ContraFect (CFRXQ) 10-Q 10 May 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2018	May 07, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
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		73,658,506

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 3,470,519	$ 6,995,046
Marketable securities	36,379,938	39,858,864
Prepaid expenses and other current assets	1,817,132	1,848,063
Total current assets	41,667,589	48,701,973
Property and equipment, net	1,138,824	1,093,903
Other assets	355,420	393,603
Total assets	43,161,833	50,189,479
Current liabilities:
Accounts payable	1,520,892	1,302,431
Accrued liabilities	2,402,055	3,118,237
Total current liabilities	3,922,947	4,420,668
Deferred rent	696,481	704,240
Warrant liabilities	25,823,996	13,549,437
Other liabilities	206,689	321,689
Total liabilities	30,650,113	18,996,034
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.0001 par value, 25,000,000 shares authorized and none outstanding at March 31, 2018 and December 31, 2017
Common stock, $0.0001 par value, 200,000,000 shares authorized; 73,658,506 and 73,656,006 shares issued and outstanding at March 31, 2018 and December 31, 2017, respectively	7,366	7,366
Additional paid-in capital	193,337,923	192,896,367
Accumulated other comprehensive loss	(91,620)	(74,820)
Accumulated deficit	(180,741,949)	(161,635,468)
Total stockholders' equity	12,511,720	31,193,445
Total liabilities and stockholders' equity	$ 43,161,833	$ 50,189,479

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2018	Dec. 31, 2017
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	200,000,000	200,000,000
Common stock, shares issued	73,658,506	73,656,006
Common stock, shares outstanding	73,658,506	73,656,006

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating expenses
Research and development	$ 4,735,340	$ 4,201,698
General and administrative	2,248,829	2,143,315
Total operating expenses	6,984,169	6,345,013
Loss from operations	(6,984,169)	(6,345,013)
Other income (expense):
Interest income	152,247	76,650
Change in fair value of warrant liabilities	(12,274,559)	(79,801)
Total other expense	(12,122,312)	(3,151)
Net loss	$ (19,106,481)	$ (6,348,164)
Per share information:
Net loss per share of common stock, basic and diluted	$ (0.26)	$ (0.15)
Basic and diluted weighted average shares outstanding	73,656,534	41,656,006

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net loss	$ (19,106,481)	$ (6,348,164)
Other comprehensive gain:
Unrealized (loss) gain on available-for-sale securities	(16,800)	5,895
Comprehensive loss	$ (19,123,281)	$ (6,342,269)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities
Net loss	$ (19,106,481)	$ (6,348,164)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	34,355	45,559
Stock-based compensation expense	437,681	380,911
Change in fair value of warrant liabilities	12,274,559	79,801
Decrease in deferred rent	(7,759)	(2,363)
Net amortization of premium on marketable securities	100,994	95,008
Changes in operating assets and liabilities:
Decrease (increase) in prepaid expenses and other current and non-current assets	69,114	(444,208)
(Decrease) increase in accounts payable, accrued liabilities and other liabilities	(612,721)	8,734
Net cash used in operating activities	(6,810,258)	(6,184,722)
Cash flows from investing activities
Purchases of marketable securities	(3,603,756)
Proceeds from sales of marketable securities	6,964,888	7,092,320
Purchases of property and equipment	(79,276)
Net cash provided by investing activities	3,281,856	7,092,320
Cash flows from financing activities
Proceeds from exercise of warrants	3,875
Net cash provided by financing activities	3,875
Net (decrease) increase in cash and cash equivalents	(3,524,527)	907,598
Cash and cash equivalents at beginning of period	6,995,046	3,806,984
Cash and cash equivalents at end of period	$ 3,470,519	$ 4,714,582

Organization and Description of

Organization and Description of Business	3 Months Ended
	Mar. 31, 2018
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, Staph aureus CF-404, 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 as of March 31, 2018 will be sufficient to fund operations through the second quarter of 2019 and expects operating losses and negative cash flows to continue at more significant levels in the future as it continues its 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.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2018
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, 2018 and for the three months ended March 31, 2018 and 2017 has been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). Certain information and footnote disclosures normally included in consolidated 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 consolidated balance sheet as of December 31, 2017 was derived from the Company’s audited consolidated financial statements. The Company’s audited consolidated financial statements as of and for the year ended December 31, 2017, 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 In the opinion of management, the unaudited financial information as of March 31, 2018 and for the three months ended March 31, 2018 and 2017 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, 2018 are not necessarily indicative of the operating results for the full fiscal year or any future periods. Principles of Consolidation The Company has a wholly-owned subsidiary, ContraFect International Limited, in Scotland that establishes legal status for interactions with the European Economic Area. This subsidiary is dormant or is otherwise non-operative. 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. Use of Estimates The preparation of the consolidated 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 consolidated 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. Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentration of 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 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. Marketable Securities Marketable securities consist of investments in 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 Investments – Debt and Equity Securities long-term 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 consolidated 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. Fair Value of Financial Instruments The Company’s financial instruments consist of cash and cash equivalents, marketable securities, accounts payable, accrued liabilities 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”) Accounting Standard Codification (“ASC”) Topic 820, Fair Value Measurements and Disclosures The three levels of the fair value hierarchy are described below: 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 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 liabilities 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, non-employee 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. Grants The Company recognizes a receivable and the related reduction in its research and development expenses when the actual reimbursable costs have been incurred and there is reasonable assurance that the Company has complied with the conditions of the grants and the amounts will be received. For the three months ended March 31, 2018 and 2017, the Company recognized a reduction to its research and development expense in the amount of approximately $370,000 and $82,000, respectively. The receivable for grants as of March 31, 2018 was $428,815 and is included in prepaid expenses and other current assets. The Company has $1,684,425 of approved grant award funding remaining as of March 31, 2018. 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. Recently Adopted Accounting Pronouncements In January 2016, the FASB issued a new Accounting Standards Update, Recognition and Measurement of Financial Assets and Financial Liabilities (ASU 2016-01) 2016-01 2016-01 In August 2016, the FASB issued Accounting Standards Update No. 2016-15 , Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments 2016-15), 2016-15 No. 2016-15 In November 2016, the FASB issued Accounting Standards Update No. 2016-18 , Statement of Cash Flows (Topic 230): Restricted Cash 2016-18), beginning-of-period end-of-period 2016-18 No. 2016-18 In May 2017, the FASB issued Accounting Standards Update 2017-09, Compensation – Stock Compensation 2017-09). 2017-09 No. 2017-09 Recent Accounting Pronouncements Not Yet Adopted In February 2016, the FASB issued a new Accounting Standards Update, Leases (ASU 2016-02) 2016-02 right-of-use 2016-02 In June 2016, the FASB issued a new Accounting Standards Update, Financial Instruments-Credit Losses (ASU 2016-13). 2016-13 available-for-sale

Marketable Securities

Marketable Securities	3 Months Ended
	Mar. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	3. Marketable Securities Marketable securities at March 31, 2018 consist of the following: Marketable Securities Amortized Unrealized Gains Unrealized Losses Fair Value Current: Corporate debt $ 36,471,558 $ 2,350 $ (93,970 ) $ 36,379,938 Marketable securities at December 31, 2017 consisted of the following: Marketable Securities Amortized Unrealized Gains Unrealized Losses Fair Value Current: Corporate debt $ 39,933,685 $ — $ (74,820 ) $ 39,858,864 At March 31, 2018, the Company held only investments that have maturities of less than one year. At March 31, 2018 and December 31, 2017, the Company held 27 and 32 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, 2018 and December 31, 2017 was $32,604,030 and $39,858,864, 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 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, 2018 and December 31, 2017.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2018
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, 2018 and December 31, 2017: Fair Value Measurement as of March 31, 2018 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents $ 3,094,855 $ — $ — Marketable securities 36,379,938 — — Warrant liabilities — — 25,823,996 Total $ 39,474,793 $ — $ 25,823,996 Fair Value Measurement as of December 31, 2017 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents $ 5,949,477 $ — $ — Marketable securities 39,858,864 — — Warrant liabilities — — 13,549,437 Total $ 45,808,341 $ — $ 13,549,437 The Company issued a warrant to the representative of the underwriter of its initial public offering (the “Representative’s Warrant”). The Company determined that this warrant should be classified as a liability and considers it as a Level 3 financial instrument (see also Note 7, “Capital Structure”). The Representative’s Warrant is re-measured As of As of March 31, December 31, Expected volatility 88.3 % 88.1 % Remaining contractual term (in years) 1.42 1.67 Risk-free interest rate 2.26 % 1.89 % Expected dividend yield — % — % The Company issued warrants to the purchasers of its 2016 Offering (the “2016 Warrants”), The Company determined that these warrants should be classified as a liability and considered as a Level 3 financial instrument (see also Note 7, “Capital Structure”). The 2016 Warrants are re-measured As of As of March 31, December 31, Expected volatility 78.4 % 80.3 % Remaining contractual term (in years) 3.33 3.58 Risk-free interest rate 2.48 % 2.09 % Expected dividend yield — % — % The Company issued warrants to the purchasers of its 2017 Offering (the “2017 Warrants”). The Company determined that these warrants should be classified as a liability and considered as a Level 3 financial instrument (see also Note 7, “Capital Structure”). The 2017 Warrants are re-measured As of As of March 31, December 31, Expected volatility 82.2 % 81.5 % Remaining contractual term (in years) 4.33 4.58 Risk-free interest rate 2.56 % 2.20 % 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, 2018 and 2017: Warrant liabilities Three Months Ended March 31, 2018 2017 Balance at beginning of period $ 13,549,437 $ 12,698,980 Increase in fair value (1) 12,274,559 79,801 Balance at end of period $ 25,823,996 $ 12,778,781 (1) The change in fair values of the warrant liabilities is recorded in other expenses in the consolidated statement of operations. The key inputs into the Black-Scholes option pricing model are the current per-share

Accrued Liabilities

Accrued Liabilities	3 Months Ended
	Mar. 31, 2018
Payables and Accruals [Abstract]
Accrued Liabilities	5. Accrued Liabilities Accrued liabilities consist of the following: March 31, 2018 December 31, 2017 Accrued research and development service fees $ 991,861 $ 578,562 Accrued compensation costs 866,616 2,107,118 Accrued professional fees 269,915 168,168 Accrued facilities operation expenses 188,637 221,103 Other accrued liabilities 85,026 43,286 Total accrued liabilities $ 2,402,055 $ 3,118,237

Net Loss Per Share of Common St

Net Loss Per Share of Common Stock	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Net Loss Per Share of Common Stock	6. 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, 2018 2017 Net loss $ (19,106,481 ) $ (6,348,164 ) Weighted average shares of common stock outstanding 73,656,534 41,656,006 Net loss per share of common stock—basic and diluted $ (0.26 ) $ (0.15 ) The following potentially dilutive securities outstanding at March 31, 2018 and 2017 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, 2018 2017 Options to purchase common stock 7,475,106 5,907,782 Warrants to purchase common stock 36,267,603 20,334,442 Total 43,742,709 26,242,224

Capital Structure

Capital Structure	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Capital Structure	7. Capital Structure Common Stock As of March 31, 2018, the Company was authorized to issue 200,000,000 shares of common stock at $0.0001 par value per share. Follow-on On July 25, 2017, the Company sold 32,000,000 shares of its common stock and warrants to purchase an additional 16,000,000 shares of its common stock in an underwritten follow-on On July 27, 2016, the Company sold 14,000,000 shares of its common stock and warrants to purchase an additional 14,000,000 shares of its common stock in an underwritten Follow-on The Company issued warrants in both follow-on re-measured Private Placement On June 12, 2015, the Company sold an aggregate of 4,728,128 common shares and warrants to purchase an additional 2,364,066 shares of common stock for gross proceeds of $20.0 million in a private placement (the “PIPE”). The warrants have an exercise price of $8.00 per share and 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 a total of 189,126 shares of common stock at an exercise price of $4.65 per share which expire on June 11, 2020 (the “Placement Agent Warrants”). The PIPE Warrants and Placement Agent Warrants have been classified as stockholders’ equity in the Company’s consolidated balance sheet. Initial Public Offering In August 2014, the Company completed an initial public offering (“IPO”), raising net proceeds of $35.0 million after underwriting discounts, commissions and offering expenses payable by us, through the issuance and sale of our units, which 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 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 July 28, 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 is re-measured Convertible Notes The Company issued approximately $15.0 million 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 IPO, the principal amount of the Convertible Notes, and all accrued and unpaid interest thereon, automatically converted into 5,109,988 shares of common stock. Each purchaser of the Convertible Notes also received a warrant with an exercise price “cap” that was analogous to “down round protection” (the “Note Warrants”). Upon the closing of the IPO 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, 2018. The Note Warrants expire five years from the date of issuance. 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, 2018, 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, 2018 and December 31, 2017: March 31, December 31, 2018 2017 Options to purchase common stock 7,475,106 6,200,151 Warrants to purchase common stock 36,267,603 36,270,103 43,742,709 42,470,254

Stock Warrants

Stock Warrants	3 Months Ended
	Mar. 31, 2018
Text Block [Abstract]
Stock Warrants	8. Stock Warrants As of March 31, 2018 and December 31, 2017, the Company had warrants outstanding as shown in the table below. March 31, 2018 December 31, 2017 Note Warrants 3,315,878 3,315,878 PIPE Warrants 2,364,066 2,364,066 2017 Warrants 15,997,500 16,000,000 2016 Warrants 14,000,000 14,000,000 Representative’s Warrant 206,410 206,410 Placement Agent Warrants 189,126 189,126 Other warrants (1) 194,623 194,623 Warrants to purchase common stock 36,267,603 36,270,103 Weighted-average exercise price per share $ 2.74 $ 2.74 (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, 2018: Exercise Prices Shares Underlying Outstanding Warrants Expiration Date £ 16,003,214 September 1, 2021 – July 25, 2022 $2.01 - $4.99 17,606,105 June 18, 2018 – July 27, 2021 $5.00 - $7.99 231,409 April 30, 2018 – July 22, 2019 ³ 2,426,875 June 11, 2018 – January 5, 2022 36,267,603

Stock Option and Incentive Plan

Stock Option and Incentive Plans	3 Months Ended
	Mar. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Option and Incentive Plans	9. 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- 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 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, 2018, is summarized as follows: Number of Options Weighted Average Weighted Contractual (in years) Aggregate Options outstanding at December 31, 2017 6,200,151 $ 3.81 Granted 2,145,000 1.44 Exercised — — Expired (782,233 ) 3.95 Forfeited (87,812 ) 1.86 Options outstanding at March 31, 2018 7,475,106 3.13 7.43 $ 553,775 Vested and exercisable at March 31, 2018 4,169,578 4.12 6.03 $ 181,325 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, 2018 and 2017 was $1.44 and $1.75, respectively. Total compensation expense recognized amounted to $437,681 and $380,911, for the three months ended March 31, 2018 and 2017, respectively. As of March 31, 2018, the total remaining unrecognized compensation cost related to unvested stock options was $3,569,426 which will be recognized over a weighted average period of approximately 3.07 years. The following assumptions were used to compute the fair value of stock option grants: Three Months 2018 2017 Risk free interest rate 2.56 % 2.11 % Expected dividend yield — — Expected term (in years) 6.06 6.06 Expected volatility 82.2 % 78.7 % Expected volatility— Expected term— Risk-free interest rate Expected dividend yield—

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	10. Income Taxes Deferred tax assets and deferred tax liabilities are recognized based on temporary differences between the financial reporting and tax basis of assets and liabilities using statutory rates. A valuation allowance is recorded against deferred tax assets if it is more likely than not that some or all of the deferred tax assets will not be realized. Due to the uncertainty surrounding the realization of the favorable tax attributes in future tax returns, the Company has recorded a full valuation allowance against the Company’s otherwise recognizable net deferred tax assets. On December 22, 2017, the SEC staff issued Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act (“SAB 118”), which allows the recording of provisional amounts during a measurement period not to extend beyond one year of the enactment date. In accordance with SAB 118, the Company determined a provisional amount for the impact on its prior year deferred tax assets and valuation allowance in its prior year financial statements. The Company has not updated the provisional amounts and expects to complete the final assessment of the impact within the measurement period.

Summary of Significant Accoun17

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying financial information as of March 31, 2018 and for the three months ended March 31, 2018 and 2017 has been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). Certain information and footnote disclosures normally included in consolidated 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 consolidated balance sheet as of December 31, 2017 was derived from the Company’s audited consolidated financial statements. The Company’s audited consolidated financial statements as of and for the year ended December 31, 2017, 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 In the opinion of management, the unaudited financial information as of March 31, 2018 and for the three months ended March 31, 2018 and 2017 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, 2018 are not necessarily indicative of the operating results for the full fiscal year or any future periods.
Principles of Consolidation	Principles of Consolidation The Company has a wholly-owned subsidiary, ContraFect International Limited, in Scotland that establishes legal status for interactions with the European Economic Area. This subsidiary is dormant or is otherwise non-operative.
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.
Use of Estimates	Use of Estimates The preparation of the consolidated 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 consolidated 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.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentration of 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
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.
Marketable Securities	Marketable Securities Marketable securities consist of investments in 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 Investments – Debt and Equity Securities long-term 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 consolidated 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.
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 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”) Accounting Standard Codification (“ASC”) Topic 820, Fair Value Measurements and Disclosures The three levels of the fair value hierarchy are described below: 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 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 liabilities 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, non-employee 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.
Grants	Grants The Company recognizes a receivable and the related reduction in its research and development expenses when the actual reimbursable costs have been incurred and there is reasonable assurance that the Company has complied with the conditions of the grants and the amounts will be received. For the three months ended March 31, 2018 and 2017, the Company recognized a reduction to its research and development expense in the amount of approximately $370,000 and $82,000, respectively. The receivable for grants as of March 31, 2018 was $428,815 and is included in prepaid expenses and other current assets. The Company has $1,684,425 of approved grant award funding remaining as of March 31, 2018.
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.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In January 2016, the FASB issued a new Accounting Standards Update, Recognition and Measurement of Financial Assets and Financial Liabilities (ASU 2016-01) 2016-01 2016-01 In August 2016, the FASB issued Accounting Standards Update No. 2016-15 , Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments 2016-15), 2016-15 No. 2016-15 In November 2016, the FASB issued Accounting Standards Update No. 2016-18 , Statement of Cash Flows (Topic 230): Restricted Cash 2016-18), beginning-of-period end-of-period 2016-18 No. 2016-18 In May 2017, the FASB issued Accounting Standards Update 2017-09, Compensation – Stock Compensation 2017-09). 2017-09 No. 2017-09
Recent Accounting Pronouncements Not Yet Adopted	Recent Accounting Pronouncements Not Yet Adopted In February 2016, the FASB issued a new Accounting Standards Update, Leases (ASU 2016-02) 2016-02 right-of-use 2016-02 In June 2016, the FASB issued a new Accounting Standards Update, Financial Instruments-Credit Losses (ASU 2016-13). 2016-13 available-for-sale

Marketable Securities (Tables)

Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Schedule of Marketable Securities	Marketable securities at March 31, 2018 consist of the following: Marketable Securities Amortized Unrealized Gains Unrealized Losses Fair Value Current: Corporate debt $ 36,471,558 $ 2,350 $ (93,970 ) $ 36,379,938 Marketable securities at December 31, 2017 consisted of the following: Marketable Securities Amortized Unrealized Gains Unrealized Losses Fair Value Current: Corporate debt $ 39,933,685 $ — $ (74,820 ) $ 39,858,864

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2018
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, 2018 and December 31, 2017: Fair Value Measurement as of March 31, 2018 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents $ 3,094,855 $ — $ — Marketable securities 36,379,938 — — Warrant liabilities — — 25,823,996 Total $ 39,474,793 $ — $ 25,823,996 Fair Value Measurement as of December 31, 2017 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents $ 5,949,477 $ — $ — Marketable securities 39,858,864 — — Warrant liabilities — — 13,549,437 Total $ 45,808,341 $ — $ 13,549,437
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, 2018 and 2017: Warrant liabilities Three Months Ended March 31, 2018 2017 Balance at beginning of period $ 13,549,437 $ 12,698,980 Increase in fair value (1) 12,274,559 79,801 Balance at end of period $ 25,823,996 $ 12,778,781 (1) The change in fair values of the warrant liabilities is recorded in other expenses in the consolidated statement of operations.
Representative's Warrant [Member]
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 As of March 31, December 31, Expected volatility 88.3 % 88.1 % Remaining contractual term (in years) 1.42 1.67 Risk-free interest rate 2.26 % 1.89 % Expected dividend yield — % — %
2016 Warrants [Member]
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 As of March 31, December 31, Expected volatility 78.4 % 80.3 % Remaining contractual term (in years) 3.33 3.58 Risk-free interest rate 2.48 % 2.09 % Expected dividend yield — % — %
2017 Warrants [Member]
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 As of March 31, December 31, Expected volatility 82.2 % 81.5 % Remaining contractual term (in years) 4.33 4.58 Risk-free interest rate 2.56 % 2.20 % Expected dividend yield — % — %

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	3 Months Ended
	Mar. 31, 2018
Payables and Accruals [Abstract]
Summary of Accrued Liabilities	Accrued liabilities consist of the following: March 31, December 31, Accrued research and development service fees $ 991,861 $ 578,562 Accrued compensation costs 866,616 2,107,118 Accrued professional fees 269,915 168,168 Accrued facilities operation expenses 188,637 221,103 Other accrued liabilities 85,026 43,286 Total accrued liabilities $ 2,402,055 $ 3,118,237

Net Loss Per Share of Common 21

Net Loss Per Share of Common Stock (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted 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, 2018 2017 Net loss $ (19,106,481 ) $ (6,348,164 ) Weighted average shares of common stock outstanding 73,656,534 41,656,006 Net loss per share of common stock—basic and diluted $ (0.26 ) $ (0.15 )
Schedule of Antidilutive Securities Excluded from Computation of Diluted Weighted Average Shares Outstanding	The following potentially dilutive securities outstanding at March 31, 2018 and 2017 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, 2018 2017 Options to purchase common stock 7,475,106 5,907,782 Warrants to purchase common stock 36,267,603 20,334,442 Total 43,742,709 26,242,224

Capital Structure (Tables)

Capital Structure (Tables)	3 Months Ended
	Mar. 31, 2018
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, 2018 and December 31, 2017: March 31, December 31, 2018 2017 Options to purchase common stock 7,475,106 6,200,151 Warrants to purchase common stock 36,267,603 36,270,103 43,742,709 42,470,254

Stock Warrants (Tables)

Stock Warrants (Tables)	3 Months Ended
	Mar. 31, 2018
Text Block [Abstract]
Schedule of Warrants Outstanding	As of March 31, 2018 and December 31, 2017, the Company had warrants outstanding as shown in the table below. March 31, 2018 December 31, 2017 Note Warrants 3,315,878 3,315,878 PIPE Warrants 2,364,066 2,364,066 2017 Warrants 15,997,500 16,000,000 2016 Warrants 14,000,000 14,000,000 Representative’s Warrant 206,410 206,410 Placement Agent Warrants 189,126 189,126 Other warrants (1) 194,623 194,623 Warrants to purchase common stock 36,267,603 36,270,103 Weighted-average exercise price per share $ 2.74 $ 2.74 (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, 2018: Exercise Prices Shares Underlying Outstanding Warrants Expiration Date £ 16,003,214 September 1, 2021 – July 25, 2022 $2.01 - $4.99 17,606,105 June 18, 2018 – July 27, 2021 $5.00 - $7.99 231,409 April 30, 2018 – July 22, 2019 ³ 2,426,875 June 11, 2018 – January 5, 2022 36,267,603

Stock Option and Incentive Pl24

Stock Option and Incentive Plans (Tables)	3 Months Ended
	Mar. 31, 2018
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, 2018, is summarized as follows: Number of Options Weighted Average Weighted Contractual (in years) Aggregate Options outstanding at December 31, 2017 6,200,151 $ 3.81 Granted 2,145,000 1.44 Exercised — — Expired (782,233 ) 3.95 Forfeited (87,812 ) 1.86 Options outstanding at March 31, 2018 7,475,106 3.13 7.43 $ 553,775 Vested and exercisable at March 31, 2018 4,169,578 4.12 6.03 $ 181,325
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 2018 2017 Risk free interest rate 2.56 % 2.11 % Expected dividend yield — — Expected term (in years) 6.06 6.06 Expected volatility 82.2 % 78.7 %

Summary of Significant Accoun25

Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2018USD ($)	Mar. 31, 2017USD ($)
Accounting Policies [Abstract]
Maturity period of highly liquid investments	Three months or less
Realized gains or losses on marketable securities	$ 0	$ 0
Number of securities in unrealized loss position for more than 12 months	0	0
Grants receivable recognized	$ 370,000	$ 82,000
Grants receivable	428,815
Grants remaining to be awarded	$ 1,684,425

Marketable Securities - Schedul

Marketable Securities - Schedule of Marketable Securities (Detail) - Corporate Debt [Member] - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Marketable Securities, Amortized Cost	$ 36,471,558	$ 39,933,685
Marketable Securities, Unrealized Gains	2,350
Marketable Securities, Unrealized Losses	(93,970)	(74,820)
Marketable Securities, Fair Value	$ 36,379,938	$ 39,858,864

Marketable Securities - Additio

Marketable Securities - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2018USD ($)Security	Dec. 31, 2017USD ($)Security
Marketable Securities [Abstract]
Maturity period classified current investments	Less than one year
Number of securities in unrealized loss position for less than one year | Security	27	32
Aggregate fair value of debt securities | $	$ 32,604,030	$ 39,858,864

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, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	$ 36,379,938	$ 39,858,864
Warrant liabilities	(25,823,996)	(13,549,437)
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	3,094,855	5,949,477
Marketable securities	36,379,938	39,858,864
Total assets (liabilities)	39,474,793	45,808,341
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant liabilities	25,823,996	13,549,437
Total assets (liabilities)	$ 25,823,996	$ 13,549,437

Fair Value Measurements - Assum

Fair Value Measurements - Assumption Used to Determine Fair Value of Warrant Liability (Detail)	Mar. 31, 2018	Dec. 31, 2017
Representative's Warrant [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Expected volatility	88.30%	88.10%
Remaining contractual term (in years)	1 year 5 months 1 day	1 year 8 months 2 days
Risk-free interest rate	2.26%	1.89%
Expected dividend yield	0.00%	0.00%
2016 Warrants [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Expected volatility	78.40%	80.30%
Remaining contractual term (in years)	3 years 3 months 29 days	3 years 6 months 29 days
Risk-free interest rate	2.48%	2.09%
Expected dividend yield	0.00%	0.00%
2017 Warrants [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Expected volatility	82.20%	81.50%
Remaining contractual term (in years)	4 years 3 months 29 days	4 years 6 months 29 days
Risk-free interest rate	2.56%	2.20%
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, 2018	Mar. 31, 2017
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	$ 13,549,437	$ 12,698,980
Increase in fair value	12,274,559	79,801
Balance at end of period	$ 25,823,996	$ 12,778,781

Accrued Liabilities - Summary o

Accrued Liabilities - Summary of Accrued Liabilities (Detail) - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Payables and Accruals [Abstract]
Accrued research and development service fees	$ 991,861	$ 578,562
Accrued compensation costs	866,616	2,107,118
Accrued professional fees	269,915	168,168
Accrued facilities operation expenses	188,637	221,103
Other accrued liabilities	85,026	43,286
Total accrued liabilities	$ 2,402,055	$ 3,118,237

Net Loss Per Share of Common 32

Net Loss Per Share of Common Stock - Schedule of Computation of Basic and Diluted Loss Per Share for Common Stockholders (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Net loss	$ (19,106,481)	$ (6,348,164)
Weighted average shares of common stock outstanding	73,656,534	41,656,006
Net loss per share of common stock-basic and diluted	$ (0.26)	$ (0.15)

Net Loss Per Share of Common 33

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, 2018	Mar. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially antidilutive securities outstanding excluded from the computation of diluted weighted average shares	43,742,709	26,242,224
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	7,475,106	5,907,782
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	36,267,603	20,334,442

Capital Structure - Additional

Capital Structure - Additional Information (Detail) - USD ($)	Mar. 31, 2018	Jul. 25, 2017	Jul. 27, 2016	Nov. 02, 2015	Jun. 12, 2015	Aug. 01, 2014	Mar. 31, 2018	Jun. 30, 2014	Dec. 31, 2017
Class of Stock [Line Items]
Common stock, shares authorized	200,000,000						200,000,000		200,000,000
Common stock, par value	$ 0.0001						$ 0.0001		$ 0.0001
Net proceeds from initial public offering						$ 35,000,000
Initial public offering, closing date							Aug. 1, 2014
Initial public offering, units description							In August 2014, the Company completed an initial public offering (“IPO”), raising net proceeds of $35.0 million after underwriting discounts, commissions and offering expenses payable by us, through the issuance and sale of our units, which 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 (“Units”).
Proceeds from exercise of warrants							$ 3,875
Number of warrants or rights outstanding	36,267,603						36,267,603		36,270,103
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
8.00% Convertible Notes due May 31, 2015 [Member]
Class of Stock [Line Items]
Convertible Notes, principal amount								$ 15,000,000
Convertible Notes, interest rate								8.00%
Convertible Notes, due date								May 31, 2015
2016 Warrants [Member]
Class of Stock [Line Items]
Number of warrants or rights outstanding	14,000,000						14,000,000		14,000,000
2017 Warrants [Member]
Class of Stock [Line Items]
Number of warrants or rights outstanding	15,997,500						15,997,500		16,000,000
Private Placement [Member]
Class of Stock [Line Items]
Number of shares issued					4,728,128
Warrants to purchase shares of common stock	189,126				2,364,066		189,126
Net proceeds received					$ 18,300,000
Warrant exercise price per share	$ 4.65				$ 8		$ 4.65
Warrants expiration period					3 years
Warrant expiration date							Jun. 11, 2020
Initial Public Offering [Member]
Class of Stock [Line Items]
Conversion of Convertible Notes together with accrued and unpaid interest into common stock, shares						5,109,988
Follow-on Offering [Member]
Class of Stock [Line Items]
Number of shares issued		32,000,000	14,000,000
Warrants to purchase shares of common stock	2,500						2,500
Aggregate gross sales proceeds from common stock		$ 40,000,000	$ 35,000,000
Net proceeds received		$ 37,100,000	$ 32,000,000
Follow-on Offering [Member] | CMPO Warrants [Member]
Class of Stock [Line Items]
Warrants to purchase shares of common stock		16,000,000	14,000,000
Follow-on Offering [Member] | 2016 Warrants [Member]
Class of Stock [Line Items]
Warrant exercise price per share			$ 3
Warrant expiration term			5 years
Fair value of warrants			$ 18,600,000
Issuance costs allocated to warrants			$ 1,600,000
Follow-on Offering [Member] | 2017 Warrants [Member]
Class of Stock [Line Items]
Warrant exercise price per share		$ 1.55
Warrant expiration term		5 years
Fair value of warrants		$ 12,400,000
Issuance costs allocated to warrants		$ 900,000
Note Warrants [Member]
Class of Stock [Line Items]
Warrant exercise price per share						$ 3
Warrants expiration period							5 years
Number of warrants or rights outstanding	3,315,878					3,321,416	3,315,878		3,315,878
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
Class B Warrants [Member] | Initial Public Offering [Member]
Class of Stock [Line Items]
Warrant exercise price per share						$ 4
Representative's Warrant [Member]
Class of Stock [Line Items]
Warrants to purchase shares of common stock	206,410						206,410
Warrant exercise price per share	$ 7.50						$ 7.50
Warrant expiration date							Jul. 28, 2019
Class of warrant purchase percentage	3.00%						3.00%
Warrant exercisable period							180 days
Number of warrants or rights outstanding	206,410						206,410		206,410
Class A Warrants [Member]
Class of Stock [Line Items]
Warrant expiration date							Feb. 1, 2017
Class A Warrants [Member] | Initial Public Offering [Member]
Class of Stock [Line Items]
Warrant exercise price per share						$ 4.80

Capital Structure - Summary of

Capital Structure - Summary of Common Stock Reserved for Future Issuance (Detail) - shares	Mar. 31, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Common Stock reserved for future issuance	43,742,709	42,470,254
Stock Options [Member]
Class of Stock [Line Items]
Common Stock reserved for future issuance	7,475,106	6,200,151
Warrants [Member]
Class of Stock [Line Items]
Common Stock reserved for future issuance	36,267,603	36,270,103

Stock Warrants - Schedule of Wa

Stock Warrants - Schedule of Warrants Outstanding (Detail) - $ / shares	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Jun. 12, 2015	Aug. 01, 2014
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	36,267,603	36,270,103
Weighted-average exercise price per share	$ 2.74	$ 2.74
Placement Agent Warrants [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	189,126	189,126
Representative's Warrant [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	206,410	206,410
Exercise Prices	$ 7.50
Other Warrants [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	194,623	194,623
Exercise Price Less Than or Equal to $2.00 [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	16,003,214
Expiration Start Date	Sep. 1, 2021
Expiration End Date	Jul. 25, 2022
Exercise Price $2.01 - $4.99 [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	17,606,105
Expiration Start Date	Jun. 18, 2018
Expiration End Date	Jul. 27, 2021
Exercise Price $5.00 - $7.99 [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	231,409
Expiration Start Date	Apr. 30, 2018
Expiration End Date	Jul. 22, 2019
Exercise Price Greater Than or Equal to $8.00 [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	2,426,875
Expiration Start Date	Jun. 11, 2018
Expiration End Date	Jan. 5, 2022
Minimum [Member] | Exercise Price $2.01 - $4.99 [Member]
Class of Warrant or Right [Line Items]
Exercise Prices	$ 2.01
Minimum [Member] | Exercise Price $5.00 - $7.99 [Member]
Class of Warrant or Right [Line Items]
Exercise Prices	5
Minimum [Member] | Exercise Price Greater Than or Equal to $8.00 [Member]
Class of Warrant or Right [Line Items]
Exercise Prices	8
Maximum [Member] | Exercise Price Less Than or Equal to $2.00 [Member]
Class of Warrant or Right [Line Items]
Exercise Prices	2
Maximum [Member] | Exercise Price $2.01 - $4.99 [Member]
Class of Warrant or Right [Line Items]
Exercise Prices	4.99
Maximum [Member] | Exercise Price $5.00 - $7.99 [Member]
Class of Warrant or Right [Line Items]
Exercise Prices	$ 7.99
Note Warrants [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	3,315,878	3,315,878		3,321,416
Exercise Prices				$ 3
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
2016 Warrants [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	14,000,000	14,000,000
2017 Warrants [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants	15,997,500	16,000,000

Stock Option and Incentive Pl37

Stock Option and Incentive Plans - Additional Information (Detail) - USD ($)	Dec. 31, 2015	Feb. 26, 2013	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Jul. 28, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock reserved pursuant to the plan			43,742,709		42,470,254
Weighted average grant date fair value of options			$ 1.44	$ 1.75
Unrecognized compensation cost related to unvested stock options			$ 3,569,426
Weighted average period of unvested stock options			3 years 26 days
Employee Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense recognized			$ 437,681	$ 380,911
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		1,571,428
Termination of service, Period		2 years
2008 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Termination of service, Period		10 years
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			6,520,477
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 Pl38

Stock Option and Incentive Plans - Summary of Stock Option Activity (Detail)	3 Months Ended
	Mar. 31, 2018USD ($)$ / sharesshares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of Options, Options outstanding, Beginning balance | shares	6,200,151
Number of Options, Granted | shares	2,145,000
Number of Options, Exercised | shares	0
Number of Options, Expired | shares	(782,233)
Number of Options, Forfeited | shares	(87,812)
Number of Options, Options outstanding, Ending balance | shares	7,475,106
Number of Options, Vested and exercisable, Ending Balance | shares	4,169,578
Weighted Average Exercise Price, Options outstanding, Beginning balance | $ / shares	$ 3.81
Weighted Average Exercise Price, Granted | $ / shares	1.44
Weighted Average Exercise Price, Exercised | $ / shares	0
Weighted Average Exercise Price, Expired | $ / shares	3.95
Weighted Average Exercise Price, Forfeited | $ / shares	1.86
Weighted Average Exercise Price, Options outstanding, Ending balance | $ / shares	3.13
Weighted Average Exercise Price, Vested and exercisable, Ending balance | $ / shares	$ 4.12
Weighted Average Remaining Contractual Life (in years), Options outstanding	7 years 5 months 5 days
Weighted Average Remaining Contractual Life (in years), Vested and exercisable	6 years 11 days
Aggregate Intrinsic value, Options outstanding | $	$ 553,775
Aggregate Intrinsic value, Vested and exercisable | $	$ 181,325

Stock Option and Incentive Pl39

Stock Option and Incentive Plans - Assumptions to Compute Fair Value of Stock Option Grants (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Risk free interest rate	2.56%	2.11%
Expected dividend yield	$ 0	$ 0
Expected term (in years)	6 years 22 days	6 years 22 days
Expected volatility	82.20%	78.70%