Histogen (HSTO) 10-Q 5 Aug 16 2016 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2016	Aug. 01, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q2
Trading Symbol	CNAT
Entity Registrant Name	Conatus Pharmaceuticals Inc.
Entity Central Index Key	1,383,701
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		22,085,886

Condensed Balance Sheets

Condensed Balance Sheets - USD ($)	Jun. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 13,459,156	$ 13,876,090
Marketable securities	16,743,372	22,632,019
Prepaid and other current assets	876,823	1,982,031
Total current assets	31,079,351	38,490,140
Property and equipment, net	311,381	344,734
Other assets	876,130	892,394
Total assets	32,266,862	39,727,268
Current liabilities:
Accounts payable and accrued expenses	1,995,628	2,545,894
Accrued compensation	1,239,731	1,436,804
Total current liabilities	3,235,359	3,982,698
Note payable	1,000,000	1,000,000
Deferred rent	190,377	204,224
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; 22,085,886 shares issued and 22,072,875 shares outstanding, excluding 13,011 shares subject to repurchase, at June 30, 2016; 19,877,857 shares issued and 19,845,611 shares outstanding, excluding 32,246 shares subject to repurchase, at December 31, 2015	2,207	1,984
Additional paid-in capital	162,461,982	155,441,280
Accumulated other comprehensive income (loss)	18,977	(3,907)
Accumulated deficit	(134,642,040)	(120,899,011)
Total stockholders’ equity	27,841,126	34,540,346
Total liabilities and stockholders’ equity	$ 32,266,862	$ 39,727,268

Condensed Balance Sheets (Paren

Condensed Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2016	Dec. 31, 2015
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
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	$ 0.0001	$ 0.0001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	22,085,886	19,877,857
Common stock, shares outstanding	22,072,875	19,845,611
Common stock, shares subject to repurchase	13,011	32,246

Condensed Statements of Operati

Condensed Statements of Operations and Comprehensive Loss - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Operating expenses:
Research and development	$ 4,246,488	$ 4,070,127	$ 8,944,950	$ 7,953,740
General and administrative	2,238,134	1,994,352	4,814,261	4,075,661
Total operating expenses	6,484,622	6,064,479	13,759,211	12,029,401
Other income (expense):
Interest income	34,377	17,977	61,355	29,396
Interest expense	(17,500)	(17,500)	(35,000)	(35,000)
Other (expense) income	(3,400)	6,748	(10,173)	(1,913)
Total other income (expense)	13,477	7,225	16,182	(7,517)
Net loss	(6,471,145)	(6,057,254)	(13,743,029)	(12,036,918)
Other comprehensive income (loss):
Net unrealized gains (losses) on marketable securities	13,241	(7,352)	22,884	3,406
Comprehensive loss	$ (6,457,904)	$ (6,064,606)	$ (13,720,145)	$ (12,033,512)
Net loss per share, basic and diluted	$ (0.30)	$ (0.31)	$ (0.65)	$ (0.69)
Weighted average shares outstanding used in computing net loss per share, basic and diluted	21,542,188	19,338,167	21,085,610	17,468,148

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows - USD ($)	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating activities
Net loss	$ (13,743,029)	$ (12,036,918)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	53,518	33,979
Stock-based compensation expense	1,710,423	1,732,019
Amortization of premium on marketable securities	27,475	204,592
Changes in operating assets and liabilities:
Prepaid and other current assets	1,105,208	237,239
Accounts payable and accrued expenses	(453,147)	(474,155)
Accrued compensation	(195,343)	(19,821)
Deferred rent	(7,700)	67,459
Net cash used in operating activities	(11,502,595)	(10,255,606)
Investing activities
Maturities of marketable securities	24,347,000	23,654,000
Purchase of marketable securities	(18,462,944)	(35,837,324)
Capital expenditures	(107,165)	(2,852)
Net cash provided by (used in) investing activities	5,776,891	(12,186,176)
Financing activities
Proceeds from issuance of common stock, net of offering costs	5,275,872	21,507,006
Deferred public offering costs		(97,297)
Proceeds from stock issuances under employee stock purchase plan and exercise of stock options	32,898	49,003
Net cash provided by financing activities	5,308,770	21,458,712
Net decrease in cash and cash equivalents	(416,934)	(983,070)
Cash and cash equivalents at beginning of period	13,876,090	9,912,674
Cash and cash equivalents at end of period	13,459,156	8,929,604
Supplemental disclosure of cash flow information:
Cash paid for interest	$ 35,000	$ 35,000

Organization and Basis of Prese

Organization and Basis of Presentation	6 Months Ended
	Jun. 30, 2016
Organization Consolidation And Presentation Of Financial Statements [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 June 30, 2016, 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 June 30, 2016, had an accumulated deficit of $134.6 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 financial statements and the notes thereto for the year ended December 31, 2015 included in the Company’s annual report on Form 10-K filed with the SEC on March 11, 2016.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2016
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 six-month periods ended June 30, 2016 and 2015. 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 ESPP 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 June 30, 2016. 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, 2015, 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 June 30, 2016. 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, 2015, 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 to purchase common stock, 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. June 30, 2016 2015 Warrants to purchase common stock 149,704 149,704 Common stock options issued and outstanding 3,564,732 2,508,878 Common stock subject to repurchase 13,011 61,392 ESPP shares pending issuance 2,472 2,440 Total 3,729,919 2,722,414 Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2014-09, Revenue from Contracts with Customers (Topic 606). In August 2014, the FASB issued 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. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842). In March 2016, the FASB issued ASU No. 2016-09, Compensation—Stock Compensation (Topic 718).

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2016
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 June 30, 2016 and December 31, 2015. Fair Value Measurements Using June 30, 2016 Quoted Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Money market funds $ 7,651,017 $ 7,651,017 $ — $ — Corporate debt securities 20,893,222 — 20,893,222 — Total assets $ 28,544,239 $ 7,651,017 $ 20,893,222 $ — Fair Value Measurements Using December 31, 2015 Quoted Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Money market funds $ 10,221,563 $ 10,221,563 $ — $ — Corporate debt securities 24,334,917 — 24,334,917 — Total assets $ 34,556,480 $ 10,221,563 $ 24,334,917 $ — 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	6 Months Ended
	Jun. 30, 2016
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 June 30, 2016 Maturity (in years) Amortized Cost Unrealized Gains Unrealized Losses Estimated Fair Value Corporate debt securities 1 or less $ 16,724,395 $ 20,884 $ (1,907 ) $ 16,743,372 Total $ 16,724,395 $ 20,884 $ (1,907 ) $ 16,743,372 As of December 31, 2015 Maturity (in years) Amortized Cost Unrealized Gains Unrealized Losses Estimated Fair Value Corporate debt securities 1 or less $ 22,635,926 $ 6,770 $ (10,677 ) $ 22,632,019 Total $ 22,635,926 $ 6,770 $ (10,677 ) $ 22,632,019

Property and Equipment

Property and Equipment	6 Months Ended
	Jun. 30, 2016
Property Plant And Equipment [Abstract]
Property and Equipment	5. Property and Equipment Property and equipment consist of the following: June 30, 2016 December 31, 2015 Furniture and fixtures $ 333,670 $ 326,788 Computer equipment and office equipment 120,679 170,946 Leasehold improvements 152,217 142,032 606,566 639,766 Less accumulated depreciation and amortization (295,185 ) (295,032 ) Total $ 311,381 $ 344,734

Note Payable

Note Payable	6 Months Ended
	Jun. 30, 2016
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	6 Months Ended
	Jun. 30, 2016
Equity [Abstract]
Stockholders' Equity	7. Stockholders’ Equity Common Stock In August 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 are made on The NASDAQ Global Market (Nasdaq) under the Company’s Registration Statement on Form S-3, filed with the SEC on August 14, 2014 and declared effective by the SEC on August 25, 2014, 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 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. During the six months ended June 30, 2016, the Company sold 2,192,634 shares of its common stock pursuant to the Sales Agreement at a weighted average price per share of $2.48 and received net proceeds of $5.3 million, after deducting offering-related transaction costs and commissions. 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 share, to Oxford Finance LLC and Silicon Valley Bank in conjunction with the Company’s entry into 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 six months ended June 30, 2016: Total Options Weighted- Average Exercise Price Balance at December 31, 2015 2,464,849 $ 6.54 Granted 1,132,500 1.96 Exercised (1,212 ) 1.24 Cancelled (31,405 ) 9.42 Balance at June 30, 2016 3,564,732 $ 5.06 Stock-Based Compensation The Company recorded stock-based compensation of $0.8 million and $0.9 million for the three months ended June 30, 2016 and 2015, respectively, and $1.7 million and $1.7 million for the six months ended June 30, 2016 and 2015, respectively. Common Stock Reserved for Future Issuance The following shares of common stock were reserved for future issuance at June 30, 2016: Warrants to purchase common stock 149,704 Common stock options issued and outstanding 3,564,732 Common stock authorized for future option grants 488,867 Common stock authorized for the ESPP 565,364 Total 4,768,667

Commitments

Commitments	6 Months Ended
	Jun. 30, 2016
Commitments And Contingencies Disclosure [Abstract]
Commitments	8. Commitments In February 2014, the Company entered into a noncancelable operating lease agreement (the Lease) for certain office space with a lease term from July 2014 through December 2019 and a renewal option for an additional five years. In May 2015, the Company entered into a first amendment to the Lease (the First Lease Amendment) for additional office space starting in September 2015 through September 2020. The First Lease Amendment also extended the term of the Lease to September 2020. The monthly base rent under the Lease and the First Lease Amendment increases approximately 3% annually from $32,784 in 2015 to $39,268 in 2020. Future minimum payments under this noncancelable operating lease total $1.8 million at June 30, 2016. Rent expense was $94,501 and $79,943 for the three months ended June 30, 2016 and 2015, respectively, and $189,003 and $151,073 for the six months ended June 30, 2016 and 2015, 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 stock purchase 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 Accoun14

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2016
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 six-month periods ended June 30, 2016 and 2015. 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 ESPP 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 June 30, 2016.
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, 2015, 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 June 30, 2016. 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, 2015, 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 to purchase common stock, 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. June 30, 2016 2015 Warrants to purchase common stock 149,704 149,704 Common stock options issued and outstanding 3,564,732 2,508,878 Common stock subject to repurchase 13,011 61,392 ESPP shares pending issuance 2,472 2,440 Total 3,729,919 2,722,414
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2014-09, Revenue from Contracts with Customers (Topic 606). In August 2014, the FASB issued 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. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842). In March 2016, the FASB issued ASU No. 2016-09, Compensation—Stock Compensation (Topic 718).

Summary of Significant Accoun15

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2016
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. June 30, 2016 2015 Warrants to purchase common stock 149,704 149,704 Common stock options issued and outstanding 3,564,732 2,508,878 Common stock subject to repurchase 13,011 61,392 ESPP shares pending issuance 2,472 2,440 Total 3,729,919 2,722,414

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2016
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 June 30, 2016 and December 31, 2015. Fair Value Measurements Using June 30, 2016 Quoted Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Money market funds $ 7,651,017 $ 7,651,017 $ — $ — Corporate debt securities 20,893,222 — 20,893,222 — Total assets $ 28,544,239 $ 7,651,017 $ 20,893,222 $ — Fair Value Measurements Using December 31, 2015 Quoted Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Money market funds $ 10,221,563 $ 10,221,563 $ — $ — Corporate debt securities 24,334,917 — 24,334,917 — Total assets $ 34,556,480 $ 10,221,563 $ 24,334,917 $ —

Marketable Securities (Tables)

Marketable Securities (Tables)	6 Months Ended
	Jun. 30, 2016
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 June 30, 2016 Maturity (in years) Amortized Cost Unrealized Gains Unrealized Losses Estimated Fair Value Corporate debt securities 1 or less $ 16,724,395 $ 20,884 $ (1,907 ) $ 16,743,372 Total $ 16,724,395 $ 20,884 $ (1,907 ) $ 16,743,372 As of December 31, 2015 Maturity (in years) Amortized Cost Unrealized Gains Unrealized Losses Estimated Fair Value Corporate debt securities 1 or less $ 22,635,926 $ 6,770 $ (10,677 ) $ 22,632,019 Total $ 22,635,926 $ 6,770 $ (10,677 ) $ 22,632,019

Property and Equipment (Tables)

Property and Equipment (Tables)	6 Months Ended
	Jun. 30, 2016
Property Plant And Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment consist of the following: June 30, 2016 December 31, 2015 Furniture and fixtures $ 333,670 $ 326,788 Computer equipment and office equipment 120,679 170,946 Leasehold improvements 152,217 142,032 606,566 639,766 Less accumulated depreciation and amortization (295,185 ) (295,032 ) Total $ 311,381 $ 344,734

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2016
Equity [Abstract]
Summary of Stock Option Activity	The following table summarizes the Company’s stock option activity under all stock option plans for the six months ended June 30, 2016: Total Options Weighted- Average Exercise Price Balance at December 31, 2015 2,464,849 $ 6.54 Granted 1,132,500 1.96 Exercised (1,212 ) 1.24 Cancelled (31,405 ) 9.42 Balance at June 30, 2016 3,564,732 $ 5.06
Summary of Common Stock Reserved for Future Issuance	The following shares of common stock were reserved for future issuance at June 30, 2016: Warrants to purchase common stock 149,704 Common stock options issued and outstanding 3,564,732 Common stock authorized for future option grants 488,867 Common stock authorized for the ESPP 565,364 Total 4,768,667

Organization and Basis of Pre20

Organization and Basis of Presentation - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Date of incorporation	Jul. 13, 2005
Accumulated deficit	$ (134,642,040)	$ (120,899,011)

Summary of Significant Accoun21

Summary of Significant Accounting Policies - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2016USD ($)Segment	Jun. 30, 2015USD ($)	Dec. 31, 2015USD ($)
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 | 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 Accoun22

Summary of Significant Accounting Policies - Summary of Outstanding Potentially Dilutive Securities Excluded in Calculation of Diluted Net Loss Per Share (Detail) - shares	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Outstanding potentially dilutive securities	3,729,919	2,722,414
ESPP shares pending issuance [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Outstanding potentially dilutive securities	2,472	2,440
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 issued and outstanding [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Outstanding potentially dilutive securities	3,564,732	2,508,878
Common stock subject to repurchase [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Outstanding potentially dilutive securities	13,011	61,392

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value (Detail) - USD ($)	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value	$ 28,544,239	$ 34,556,480
Money market funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value	7,651,017	10,221,563
Corporate debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value	20,893,222	24,334,917
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value	7,651,017	10,221,563
Level 1 [Member] | Money market funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value	7,651,017	10,221,563
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value	20,893,222	24,334,917
Level 2 [Member] | Corporate debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value	$ 20,893,222	$ 24,334,917

Marketable Securities - Summary

Marketable Securities - Summary of Marketable Securities (Detail) - USD ($)	Jun. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 16,724,395	$ 22,635,926
Unrealized Gains	20,884	6,770
Unrealized Losses	(1,907)	(10,677)
Estimated Fair Value	16,743,372	22,632,019
Corporate debt securities 1 or less years of maturity [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	16,724,395	22,635,926
Unrealized Gains	20,884	6,770
Unrealized Losses	(1,907)	(10,677)
Estimated Fair Value	$ 16,743,372	$ 22,632,019

Property and Equipment - Schedu

Property and Equipment - Schedule of Property and Equipment (Detail) - USD ($)	Jun. 30, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 606,566	$ 639,766
Less accumulated depreciation and amortization	(295,185)	(295,032)
Total	311,381	344,734
Furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	333,670	326,788
Computer equipment and office equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	120,679	170,946
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 152,217	$ 142,032

Note Payable - Additional Infor

Note Payable - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015	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	Jul. 29, 2020

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Aug. 31, 2014	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2013	Dec. 31, 2015	Jul. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, value of shares issued under sales agreement		$ 2,207		$ 2,207			$ 1,984
Net proceeds from the issuance of common stock				$ 5,275,872	$ 21,507,006
Warrants exercisable, outstanding		149,704		149,704
Stock-based compensation		$ 800,000	$ 900,000	$ 1,710,423	$ 1,732,019
2013 Warrants [Member] | Convertible promissory notes [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrant expiration date				May 30, 2018
2013 Warrants [Member] | Series B Preferred Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrant exercisable to purchase shares						1,124,026
2013 Warrants [Member] | Series B Preferred Stock [Member] | Convertible promissory notes [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Exercise price of warrant per share						$ 0.90
Lender Warrants [Member] | Series B Convertible Preferred Stock | Term Loan One
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Exercise price of warrant per share						$ 0.90
Warrant issued						111,112
Warrant expiration date				Jul. 3, 2023
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
Common Stock [Member] | 2013 Warrants [Member] | Convertible promissory notes [Member] | Post IPO [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
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
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				2,192,634
Net proceeds from the issuance of common stock				$ 5,300,000
Sales Agreement with MLV & Co LLC [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, value of shares issued under sales agreement	$ 50,000,000
Percentage of commission of gross sales price per share	3.00%
Sales Agreement with MLV & Co LLC [Member] | Weighted Average [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, price per share		$ 2.48		$ 2.48

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Stock Option Activity (Detail)	6 Months Ended
	Jun. 30, 2016$ / sharesshares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Total Options, Beginning balance | shares	2,464,849
Total Options, Granted | shares	1,132,500
Total Options, Exercised | shares	(1,212)
Total Options, Cancelled | shares	(31,405)
Total Options, Ending balance | shares	3,564,732
Weighted-Average Exercise Price, Beginning balance | $ / shares	$ 6.54
Weighted-Average Exercise Price, Granted | $ / shares	1.96
Weighted-Average Exercise Price, Exercised | $ / shares	1.24
Weighted-Average Exercise Price, Cancelled | $ / shares	9.42
Weighted-Average Exercise Price, Ending balance | $ / shares	$ 5.06

Stockholders' Equity - Summar29

Stockholders' Equity - Summary of Common Stock Reserved for Future Issuance (Detail)	Jun. 30, 2016shares
Equity [Abstract]
Warrants to purchase common stock	149,704
Common stock options issued and outstanding	3,564,732
Common stock authorized for future option grants	488,867
Common stock authorized for the ESPP	565,364
Total	4,768,667

Commitments - Additional Inform

Commitments - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	May 31, 2015	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Jul. 31, 2010
Operating Leased Assets [Line Items]
Rent expense		$ 94,501	$ 79,943	$ 189,003	$ 151,073
Amount payable upon the achievement of specified regulatory milestone						$ 18,000,000
Operating lease term July 2014 through December 2019 [Member]
Operating Leased Assets [Line Items]
Lease renewal term				5 years
Future minimum payments for noncancelable operating lease		$ 1,800,000		$ 1,800,000
Operating lease term September 2015 through September 2020 [Member]
Operating Leased Assets [Line Items]
Percentage of base rent escalator	3.00%
Rent expense	$ 32,784
Lease agreement rent expense for future period	$ 39,268