activities
Maturities of marketable securities	14,578,000	13,031,000
Purchase of marketable securities	-10,211,361	-9,642,248
Capital expenditures		-12,918
Net cash provided by investing activities	4,366,639	3,375,834
Financing activities
Deferred public offering costs	-30,965
Proceeds from exercise of stock options	2,106	12,000
Net cash (used in) provided by financing activities	-28,859	12,000
Net decrease in cash and cash equivalents	-1,609,959	-1,673,291
Cash and cash equivalents at beginning of period	9,912,674	4,158,953
Cash and cash equivalents at end of period	8,302,715	2,485,662
Supplemental disclosure of cash flow information:
Cash paid for interest	17,500	17,500
Supplemental schedule of noncash investing and financing activities
Deferred public offering costs included in accounts payable	$185,688

Organization_and_Basis_of_Pres

Organization and Basis of Presentation	3 Months Ended
	Mar. 31, 2015
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, 2015, the Company has devoted substantially all of its efforts to product development and has not realized revenues from its planned principal operations.
	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, 2015, had an accumulated deficit of $102.7 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 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 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 financial statements are not necessarily indicative of the results that may be expected for any future periods. These unaudited interim condensed financial statements should be read in conjunction with the audited consolidated financial statements and the notes thereto for the year ended December 31, 2014 included in the Company’s annual report on Form 10-K filed with the SEC on March 13, 2015.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies		2	Summary of Significant Accounting Policies
	Use of Estimates
	The preparation of condensed 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.
	Marketable Securities
	The Company classifies its marketable securities as available-for-sale and records such assets at estimated fair value in the condensed balance sheets, with unrealized gains and losses, if any, reported as a component of other comprehensive income (loss) within the condensed statements of operations and comprehensive loss and as a separate component of stockholders’ equity. The Company classifies marketable securities with remaining maturities greater than one year as current assets because such marketable securities are available to fund the Company’s current operations. 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 were no realized gains and losses for the three-month periods ended March 31, 2015 and 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.
	Stock-Based Compensation
	Stock-based compensation expense for stock option grants under the Company’s stock option plans is recorded at the estimated fair value of the award as of the grant date and is recognized as expense on a straight-line basis over the requisite service period of the stock-based award. Stock-based compensation expense for employee stock purchases under the Company’s 2013 Employee Stock Purchase Plan (the ESPP) is recorded at the estimated fair value of the purchase as of the plan enrollment date and is recognized as expense on a straight-line basis over the applicable six-month ESPP offering period. The estimation of stock option and employee stock purchase plan fair value requires management to make estimates and judgments about, among other things, employee exercise behavior, forfeiture rates and volatility of the Company’s common stock. The judgments directly affect the amount of compensation expense that will be recognized.
	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, 2015.
	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, 2014, there are no unrecognized tax benefits included in the condensed balance sheet that would, if recognized, affect the Company’s effective tax rate, and the Company has noted no material changes through March 31, 2015. The Company has not recognized interest and penalties in the condensed balance sheets or condensed statements of operations and comprehensive loss. The Company is subject to U.S. and California taxation. As of December 31, 2014, the Company’s tax years beginning 2005 to date are subject to examination by taxing authorities.
	Comprehensive Loss
	The Company is required to report all components of comprehensive loss, including net loss, in the condensed 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 marketable securities. Comprehensive gains (losses) have been reflected in the condensed statements of operations and comprehensive loss for all periods presented.
	Segment Reporting
	Operating segments are identified as components of an enterprise about which separate discrete financial information is used in making decisions regarding resource allocation and assessing performance. To date, the Company has viewed its operations and managed its business as one segment operating primarily in the United States.
	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 warrants, outstanding stock options under the Company’s stock option plans, common stock subject to repurchase by the Company and potential shares to be purchased under the ESPP, 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 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:
			March 31,
			2015		2014
	Warrants to purchase common stock			149,704		149,704
	Common stock options			2,370,073		1,615,719
	Common stock subject to repurchase			103,177		207,680
	ESPP shares pending issuance			5,154		—
	Total			2,628,108		1,973,103
	Recent Accounting Pronouncements
	In August 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2014-15, Presentation of Financial Statements—Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern. This guidance requires management to perform interim and annual assessments on whether there are conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern within one year of the date the financial statements are issued. If such conditions or events exist, certain disclosures are required. ASU No. 2014-15 is effective for the annual period ending after December 15, 2016, and for annual and interim periods thereafter. Early adoption is permitted. The Company is currently evaluating the impact of the pending adoption of ASU No. 2014-15 on its financial statements and related disclosures.

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2015
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, 2015 and December 31, 2014.
					Fair Value Measurements Using
			March 31,		Quoted Prices in		Significant		Significant
			2015		Active Markets		Other		Unobservable
					for Identical		Observable		Inputs
					Assets (Level 1)		Inputs (Level 2)		(Level 3)
	Assets
	Money market funds		$	6,671,248	$	6,671,248	$	—	$	—
	Corporate debt securities			22,700,616		—		22,700,616		—
	Total assets		$	29,371,864	$	6,671,248		22,700,616	$	—
					Fair Value Measurements Using
			December 31,		Quoted Prices in		Significant		Significant
			2014		Active Markets		Other		Unobservable
					for Identical		Observable		Inputs
					Assets (Level 1)		Inputs (Level 2)		(Level 3)
	Assets
	Money market funds		$	6,998,111	$	6,998,111	$	—	$	—
	Municipal bonds			70,000		—		70,000		—
	Corporate debt securities			28,589,331		—		28,589,331		—
	Total assets		$	35,657,442	$	6,998,111	$	28,659,331	$	—
	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.

Marketable_Securities

Marketable Securities	3 Months Ended
	Mar. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	4	Marketable Securities
	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, 2015		Maturity		Amortized		Unrealized		Unrealized			Estimated
			(in years)		Cost		Gains		Losses			Fair Value
	Corporate debt securities			1 or less	$	22,703,155	$	2,675	$	(5,214	)	$	22,700,616
	Total				$	22,703,155	$	2,675	$	(5,214	)	$	22,700,616
	As of December 31, 2014		Maturity		Amortized		Unrealized		Unrealized			Estimated
			(in years)		Cost		Gains		Losses			Fair Value
	Corporate debt securities			1 or less	$	25,795,008	$	1,137	$	(9,223	)	$	25,786,922
	Corporate debt securities			1 - 2		1,307,561		—		(5,211	)		1,302,350
	Municipal bonds			1 or less		70,000		—		—			70,000
	Total				$	27,172,569	$	1,137	$	(14,434	)	$	27,159,272

Property_and_Equipment

Property and Equipment	3 Months Ended
	Mar. 31, 2015
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	2015			2014
			Years
	Furniture and fixtures		4	$	239,788		$	239,788
	Computer equipment and office equipment		4		162,921			162,921
	Leasehold improvements		5		61,533			61,533
					464,242			464,242
	Less accumulated depreciation and amortization				(244,272	)		(227,176	)
				$	219,970		$	237,066

Note_Payable

Note Payable	3 Months Ended
	Mar. 31, 2015
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. (Pfizer). 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 Company’s initial public offering (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.

Stockholders_Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stockholders' Equity		7	Stockholders’ Equity
	Common Stock
	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.
	On August 14, 2014, the Company entered into an At Market Issuance Sales Agreement (the Sales Agreement) with MLV & Co. LLC (MLV), pursuant to which the Company may sell from time to time, at its option, up to an aggregate of $50.0 million of shares of its common stock through MLV, as sales agent. Sales of the Company’s common stock made pursuant to the Sales Agreement, if any, will be made on The NASDAQ Global Market (Nasdaq) by means of ordinary brokers’ transactions at market prices. Additionally, under the terms of the Sales Agreement, the Company may also sell shares of its common stock through MLV, on Nasdaq or otherwise, at negotiated prices or at prices related to the prevailing market price. Under the terms of the Sales Agreement, MLV may not engage in any proprietary trading or trading as principal for MLV’s own account. MLV has agreed to use commercially reasonable efforts consistent with its normal trading and sales practices to sell the Company’s common stock from time to time, based upon the Company’s instructions (including any price, time or size limits or other customary parameters or conditions the Company may impose). The Company cannot provide any assurances that it will issue any shares pursuant to the Sales Agreement. The Company has agreed to pay a commission rate equal to up to 3% of the gross sales price per share sold. The Company has also agreed to provide MLV with customary indemnification and contribution rights. The Company has incurred legal and accounting costs of approximately $0.3 million, as of March 31, 2015, in connection with the commencement of the Sales Agreement, which are recorded in other assets on the balance sheet until such time as the Company issues shares pursuant to the Sales Agreement. As of March 31, 2015, no shares were issued pursuant to the Sales Agreement.
	In April 2015, the Company completed a public offering of 4,025,000 shares of its common stock at a public offering price of $5.75 per share. The shares were registered pursuant to a registration statement on Form S-3 filed on August 14, 2014. The Company received net proceeds of approximately $21.4 million, after deducting underwriting discounts and commissions and estimated offering-related transaction costs. The Company has incurred legal and accounting costs of approximately $0.2 million, as of March 31, 2015, in connection with this public offering, including certain costs associated with the preparation of the related registration statement on Form S-3, which are recorded in other assets on the balance sheet.
	Warrants
	In 2013, the Company issued warrants exercisable for 1,124,026 shares of Series B preferred stock, at an exercise price of $0.90 per share, to certain existing investors in conjunction with a private placement (the 2013 Warrants) and warrants exercisable for 111,112 shares of Series B preferred stock, at an exercise price of $0.90 per shares, to Oxford Finance LLC and Silicon Valley Bank in conjunction with a loan and security agreement (the Lender Warrants). Upon completion of the IPO, the 2013 Warrants and the Lender Warrants became exercisable for 136,236 and 13,468 shares of common stock, respectively, at an exercise price of $7.43 per share. The 2013 Warrants and the Lender Warrants will expire on May 30, 2018 and July 3, 2023, respectively.
	Stock Options
	The following table summarizes the Company’s stock option activity under all stock option plans for the three months ended March 31, 2015:
			Total			Weighted-
			Options			Average
						Exercise
						Price
	Balance at December 31, 2014			1,859,034		$	6.84
	Granted			552,250			6.43
	Exercised			(19,211	)		1.02
	Cancelled			(22,000	)		8.32
	Balance at March 31, 2015			2,370,073		$	6.78
	Stock-Based Compensation
	The Company recorded stock-based compensation of $821,672 and $379,433 for the three months ended March 31, 2015 and 2014, respectively.
	Common Stock Reserved for Future Issuance
	The following shares of common stock are reserved for future issuance at March 31, 2015:
	Common stock warrants			149,704
	Stock options issued and outstanding			2,370,073
	Authorized for future option grants			661,038
	Authorized for the ESPP			450,000
				3,630,815

Commitments

Commitments	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments		8	Commitments
	In February 2014, the Company entered into a noncancelable operating lease for certain office space starting in July 2014 through December 2019 with a renewal option for an additional five years. Future minimum payments under this noncancelable operating lease total approximately $1.4 million at March 31, 2015.
	Rent expense was $71,130 and $44,883 for the three months ended March 31, 2015 and 2014, respectively.
	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., which was subsequently spun off to the Company’s stockholders in January 2013. Under the agreement, the Company may be required to make payments to Pfizer totaling $18.0 million upon the achievement of specified regulatory milestones.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates
	The preparation of condensed 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.
Marketable Securities	Marketable Securities
	The Company classifies its marketable securities as available-for-sale and records such assets at estimated fair value in the condensed balance sheets, with unrealized gains and losses, if any, reported as a component of other comprehensive income (loss) within the condensed statements of operations and comprehensive loss and as a separate component of stockholders’ equity. The Company classifies marketable securities with remaining maturities greater than one year as current assets because such marketable securities are available to fund the Company’s current operations. 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 were no realized gains and losses for the three-month periods ended March 31, 2015 and 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.
Stock-Based Compensation	Stock-Based Compensation
	Stock-based compensation expense for stock option grants under the Company’s stock option plans is recorded at the estimated fair value of the award as of the grant date and is recognized as expense on a straight-line basis over the requisite service period of the stock-based award. Stock-based compensation expense for employee stock purchases under the Company’s 2013 Employee Stock Purchase Plan (the ESPP) is recorded at the estimated fair value of the purchase as of the plan enrollment date and is recognized as expense on a straight-line basis over the applicable six-month ESPP offering period. The estimation of stock option and employee stock purchase plan fair value requires management to make estimates and judgments about, among other things, employee exercise behavior, forfeiture rates and volatility of the Company’s common stock. The judgments directly affect the amount of compensation expense that will be recognized.
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, 2015.
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, 2014, there are no unrecognized tax benefits included in the condensed balance sheet that would, if recognized, affect the Company’s effective tax rate, and the Company has noted no material changes through March 31, 2015. The Company has not recognized interest and penalties in the condensed balance sheets or condensed statements of operations and comprehensive loss. The Company is subject to U.S. and California taxation. As of December 31, 2014, the Company’s tax years beginning 2005 to date are subject to examination by taxing authorities.
Comprehensive Loss	Comprehensive Loss
	The Company is required to report all components of comprehensive loss, including net loss, in the condensed 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 marketable securities. Comprehensive gains (losses) have been reflected in the condensed statements of operations and comprehensive loss for all periods presented.
Segment Reporting	Segment Reporting
	Operating segments are identified as components of an enterprise about which separate discrete financial information is used in making decisions regarding resource allocation and assessing performance. To date, the Company has viewed its operations and managed its business as one segment operating primarily in the United States.
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 warrants, outstanding stock options under the Company’s stock option plans, common stock subject to repurchase by the Company and potential shares to be purchased under the ESPP, 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 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:
		March 31,
		2015		2014
	Warrants to purchase common stock		149,704		149,704
	Common stock options		2,370,073		1,615,719
	Common stock subject to repurchase		103,177		207,680
	ESPP shares pending issuance		5,154		—
	Total		2,628,108		1,973,103
Recent Accounting Pronouncements	Recent Accounting Pronouncements
	In August 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2014-15, Presentation of Financial Statements—Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern. This guidance requires management to perform interim and annual assessments on whether there are conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern within one year of the date the financial statements are issued. If such conditions or events exist, certain disclosures are required. ASU No. 2014-15 is effective for the annual period ending after December 15, 2016, and for annual and interim periods thereafter. Early adoption is permitted. The Company is currently evaluating the impact of the pending adoption of ASU No. 2014-15 on its financial statements and related disclosures.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
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:
		March 31,
		2015		2014
	Warrants to purchase common stock		149,704		149,704
	Common stock options		2,370,073		1,615,719
	Common stock subject to repurchase		103,177		207,680
	ESPP shares pending issuance		5,154		—
	Total		2,628,108		1,973,103

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
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, 2015 and December 31, 2014.
				Fair Value Measurements Using
		March 31,		Quoted Prices in		Significant		Significant
		2015		Active Markets		Other		Unobservable
				for Identical		Observable		Inputs
				Assets (Level 1)		Inputs (Level 2)		(Level 3)
	Assets
	Money market funds	$	6,671,248	$	6,671,248	$	—	$	—
	Corporate debt securities		22,700,616		—		22,700,616		—
	Total assets	$	29,371,864	$	6,671,248		22,700,616	$	—
				Fair Value Measurements Using
		December 31,		Quoted Prices in		Significant		Significant
		2014		Active Markets		Other		Unobservable
				for Identical		Observable		Inputs
				Assets (Level 1)		Inputs (Level 2)		(Level 3)
	Assets
	Money market funds	$	6,998,111	$	6,998,111	$	—	$	—
	Municipal bonds		70,000		—		70,000		—
	Corporate debt securities		28,589,331		—		28,589,331		—
	Total assets	$	35,657,442	$	6,998,111	$	28,659,331	$	—

Marketable_Securities_Tables

Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Summary of Marketable Securities	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, 2015	Maturity		Amortized		Unrealized		Unrealized			Estimated
		(in years)		Cost		Gains		Losses			Fair Value
	Corporate debt securities		1 or less	$	22,703,155	$	2,675	$	(5,214	)	$	22,700,616
	Total			$	22,703,155	$	2,675	$	(5,214	)	$	22,700,616
	As of December 31, 2014	Maturity		Amortized		Unrealized		Unrealized			Estimated
		(in years)		Cost		Gains		Losses			Fair Value
	Corporate debt securities		1 or less	$	25,795,008	$	1,137	$	(9,223	)	$	25,786,922
	Corporate debt securities		1 - 2		1,307,561		—		(5,211	)		1,302,350
	Municipal bonds		1 or less		70,000		—		—			70,000
	Total			$	27,172,569	$	1,137	$	(14,434	)	$	27,159,272

Property_and_Equipment_Tables

Property and Equipment (Tables)	3 Months Ended
	Mar. 31, 2015
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment consist of the following:
		Useful	March 31,			December 31,
		Life in	2015			2014
		Years
	Furniture and fixtures	4	$	239,788		$	239,788
	Computer equipment and office equipment	4		162,921			162,921
	Leasehold improvements	5		61,533			61,533
				464,242			464,242
	Less accumulated depreciation and amortization			(244,272	)		(227,176	)
			$	219,970		$	237,066

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [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, 2015:
		Total			Weighted-
		Options			Average
					Exercise
					Price
	Balance at December 31, 2014		1,859,034		$	6.84
	Granted		552,250			6.43
	Exercised		(19,211	)		1.02
	Cancelled		(22,000	)		8.32
	Balance at March 31, 2015		2,370,073		$	6.78
Summary of Common Stock Reserved for Future Issuance	The following shares of common stock are reserved for future issuance at March 31, 2015:
	Common stock warrants		149,704
	Stock options issued and outstanding		2,370,073
	Authorized for future option grants		661,038
	Authorized for the ESPP		450,000
			3,630,815

Organization_and_Basis_of_Pres1

Organization and Basis of Presentation - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Date of incorporation	13-Jul-05
Accumulated deficit	($102,730,049)	($96,750,385)

Summary_of_Significant_Account3

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
	Segment
Property, Plant and Equipment [Line Items]
Realized gains and losses on investments	$0	$0
Other-than-temporary declines in value of marketable securities	0
Impairment losses not recognized	0
Unrecognized tax benefits	$0
Number of operating segment	1
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 - Summary of Outstanding Potentially Dilutive Securities Excluded in Calculation of Diluted Net Loss Per Share (Detail)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Outstanding potentially dilutive securities	2,628,108	1,973,103
Warrants to purchase common stock [Member] | Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Outstanding potentially dilutive securities	149,704	149,704
Common stock options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Outstanding potentially dilutive securities	2,370,073	1,615,719
ESPP shares pending issuance [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Outstanding potentially dilutive securities	5,154
Common stock subject to repurchase [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Outstanding potentially dilutive securities	103,177	207,680

Fair_Value_Measurements_Summar

Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value	$29,371,864	$35,657,442
Money market funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value	6,671,248	6,998,111
Municipal bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value		70,000
Corporate debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value	22,700,616	28,589,331
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value	6,671,248	6,998,111
Level 1 [Member] | Money market funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value	6,671,248	6,998,111
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value	22,700,616	28,659,331
Level 2 [Member] | Municipal bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value		70,000
Level 2 [Member] | Corporate debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value	$22,700,616	$28,589,331

Marketable_Securities_Summary_

Marketable Securities - Summary of Marketable Securities (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$22,703,155	$27,172,569
Unrealized Gains	2,675	1,137
Unrealized Losses	-5,214	-14,434
Estimated Fair Value	22,700,616	27,159,272
Corporate debt securities [Member] | 1 or less years of maturity [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	22,703,155	25,795,008
Unrealized Gains	2,675	1,137
Unrealized Losses	-5,214	-9,223
Estimated Fair Value	22,700,616	25,786,922
Corporate debt securities [Member] | 1 - 2 years of maturity [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		1,307,561
Unrealized Losses		-5,211
Estimated Fair Value		1,302,350
Municipal bonds [Member] | 1 or less years of maturity [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		70,000
Estimated Fair Value		$70,000

Property_and_Equipment_Schedul

Property and Equipment - Schedule of Property and Equipment (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$464,242	$464,242
Less accumulated depreciation and amortization	-244,272	-227,176
Property and equipment, net	219,970	237,066
Furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Useful Life	4 years
Property and equipment, gross	239,788	239,788
Computer equipment and office equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Useful Life	4 years
Property and equipment, gross	162,921	162,921
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Useful Life	5 years
Property and equipment, gross	$61,533	$61,533

Note_Payable_Additional_Inform

Note Payable - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Jul. 31, 2010
Debt Instrument [Line Items]
Note payable	1,000,000	$1,000,000
Promissory note [Member] | Pfizer Inc. [Member]
Debt Instrument [Line Items]
Note payable			$1,000,000
Debt instrument, interest rate	7.00%
Debt instrument, maturity date	29-Jul-20

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended		1 Months Ended	0 Months Ended
	Jul. 31, 2013	Mar. 31, 2015	Mar. 31, 2014	Apr. 30, 2015	Aug. 14, 2014	Dec. 31, 2014	31-May-13
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares issued under sales agreement	6,000,000
Initial public offering of common stock, price per share	$11
Net proceeds from the issuance of common stock	$58,600,000
Common stock, value of shares issued under sales agreement		1,561				1,556
Warrants exercisable, outstanding		149,704
Stock-based compensation		821,672	379,433
Subsequent Events [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares issued under sales agreement				4,025,000
Initial public offering of common stock, price per share				$5.75
Net proceeds from the issuance of common stock				21,400,000
2013 Warrants [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants exercisable shares							1,124,026
Exercise price of warrant per share							$0.90
Warrant expiration date		30-May-18
Lender Warrants [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants exercisable shares							111,112
Exercise price of warrant per share							$0.90
Warrant expiration date		3-Jul-23
Sales Agreement with MLV & Co LLC [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares issued under sales agreement		0
Common stock, value of shares issued under sales agreement					50,000,000
Legal and accounting costs		300,000
Sales Agreement with MLV & Co LLC [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of commission of gross sales price per share					3.00%
IPO [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Legal and accounting costs		$200,000
Common Stock [Member] | 2013 Warrants [Member] | Convertible promissory notes [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrant per share							$7.43
Warrants exercisable, outstanding							136,236
Common Stock [Member] | Lender Warrants [Member] | Convertible promissory notes [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrant per share							$7.43
Warrants exercisable, outstanding							13,468

Stockholders_Equity_Summary_of

Stockholders' Equity - Summary of Stock Option Activity (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Total Options, Beginning balance	1,859,034
Total Options, Granted	552,250
Total Options, Exercised	-19,211
Total Options, Cancelled	-22,000
Total Options, Ending balance	2,370,073
Weighted-Average Exercise Price, Beginning balance	$6.84
Weighted-Average Exercise Price, Granted	$6.43
Weighted-Average Exercise Price, Exercised	$1.02
Weighted-Average Exercise Price, Cancelled	$8.32
Weighted-Average Exercise Price, Ending balance	$6.78

Stockholders_Equity_Summary_of1

Stockholders' Equity - Summary of Common Stock Reserved for Future Issuance (Detail)	Mar. 31, 2015
Equity [Abstract]
Common stock warrants	149,704
Stock options issued and outstanding	2,370,073
Authorized for future option grants	661,038
Authorized for the ESPP	450,000
Shares of common stock are reserved for future issuance	3,630,815

Commitments_Additional_Informa

Commitments - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Jul. 31, 2010
Operating Leased Assets [Line Items]
Rent expense	$71,130	$44,883
Stock purchase agreement, amount payable upon the achievement of specified regulatory milestone			18,000,000
Operating lease term July 2014 through November 2019 [Member]
Operating Leased Assets [Line Items]
Future minimum payments for noncancelable operating lease	$1,400,000
Lease renewal term	5 years