ContraFect (CFRXQ) 10-Q 10 May 16 2016 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2016	May. 05, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q1
Trading Symbol	CFRX
Entity Registrant Name	CONTRAFECT Corp
Entity Central Index Key	1,478,069
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		27,485,542

Balance Sheets

Balance Sheets - USD ($)	Mar. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 7,638,646	$ 9,972,781
Marketable securities	18,627,367	22,948,872
Prepaid expenses and other current assets	1,109,706	1,176,895
Total current assets	27,375,719	34,098,548
Property and equipment, net	1,516,198	1,618,968
Other assets	143,621	143,621
Total assets	29,035,538	35,861,137
Current liabilities:
Accounts payable	1,821,341	1,517,417
Accrued liabilities	3,109,737	2,251,767
Total current liabilities	4,931,078	3,769,184
Deferred rent	987,260	972,119
Warrant liabilities	256,054	444,324
Total liabilities	6,174,392	5,185,627
Commitments and contingencies	0	0
Stockholders' equity:
Preferred stock, $0.0001 par value, 25,000,000 shares authorized and none outstanding at March 31, 2016 and December 31, 2015	0	0
Common stock, $0.0001 par value, 100,000,000 shares authorized; 27,485,542 and 27,482,692 shares issued and outstanding at March 31, 2016 and December 31, 2015, respectively	2,748	2,748
Additional paid-in capital	149,363,352	148,282,546
Accumulated other comprehensive loss	(2,381)	(30,373)
Accumulated deficit	(126,502,573)	(117,579,411)
Total stockholders' equity	22,861,146	30,675,510
Total liabilities and stockholders' equity	$ 29,035,538	$ 35,861,137

Balance Sheets (Parenthetical)

Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	25,000,000	25,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	27,485,542	27,482,692
Common stock, shares outstanding	27,485,542	27,482,692

Statements of Operations

Statements of Operations - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Operating expenses:
Research and development	$ 4,430,670	$ 2,422,106
General and administrative	4,724,133	2,272,970
Total operating expenses	9,154,803	4,695,076
Loss from operations	(9,154,803)	(4,695,076)
Other income (expense):
Interest income	43,371	55,368
Change in fair value of warrant liabilities	188,270	(212,055)
Total other income (expense)	231,641	(156,687)
Net loss	$ (8,923,162)	$ (4,851,763)
Per share information:
Net loss per share of common stock, basic and diluted	$ (0.32)	$ (0.24)
Basic and diluted weighted average shares outstanding	27,483,909	20,221,463

Statements of Comprehensive Los

Statements of Comprehensive Loss - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Statement of Comprehensive Income [Abstract]
Net loss	$ (8,923,162)	$ (4,851,763)
Other comprehensive loss:
Net unrealized gain (loss) on available-for-sale securities	27,992	(47,706)
Comprehensive loss	$ (8,895,170)	$ (4,899,469)

Statements of Cash Flows

Statements of Cash Flows - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities
Net loss	$ (8,923,162)	$ (4,851,763)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	134,381	134,336
Stock-based compensation expense	1,080,806	420,029
Change in fair value of warrant liabilities	(188,270)	212,055
Increase in deferred rent	15,141	14,826
Other non-cash charges and expenses	0	(28,977)
Net amortization of premium paid on marketable securities	133,529	0
Changes in operating assets and liabilities:
Decrease in prepaid expenses and other current assets	67,187	97,061
Increase (decrease) in accounts payable and accrued liabilities	1,161,894	(491,406)
Net cash used in operating activities	(6,518,494)	(4,493,839)
Cash flows from investing activities
Purchases of marketable securities	(1,994,030)	(9,374,346)
Proceeds from maturities of marketable securities	6,210,000	500,000
Purchases of property and equipment	(31,611)
Net cash provided by (used in) investing activities	4,184,359	(8,874,346)
Cash flows from financing activities
Proceeds from exercise of warrants	0	400
Net cash provided by financing activities	0	400
Net decrease in cash and cash equivalents	(2,334,135)	(13,367,785)
Cash and cash equivalents at beginning of period	9,972,781	25,722,453
Cash and cash equivalents at end of period	$ 7,638,646	$ 12,354,668

Organization and Description of

Organization and Description of Business	3 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
Organization and Description of Business	1. Organization and Description of Business Organization and Business ContraFect Corporation (the “Company”) is a clinical-stage biotechnology company focused on protein and antibody therapeutic products for life-threatening infectious diseases, particularly those treated in hospital-based settings. The Company intends to address multi-drug resistant infections using its therapeutic product candidates from its lysin and monoclonal antibody platforms to target conserved regions of either bacteria or viruses. The Company’s most advanced product candidates are CF-301, a lysin for the treatment of Staph aureus bacteremia, and CF-404, a combination of mAbs for the treatment of life-threatening seasonal and pandemic varieties of influenza. The Company has incurred losses from operations since inception as a research and development organization and has relied on its ability to fund its operations through public and private debt and equity financings. Management believes its cash, cash equivalents and marketable securities balances will be sufficient to fund operations into the first half of 2017 and expects operating losses and negative cash flows to continue at more significant levels in the future as it initiates additional clinical trials. Transition to profitability is dependent upon the successful development, approval, and commercialization of its product candidates and achieving a level of revenues adequate to support the Company’s cost structure. The Company may never achieve profitability, and unless and until it does, the Company will continue to need to raise additional capital. Management intends to fund future operations through additional public or private equity financings, and may seek additional capital through arrangements with strategic partners or from other sources. There can be no assurances that such financing will be available to the Company on satisfactory terms, or at all. In June 2015, the Company completed a private placement of securities to institutional investors whereby the investors received an aggregate of 4,728,128 shares of the Company’s common stock and warrants to purchase an additional 2,364,066 shares of common stock at an exercise price of $8.00 per share. The Company received net proceeds of $18.3 million, net of expenses. On November 2, 2015, the Company’s Class B Warrants to purchase common stock expired in accordance with their terms. As of November 2, 2015, holders of the Class B Warrants had exercised 4,812,328 Class B Warrants, resulting in the issuance of 2,406,164 shares of the Company’s common stock and the receipt by the Company of approximately $9.6 million in gross proceeds. The 2,068,005 Class B Warrants that were not exercised prior to expiration were terminated and are no longer exercisable. The significant increases in common stock outstanding in June and November 2015 are expected to impact the year-over-year comparability of the Company’s net loss per share calculations.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying financial information as of March 31, 2016 and for the three months ended March 31, 2016 and 2015 has been prepared by the Company, without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) have been condensed or omitted pursuant to such rules and regulations. The December 31, 2015 balance sheet was derived from the Company’s audited financial statements. The Company’s audited financial statements as of and for the year ended December 31, 2015, including all related disclosures and the complete listing of significant accounting policies as described in Note 2 thereof, are included in the Company’s Annual Report on Form 10-K that was filed with the SEC on March 15, 2016. In the opinion of management, the unaudited financial information as of March 31, 2016 and for the three months ended March 31, 2016 and 2015 reflects all adjustments, which are normal recurring adjustments, necessary to present a fair statement of financial position, results of operations and cash flows. The results of operations for the three months ended March 31, 2016 are not necessarily indicative of the operating results for the full fiscal year or any future periods. Significant Risks and Uncertainties The Company’s operations are subject to a number of factors that can affect its operating results and financial condition. Such factors include, but are not limited to: the results of clinical testing and trial activities of the Company’s products, the Company’s ability to obtain regulatory approval to market its products, competition from products manufactured and sold or being developed by other companies, the price of, and demand for, the Company’s products, the Company’s ability to negotiate favorable licensing or other manufacturing and marketing agreements for its products and the Company’s ability to raise capital. See “Risk Factors” contained elsewhere in this Quarterly Report on Form 10-Q for additional risks and uncertainties. Use of Estimates The preparation of financial statements in conformity with U.S. 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. The Company bases estimates and assumptions on historical experience when available and on various factors that it believes to be reasonable under the circumstances. On an ongoing basis, the Company evaluates its estimates and assumptions, including those related to accruals, fair value measurements, stock-based compensation, warrant valuation and income taxes. The Company’s actual results may differ from these estimates under different assumptions or conditions. There have been no significant changes from the Company’s original estimates in any periods presented. Cash and Cash Equivalents The Company considers all highly liquid investments with maturities at the date of purchase of three months or less to be cash equivalents. Cash and cash equivalents include bank demand deposits, marketable securities with maturities of three months or less at purchase, and money market funds that invest primarily in certificates of deposit, commercial paper and U.S. government and U.S. government agency obligations. Cash equivalents are reported at fair value. Concentrations of Credit Risk Financial instruments which potentially subject the Company to credit risk consist primarily of cash, cash equivalents and marketable securities. The Company holds these investments in highly rated financial institutions, and, by policy, limits the amounts of credit exposure to any one financial institution. These amounts at times may exceed federally insured limits. The Company has not experienced any credit losses in such accounts and does not believe it is exposed to any significant credit risk on these funds. The Company has no off-balance sheet concentrations of credit risk, such as foreign currency exchange contracts, option contracts or other hedging arrangements. Fair Value of Financial Instruments The Company’s financial instruments consist of cash and cash equivalents, marketable securities, accounts payable, accrued liabilities, convertible notes and warrant liabilities. Fair value estimates of these instruments are made at a specific point in time, based on relevant market information. These estimates may be subjective in nature and involve uncertainties and matters of significant judgment and therefore cannot be determined with precision. The fair value of the Company’s warrant liabilities are based upon unobservable inputs, as described further below. The Company is required to disclose information on all assets and liabilities reported at fair value that enables an assessment of the inputs used in determining the reported fair values. Financial Accounting Standards Board (“FASB”) ASC Topic 820, Fair Value Measurements and Disclosures Level 1—Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. Level 2—Valuations based on quoted prices for similar assets or liabilities in markets that are not active or for which all significant inputs are observable, either directly or indirectly. Level 3—Valuations that require inputs that reflect the Company’s own assumptions that are both significant to the fair value measurement and unobservable. To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The Company had no liabilities classified as Level 1 or Level 2. The carrying amounts reported in the accompanying financial statements for accounts payable and accrued expenses approximate their respective fair values due to their short-term maturities. The fair value of the warrant is discussed in Note 4, “Fair Value Measurements.” Share-based Compensation The Company accounts for stock-based compensation in accordance with ASC 718, Compensation—Stock Compensation, The fair value of options is calculated using the Black-Scholes option pricing model to determine the fair value of stock options on the date of grant based on key assumptions such as stock price, expected volatility and expected term. The Company’s estimates of these assumptions are primarily based on historical data, peer company data and judgment regarding future trends and factors. Net Loss Per Share Basic net loss per share is calculated by dividing net loss by the weighted average shares outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share is calculated by adjusting weighted average shares outstanding for the dilutive effect of common stock equivalents outstanding for the period, determined using the treasury-stock method. For purposes of the dilutive net loss per share calculation, stock options and warrants are considered to be common stock equivalents but are excluded from the calculation of diluted net loss per share, as their effect would be anti-dilutive given the Company’s net loss; therefore, basic and diluted net loss per share were the same for all periods presented. Comprehensive Income (Loss) Comprehensive income (loss) is defined as the change in equity of a business enterprise during a period from transactions, and other events and circumstances from non-owner sources, and currently consists of net loss and changes in unrealized gains and losses on available-for-sale securities. Recent Accounting Pronouncements In August 2014, the FASB issued a new Accounting Standards Update, Presentation of Financial Statements—Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (ASU 2014-15) In November 2015, the FASB issued a new Accounting Standards Update, Balance Sheet Classification of Deferred Taxes (ASU 2015-17) In January 2016, the FASB issued a new Accounting Standards Update, Recognition and Measurement of Financial Assets and Financial Liabilities (ASU 2016-01) In February 2016, the FASB issued a new Accounting Standards Update, Leases (ASU 2016-02) In March 2016, the FASB issued a new Accounting Standards Update, Improvements to Employee Share-Based Payment Accounting (ASU 2016-09)

Marketable Securities

Marketable Securities	3 Months Ended
	Mar. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	3. Marketable Securities Marketable securities at March 31, 2016 and December 31, 2015 consisted of investments in short-term corporate debt securities. Management determines the appropriate classification of the securities at the time they are acquired and evaluates the appropriateness of such classifications at each balance sheet date. The Company classifies its marketable securities as available-for-sale pursuant to ASC 320, Investments – Debt and Equity Securities The Company reviews marketable securities for other-than-temporary impairment whenever the fair value of a marketable security is less than the amortized cost and evidence indicates that a marketable security’s carrying amount is not recoverable within a reasonable period of time. Other-than-temporary impairments of investments are recognized in the statements of operations if the Company has experienced a credit loss, has the intent to sell the marketable security, or if it is more likely than not that the Company will be required to sell the marketable security before recovery of the amortized cost basis. Evidence considered in this assessment includes reasons for the impairment, compliance with the Company’s investment policy, the severity and the duration of the impairment and changes in value subsequent to the end of the period. Marketable securities at March 31, 2016 consist of the following: Marketable Securities Amortized Cost Unrealized Gains Unrealized Losses Fair Value Current: Corporate debt $ 18,629,748 $ 1,315 $ (3,696 ) $ 18,627,367 Marketable securities at December 31, 2015 consisted of the following: Marketable Securities Amortized Cost Unrealized Gains Unrealized Losses Fair Value Current: Corporate debt $ 22,979,245 $ 199 $ (30,572 ) $ 22,948,872 At March 31, 2016 and December 31, 2015, the Company held only current investments. Investments classified as current have maturities of less than one year. Investments that would be classified as non-current are those that have maturities of greater than one year and management does not intend to liquidate within the next twelve months. At March 31, 2016 and December 31, 2015, the Company held 13 and 28 debt securities, respectively, that individually and in total were in an immaterial unrealized loss position for less than one year. The aggregate fair value of debt securities in an unrealized loss position at March 31, 2016 and December 31, 2015 was $10,577,109 and $21,137,424, respectively. The Company evaluated its securities for other-than-temporary impairment and considered the decline in market value for the securities to be primarily attributable to current economic and market conditions. It is not more likely than not that the Company will be required to sell the securities, and the Company does not intend to do so prior to the recovery of the amortized cost basis. Based on this analysis, these marketable securities were not considered to be other-than-temporarily impaired as of March 31, 2016 and December 31, 2015.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. Fair Value Measurements The following fair value hierarchy table presents information about the Company’s financial assets and liabilities measured at fair value on a recurring basis as of March 31, 2016 and December 31, 2015: Fair Value Measurement as of March 31, 2016 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents $ 7,579,420 $ — $ — Marketable securities 18,627,367 — — Warrant liability — — 256,054 Total $ 26,206,787 $ — $ 256,054 Fair Value Measurement as of December 31, 2015 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents $ 9,607,134 $ — $ — Marketable securities 22,948,872 — — Warrant liability — — 444,324 Total $ 32,556,006 $ — $ 444,324 The Company issued a warrant to the representative of the underwriter of its initial public offering (the “Representative’s Warrant”), The Company evaluated the Representative’s Warrant against current accounting guidance and determined that this warrant should be classified as a liability and considers it as a Level 3 financial instrument (see also Note 8, “Capital Structure”). The warrant will be re-measured at each subsequent reporting period and changes in fair value will be recognized in the statement of operations. The following assumptions were used in a Black-Scholes option-pricing model to determine the fair value of the warrant liability: As of March 31, 2016 As of December 31, 2015 Expected volatility 79.90 % 78.1 % Remaining contractual term (in years) 3.42 3.67 Risk-free interest rate 1.04 % 1.54 % Expected dividend yield — % — % The following tables present a reconciliation of the Company’s financial liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the three months ended March 31, 2016 and 2015: Warrant liabilities Three Months Ended March 31, 2016 2015 Balance at beginning of period $ 444,324 $ 313,004 Increase (decrease) in fair value (1) (188,270 ) 212,055 Balance at end of period $ 256,054 $ 525,059 (1) The change in the fair values of the warrant liabilities are recorded in other expenses in the statement of operations. The key inputs into the Black-Scholes option pricing model are the per share value and the expected volatility of the Company’s common stock. Significant changes in these inputs will directly increase or decrease the estimated fair value of the Company’s warrant liability.

Accrued Expenses

Accrued Expenses	3 Months Ended
	Mar. 31, 2016
Payables and Accruals [Abstract]
Accrued Expenses	5. Accrued Expenses Accrued expenses consist of the following: March 31, 2016 December 31, 2015 Accrued compensation costs $ 1,690,113 $ 1,133,742 Accrued research and development fees 624,190 590,307 Accrued professional fees 543,774 317,796 Other 251,660 209,922 $ 3,109,737 $ 2,251,767

Senior Convertible Notes

Senior Convertible Notes	3 Months Ended
	Mar. 31, 2016
Debt Disclosure [Abstract]
Senior Convertible Notes	6. Senior Convertible Notes The Company issued approximately $15.0 million in aggregate principal amount of its 8.00% Convertible Notes due May 31, 2015 (the “Convertible Notes”) from June 2013 through June 2014. On August 1, 2014, in conjunction with the closing of the Company’s initial public offering, the principal amount of the Convertible Notes, and all accrued and unpaid interest thereon, automatically converted into 5,109,988 shares of common stock. Upon the closing of the offering, the Company accelerated the amortization of the remaining debt discount balance to interest expense. Each purchaser of the Convertible Notes received a warrant (the “Note Warrants”). Upon the closing of the initial public offering and based on the terms of the Note Warrants, the Company determined the total number of shares of the Company’s common stock underlying the Note Warrants to be 3,321,416 at an exercise price of $3.00 per share. There were 3,315,878 shares of common stock underlying the outstanding Note Warrants as of March 31, 2016 and December 31, 2015. The Note Warrants expire five years from the date of issuance.

Net Loss Per Share of Common St

Net Loss Per Share of Common Stock	3 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Net Loss Per Share of Common Stock	7. Net Loss Per Share of Common Stock Diluted net loss per share is the same as basic net loss per share for all periods presented because the effects of potentially dilutive items were anti-dilutive given the Company’s net loss. Basic net loss per share is computed by dividing net loss by the weighted-average number of shares of common stock outstanding. The following table sets forth the computation of basic and diluted net loss per share for common stockholders: Three Months Ended March 31, 2016 2015 Net loss $ (8,923,162 ) $ (4,851,763 ) Weighted average shares of common stock outstanding 27,483,909 20,221,463 Net loss per share of common stock—basic and diluted $ (0.32 ) $ (0.24 ) The following potentially dilutive securities outstanding at March 31, 2016 and 2015 have been excluded from the computation of diluted weighted average shares outstanding, as they would have been anti-dilutive given the Company’s net loss: March 31, 2016 2015 Options to purchase common stock 4,711,508 3,791,577 Warrants to purchase common stock 13,503,107 14,577,261 18,214,615 18,368,838

Capital Structure

Capital Structure	3 Months Ended
	Mar. 31, 2016
Equity [Abstract]
Capital Structure	8. Capital Structure Common Stock As of March 31, 2016, the Company was authorized to issue 100,000,000 shares of common stock at $0.0001 par value per share. Private Placement On June 12, 2015, the Company closed a private placement of its securities with a group of institutional investors (the “PIPE”). Each investor received one share of common stock and a warrant to purchase one-half share of common stock at a price of $4.23 per common share purchased. The closing of the PIPE resulted in the issuance of an aggregate of 4,728,128 common shares and warrants to purchase an additional 2,364,066 shares of common stock at an exercise price of $8.00 per full share, which expire three years form the date of issuance (the “PIPE Warrants”). The Company received net proceeds from the PIPE of $18.3 million, after deducting expenses payable by the Company. The placement agents in the PIPE received warrants to purchase 4% of the total number of shares of common stock sold in the PIPE (the “Placement Agent Warrants”), for a total of 189,126 shares of common stock underlying the Placement Agent Warrants. The Placement Warrants became exercisable upon issuance at an exercise price of $4.65 per share and expire on June 11, 2020. The common stock and accompanying PIPE Warrants and Placement Agent Warrants have been classified as stockholders’ equity in the Company’s balance sheet. Initial Public Offering In July 2014, the stockholders approved an amended certificate of incorporation that became effectively immediately upon the closing of the Company’s IPO. The approved certificate increased the number of authorized shares of common stock to 100,000,000 shares. On August 1, 2014, the Company closed an initial public offering of its units (the “IPO”). Each unit consisted of one share of common stock, one Class A Warrant to purchase one share of common stock at an exercise price of $4.80 per share and one Class B Warrant to purchase one-half share of common stock at an exercise price of $4.00 per full share (the “Units”). The closing of the IPO resulted in the sale of an aggregate of 6,880,333 Units at a public offering price of $6.00 per Unit, less underwriting discounts and commissions and the underwriter’s expenses, including 880,333 Units issued upon the exercise by the underwriters of their option to purchase additional Units at the public offering price to cover over-allotments. The Company received net proceeds from the IPO of $35.0 million, after deducting underwriting discounts, commissions, and expenses payable by the Company. Following the IPO, the Units separated and the shares of common stock, Class A Warrants and Class B Warrants began to trade separately. The common stock and accompanying Class A and Class B Warrants have been classified as stockholders’ equity in the Company’s balance sheet. On November 2, 2015, the Company’s Class B Warrants to purchase common stock expired in accordance with their terms. As of November 2, 2015, holders of the Class B Warrants had exercised 4,812,328 Class B Warrants, resulting in the issuance of 2,406,164 shares of the Company’s common stock and the receipt by the Company of approximately $9.6 million in gross proceeds. The 2,068,005 Class B Warrants that were not exercised prior to expiration have terminated and are no longer exercisable. Representative’s Warrant The Maxim Group, LLC, the representative of the underwriter in the IPO, received the Representative’s Warrant to purchase 3% of the total number of shares of common stock sold in the IPO, including those shares sold upon the exercise of the over-allotment option, for a total of 206,410 shares of common stock underlying the Representative’s Warrant. The Representative’s Warrant is exercisable at an exercise price of $7.50 per share beginning 180 days after the effective date of the Company’s registration statement (January 24, 2015) and expiring on August 27, 2019. The Company classified the Representative’s Warrant as a liability since it did not meet the requirements to be included in equity. The fair value of the Representative’s warrant will be re-measured at each reporting period and changes in fair value will be recognized in the statement of operations (see Note 4, “Fair Value Measurements”). Voting The holders of shares of common stock are entitled to one vote for each share of common stock held at all meetings of stockholders and written actions in lieu of meetings. Dividends The holders of shares of common stock are entitled to receive dividends, if and when declared by the board of directors. As of March 31, 2016, no dividends have been declared or paid on the Company’s common stock since inception. Reserved for Future Issuance The Company has reserved for future issuance the following number of shares of common stock as of March 31, 2016 and December 31, 2015: March 31, 2016 December 31, 2015 Options to purchase common stock 4,711,508 4,313,755 Warrants to purchase common stock 13,503,107 13,503,107 18,214,615 17,816,862 Sales Agreement In January 2016, the Company entered into a Sales Agreement with Cowen and Company, LLC (“Cowen”) to sell shares of the Company’s common stock, with aggregate gross sales proceeds of up to $30 million, through an “at the market” equity offering program under which Cowen will act as sales agent. The Company has not sold any shares under the program.

Stock Warrants

Stock Warrants	3 Months Ended
	Mar. 31, 2016
Text Block [Abstract]
Stock Warrants	9. Stock Warrants As of March 31, 2016 and December 31, 2015, the Company had warrants outstanding as shown in the table below. March 31, 2016 December 31, 2015 Note Warrants 3,315,878 3,315,878 Class A Warrants 6,880,333 6,880,333 PIPE Warrants 2,364,066 2,364,066 Representative’s Warrant 206,410 206,410 Placement Agent Warrants 189,126 189,126 Other warrants (1) 547,294 547,294 Warrants to purchase common stock 13,503,107 13,503,107 Weighted-average exercise price per share $ 5.02 $ 5.02 (1) Other warrants are comprised of warrants issued prior to the Company’s IPO, generally in exchange for services rendered to the Company. The following table summarizes information regarding the Company’s warrants outstanding at March 31, 2016: Exercise Prices Shares Underlying Outstanding Warrants Expiration Date £ 3,588,406 August 31, 2016 – September 1, 2021 $4.01-$4.99 7,069,459 February 1, 2017 – June 11, 2020 $5.00 - $9.99 2,656,900 December 10, 2016 – June 27, 2021 ³ 188,342 August 31, 2016 – January 5, 2022 13,503,107

Stock Option and Incentive Plan

Stock Option and Incentive Plans	3 Months Ended
	Mar. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Option and Incentive Plans	10. Stock Option and Incentive Plans Amended and Restated 2008 Equity Incentive Plan In July 2008, the Company adopted the 2008 Equity Incentive Plan (the “Plan”). The Plan allows for the granting of non-qualified stock options, restricted stock, stock appreciation rights and other performance awards to the Company’s employees, members of the board of directors and consultants of the Company. Upon the original adoption of the Plan, the number of shares of common stock reserved pursuant to the Plan was 214,285. On December 12, 2011, the Plan was amended to increase the number of shares of common stock available under the Plan to 900,000. On February 24, 2014, the board of directors increased the number of shares of common stock available under the Plan to 1,857,142. On April 29, 2014, the board of directors increased the number of shares of common stock available under the Plan to 2,357,142. The Company expects no further grants to be made under the Plan. 2014 Omnibus Incentive Plan In April 2014, the Company’s board of directors adopted the 2014 Omnibus Incentive Plan (the “2014 Plan”). The 2014 Plan was approved by the Company’s stockholders on July 3, 2014. The 2014 Plan allows for the granting of incentive and non-qualified stock options, restricted stock and stock unit awards, stock appreciation rights and other performance-based awards to the Company’s employees, members of the board of directors and consultants of the Company. On July 28, 2014, the effective date of the 2014 Plan, the number of shares of common stock reserved pursuant to the 2014 Plan was 571,429. The 2014 Plan provides for an annual increase, to be added on the first day of each fiscal year, beginning with the fiscal year ended December 31, 2014 and continuing until the expiration of the 2014 Plan, equal to the lesser of (i) 4% of the outstanding shares of common stock on such date or (ii) an amount determined by the Company’s board of directors. Consistent with the provision for an annual increase, an additional 1,907,997 shares of common stock have been reserved under the 2014 Plan. The Company recognized compensation expense for share-based compensation based on the fair value of the underlying instrument. The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model. A summary of stock option activity for the three months ended March 31, 2016, is summarized as follows: Number of Options Weighted Average Exercise Price Weighted Average Remaining Contractual Life (in years) Aggregate Intrinsic Value Options outstanding at December 31, 2015 4,313,755 $ 4.87 Granted 776,100 3.39 Exercised (21,356 ) 3.07 Expired (68,279 ) 5.10 Forfeited (288,712 ) 4.61 Options outstanding at March 31, 2016 4,711,508 $ 4.64 6.27 $ 126,917 Vested and exercisable at March 31, 2016 3,251,921 $ 4.90 5.19 $ 27,548 Of the option grants outstanding to purchase 4,711,508 shares of common stock, grants to purchase 667,870 shares of common stock were issued and are outstanding outside the Company’s incentive plans. The fair value of each option grant is estimated on the date of the grant using the Black-Scholes option-pricing model. The weighted average grant date fair value of options granted during the three months ended March 31, 2016 and 2015 was $3.39 and $4.62, respectively. Total compensation expense recognized amounted to $1,080,806 and $365,729 for the three months ended March 31, 2016 and 2015, respectively. As of March 31, 2016, the total remaining unrecognized compensation cost related to unvested stock options was $ 4,255,165 which will be recognized over a weighted average period of approximately 2.43 years. The following assumptions were used to compute the fair value of stock option grants: Three Months Ended March 31, 2016 2015 Risk free interest rate 1.21 % 1.62 % Expected dividend yield — — Expected term (in years) 4.87 5.97 Expected volatility 79.7 % 73.6 % Expected volatility— Expected term— Risk-free interest rate— Expected dividend yield—

Significant Agreements

Significant Agreements	3 Months Ended
	Mar. 31, 2016
Equity [Abstract]
Significant Agreements	11. Significant Agreements On March 25, 2016, the Company entered into a separation agreement and release of claims with its former Chief Executive Officer, Julia P. Gregory. Subject to Ms. Gregory’s continued compliance with restrictive covenants contained in her employment agreement with the Company, the separation agreement provides for Ms. Gregory to receive severance payments totaling approximately $1.2 million for a period of 18 months following the effective date of Ms. Gregory’s retirement, the accelerated vesting of all unvested portions of stock option grants dated April 29, 2014 and February 8, 2016, and continued medical, dental and vision coverage paid for by the Company under the Company’s group healthcare plans for up to eighteen months following the effective date of Ms. Gregory’s retirement. The total amount of these charges was recognized as part of general and administrative expenses for the period ended March 31, 2016. Ms. Gregory will have a period of two years following the effective date of her retirement to exercise her vested Company stock options.

Summary of Significant Accoun18

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying financial information as of March 31, 2016 and for the three months ended March 31, 2016 and 2015 has been prepared by the Company, without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) have been condensed or omitted pursuant to such rules and regulations. The December 31, 2015 balance sheet was derived from the Company’s audited financial statements. The Company’s audited financial statements as of and for the year ended December 31, 2015, including all related disclosures and the complete listing of significant accounting policies as described in Note 2 thereof, are included in the Company’s Annual Report on Form 10-K that was filed with the SEC on March 15, 2016. In the opinion of management, the unaudited financial information as of March 31, 2016 and for the three months ended March 31, 2016 and 2015 reflects all adjustments, which are normal recurring adjustments, necessary to present a fair statement of financial position, results of operations and cash flows. The results of operations for the three months ended March 31, 2016 are not necessarily indicative of the operating results for the full fiscal year or any future periods.
Significant Risks and Uncertainties	Significant Risks and Uncertainties The Company’s operations are subject to a number of factors that can affect its operating results and financial condition. Such factors include, but are not limited to: the results of clinical testing and trial activities of the Company’s products, the Company’s ability to obtain regulatory approval to market its products, competition from products manufactured and sold or being developed by other companies, the price of, and demand for, the Company’s products, the Company’s ability to negotiate favorable licensing or other manufacturing and marketing agreements for its products and the Company’s ability to raise capital. See “Risk Factors” contained elsewhere in this Quarterly Report on Form 10-Q for additional risks and uncertainties.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. 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. The Company bases estimates and assumptions on historical experience when available and on various factors that it believes to be reasonable under the circumstances. On an ongoing basis, the Company evaluates its estimates and assumptions, including those related to accruals, fair value measurements, stock-based compensation, warrant valuation and income taxes. The Company’s actual results may differ from these estimates under different assumptions or conditions. There have been no significant changes from the Company’s original estimates in any periods presented.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with maturities at the date of purchase of three months or less to be cash equivalents. Cash and cash equivalents include bank demand deposits, marketable securities with maturities of three months or less at purchase, and money market funds that invest primarily in certificates of deposit, commercial paper and U.S. government and U.S. government agency obligations. Cash equivalents are reported at fair value.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments which potentially subject the Company to credit risk consist primarily of cash, cash equivalents and marketable securities. The Company holds these investments in highly rated financial institutions, and, by policy, limits the amounts of credit exposure to any one financial institution. These amounts at times may exceed federally insured limits. The Company has not experienced any credit losses in such accounts and does not believe it is exposed to any significant credit risk on these funds. The Company has no off-balance sheet concentrations of credit risk, such as foreign currency exchange contracts, option contracts or other hedging arrangements.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company’s financial instruments consist of cash and cash equivalents, marketable securities, accounts payable, accrued liabilities, convertible notes and warrant liabilities. Fair value estimates of these instruments are made at a specific point in time, based on relevant market information. These estimates may be subjective in nature and involve uncertainties and matters of significant judgment and therefore cannot be determined with precision. The fair value of the Company’s warrant liabilities are based upon unobservable inputs, as described further below. The Company is required to disclose information on all assets and liabilities reported at fair value that enables an assessment of the inputs used in determining the reported fair values. Financial Accounting Standards Board (“FASB”) ASC Topic 820, Fair Value Measurements and Disclosures Level 1—Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. Level 2—Valuations based on quoted prices for similar assets or liabilities in markets that are not active or for which all significant inputs are observable, either directly or indirectly. Level 3—Valuations that require inputs that reflect the Company’s own assumptions that are both significant to the fair value measurement and unobservable. To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The Company had no liabilities classified as Level 1 or Level 2. The carrying amounts reported in the accompanying financial statements for accounts payable and accrued expenses approximate their respective fair values due to their short-term maturities. The fair value of the warrant is discussed in Note 4, “Fair Value Measurements.”
Share-based Compensation	Share-based Compensation The Company accounts for stock-based compensation in accordance with ASC 718, Compensation—Stock Compensation, The fair value of options is calculated using the Black-Scholes option pricing model to determine the fair value of stock options on the date of grant based on key assumptions such as stock price, expected volatility and expected term. The Company’s estimates of these assumptions are primarily based on historical data, peer company data and judgment regarding future trends and factors.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is calculated by dividing net loss by the weighted average shares outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share is calculated by adjusting weighted average shares outstanding for the dilutive effect of common stock equivalents outstanding for the period, determined using the treasury-stock method. For purposes of the dilutive net loss per share calculation, stock options and warrants are considered to be common stock equivalents but are excluded from the calculation of diluted net loss per share, as their effect would be anti-dilutive given the Company’s net loss; therefore, basic and diluted net loss per share were the same for all periods presented.
Comprehensive Income (Loss)	Comprehensive Income (Loss) Comprehensive income (loss) is defined as the change in equity of a business enterprise during a period from transactions, and other events and circumstances from non-owner sources, and currently consists of net loss and changes in unrealized gains and losses on available-for-sale securities.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In August 2014, the FASB issued a new Accounting Standards Update, Presentation of Financial Statements—Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (ASU 2014-15) In November 2015, the FASB issued a new Accounting Standards Update, Balance Sheet Classification of Deferred Taxes (ASU 2015-17) In January 2016, the FASB issued a new Accounting Standards Update, Recognition and Measurement of Financial Assets and Financial Liabilities (ASU 2016-01) In February 2016, the FASB issued a new Accounting Standards Update, Leases (ASU 2016-02) In March 2016, the FASB issued a new Accounting Standards Update, Improvements to Employee Share-Based Payment Accounting (ASU 2016-09)

Marketable Securities (Tables)

Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Schedule of Marketable Securities	Marketable securities at March 31, 2016 consist of the following: Marketable Securities Amortized Cost Unrealized Gains Unrealized Losses Fair Value Current: Corporate debt $ 18,629,748 $ 1,315 $ (3,696 ) $ 18,627,367 Marketable securities at December 31, 2015 consisted of the following: Marketable Securities Amortized Cost Unrealized Gains Unrealized Losses Fair Value Current: Corporate debt $ 22,979,245 $ 199 $ (30,572 ) $ 22,948,872

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Information about Company's Financial Assets and Liabilities Measured at Fair Value on Recurring Basis	The following fair value hierarchy table presents information about the Company’s financial assets and liabilities measured at fair value on a recurring basis as of March 31, 2016 and December 31, 2015: Fair Value Measurement as of March 31, 2016 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents $ 7,579,420 $ — $ — Marketable securities 18,627,367 — — Warrant liability — — 256,054 Total $ 26,206,787 $ — $ 256,054 Fair Value Measurement as of December 31, 2015 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents $ 9,607,134 $ — $ — Marketable securities 22,948,872 — — Warrant liability — — 444,324 Total $ 32,556,006 $ — $ 444,324
Assumption Used to Determine Fair Value of Warrant Liability	The following assumptions were used in a Black-Scholes option-pricing model to determine the fair value of the warrant liability: As of March 31, 2016 As of December 31, 2015 Expected volatility 79.90 % 78.1 % Remaining contractual term (in years) 3.42 3.67 Risk-free interest rate 1.04 % 1.54 % Expected dividend yield — % — %
Reconciliation of Company's Financial Liabilities Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3)	The following tables present a reconciliation of the Company’s financial liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the three months ended March 31, 2016 and 2015: Warrant liabilities Three Months Ended March 31, 2016 2015 Balance at beginning of period $ 444,324 $ 313,004 Increase (decrease) in fair value (1) (188,270 ) 212,055 Balance at end of period $ 256,054 $ 525,059 (1) The change in the fair values of the warrant liabilities are recorded in other expenses in the statement of operations.

Accrued Expenses (Tables)

Accrued Expenses (Tables)	3 Months Ended
	Mar. 31, 2016
Payables and Accruals [Abstract]
Summary of Accrued Expenses	Accrued expenses consist of the following: March 31, 2016 December 31, 2015 Accrued compensation costs $ 1,690,113 $ 1,133,742 Accrued research and development fees 624,190 590,307 Accrued professional fees 543,774 317,796 Other 251,660 209,922 $ 3,109,737 $ 2,251,767

Net Loss Per Share of Common 22

Net Loss Per Share of Common Stock (Tables)	3 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted Net Loss Per Share for Common Stockholders	The following table sets forth the computation of basic and diluted net loss per share for common stockholders: Three Months Ended March 31, 2016 2015 Net loss $ (8,923,162 ) $ (4,851,763 ) Weighted average shares of common stock outstanding 27,483,909 20,221,463 Net loss per share of common stock—basic and diluted $ (0.32 ) $ (0.24 )
Schedule of Antidilutive Securities Excluded from Computation of Diluted Weighted Average Shares Outstanding	The following potentially dilutive securities outstanding at March 31, 2016 and 2015 have been excluded from the computation of diluted weighted average shares outstanding, as they would have been anti-dilutive given the Company’s net loss: March 31, 2016 2015 Options to purchase common stock 4,711,508 3,791,577 Warrants to purchase common stock 13,503,107 14,577,261 18,214,615 18,368,838

Capital Structure (Tables)

Capital Structure (Tables)	3 Months Ended
	Mar. 31, 2016
Equity [Abstract]
Summary of Common Stock Reserved for Future Issuance	The Company has reserved for future issuance the following number of shares of common stock as of March 31, 2016 and December 31, 2015: March 31, 2016 December 31, 2015 Options to purchase common stock 4,711,508 4,313,755 Warrants to purchase common stock 13,503,107 13,503,107 18,214,615 17,816,862

Stock Warrants (Tables)

Stock Warrants (Tables)	3 Months Ended
	Mar. 31, 2016
Text Block [Abstract]
Schedule of Warrants Outstanding	As of March 31, 2016 and December 31, 2015, the Company had warrants outstanding as shown in the table below. March 31, 2016 December 31, 2015 Note Warrants 3,315,878 3,315,878 Class A Warrants 6,880,333 6,880,333 PIPE Warrants 2,364,066 2,364,066 Representative’s Warrant 206,410 206,410 Placement Agent Warrants 189,126 189,126 Other warrants (1) 547,294 547,294 Warrants to purchase common stock 13,503,107 13,503,107 Weighted-average exercise price per share $ 5.02 $ 5.02 (1) Other warrants are comprised of warrants issued prior to the Company’s IPO, generally in exchange for services rendered to the Company. The following table summarizes information regarding the Company’s warrants outstanding at March 31, 2016: Exercise Prices Shares Underlying Outstanding Warrants Expiration Date £ 3,588,406 August 31, 2016 – September 1, 2021 $4.01-$4.99 7,069,459 February 1, 2017 – June 11, 2020 $5.00 - $9.99 2,656,900 December 10, 2016 – June 27, 2021 ³ 188,342 August 31, 2016 – January 5, 2022 13,503,107

Stock Option and Incentive Pl25

Stock Option and Incentive Plans (Tables)	3 Months Ended
	Mar. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Stock Option Activity	A summary of stock option activity for the three months ended March 31, 2016, is summarized as follows: Number of Options Weighted Average Exercise Price Weighted Average Remaining Contractual Life (in years) Aggregate Intrinsic Value Options outstanding at December 31, 2015 4,313,755 $ 4.87 Granted 776,100 3.39 Exercised (21,356 ) 3.07 Expired (68,279 ) 5.10 Forfeited (288,712 ) 4.61 Options outstanding at March 31, 2016 4,711,508 $ 4.64 6.27 $ 126,917 Vested and exercisable at March 31, 2016 3,251,921 $ 4.90 5.19 $ 27,548
Assumptions to Compute Fair Value of Stock Option Grants	The following assumptions were used to compute the fair value of stock option grants: Three Months Ended March 31, 2016 2015 Risk free interest rate 1.21 % 1.62 % Expected dividend yield — — Expected term (in years) 4.87 5.97 Expected volatility 79.7 % 73.6 %

Organization and Description 26

Organization and Description of Business - Additional Information (Detail) - USD ($)	Nov. 02, 2015	Jun. 12, 2015	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Organization And Description Of Business [Line Items]
Additional stock reserved for future issuance			18,214,615		17,816,862
Proceeds from exercise of warrants			$ 0	$ 400
Private Placement [Member]
Organization And Description Of Business [Line Items]
Number of securities received by investors		4,728,128
Additional stock reserved for future issuance		2,364,066
Warrant exercise price per share		$ 8	$ 4.65
Net proceeds received		$ 18,300,000
Warrants expiration date			Jun. 11, 2020
Class B Warrants [Member]
Organization And Description Of Business [Line Items]
Warrants exercised	4,812,328
Common stock shares issued upon exercise of warrants	2,406,164
Proceeds from exercise of warrants	$ 9,600,000
Unexercised warrants terminated	2,068,005
Warrants expiration date			Nov. 2, 2015

Summary of Significant Accoun27

Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2016USD ($)
Summary Of Significant Accounting Policies [Line Items]
Maturity period of highly liquid investments	Three months or less
Level 1 [Member]
Summary Of Significant Accounting Policies [Line Items]
Liabilities	$ 0
Level 2 [Member]
Summary Of Significant Accounting Policies [Line Items]
Liabilities	$ 0

Marketable Securities - Additio

Marketable Securities - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2016USD ($)Debt_Security	Dec. 31, 2015USD ($)Debt_Security
Marketable Securities [Abstract]
Realized gains or losses on marketable securities	$ 0
Maturity period classified current investments	Less than one year
Maturity period classified non-current investments	Greater than one year and management does not intend to liquidate within the next twelve months.
Number of debt securities held | Debt_Security	13	28
Aggregate fair value of debt securities	$ 10,577,109	$ 21,137,424

Marketable Securities - Schedul

Marketable Securities - Schedule of Marketable Securities (Detail) - USD ($)	Mar. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Marketable Securities, Fair Value	$ 18,627,367	$ 22,948,872
Corporate Debt [Member]
Schedule of Available-for-sale Securities [Line Items]
Marketable Securities, Amortized Cost	18,629,748	22,979,245
Marketable Securities, Unrealized Gains	1,315	199
Marketable Securities, Unrealized Losses	(3,696)	(30,572)
Marketable Securities, Fair Value	$ 18,627,367	$ 22,948,872

Fair Value Measurements - Infor

Fair Value Measurements - Information about Company's Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($)	Mar. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	$ 18,627,367	$ 22,948,872
Warrant liability	256,054	444,324
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	7,579,420	9,607,134
Marketable securities	18,627,367	22,948,872
Total assets	26,206,787	32,556,006
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant liability	256,054	444,324
Total liabilities	$ 256,054	$ 444,324

Fair Value Measurements - Assum

Fair Value Measurements - Assumption Used to Determine Fair Value of Warrant Liability (Detail) - Representative's Warrant [Member]	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Expected volatility	79.90%	78.10%
Remaining contractual term (in years)	3 years 5 months 1 day	3 years 8 months 1 day
Risk-free interest rate	1.04%	1.54%
Expected dividend yield	0.00%	0.00%

Fair Value Measurements - Recon

Fair Value Measurements - Reconciliation of Company's Financial Liabilities Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3) (Detail) - Warrant Liabilities [Member] - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	$ 444,324	$ 313,004
Increase (decrease) in fair value	(188,270)	212,055
Balance at end of period	$ 256,054	$ 525,059

Accrued Expenses - Summary of A

Accrued Expenses - Summary of Accrued Expenses (Detail) - USD ($)	Mar. 31, 2016	Dec. 31, 2015
Payables and Accruals [Abstract]
Accrued compensation costs	$ 1,690,113	$ 1,133,742
Accrued research and development fees	624,190	590,307
Accrued professional fees	543,774	317,796
Other	251,660	209,922
Accrued expenses and other current liabilities	$ 3,109,737	$ 2,251,767

Senior Convertible Notes - Addi

Senior Convertible Notes - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	Aug. 01, 2014	Mar. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Initial public offering, closing date		Aug. 1, 2014
8.00% Convertible Notes due May 31, 2015 [Member]
Debt Instrument [Line Items]
Convertible Notes, principal amount		$ 15
Convertible Notes, interest rate		8.00%
Convertible Notes, due date		May 31, 2015
Initial Public Offering [Member]
Debt Instrument [Line Items]
Conversion of Convertible Notes together with accrued and unpaid interest into common stock, shares	5,109,988
Note Warrants [Member]
Debt Instrument [Line Items]
Common stock issuable upon exercise of warrant	3,321,416	3,315,878	3,315,878
Warrant exercise price per share	$ 3
Warrants expiration period		5 years
Warrants, Description		Each purchaser of the Convertible Notes received a warrant (the “Note Warrants”).

Net Loss Per Share of Common 35

Net Loss Per Share of Common Stock - Schedule of Computation of Basic and Diluted Net Loss Per Share for Common Stockholders (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Earnings Per Share [Abstract]
Net loss	$ (8,923,162)	$ (4,851,763)
Weighted average shares of common stock outstanding	27,483,909	20,221,463
Net loss per share of common stock-basic and diluted	$ (0.32)	$ (0.24)

Net Loss Per Share of Common 36

Net Loss Per Share of Common Stock - Schedule of Antidilutive Securities Excluded from Computation of Diluted Weighted Average Shares Outstanding (Detail) - shares	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially antidilutive securities outstanding excluded from the computation of diluted weighted average shares	18,214,615	18,368,838
Employee Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially antidilutive securities outstanding excluded from the computation of diluted weighted average shares	4,711,508	3,791,577
Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially antidilutive securities outstanding excluded from the computation of diluted weighted average shares	13,503,107	14,577,261

Capital Structure - Additional

Capital Structure - Additional Information (Detail) - USD ($)	Mar. 31, 2016	Nov. 02, 2015	Jun. 12, 2015	Aug. 01, 2014	Jan. 31, 2016	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Jul. 31, 2014
Class of Stock [Line Items]
Common stock, shares authorized	100,000,000					100,000,000		100,000,000	100,000,000
Common stock, par value	$ 0.0001					$ 0.0001		$ 0.0001
Additional stock reserved for future issuance	18,214,615					18,214,615		17,816,862
IPO, closing date						Aug. 1, 2014
Initial public offering, units description						Each unit consisted of one share of common stock, one Class A Warrant to purchase one share of common stock at an exercise price of $4.80 per share and one Class B Warrant to purchase one-half share of common stock at an exercise price of $4.00 per full share (the "Units").
Net proceeds from initial public offering				$ 35,000,000
Proceeds from exercise of warrants						$ 0	$ 400
Common stock, voting rights						The holders of shares of common stock are entitled to one vote for each share of common stock held at all meetings of stockholders and written actions in lieu of meetings.
Dividends declared or paid	$ 0
Initial Public Offering [Member]
Class of Stock [Line Items]
Common stock units sold by initial public offering				6,880,333
Public offering price, per unit				$ 6
Common stock units issued upon exercise of option by underwriters				880,333
Private Placement [Member]
Class of Stock [Line Items]
Private placement, securities description						Each investor received one share of common stock and a warrant to purchase one-half share of common stock at a price of $4.23 per common share purchased.
Warrant exercise price per share	$ 4.65		$ 8			$ 4.65
Exercise price per common share			$ 4.23
Number of securities received by investors			4,728,128
Additional stock reserved for future issuance			2,364,066
Net proceeds received			$ 18,300,000
Warrants expiration period			3 years
Class of warrant purchase percentage	4.00%					4.00%
Common stock issuable upon exercise of warrant	189,126					189,126
Warrant expiration date						Jun. 11, 2020
At the Market Equity Offering Program [Member] | Maximum [Member] | Cowen and Company, LLC [Member]
Class of Stock [Line Items]
Aggregate gross sales proceeds from common stock					$ 30,000,000
Representative's Warrant [Member]
Class of Stock [Line Items]
Warrant exercise price per share	$ 7.50					$ 7.50
Class of warrant purchase percentage	3.00%					3.00%
Common stock issuable upon exercise of warrant	206,410					206,410
Warrant expiration date						Aug. 27, 2019
Warrant exercisable period						180 days
Class A Warrants [Member] | Initial Public Offering [Member]
Class of Stock [Line Items]
Warrant exercise price per share				$ 4.80
Class B Warrants [Member]
Class of Stock [Line Items]
Warrant expiration date						Nov. 2, 2015
Warrants exercised		4,812,328
Common stock shares issued upon exercise of warrants		2,406,164
Proceeds from exercise of warrants		$ 9,600,000
Unexercised warrants terminated		2,068,005
Class B Warrants [Member] | Initial Public Offering [Member]
Class of Stock [Line Items]
Warrant exercise price per share				$ 4

Capital Structure - Summary of

Capital Structure - Summary of Common Stock Reserved for Future Issuance (Detail) - shares	Mar. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Common Stock reserved for future issuance	18,214,615	17,816,862
Stock Options [Member]
Class of Stock [Line Items]
Common Stock reserved for future issuance	4,711,508	4,313,755
Warrants [Member]
Class of Stock [Line Items]
Common Stock reserved for future issuance	13,503,107	13,503,107

Stock Warrants - Schedule of Wa

Stock Warrants - Schedule of Warrants Outstanding (Detail) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Jun. 12, 2015	Aug. 01, 2014
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	13,503,107	13,503,107
Weighted-average exercise price per share	$ 5.02	$ 5.02
Placement Agent Warrants [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	189,126	189,126
Class A Warrants [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	6,880,333	6,880,333
Representative's Warrant [Member]
Class of Warrant or Right [Line Items]
Exercise Prices	$ 7.50
Shares Underlying Outstanding Warrants	206,410	206,410
Other Warrants [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	547,294	547,294
Exercise Price Less Than or Equal to $4.00 [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	3,588,406
Expiration Start Date	Aug. 31, 2016
Expiration End Date	Sep. 1, 2021
Exercise Price $4.01 - $4.99 [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	7,069,459
Expiration Start Date	Feb. 1, 2017
Expiration End Date	Jun. 11, 2020
Exercise Price $5.00 - $9.99 [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	2,656,900
Expiration Start Date	Dec. 10, 2016
Expiration End Date	Jun. 27, 2021
Exercise Price Greater Than or Equal to $10.00 [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	188,342
Expiration Start Date	Aug. 31, 2016
Expiration End Date	Jan. 5, 2022
Minimum [Member] | Exercise Price $4.01 - $4.99 [Member]
Class of Warrant or Right [Line Items]
Exercise Prices	$ 4.01
Minimum [Member] | Exercise Price $5.00 - $9.99 [Member]
Class of Warrant or Right [Line Items]
Exercise Prices	5
Minimum [Member] | Exercise Price Greater Than or Equal to $10.00 [Member]
Class of Warrant or Right [Line Items]
Exercise Prices	10
Maximum [Member] | Exercise Price Less Than or Equal to $4.00 [Member]
Class of Warrant or Right [Line Items]
Exercise Prices	4
Maximum [Member] | Exercise Price $4.01 - $4.99 [Member]
Class of Warrant or Right [Line Items]
Exercise Prices	4.99
Maximum [Member] | Exercise Price $5.00 - $9.99 [Member]
Class of Warrant or Right [Line Items]
Exercise Prices	$ 9.99
Note Warrants [Member]
Class of Warrant or Right [Line Items]
Exercise Prices				$ 3
Shares Underlying Outstanding Warrants	3,315,878	3,315,878
Private Placement [Member]
Class of Warrant or Right [Line Items]
Exercise Prices	$ 4.65		$ 8
Warrants [Member] | Private Placement [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	2,364,066	2,364,066

Stock Option and Incentive Pl40

Stock Option and Incentive Plans - Additional Information (Detail) - USD ($)	Dec. 31, 2014	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Jul. 28, 2014	Apr. 29, 2014	Feb. 24, 2014	Dec. 12, 2011	Jul. 31, 2008
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock reserved pursuant to the plan		18,214,615		17,816,862
Number of common stock shares outstanding		4,711,508		4,313,755
Number of common stock available for grant		667,870
Weighted average period of unvested stock options		2 years 5 months 5 days
Weighted average grant date fair value of options		$ 3.39	$ 4.62
Unrecognized compensation cost related to unvested stock options		$ 4,255,165
Employee Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense recognized		$ 1,080,806	$ 365,729
Amended and Restated 2008 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock reserved pursuant to the plan						2,357,142	1,857,142	900,000
2008 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock reserved pursuant to the plan									214,285
2014 Omnibus Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock reserved pursuant to the plan					571,429
Number of additional shares increases of common stock reserved pursuant to the plan		1,907,997
2014 Omnibus Incentive Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual increase of plan, percentage of common stock shares outstanding	4.00%

Stock Option and Incentive Pl41

Stock Option and Incentive Plans - Summary of Stock Option Activity (Detail)	3 Months Ended
	Mar. 31, 2016USD ($)$ / sharesshares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of Options, Options outstanding, Beginning balance | shares	4,313,755
Number of Options, Granted | shares	776,100
Number of Options, Exercised | shares	(21,356)
Number of Options, Expired | shares	(68,279)
Number of Options, Forfeited | shares	(288,712)
Number of Options, Options outstanding, Ending balance | shares	4,711,508
Number of Options, Vested and exercisable, Ending Balance | shares	3,251,921
Weighted Average Exercise Price, Options outstanding, Beginning balance | $ / shares	$ 4.87
Weighted Average Exercise Price, Granted | $ / shares	3.39
Weighted Average Exercise Price, Exercised | $ / shares	3.07
Weighted Average Exercise Price, Expired | $ / shares	5.10
Weighted Average Exercise Price, Forfeited | $ / shares	4.61
Weighted Average Exercise Price, Options outstanding, Ending balance | $ / shares	4.64
Weighted Average Exercise Price, Vested and exercisable, Ending balance | $ / shares	$ 4.90
Weighted Average Remaining Contractual Life (in years), Options outstanding	6 years 3 months 7 days
Weighted Average Remaining Contractual Life (in years), Vested and exercisable	5 years 2 months 9 days
Aggregate Intrinsic value, Options outstanding | $	$ 126,917
Aggregate Intrinsic value, Vested and exercisable | $	$ 27,548

Stock Option and Incentive Pl42

Stock Option and Incentive Plans - Assumptions to Compute Fair Value of Stock Option Grants (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Risk free interest rate	1.21%	1.62%
Expected dividend yield	$ 0	$ 0
Expected term (in years)	4 years 10 months 13 days	5 years 11 months 19 days
Expected volatility	79.70%	73.60%

Significant Agreements - Additi

Significant Agreements - Additional Information (Detail) - General and Administrative Expense [Member] - Supplemental Employee Retirement Plan [Member] $ in Millions	3 Months Ended
	Mar. 31, 2016USD ($)
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Agreement Description	On March 25, 2016, the Company entered into a separation agreement and release of claims with its former Chief Executive Officer, Julia P. Gregory. Subject to Ms. Gregory’s continued compliance with restrictive covenants contained in her employment agreement with the Company, the separation agreement provides for Ms. Gregory to receive severance payments totaling approximately $1.2 million for a period of 18 months following the effective date of Ms. Gregory’s retirement, the accelerated vesting of all unvested portions of stock option grants dated April 29, 2014 and February 8, 2016, and continued medical, dental and vision coverage paid for by the Company under the Company’s group healthcare plans for up to eighteen months following the effective date of Ms. Gregory’s retirement. The total amount of these charges was recognized as part of general and administrative expenses for the period ended March 31, 2016. Ms. Gregory will have a period of two years following the effective date of her retirement to exercise her vested Company stock options.
Separation Agreement Date	Mar. 25, 2016
Severance payment on effective date of retirement, as per the agreement	$ 1.2
Stock option grant dates subject to accelerated vesting under agreement	April 29, 2014 and February 8, 2016
Severance payments period following the effective date of retirement	18 months
Health care period after retirement, as per the agreement	18 months
Exercise period of vested stock options from retirement date, as per the agreement	2 years