ContraFect (CFRXQ) 10-Q 9 Aug 19 2019 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2019	Aug. 07, 2019
Document and Entity Information [Abstract]
Document Type	10-Q
Entity Interactive Data Current	Yes
Amendment Flag	false
Document Period End Date	Jun. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Trading Symbol	CFRX
Entity Registrant Name	CONTRAFECT Corp
Entity Central Index Key	0001478069
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Current Reporting Status	Yes
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Title of 12(b) Security	Common Stock
Security Exchange Name	NASDAQ
Entity Address, State or Province	NY
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		79,409,556

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 7,377,139	$ 8,320,317
Marketable securities	6,851,515	22,131,936
Prepaid expenses and other current assets	1,986,484	988,799
Total current assets	16,215,138	31,441,052
Property and equipment, net	1,195,506	1,076,099
Operating lease right-of-use assets	3,150,932
Other assets	355,420	355,420
Total assets	20,916,996	32,872,571
Current liabilities:
Accounts payable	1,252,198	1,427,287
Accrued liabilities	2,032,616	4,369,732
Current portion of lease liabilities	625,541
Total current liabilities	3,910,355	5,797,019
Deferred rent		679,182
Warrant liabilities	4,345,902	20,781,663
Long-term portion of lease liabilities	3,399,926
Other liabilities	72,747	72,747
Total liabilities	11,728,930	27,330,611
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.0001 par value, 25,000,000 shares authorized and none outstanding at June 30, 2019 and December 31, 2018
Common stock, $0.0001 par value, 200,000,000 shares authorized; 79,409,556 shares issued and outstanding at June 30, 2019 and December 31, 2018, respectively	7,941	7,941
Additional paid-in capital	205,577,912	204,884,211
Accumulated other comprehensive income (loss)	1,996	(30,300)
Accumulated deficit	(196,399,783)	(199,319,892)
Total stockholders' equity	9,188,066	5,541,960
Total liabilities and stockholders' equity	$ 20,916,996	$ 32,872,571

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2019	Dec. 31, 2018
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	79,409,556	79,409,556
Common stock, shares outstanding	79,409,556	79,409,556

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Operating expenses
Research and development	$ 4,804,076	$ 5,252,334	$ 8,911,216	$ 9,987,674
General and administrative	2,603,403	2,244,120	4,857,996	4,492,949
Total operating expenses	7,407,479	7,496,454	13,769,212	14,480,623
Loss from operations	(7,407,479)	(7,496,454)	(13,769,212)	(14,480,623)
Other income (expense):
Interest income	104,441	163,145	253,560	315,392
Change in fair value of warrant liabilities	(1,363,868)	(12,802,583)	16,435,761	(25,077,142)
Total other income (expense)	(1,259,427)	(12,639,438)	16,689,321	(24,761,750)
Net income (loss)	$ (8,666,906)	$ (20,135,892)	$ 2,920,109	$ (39,242,373)
Basic net income (loss) per share	$ (0.11)	$ (0.27)	$ 0.04	$ (0.53)
Shares used in computing basic net income (loss) per share	79,409,556	73,658,529	79,409,556	73,657,537
Diluted net income (loss) per share	$ (0.11)	$ (0.27)	$ 0.04	$ (0.53)
Shares used in computing diluted net income (loss) per share	79,406,556	73,658,529	79,457,926	73,657,537

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (8,666,906)	$ (20,135,892)	$ 2,920,109	$ (39,242,373)
Other comprehensive gain:
Unrealized gain on available-for-sale securities	960	47,568	32,296	30,768
Comprehensive income (loss)	$ (8,665,946)	$ (20,088,324)	$ 2,952,405	$ (39,211,605)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]
Beginning Balance at Dec. 31, 2017	$ 31,193,445	$ 7,366	$ 192,896,367	$ (74,820)	$ (161,635,468)
Beginning Balance, Shares at Dec. 31, 2017		73,656,006
Share-based compensation	437,681		437,681
Unrealized gain (loss) on marketable securities	(16,800)			(16,800)
Issuance of common stock for exercise of warrants	3,875		3,875
Issuance of common stock for exercise of warrants, Shares		2,500
Net income (loss)	(19,106,481)				(19,106,481)
Ending balance at Mar. 31, 2018	12,511,720	$ 7,366	193,337,923	(91,620)	(180,741,949)
Ending balance, Shares at Mar. 31, 2018		73,658,506
Beginning Balance at Dec. 31, 2017	31,193,445	$ 7,366	192,896,367	(74,820)	(161,635,468)
Beginning Balance, Shares at Dec. 31, 2017		73,656,006
Net income (loss)	(39,242,373)
Ending balance at Jun. 30, 2018	(7,158,843)	$ 7,366	193,755,684	(44,052)	(200,877,841)
Ending balance, Shares at Jun. 30, 2018		73,659,556
Beginning Balance at Mar. 31, 2018	12,511,720	$ 7,366	193,337,923	(91,620)	(180,741,949)
Beginning Balance, Shares at Mar. 31, 2018		73,658,506
Share-based compensation	416,133		416,133
Unrealized gain (loss) on marketable securities	47,568			47,568
Issuance of common stock for exercise of warrants	1,628		1,628
Issuance of common stock for exercise of warrants, Shares		1,050
Net income (loss)	(20,135,892)				(20,135,892)
Ending balance at Jun. 30, 2018	(7,158,843)	$ 7,366	193,755,684	(44,052)	(200,877,841)
Ending balance, Shares at Jun. 30, 2018		73,659,556
Beginning Balance at Dec. 31, 2018	5,541,960	$ 7,941	204,884,211	(30,300)	(199,319,892)
Beginning Balance, Shares at Dec. 31, 2018		79,409,556
Share-based compensation	323,774		323,774
Unrealized gain (loss) on marketable securities	31,336			31,336
Net income (loss)	11,587,015				11,587,015
Ending balance at Mar. 31, 2019	17,484,085	$ 7,941	205,207,985	1,036	(187,732,877)
Ending balance, Shares at Mar. 31, 2019		79,409,556
Beginning Balance at Dec. 31, 2018	5,541,960	$ 7,941	204,884,211	(30,300)	(199,319,892)
Beginning Balance, Shares at Dec. 31, 2018		79,409,556
Net income (loss)	2,920,109
Ending balance at Jun. 30, 2019	9,188,066	$ 7,941	205,577,912	1,996	(196,399,783)
Ending balance, Shares at Jun. 30, 2019		79,409,556
Beginning Balance at Mar. 31, 2019	17,484,085	$ 7,941	205,207,985	1,036	(187,732,877)
Beginning Balance, Shares at Mar. 31, 2019		79,409,556
Share-based compensation	369,927		369,927
Unrealized gain (loss) on marketable securities	960			960
Net income (loss)	(8,666,906)				(8,666,906)
Ending balance at Jun. 30, 2019	$ 9,188,066	$ 7,941	$ 205,577,912	$ 1,996	$ (196,399,783)
Ending balance, Shares at Jun. 30, 2019		79,409,556

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities
Net income (loss)	$ 2,920,109	$ (39,242,373)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Depreciation	84,413	71,081
Stock-based compensation expense	693,701	853,814
Change in fair value of warrant liabilities	(16,435,761)	25,077,142
Decrease in deferred rent		(13,526)
Net amortization of premium on marketable securities	121,592	315,673
Changes in operating assets and liabilities:
Increase in prepaid expenses and other current and non-current assets	(1,009,217)	(315,653)
(Decrease) increase in accounts payable, accrued liabilities and other liabilities	(2,489,141)	52,631
Net cash used in operating activities	(16,114,304)	(13,201,211)
Cash flows from investing activities
Purchases of marketable securities		(11,129,302)
Proceeds from sales of marketable securities	15,191,125	21,978,888
Purchases of property and equipment	(19,999)	(79,276)
Net cash provided by investing activities	15,171,126	10,770,310
Cash flows from financing activities
Proceeds from exercise of warrants		5,503
Net cash provided by financing activities		5,503
Net decrease in cash and cash equivalents	(943,178)	(2,425,398)
Cash and cash equivalents at beginning of period	8,320,317	6,995,046
Cash and cash equivalents at end of period	7,377,139	$ 4,569,648
Supplemental disclosures of cash flow information:
Right-of-use assets obtained in exchange for lease obligations	4,148,672
Leasehold improvement obtained in exchange for lease incentive obligations	$ 189,227

Organization and Description of

Organization and Description of Business	6 Months Ended
	Jun. 30, 2019
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 biologic 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 portfolio of direct lytic agents (DLAs), including lysins and amurin peptides. The Company’s most advanced product candidate is exebacase, a lysin which targets Staph aureus Staph aureus Staph aureus The Company has incurred losses from operations since inception as a research and development organization and has an accumulated deficit of $196.4 million as of June 30, 2019. For the six months ended June 30, 2019, the Company used $16.1 million of cash in operations. The Company expects operating losses and negative cash flows to continue at significant levels in the future as it continues its clinical trials. Without additional funding, the Company believes it will not have sufficient funds to meet its obligations within the next twelve months from the date of issuance of these consolidated financial statements. These factors raise substantial doubt about the Company’s ability to continue as a going concern. The Company plans to continue to fund its operations through public or private debt and equity financings, but there can be no assurances that such financing will continue to be available to the Company on satisfactory terms, or at all. As such, under the requirements of ASC 205-40, The consolidated financial statements have been prepared assuming that the Company will continue as a going concern, which contemplates continuity of operations, the realization of assets and the satisfaction of liabilities and commitments in the normal course of business.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying financial information as of June 30, 2019 and for the three and six months ended June 30, 2019 and 2018 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, 2018 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, 2018, 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 June 30, 2019 and for the three and six months ended June 30, 2019 and 2018 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 June 30, 2019 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. 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 and U.S. Treasury 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 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 share-based compensation in accordance with ASC 718, Compensation—Stock Compensation, non-employees non-employee non-employee non-employees, 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 for employee and non-employee non-employee 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. Company recognized a reduction to its research and development expense in the amount of approximately $0.5 million and $0.4 million 1.2 million and $0.8 million respectively. The receivable for grants as of June 30, 2019 and December 31, 2018 was approximately $0.6 million and $0.2 million respectively, and is included in prepaid expenses and other current assets on the balance sheet. The Company has approximately $10.6 million of approved grant award funding remaining as of June 30, 2019. Net Income (Loss) Per Share Basic net income (loss) per share is calculated by dividing net income (loss) by the weighted average shares outstanding during the period, without consideration for common stock equivalents. Diluted net income (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 a 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. Common stock equivalents may also be excluded from the calculation of diluted net income per share if the exercise prices exceed the average market price for the reporting period. Recently Adopted Accounting Pronouncements Leases The Company adopted Accounting Standards Update No. 2016-02- Leases (Topic 842) non-lease The Company recognizes right-of-use Impact of adoption of Topic 842 Adoption of the new standard resulted in the recording of ROU assets, net of deferred rent and a lease incentive obligation, of $3.3 million and lease liabilities of approximately $4.1 million as of January 1, 2019. The lease liability was classified between a current portion of $0.6 million and a long-term portion of $3.5 million. The standard did not impact consolidated net income and had no impact on cash flows. Non-employee The Company adopted Accounting Standards Update, Compensation-Stock Compensation (ASU 2018-07), non-employees 2018-07 Statements of equity In August 2018, the Securities and Exchange Commission (“SEC”) adopted the final rule under SEC Release No. 33-10532, Recent Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued a new Accounting Standards Update, Financial Instruments-Credit Losses (ASU 2016-13). 2016-13 available-for-sale In August 2018, the FASB issued Accounting Standards Update, Fair Value Measurement: Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement, (ASU 2018-13). 2018-13

Marketable Securities

Marketable Securities	6 Months Ended
	Jun. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	3. Marketable Securities Marketable securities at June 30, 2019 consisted of the following: Marketable Securities Amortized Cost Unrealized Gains Unrealized Losses Fair Value Current: Corporate debt $ 6,849,519 $ 2,830 $ (834 ) $ 6,851,515 Marketable securities at December 31, 2018 consisted of the following: Marketable Securities Amortized Cost Unrealized Gains Unrealized Losses Fair Value Current: Corporate debt $ 19,179,530 $ 314 $ (31,160 ) $ 19,148,684 U.S. Treasury securities 2,982,706 546 — 2,983,252 $ 22,162,236 $ 860 $ (31,160 ) $ 22,131,936 U.S. Treasury securities include government debt instruments issued by the U.S. Department of the Treasury. Corporate debt includes obligations issued by investment-grade corporations, and may include issues that have been guaranteed by governments and government agencies. At June 30, 2019 and December 31, 2018, the Company held only investments that have maturities of less than one year. At June 30, 2019 and December 31, 2018, the Company held 2 and 21 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 June 30, 2019 and December 31, 2018 was $1,839,053 and $18,551,296, 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 June 30, 2019 and December 31, 2018.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 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 June 30, 2019 and December 31, 2018: Fair Value Measurement as of June 30, 2019 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents $ 6,083,788 $ — $ — Marketable securities 6,851,515 — — Warrant liabilities — — 4,345,902 Total $ 12,935,303 $ — $ 4,345,902 Fair Value Measurement as of December 31, 2018 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents $ 6,850,772 $ — $ — Marketable securities 22,131,936 — — Warrant liabilities — — 20,781,663 Total $ 28,982,708 $ — $ 20,781,663 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 8, “Capital Structure”). The Representative’s Warrant is re-measured As of June 30, 2019 As of December 31, 2018 Expected volatility 124.2 % 70.9 % Remaining contractual term (in years) 0.17 0.67 Risk-free interest rate 1.92 % 2.63 % 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 8, “Capital Structure”). The 2016 Warrants are re-measured The following assumptions were used in a Black-Scholes option-pricing model to determine the fair value of the warrant liability: As of June 30, 2019 As of December 31, 2018 Expected volatility 100.58 % 72.6 % Remaining contractual term (in years) 2.08 2.58 Risk-free interest rate 1.75 % 2.46 % 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 8, “Capital Structure”). The 2017 Warrants are re-measured As of June 30, 2019 As of December 31, 2018 Expected volatility 97.1 % 87.3 % Remaining contractual term (in years) 3.08 3.58 Risk-free interest rate 1.71 % 2.49 % 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 and six months ended June 30, 2019 and 2018: Warrant liabilities Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Balance at beginning of period $ 2,982,034 $ 25,823,996 $ 20,781,663 $ 13,549,437 Increase in fair value (1) 1,363,868 12,802,583 (16,435,761 ) 25,077,142 Balance at end of period $ 4,345,902 $ 38,626,579 $ 4,345,902 $ 38,626,579 (1) The change in fair values of the warrant liabilities is recorded in other income (expense) 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	6 Months Ended
	Jun. 30, 2019
Payables and Accruals [Abstract]
Accrued Liabilities	5. Accrued Liabilities Accrued liabilities consist of the following: June 30, 2019 December 31, 2018 Accrued compensation costs $ 647,984 $ 1,585,689 Accrued professional fees 593,616 433,498 Accrued research and development service fees 512,405 2,076,764 Accrued facilities operation expenses 255,836 232,673 Other accrued liabilities 22,775 41,108 Total accrued liabilities $ 2,032,616 $ 4,369,732

Net Income (Loss) Per Share of

Net Income (Loss) Per Share of Common Stock	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Net Income (Loss) Per Share of Common Stock	6. Net Income (Loss) Per Share of Common Stock Basic net income (loss) per share is computed by dividing net income (loss) by the weighted-average number of shares of common stock outstanding. For the three months ended June 30, 2019 and the three and six months ended June 30, 2018, the Company incurred a net loss and therefore diluted net loss per share is the same as basic net loss per share as the Company excluded certain potentially dilutive securities from the computation of diluted weighted average shares outstanding as they would have been anti-dilutive. For the six months ended June 30, 2019, the Company had net income and included 48,370 shares of common stock in the computation of diluted weighted average shares outstanding from the exercise of stock options utilizing treasury method accounting. The following table sets forth the computation of basic and diluted net income (loss) per share for common stockholders: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Net income (loss) $ (8,666,906 ) $ (20,135,892 ) $ 2,920,109 $ (39,242,373 ) Shares used in computing basic net income (loss) per share 79,409,556 73,658,529 79,409,556 73,657,537 Basic net income (loss) per share $ (0.11 ) $ (0.27 ) $ 0.04 $ (0.53 ) Shares used in computing diluted net income (loss) per share 79,409,556 73,658,529 79,457,926 73,657,537 Diluted net income (loss) per share $ (0.11 ) $ (0.27 ) $ 0.04 $ (0.53 ) The following table sets forth the potentially dilutive securities outstanding for the three and six months ended June 30, 2019 and 2018 that were excluded from the computation of diluted weighted average shares outstanding: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Options to purchase common stock 12,364,994 7,266,054 12,316,624 7,266,054 Warrants to purchase common stock 30,572,324 31,678,614 30,572,324 31,678,614 Total 42,917,318 38,944,668 42,917,948 38,944,668

Commitments

Commitments	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments	7. Commitments Leases As described further in “Note 2, Summary of Significant Accounting Policies”, adopted Topic 842 as of January 1, 2019. Prior period amounts have not been adjusted and continue to be reported in accordance with historic accounting under Topic 840. In December 2010, the Company entered into a non-cancellable In January 2012, the Company entered into a non-cancellable The Company performed an evaluation of its other contracts in accordance with Topic 842 and is determined that, except for the leases described above, none of its contracts contain a lease. The balance sheet classification of the Company’s lease liabilities was as follows: Description June 30, 2019 December 31, 2018 Operating lease liabilities: Current portion of lease liabilities $ 625,541 $ — Long-term portion of lease liabilities $ 3,399,926 $ — Operating lease liabilities are based on the net present value of the remaining lease payments over the remaining lease term. The leases are renewable at the end of the lease term at option. For the purposes of determining the remaining lease term in contemplation of available extensions, the Company did not consider either renewal to be probable at this time. In determining the present value of lease payments, the Company estimated its incremental borrowing rate based on the information available at the adoption date of Topic 842. As of January 1, 2019, the remaining lease term was 9.0 years and the discount rate used to determine the operating lease liability was 9.93%. As of June 30, 2019, the maturities of operating lease liabilities were as follows: Amount July 1, 2019-December 31, 2019 $ 326,662 Year ending December 31: 2020 666,391 2021 679,719 2022 693,313 2023 707,179 Thereafter 2,973,011 Total lease payments 6,046,275 Less: Present value adjustment (2,020,808 ) Operating lease liabilities $ 4,025,467 Cash paid for amounts included in the measurement of lease liabilities for the three and six months ended June 30, 2019 was $159,573 and $318,711, respectively, and was included in net cash used in operating activities in the Consolidated Statements of Cash Flows. Rent expense is recognized using the straight-line method over the term of each lease. Rent expense for the three $154,000, $307,000 and $308,000, respectively.

Capital Structure

Capital Structure	6 Months Ended
	Jun. 30, 2019
Federal Home Loan Banks [Abstract]
Capital Structure	8. Capital Structure Common Stock As of June 30, 2019, the Company was authorized to issue 200,000,000 shares of common stock at $0.0001 par value per share. Follow-on On August 3, 2018, the Company completed an underwritten public offering of 5,750,000 shares of its common stock, including shares sold pursuant to the fully exercised overallotment option granted to the underwriters in connection with the offering, at a public offering price of $2.00 per share, resulting in net proceeds to the Company of approximately $10.4 million after underwriting discounts and commissions and offering expenses payable by the Company. 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 2017 Warrants and 2016 Warrants contain a fundamental transaction provision that obligates the Company to cash settle the warrants under a limited set of conditions not entirely within the Company’s control. Due to this conditional obligation, the Company determined that both the 2017 Warrants and the 2016 Warrants should be classified as liabilities in the Company’s consolidated balance sheet. At issuance, the Company determined the fair value of the 2017 Warrants and 2016 Warrants to be $12.4 million and $18.6 million, respectively, and reclassified these balances from stockholders’ equity to warrant liability. The fair value of these warrants is re-measured 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 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 were classified to stockholders’ equity in the Company’s balance sheet. Representative’s Warrant The Maxim Group, LLC, the representative of the underwriter in the Company’s initial public offering (“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 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 June 30, 2019, 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 June 30, 2019 and December 31, 2018: June 30, 2019 December 31, 2018 Options to purchase common stock 12,364,994 7,187,885 Warrants to purchase common stock 30,572,324 31,243,026 42,937,318 38,430,911

Stock Warrants

Stock Warrants	6 Months Ended
	Jun. 30, 2019
Text Block [Abstract]
Stock Warrants	9. Stock Warrants As of June 30, 2019 and December 31, 2018, the Company had warrants outstanding as shown in the table below. June 30, 2019 December 31, 2018 Note Warrants — 670,702 2017 Warrants 15,996,450 15,996,450 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) 180,338 180,338 Warrants to purchase common stock 30,572,324 31,243,026 Weighted-average exercise price per share $ 2.30 $ 2.31 (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 June 30, 2019: Exercise Prices Shares Underlying Outstanding Warrants Expiration Date £ 16,002,164 September 1, 2021 – July 25, 2022 $2.01 - $4.99 14,290,227 July 28, 2019 – July 27, 2021 ³ 279,933 July 22, 2019 – January 5, 2022 30,572,324

Stock Option and Incentive Plan

Stock Option and Incentive Plans	6 Months Ended
	Jun. 30, 2019
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”). On February 26, 2013, the board of directors approved an amended and restated plan (the “Amended Plan”) under which the number of shares of common stock available for issuance was 1,571,428. For new awards, the period that vested awards would remain exercisable upon termination of service was reduced from ten years to two years. The board of directors also increased the number of shares of common stock available under the Company’s Amended Plan on February 24, 2014 and April 29, 2014 to 1,857,142 and 2,357,142, respectively. 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 six months ended June 30, 2019, 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, 2018 7,187,885 $ 3.17 Granted 5,505,000 0.40 Exercised — — Expired (192,266 ) 2.92 Forfeited (135,625 ) 1.22 Options outstanding at June 30, 2019 12,364,994 1.96 7.67 $ 585,100 Vested and exercisable at June 30, 2019 5,540,325 3.49 5.63 $ 29,138 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 June 30, 2019 and 2018 was $0.41, and $1.63, respectively, and the $0.40 and $1.45, respectively. Total compensation expense recognized amounted to $369,927 and $416,133 $693,701 and $853,814 for the six months ended June 30, 2019 and 2018, respectively. As of June 30, 2019, the total remaining unrecognized compensation cost related to unvested stock options was approximately $3.2 million which will be recognized over a weighted average period of approximately 2.83 years. The following assumptions were used to compute the fair value of stock options granted during the period: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Risk free interest rate 2.28 % 2.81 % 2.37 % 2.57 % Expected dividend yield — — — — Expected term (in years) 6.09 5.40 6.08 6.02 Expected volatility 90.0 % 82.5 % 89.7 % 82.3 % Expected volatility— Expected term— Risk-free interest rate Expected dividend yield—

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying financial information as of June 30, 2019 and for the three and six months ended June 30, 2019 and 2018 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, 2018 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, 2018, 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 June 30, 2019 and for the three and six months ended June 30, 2019 and 2018 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 June 30, 2019 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.
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 and U.S. Treasury 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 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 share-based compensation in accordance with ASC 718, Compensation—Stock Compensation, non-employees non-employee non-employee non-employees, 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 for employee and non-employee non-employee
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. Company recognized a reduction to its research and development expense in the amount of approximately $0.5 million and $0.4 million 1.2 million and $0.8 million respectively. The receivable for grants as of June 30, 2019 and December 31, 2018 was approximately $0.6 million and $0.2 million respectively, and is included in prepaid expenses and other current assets on the balance sheet. The Company has approximately $10.6 million of approved grant award funding remaining as of June 30, 2019.
Net Income (Loss) Per Share	Net Income (Loss) Per Share Basic net income (loss) per share is calculated by dividing net income (loss) by the weighted average shares outstanding during the period, without consideration for common stock equivalents. Diluted net income (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 a 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. Common stock equivalents may also be excluded from the calculation of diluted net income per share if the exercise prices exceed the average market price for the reporting period.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements Leases The Company adopted Accounting Standards Update No. 2016-02- Leases (Topic 842) non-lease The Company recognizes right-of-use Impact of adoption of Topic 842 Adoption of the new standard resulted in the recording of ROU assets, net of deferred rent and a lease incentive obligation, of $3.3 million and lease liabilities of approximately $4.1 million as of January 1, 2019. The lease liability was classified between a current portion of $0.6 million and a long-term portion of $3.5 million. The standard did not impact consolidated net income and had no impact on cash flows. Non-employee The Company adopted Accounting Standards Update, Compensation-Stock Compensation (ASU 2018-07), non-employees 2018-07 Statements of equity In August 2018, the Securities and Exchange Commission (“SEC”) adopted the final rule under SEC Release No. 33-10532, Recent Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued a new Accounting Standards Update, Financial Instruments-Credit Losses (ASU 2016-13). 2016-13 available-for-sale In August 2018, the FASB issued Accounting Standards Update, Fair Value Measurement: Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement, (ASU 2018-13). 2018-13

Marketable Securities (Tables)

Marketable Securities (Tables)	6 Months Ended
	Jun. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Schedule of Marketable Securities	Marketable securities at June 30, 2019 consisted of the following: Marketable Securities Amortized Cost Unrealized Gains Unrealized Losses Fair Value Current: Corporate debt $ 6,849,519 $ 2,830 $ (834 ) $ 6,851,515 Marketable securities at December 31, 2018 consisted of the following: Marketable Securities Amortized Cost Unrealized Gains Unrealized Losses Fair Value Current: Corporate debt $ 19,179,530 $ 314 $ (31,160 ) $ 19,148,684 U.S. Treasury securities 2,982,706 546 — 2,983,252 $ 22,162,236 $ 860 $ (31,160 ) $ 22,131,936

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2019
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 June 30, 2019 and December 31, 2018: Fair Value Measurement as of June 30, 2019 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents $ 6,083,788 $ — $ — Marketable securities 6,851,515 — — Warrant liabilities — — 4,345,902 Total $ 12,935,303 $ — $ 4,345,902 Fair Value Measurement as of December 31, 2018 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents $ 6,850,772 $ — $ — Marketable securities 22,131,936 — — Warrant liabilities — — 20,781,663 Total $ 28,982,708 $ — $ 20,781,663
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 and six months ended June 30, 2019 and 2018: Warrant liabilities Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Balance at beginning of period $ 2,982,034 $ 25,823,996 $ 20,781,663 $ 13,549,437 Increase in fair value (1) 1,363,868 12,802,583 (16,435,761 ) 25,077,142 Balance at end of period $ 4,345,902 $ 38,626,579 $ 4,345,902 $ 38,626,579 (1) The change in fair values of the warrant liabilities is recorded in other income (expense) 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 June 30, 2019 As of December 31, 2018 Expected volatility 124.2 % 70.9 % Remaining contractual term (in years) 0.17 0.67 Risk-free interest rate 1.92 % 2.63 % 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 June 30, 2019 As of December 31, 2018 Expected volatility 100.58 % 72.6 % Remaining contractual term (in years) 2.08 2.58 Risk-free interest rate 1.75 % 2.46 % 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 June 30, 2019 As of December 31, 2018 Expected volatility 97.1 % 87.3 % Remaining contractual term (in years) 3.08 3.58 Risk-free interest rate 1.71 % 2.49 % Expected dividend yield — % — %

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	6 Months Ended
	Jun. 30, 2019
Payables and Accruals [Abstract]
Summary of Accrued Expenses	Accrued liabilities consist of the following: June 30, 2019 December 31, 2018 Accrued compensation costs $ 647,984 $ 1,585,689 Accrued professional fees 593,616 433,498 Accrued research and development service fees 512,405 2,076,764 Accrued facilities operation expenses 255,836 232,673 Other accrued liabilities 22,775 41,108 Total accrued liabilities $ 2,032,616 $ 4,369,732

Net Income (Loss) Per Share o_2

Net Income (Loss) Per Share of Common Stock (Tables)	6 Months Ended
	Jun. 30, 2019
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 income (loss) per share for common stockholders: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Net income (loss) $ (8,666,906 ) $ (20,135,892 ) $ 2,920,109 $ (39,242,373 ) Shares used in computing basic net income (loss) per share 79,409,556 73,658,529 79,409,556 73,657,537 Basic net income (loss) per share $ (0.11 ) $ (0.27 ) $ 0.04 $ (0.53 ) Shares used in computing diluted net income (loss) per share 79,409,556 73,658,529 79,457,926 73,657,537 Diluted net income (loss) per share $ (0.11 ) $ (0.27 ) $ 0.04 $ (0.53 )
Schedule of Antidilutive Securities Excluded from Computation of Diluted Weighted Average Shares Outstanding	The following table sets forth the potentially dilutive securities outstanding for the three and six months ended June 30, 2019 and 2018 that were excluded from the computation of diluted weighted average shares outstanding: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Options to purchase common stock 12,364,994 7,266,054 12,316,624 7,266,054 Warrants to purchase common stock 30,572,324 31,678,614 30,572,324 31,678,614 Total 42,917,318 38,944,668 42,917,948 38,944,668

Commitments (Tables)

Commitments (Tables)	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Schedule of Classification of Lease Liabilities	The balance sheet classification of the Company’s lease liabilities was as follows: Description June 30, 2019 December 31, 2018 Operating lease liabilities: Current portion of lease liabilities $ 625,541 $ — Long-term portion of lease liabilities $ 3,399,926 $ —
Maturities Of Operating Lease Liabilities	Amount July 1, 2019-December 31, 2019 $ 326,662 Year ending December 31: 2020 666,391 2021 679,719 2022 693,313 2023 707,179 Thereafter 2,973,011 Total lease payments 6,046,275 Less: Present value adjustment (2,020,808 ) Operating lease liabilities $ 4,025,467

Capital Structure (Tables)

Capital Structure (Tables)	6 Months Ended
	Jun. 30, 2019
Federal Home Loan Banks [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 June 30, 2019 and December 31, 2018: June 30, 2019 December 31, 2018 Options to purchase common stock 12,364,994 7,187,885 Warrants to purchase common stock 30,572,324 31,243,026 42,937,318 38,430,911

Stock Warrants (Tables)

Stock Warrants (Tables)	6 Months Ended
	Jun. 30, 2019
Text Block [Abstract]
Schedule of Warrants Outstanding	As of June 30, 2019 and December 31, 2018, the Company had warrants outstanding as shown in the table below. June 30, 2019 December 31, 2018 Note Warrants — 670,702 2017 Warrants 15,996,450 15,996,450 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) 180,338 180,338 Warrants to purchase common stock 30,572,324 31,243,026 Weighted-average exercise price per share $ 2.30 $ 2.31 (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 June 30, 2019: Exercise Prices Shares Underlying Outstanding Warrants Expiration Date £ 16,002,164 September 1, 2021 – July 25, 2022 $2.01 - $4.99 14,290,227 July 28, 2019 – July 27, 2021 ³ 279,933 July 22, 2019 – January 5, 2022 30,572,324

Stock Option and Incentive Pl_2

Stock Option and Incentive Plans (Tables)	6 Months Ended
	Jun. 30, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Stock Option Activity	A summary of stock option activity for the six months ended June 30, 2019, 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, 2018 7,187,885 $ 3.17 Granted 5,505,000 0.40 Exercised — — Expired (192,266 ) 2.92 Forfeited (135,625 ) 1.22 Options outstanding at June 30, 2019 12,364,994 1.96 7.67 $ 585,100 Vested and exercisable at June 30, 2019 5,540,325 3.49 5.63 $ 29,138
Assumptions to Compute Fair Value of Stock Option Grants	The following assumptions were used to compute the fair value of stock options granted during the period: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Risk free interest rate 2.28 % 2.81 % 2.37 % 2.57 % Expected dividend yield — — — — Expected term (in years) 6.09 5.40 6.08 6.02 Expected volatility 90.0 % 82.5 % 89.7 % 82.3 %

Organization and Description _2

Organization and Description of Business - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Organization And Description Of Business [Line Items]
Accumulated deficit	$ (196,399,783)		$ (199,319,892)
Net cash used in operating activities	$ (16,114,304)	$ (13,201,211)

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Jan. 01, 2019USD ($)	Dec. 31, 2018USD ($)
Summary Of Significant Accounting Policies [Line Items]
Maturity period of highly liquid investments			Three months or less
Realized gains or losses on marketable securities	$ 0	$ 0	$ 0	$ 0
Number of securities in unrealized loss position for more than 12 months	0		0			0
Grants receivable recognized	$ 500,000	$ 1,200,000	$ 400,000	$ 800,000
Grants receivable	600,000		600,000			$ 200,000
Grants remaining to be awarded	10,600,000		10,600,000
Current portion of lease liabilities	625,541		625,541
Long-term portion of lease liabilities	3,399,926		3,399,926
Operating lease right-of use assets	3,150,932		3,150,932
Operating lease liabilities	$ 4,025,467		$ 4,025,467
Adjustments due to the adoption of Topic 842
Summary Of Significant Accounting Policies [Line Items]
Current portion of lease liabilities					$ 600,000
Long-term portion of lease liabilities					3,500,000
Operating lease right-of use assets					3,300,000
Operating lease liabilities					$ 4,100,000

Marketable Securities - Schedul

Marketable Securities - Schedule of Marketable Securities (Detail) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Schedule of Available-for-sale Securities [Line Items]
Marketable Securities, Amortized Cost		$ 22,162,236
Marketable Securities, Unrealized Gains		860
Marketable Securities, Unrealized Losses		(31,160)
Marketable Securities, Fair Value		22,131,936
Corporate Debt [Member]
Schedule of Available-for-sale Securities [Line Items]
Marketable Securities, Amortized Cost	$ 6,849,519	19,179,530
Marketable Securities, Unrealized Gains	2,830	314
Marketable Securities, Unrealized Losses	(834)	(31,160)
Marketable Securities, Fair Value	$ 6,851,515	19,148,684
US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Marketable Securities, Amortized Cost		2,982,706
Marketable Securities, Unrealized Gains		546
Marketable Securities, Fair Value		$ 2,983,252

Marketable Securities - Additio

Marketable Securities - Additional Information (Detail)	6 Months Ended	12 Months Ended
	Jun. 30, 2019USD ($)Security	Dec. 31, 2018USD ($)Security
Marketable Securities [Abstract]
Maturity period classified current investments	Less than one year	Less than one year
Number of securities in unrealized loss position for less than one year | Security	2	21
Aggregate fair value of debt securities | $	$ 1,839,053	$ 18,551,296

Fair Value Measurements - Infor

Fair Value Measurements - Information about Company's Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	$ 6,851,515	$ 22,131,936
Warrant liabilities	(4,345,902)	(20,781,663)
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	6,083,788	6,850,772
Marketable securities	6,851,515	22,131,936
Total assets (liabilities)	12,935,303	28,982,708
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant liabilities	4,345,902	20,781,663
Total assets (liabilities)	$ 4,345,902	$ 20,781,663

Fair Value Measurements - Assum

Fair Value Measurements - Assumption Used to Determine Fair Value of Warrant Liability (Detail)	Jun. 30, 2019yr	Dec. 31, 2018yr
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of warrant liability	0.17	0.67
Representative's Warrant [Member] | Expected Volatility [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of warrant liability	124.2	70.9
Representative's Warrant [Member] | Risk-free Interest Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of warrant liability	1.92	2.63
2016 Warrants [Member] | Expected Volatility [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of warrant liability	100.58	72.6
2016 Warrants [Member] | Remaining Contractual term (in years) [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of warrant liability	2.08	2.58
2016 Warrants [Member] | Risk-free Interest Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of warrant liability	1.75	2.46
2017 Warrants [Member] | Expected Volatility [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of warrant liability	97.1	87.3
2017 Warrants [Member] | Remaining Contractual term (in years) [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of warrant liability	3.08	3.58
2017 Warrants [Member] | Risk-free Interest Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of warrant liability	1.71	2.49

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		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period		$ 2,982,034	$ 25,823,996	$ 20,781,663	$ 13,549,437
Increase (decrease) in fair value	[1]	1,363,868	12,802,583	(16,435,761)	25,077,142
Balance at end of period		$ 4,345,902	$ 38,626,579	$ 4,345,902	$ 38,626,579
[1]	The change in fair values of the warrant liabilities is recorded in other income (expense) in the consolidated statement of operations.

Accrued Liabilities - Summary o

Accrued Liabilities - Summary of Accrued Liabilities (Detail) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Accrued compensation costs	$ 647,984	$ 1,585,689
Accrued professional fees	593,616	433,498
Accrued research and development service fees	512,405	2,076,764
Accrued facilities operation expenses	255,836	232,673
Other accrued liabilities	22,775	41,108
Total accrued liabilities	$ 2,032,616	$ 4,369,732

Net Income (Loss) Per Share o_3

Net Income (Loss) Per Share of Common Stock - Additional Information (Detail) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Shares used in computing diluted weighted average shares outstanding	79,406,556	73,658,529	79,457,926	73,657,537
Employee Stock Options [Member]
Shares used in computing diluted weighted average shares outstanding			48,370

Net Income (Loss) Per Share o_4

Net Income (Loss) Per Share of Common Stock - Schedule of Computation of Basic and Diluted Net Income (Loss) Per Share for Common Stockholders (Detail) - USD ($)	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Net income (loss)	$ (8,666,906)	$ 11,587,015	$ (20,135,892)	$ (19,106,481)	$ 2,920,109	$ (39,242,373)
Shares used in computing basic net income (loss) per share	79,409,556		73,658,529		79,409,556	73,657,537
Basic net income (loss) per share	$ (0.11)		$ (0.27)		$ 0.04	$ (0.53)
Shares used in computing diluted net income (loss) per share	79,406,556		73,658,529		79,457,926	73,657,537
Diluted net income (loss) per share	$ (0.11)		$ (0.27)		$ 0.04	$ (0.53)

Net Income (Loss) Per Share o_5

Net Income (Loss) Per Share of Common Stock - Schedule of Antidilutive Securities Excluded from Computation of Diluted Weighted Average Shares Outstanding (Detail) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially antidilutive securities outstanding excluded from the computation of diluted weighted average shares	42,917,318	38,944,668	42,917,948	38,944,668
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	12,364,994	7,266,054	12,316,624	7,266,054
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	30,572,324	31,678,614	30,572,324	31,678,614

Commitments - Additional Inform

Commitments - Additional Information (Detail)	1 Months Ended			3 Months Ended		6 Months Ended
	Jan. 31, 2012ft²ExtensionOptions	Dec. 31, 2011ExtensionOptions	Dec. 31, 2010	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Jan. 01, 2019
Loss Contingencies [Line Items]
Non-cancellable operating lease, expiration date	2027-12		2025-12
Extended lease agreement, date		2027-12
Number of lease extension options | ExtensionOptions	2	2
Lease renewal termination period	5 years	5 years
Area of space relinquished from lease agreement | ft²	10,912
Rent expense				$ 154,000	$ 154,000	$ 307,000	$ 308,000
Operating lease, remaining lease term								9 years
Operating lease, discount rate, percent								9.93%
Cash paid for amounts included in the measurement of lease liabilities				$ 159,573		$ 318,711

Commitments - Schedule of Class

Commitments - Schedule of Classification of Lease Liabilities (Detail) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Operating lease liabilities:
Current portion of lease liabilities	$ 625,541
Long-term portion of lease liabilities	$ 3,399,926

Commitments - Maturities Of Ope

Commitments - Maturities Of Operating Lease Liabilities (Detail)	Jun. 30, 2019USD ($)
Commitments and Contingencies Disclosure [Abstract]
July 1, 2019-December 31, 2019	$ 326,662
2020	666,391
2021	679,719
2022	693,313
2023	707,179
Thereafter	2,973,011
Total lease payments	6,046,275
Less: Present value adjustment	(2,020,808)
Operating lease liabilities	$ 4,025,467

Capital Structure - Additional

Capital Structure - Additional Information (Detail) - USD ($)	Aug. 03, 2018	Jul. 25, 2017	Jul. 27, 2016	Jun. 12, 2015	Aug. 01, 2014	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Jun. 30, 2014
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
Initial public offering, closing date								Aug. 1, 2014
Number of warrants or rights outstanding						30,572,324		30,572,324		31,243,026
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						15,996,450		15,996,450		15,996,450
Private Placement [Member]
Class of Stock [Line Items]
Number of shares issued				4,728,128
Net proceeds received				$ 18,300,000
Warrants to purchase shares of common stock				2,364,066		189,126		189,126
Warrant exercise price per share				$ 8		$ 4.65		$ 4.65
Private placement, securities description								one-half</div> share of common stock at a price of $4.23 per common share purchased.<table border="0" style="width:100%; table-layout:fixed;" cellspacing="0" cellpadding="0"><tr><td></td></tr></table>" id="sjs-I26">Each investor received one share of common stock and a warrant to purchase &lt;div style="white-space: nowrap; color: rgb(0, 0, 0); letter-spacing: 0px; top: 0px;;display:inline;">one-half&lt;/div> share of common stock at a price of $4.23 per common share purchased.&lt;table border="0" style="width:100%; table-layout:fixed;" cellspacing="0" cellpadding="0">&lt;tr>&lt;td>&lt;/td>&lt;/tr>&lt;/table>
Exercise price per common share				$ 4.23
Class of warrant purchase percentage						4.00%		4.00%
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	5,750,000	32,000,000	14,000,000
Public offering price, per unit	$ 2
Net proceeds received	$ 10,400,000	$ 37,100,000	$ 32,000,000
Warrants to purchase shares of common stock		16,000,000	14,000,000
Aggregate gross sales proceeds from common stock		$ 40,000,000	$ 35,000,000
Warrant exercise price per share		$ 1.55	$ 3
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]
Warrants to purchase shares of common stock							1,050		3,550
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
Number of warrants or rights outstanding					3,321,416					670,702
Class of warrant or rights, expired						414,790		670,702		2,645,176
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
Class of warrant purchase percentage						3.00%		3.00%
Warrant expiration date								Jul. 28, 2019
Warrant exercisable period								180 days
Number of warrants or rights outstanding						206,410		206,410		206,410

Capital Structure - Summary of

Capital Structure - Summary of Common Stock Reserved for Future Issuance (Detail) - shares	Jun. 30, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Common Stock reserved for future issuance	42,937,318	38,430,911
Stock Options [Member]
Class of Stock [Line Items]
Common Stock reserved for future issuance	12,364,994	7,187,885
Warrants [Member]
Class of Stock [Line Items]
Common Stock reserved for future issuance	30,572,324	31,243,026

Stock Warrants - Schedule of Wa

Stock Warrants - Schedule of Warrants Outstanding (Detail) - $ / shares		6 Months Ended
		Jun. 30, 2019	Dec. 31, 2018	Aug. 01, 2014
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants		30,572,324	31,243,026
Weighted-average exercise price per share		$ 2.30	$ 2.31
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	[1]	180,338	180,338
Exercise Price Less Than or Equal to $2.00 [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants		16,002,164
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		14,290,227
Expiration Start Date		Jul. 28, 2019
Expiration End Date		Jul. 27, 2021
Exercise Price Greater Than or Equal to $ 5.00 [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants		279,933
Expiration Start Date		Jul. 22, 2019
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 Greater Than or Equal to $ 5.00 [Member]
Class of Warrant or Right [Line Items]
Exercise Prices		5
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
Note Warrants [Member]
Class of Warrant or Right [Line Items]
Shares Underlying Outstanding Warrants			670,702	3,321,416
Exercise Prices				$ 3
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		15,996,450	15,996,450
[1]	Other warrants are comprised of warrants issued prior to the Company’s IPO, generally in exchange for services rendered to the Company.

Stock Option and Incentive Pl_3

Stock Option and Incentive Plans - Additional Information (Detail) - USD ($)	Dec. 31, 2015	Feb. 26, 2013	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Jul. 28, 2014	Apr. 29, 2014	Feb. 24, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock reserved pursuant to the plan			42,937,318		42,937,318		38,430,911
Weighted average grant date fair value of options			$ 0.41	$ 1.63	$ 0.40	$ 1.45
Unrecognized compensation cost related to unvested stock options			$ 3,200,000		$ 3,200,000
Weighted average period of unvested stock options					2 years 9 months 29 days
Employee Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense recognized			$ 369,927	$ 416,133	$ 693,701	$ 853,814
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]
Number of shares of common stock reserved pursuant to the plan									2,357,142	1,857,142
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					9,696,859
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 Pl_4

Stock Option and Incentive Plans - Summary of Stock Option Activity (Detail)	6 Months Ended
	Jun. 30, 2019USD ($)$ / sharesshares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of Options, Options outstanding, Beginning balance | shares	7,187,885
Number of Options, Granted | shares	5,505,000
Number of Options, Exercised | shares	0
Number of Options, Expired | shares	(192,266)
Number of Options, Forfeited | shares	(135,625)
Number of Options, Options outstanding, Ending balance | shares	12,364,994
Number of Options, Vested and exercisable, Ending Balance | shares	5,540,325
Weighted Average Exercise Price, Options outstanding, Beginning balance | $ / shares	$ 3.17
Weighted Average Exercise Price, Granted | $ / shares	0.40
Weighted Average Exercise Price, Exercised | $ / shares	0
Weighted Average Exercise Price, Expired | $ / shares	2.92
Weighted Average Exercise Price, Forfeited | $ / shares	1.22
Weighted Average Exercise Price, Options outstanding, Ending balance | $ / shares	1.96
Weighted Average Exercise Price, Vested and exercisable, Ending balance | $ / shares	$ 3.49
Weighted Average Remaining Contractual Life (in years), Options outstanding	7 years 8 months 1 day
Weighted Average Remaining Contractual Life (in years), Vested and exercisable	5 years 7 months 17 days
Aggregate Intrinsic value, Options outstanding | $	$ 585,100
Aggregate Intrinsic value, Vested and exercisable | $	$ 29,138

Stock Option and Incentive Pl_5

Stock Option and Incentive Plans - Assumptions to Compute Fair Value of Stock Option Grants (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Risk free interest rate	2.28%	2.81%	2.37%	2.57%
Expected dividend yield	$ 0		$ 0
Expected term (in years)	6 years 1 month 2 days	5 years 4 months 24 days	6 years 29 days	6 years 7 days
Expected volatility	90.00%	82.50%	89.70%	82.30%