Corbus Pharmaceuticals (CRBP) 10-K 12 Mar 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Mar. 06, 2019	Jun. 30, 2018
Document And Entity Information
Entity Registrant Name	Corbus Pharmaceuticals Holdings, Inc.
Entity Central Index Key	0001595097
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business Flag	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Shell Company	false
Entity Public Float			$ 271,269,436
Entity Common Stock, Shares Outstanding		64,395,221
Trading Symbol	CRBP
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2018

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 41,748,468	$ 62,537,495
Restricted cash		158,991
Prepaid expenses and other current assets	2,491,844	2,808,244
Total current assets	44,240,312	65,504,730
Property and equipment, net	2,705,206	1,432,655
Other assets	43,823	40,776
Total assets	46,989,341	66,978,161
Current liabilities:
Notes payable	394,305	332,861
Accounts payable	6,345,335	3,130,295
Accrued expenses	9,851,191	4,741,519
Deferred revenue, current	1,462,503
Deferred rent, current	35,996
Total current liabilities	18,089,330	8,204,675
Deferred rent, noncurrent	1,375,891	989,550
Other liabilities		375
Total liabilities	19,465,221	9,194,600
Commitments and Contingencies
Stockholders' equity
Preferred Stock $0.0001 par value:10,000,000 shares authorized, no shares issued and outstanding at December 31, 2018 and 2017
Common stock, $0.0001 par value; 150,000,000 shares authorized at December 31, 2018 and 2017, 57,247,496 and 55,603,427 shares issued and outstanding at December 31, 2018 and 2017, respectively	5,725	5,560
Additional paid-in capital	148,888,635	123,476,102
Accumulated deficit	(121,370,240)	(65,698,101)
Total stockholders' equity	27,524,120	57,783,561
Total liabilities and stockholders' equity	$ 46,989,341	$ 66,978,161

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued
Preferred stock, shares outstanding
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	57,247,496	55,603,427
Common stock, shares outstanding	57,247,496	55,603,427

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Revenue from awards	$ 4,822,272	$ 2,440,195
Operating expenses:
Research and development	48,613,957	26,038,965
General and administrative	12,956,022	8,964,046
Total operating expenses	61,569,979	35,003,011
Operating loss	(56,747,707)	(32,562,816)
Other income (expense), net:
Interest income, net	982,777	183,112
Foreign currency exchange gain (loss)	92,791	(41,908)
Other income, net	1,075,568	141,204
Net loss	$ (55,672,139)	$ (32,421,612)
Net loss per share, basic and diluted	$ (0.98)	$ (0.65)
Weighted average number of common shares outstanding, basic and diluted	56,999,741	50,176,953

Statements of Stockholders' Equ

Statements of Stockholders' Equity - USD ($)	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Total
Balance at Dec. 31, 2016	$ 4,468	$ 42,191,256	$ (33,276,489)	$ 8,919,235
Balance, shares at Dec. 31, 2016	44,681,745
Stock-based compensation expense		5,694,489		5,694,489
Issuance of common stock, net of issuance costs	$ 1,065	75,400,894		75,401,959
Issuance of common stock, net of issuance costs, shares	10,648,948
Issuance of common stock upon exercise of stock options	$ 27	189,463		$ 189,490
Issuance of common stock upon exercise of stock options, shares	272,734			272,734
Net loss			(32,421,612)	$ (32,421,612)
Balance at Dec. 31, 2017	$ 5,560	123,476,102	(65,698,101)	57,783,561
Balance, shares at Dec. 31, 2017	55,603,427
Stock-based compensation expense		7,609,508		7,609,508
Issuance of common stock, net of issuance costs	$ 150	11,235,170		11,235,320
Issuance of common stock, net of issuance costs, shares	1,500,000
Issuance of common stock upon exercise of stock options	$ 14	347,631		$ 347,645
Issuance of common stock upon exercise of stock options, shares	139,069			139,069
Issuance of common stock upon exercise of warrants	$ 1	4,999		$ 5,000
Issuance of common stock upon exercise of warrants, shares	5,000
Fair value of warrant issued in connection with Investment Agreement		6,215,225		6,215,225
Net loss			(55,672,139)	(55,672,139)
Balance at Dec. 31, 2018	$ 5,725	$ 148,888,635	$ (121,370,240)	$ 27,524,120
Balance, shares at Dec. 31, 2018	57,247,496

Statements of Stockholders' E_2

Statements of Stockholders' Equity (Parenthetical) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Statement of Stockholders' Equity [Abstract]
Stock issuance cost	$ 464,680	$ 2,969,837

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net loss	$ (55,672,139)	$ (32,421,612)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	7,609,508	5,694,489
Depreciation and amortization	493,938	255,652
Loss(gain) on foreign exchange	70,448	(8,490)
Deferred rent	422,337	913,563
Changes in operating assets and liabilities:
Decrease in customer receivable	12,500,000	1,000,000
Decrease (increase) in prepaid expenses and other current assets	281,625	(1,877,983)
Increase in other assets	(3,047)	(40,776)
Increase (decrease) in accounts payable	3,904,021	(885,797)
Increase in accrued expenses	5,113,551	1,514,521
Decrease in deferred revenue	(4,787,497)	(1,940,195)
Net cash used in operating activities	(30,067,255)	(27,796,628)
Cash flows from investing activities:
Purchases of property and equipment	(2,300,416)	(707,429)
Net cash used in investing activities	(2,300,416)	(707,429)
Cash flows from financing activities:
Proceeds from issuance of notes payable	491,629	415,265
Principal payments on notes payable	(430,184)	(354,161)
Proceeds from issuance of common stock	12,052,645	78,891,699
Issuance costs paid for common stock financings	(690,181)	(2,940,685)
Principal payments under capital lease obligations	(4,256)	(3,832)
Net cash provided by financing activities	11,419,653	76,008,286
Net (decrease) increase in cash, cash equivalents, and restricted cash	(20,948,018)	47,504,229
Cash, cash equivalents, and restricted cash at beginning of the year	62,696,486	15,192,257
Cash, cash equivalents, and restricted cash at end of the year	41,748,468	62,696,486
Supplemental disclosure of cash flow information and non cash transactions:
Cash paid during the period for interest	10,437	12,377
Fair value of warrant issued in connection with Investment Agreement	6,215,225
Purchases of property and equipment included in accounts payable or accrued expenses	1,168	579,734
Write off of fully amortized leasehold improvements	191,244
Unpaid stock issuance costs		$ 225,501

Nature of Operations

Nature of Operations	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations	1. NATURE OF OPERATIONS Business Corbus Pharmaceuticals Holdings, Inc. (“the Company”) is a clinical stage pharmaceutical company, focused on the development and commercialization of novel therapeutics to treat rare, chronic, and serious inflammatory and fibrotic diseases. Since its inception, the Company has devoted substantially all of its efforts to business planning, research and development, recruiting management and technical staff, acquiring operating assets and raising capital. The Company’s business is subject to significant risks and uncertainties and the Company will be dependent on raising substantial additional capital before it becomes profitable and it may never achieve profitability.

Liquidity

Liquidity	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Liquidity	2. LIQUIDITY The Company anticipates operating losses to continue for the foreseeable future due to, among other things, costs related to research funding, development of its product candidates and its preclinical and clinical programs, strategic alliances and the development of its administrative organization. The Company has incurred recurring losses since inception and as of December 31, 2018, had an accumulated deficit of $121,370,240. On January 3, 2019, the Company entered into a strategic collaboration with Kaken Pharmaceutical Co., Ltd. (“Kaken”) (See Note 15). On January 30, 2019, the Company consummated an underwritten public offering of shares of its common stock (“January 2019 Offering”) (See Note 15). The Company expects the cash and cash equivalents of $41,748,468 at December 31, 2018 together with the $27 million of upfront payment to be received from Kaken, less the $2.7 million royalty (which is 10% of such upfront payment) that the Company will owe to CFF pursuant to the Investment Agreement (See Note 9), and the approximately $37.6 million of net proceeds from the January 2019 Offering, to be sufficient to meet its operating and capital requirements at least 12 months from the filing of this 10-K. Should the Company be unable to raise sufficient additional capital, the Company may be required to undertake cost-cutting measures including delaying or discontinuing certain clinical activities. The Company will need to raise significant additional capital to continue to fund the clinical trials for lenabasum and CRB-4001 (see Note 4). The Company may seek to sell common or preferred equity or convertible debt securities, enter into a credit facility or another form of third-party funding, or seek other debt financing. The sale of equity and convertible debt securities may result in dilution to the Company’s stockholders and certain of those securities may have rights senior to those of the Company’s common shares. If the Company raises additional funds through the issuance of preferred stock, convertible debt securities or other debt financing, these securities or other debt could contain covenants that would restrict the Company’s operations. Any other third-party funding arrangement could require the Company to relinquish valuable rights. The source, timing and availability of any future financing will depend principally upon market conditions, and, more specifically, on the progress of the Company’s clinical development programs. Funding may not be available when needed, at all, or on terms acceptable to the Company. Lack of necessary funds may require the Company, among other things, to delay, scale back or eliminate some or all of the Company’s planned clinical trials.

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Significant Accounting Policies	3. SIGNIFICANT ACCOUNTING POLICIES A summary of the significant accounting policies followed by the Company in the preparation of the financial statements is as follows: Use of Estimates The process of preparing financial statements in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates and changes in estimates may occur. The most significant estimates are related to stock-based compensation expense, the accrual of research, product development and clinical obligations, the recognition of revenue under the Investment Agreement (see Note 9) and the valuation of the CFF Warrant discussed in Note 9). Cash and Cash Equivalents The Company considers only those investments which are highly liquid, readily convertible to cash, and that mature within three months from date of purchase to be cash equivalents. Marketable investments are those with original maturities in excess of three months. At December 31, 2018 and 2017, cash equivalents were comprised of money market funds. The Company had no marketable investments at December 31, 2018 and 2017. Restricted cash as of December 31, 2017 in the amount of $108,991 was classified in current assets and included a collateral account for the Company’s corporate credit cards. The collateral account was closed in the first quarter of 2018 and accordingly the cash became unrestricted. Additionally, as of December 31, 2017, restricted cash included a stand-by letter of credit issued in favor of a landlord for $50,000 which was classified in current assets as of December 31, 2017. This stand-by letter of credit was terminated in the first quarter of 2018 in connection with the August 2017 Lease Agreement discussed in Note 6, and accordingly, the cash became unrestricted. Cash, cash equivalents, and restricted cash consists of the following: December 31, 2018 2017 Cash $ 808,943 $ 206,510 Money market fund 40,939,525 62,330,985 Cash and cash equivalents 41,748,468 62,537,495 Restricted cash — 158,991 Total cash, cash equivalents, and restricted cash shown in the statement of cash flows $ 41,748,468 $ 62,696,486 As of December 31, 2018, all of the Company’s cash was held in the United States, except for approximately $702,000 of cash which was held in our subsidiary in the United Kingdom. As of December 31, 2017, all of the Company’s cash was held in the United States. Financial Instruments The carrying amounts reported in the consolidated balance sheet for cash and cash equivalents, receivables, accounts payable and accrued expenses approximate their fair value based on the short-term nature of these instruments. The carrying values of the notes payable approximate their fair value due to the fact that they are at market terms. Property and Equipment The estimated life for the Company’s property and equipment is as follows: three years for computer hardware and software and three to five years for office furniture and equipment. The Company’s leasehold improvements and assets under capital lease are amortized over the shorter of their useful lives or the respective leases. See Note 5 for details of property and equipment and Note 6 for operating and capital lease commitments. Research and Development Expenses Costs incurred for research and development are expensed as incurred. Nonrefundable advance payments for goods or services that have the characteristics that will be used or rendered for future research and development activities pursuant to executory contractual arrangements with third party research organizations are deferred and recognized as an expense as the related goods are delivered or the related services are performed. Accruals for Research and Development Expenses and Clinical Trials As part of the process of preparing its financial statements, the Company is required to estimate its expenses resulting from its obligations under contracts with vendors, clinical research organizations and consultants and under clinical site agreements in connection with conducting clinical trials. The financial terms of these contracts are subject to negotiations, which vary from contract to contract and may result in payment terms that do not match the periods over which materials or services are provided under such contracts. The Company’s objective is to reflect the appropriate expenses in its financial statements by matching those expenses with the period in which services are performed and efforts are expended. The Company accounts for these expenses according to the timing of various aspects of the expenses. The Company determines the accrual estimates by taking into account discussion with applicable personnel and outside service providers as to the progress of clinical trials, or the services completed. During the course of a clinical trial, the Company adjusts its clinical expense recognition if actual results differ from its estimates. The Company makes estimates of its accrued expenses as of each balance sheet date based on the facts and circumstances known to it at that time. The Company’s clinical trial accruals are dependent upon the timely and accurate reporting of contract research organizations and other third-party vendors. Although the Company does not expect its estimates to be materially different from amounts actually incurred, its understanding of the status and timing of services performed relative to the actual status and timing of services performed may vary and may result in it reporting amounts that are too high or too low for any particular period. For the years ended December 31, 2018 and 2017, there were no material adjustments to the Company’s prior period estimates of accrued expenses for clinical trials. Leases and Deferred Rent The Company leases its office space. Leases are evaluated and classified as operating or capital leases for financial reporting purposes. The Company’s office space leases qualify as operating leases. For operating leases that contain rent escalations and rent holidays, the Company records the total rent payable during the lease term on a straight-line basis over the term of the lease and records the difference between the rents paid and the straight-line rent as deferred rent. Additionally, any tenant improvement allowances received from the lessor are recorded as a reduction to rent expense over the term of the lease. Concentrations of Credit Risk The Company has no significant off-balance-sheet concentration of credit risk such as foreign exchange contracts, option contracts or other hedging arrangements. The Company may from time to time have cash in banks in excess of Federal Deposit Insurance Corporation insurance limits. However, the Company believes the risk of loss is minimal as these banks are large financial institutions. Segment Information Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker, or decision-making group, in making decisions regarding resource allocation and assessing performance. To date, the Company has viewed its operations and manages its business as principally one operating segment, which is developing and commercializing therapeutics to treat rare life-threatening inflammatory and fibrotic diseases. As of December 31, 2018 and 2017, all of the Company’s assets were located in the United States, except for approximately $702,000 of cash, $1,183,000 of prepaid expenses, $28,000 of other assets, and $54,000 of property and equipment, net which were held in our subsidiary in the United Kingdom as of December 31, 2018. Income Taxes For federal and state income taxes, deferred tax assets and liabilities are recognized based upon temporary differences between the financial statement and the tax basis of assets and liabilities. Deferred income taxes are based upon prescribed rates and enacted laws applicable to periods in which differences are expected to reverse. A valuation allowance is recorded to reduce a net deferred tax benefit when it is not more likely than not that the tax benefit from the deferred tax assets will be realized. Accordingly, given the cumulative losses since inception, the Company has provided a valuation allowance equal to 100% of the deferred tax assets in order to eliminate the deferred tax assets amounts. Tax positions taken or expected to be taken in the course of preparing the Company’s tax returns are required to be evaluated to determine whether the tax positions are “more-likely-than-not” of being sustained by the applicable tax authority. Tax positions not deemed to meet a more-likely-than-not threshold, as well as accrued interest and penalties, if any, would be recorded as a tax expense in the current year. There were no uncertain tax positions that require accrual or disclosure to the financial statements as of December 31, 2018 or 2017. On December 22, 2017, Staff Accounting Bulletin No. 118 (“SAB 118”) was issued to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Tax Act. In accordance with SAB 118, the Company had recorded a provisional estimate in these financial statements for the effect of the corporate tax rate change. The Company finalized its estimates during the fourth quarter of 2018, described more fully in Note 10. Impairment of Long-lived Assets The Company continually monitors events and changes in circumstances that could indicate that carrying amounts of long-lived assets may not be recoverable. An impairment loss is recognized when expected undiscounted cash flows of an asset are less than an asset’s carrying value. Accordingly, when indicators of impairment are present, the Company evaluates the carrying value of such assets in relation to the operating performance and future undiscounted cash flows of the underlying assets. An impairment loss equal to the excess of the fair value of the asset over its carrying amount, is recorded when it is determined that the carrying value of the asset may not be recoverable. No impairment charges were recorded for the years ended December 31, 2018 and 2017. Stock-based Payments The Company recognizes compensation costs resulting from the issuance of stock-based awards to employees, non-employees and directors as an expense in the statement of operations over the service period based on a measurement of fair value for each stock-based award. The fair value of each option grant to employees is estimated as of the date of grant using the Black-Scholes option-pricing model, net of estimated forfeitures. The fair value is amortized as compensation cost on a straight-line basis over the requisite service period of the awards, which is generally the vesting period. Stock options granted to non-employee consultants are revalued at the end of each reporting period until vested using the Black-Scholes option-pricing model and the changes in their fair value are recorded as adjustments to expense over the related vesting period. On March 30, 2016, the FASB issued ASU No. 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting . Net Loss Per Common Share Basic and diluted net loss per share of the Company’s common stock has been computed by dividing net loss by the weighted average number of shares outstanding during the period. For years in which there is a net loss, options and warrants are anti-dilutive and therefore excluded from diluted loss per share calculations. The following table sets forth the computation of basic and diluted earnings per share for the years ended December 31, 2018 and 2017: Years Ended December 31, 2018 2017 Basic and diluted net loss per share of common stock: Net loss $ (55,672,139 ) $ (32,421,612 ) Weighted average shares of common stock outstanding 56,999,741 50,176,953 Net loss per share of common stock-basic and diluted $ (0.98 ) $ (0.65 ) The impact of the following potentially dilutive securities outstanding as of December 31, 2018 and 2017 have been excluded from the computation of dilutive weighted average shares outstanding as the inclusion would be antidilutive. December 31, 2018 2017 Warrants 2,283,500 1,288,500 Stock options 9,593,990 7,844,966 11,877,490 9,133,466 Recent Accounting Pronouncements Revenue Recognition In May 2014, the FASB issued guidance codified in Accounting Standards Codification (ASC) 606, Revenue Recognition — Revenue from Contracts with Customers ASC 605, Revenue Recognition The Company adopted ASC 606 in the first quarter of 2018 using the modified retrospective method according to which the cumulative effect of initially applying ASC 606 is recognized at the date of initial application, and elected to utilize a practical expedient and did not restate contracts that were completed as of the date of adoption. Since the Company has concluded its performance obligations and has completed recognizing revenue under the 2015 CFFT Award in the third quarter of 2017 (See Note 9), there was no cumulative effect to record at the date of the Company’s adoption of ASC 606 and no revenue to recognize for the first quarter of 2018 related to the 2015 CFFT Award. Revenue for the quarter and the year ended December 31, 2018 was $1,927,306 and $4,822,272, respectively, recognized in accordance with ASC 606 and pertains only to the 2018 CFF Award discussed in Note 9. The total impact to revenue as a result of the adoption of ASC 606 was higher revenue of approximately $325,000 for the quarter ended December 31, 2018 and lower revenue of approximately $201,000 for the year ended December 31, 2018. The Company will assess any new agreements it enters into under ASC 606, including whether such agreements fall under the scope of such standard. This standard applies to all contracts with customers, except for contracts that are within the scope of other standards, such as leases, insurance, collaboration arrangements and financial instruments. Under ASC 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of ASC 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations, and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. Revenue associated with the 2018 CFF Award performance obligation is being recognized as revenue as the research and development services are provided using an input method, according to the costs incurred as related to the research and development activities and the costs expected to be incurred in the future to satisfy the performance obligation. The transfer of control occurs over this time period and, in management’s judgment, is the best measure of progress towards satisfying the performance obligation. The research and development services related to this performance obligation are expected to be performed over an approximately two and a half-year period expected to be completed in the second quarter of 2020. Amounts received prior to revenue recognition are recorded as deferred revenue. Amounts expected to be recognized as revenue within the 12 months following the balance sheet date are classified as current portion of deferred revenue in the accompanying consolidated balance sheets. Amounts not expected to be recognized as revenue within the 12 months following the balance sheet date would be classified as deferred revenue, net of current portion. Amounts recognized as revenue, but not yet received or invoiced are generally recognized as contract assets. Accounting for Leases In February 2016, the FASB issued ASU No . Leases (Topic 842), . Nonemployee Share-Based Payment Accounting In June 2018, the FASB issued ASU 2018-07, Compensation-Stock Compensation (Topic 718), Improvements to Nonemployee Share-Based Payment Accounting Collaborative Arrangements In November 2018, the FASB issued ASU 2018-08, Collaborative Arrangements (Topic 808): Clarifying the Interaction between Topic 808 and Topic 606 . ASU 2018-08 clarifies the interaction between the accounting guidance for collaborative arrangements and revenue from contracts with customers. . Early adoption, including adoption in any interim period, is permitted. The Company is currently .

License Agreement

License Agreement	12 Months Ended
	Dec. 31, 2018
License Agreement
License Agreement	4. LICENSE AGREEMENT The Company, entered into a License Agreement (the “Jenrin Agreement”) with Jenrin Discovery, LLC, a privately-held Delaware limited liability company (“Jenrin”), effective September 20, 2018. Pursuant to the Jenrin Agreement, Jenrin granted the Company exclusive worldwide rights to develop and commercialize the Licensed Products (as defined in the Jenrin Agreement) which includes the Jenrin library of over 600 compounds and multiple issued and pending patent filings. The compounds are designed to treat inflammatory and fibrotic diseases by targeting the endocannabinoid system. The lead product candidate is CRB-4001, a peripherally-restricted CB-1 inverse agonist targeting fibrotic liver, lung, heart and kidney diseases. The Company plans to commence a Phase 1 clinical trial of CRB-4001 in 2019. In consideration of the license and other rights granted by Jenrin, the Company paid Jenrin a $250,000 upfront cash payment and is obligated to pay potential milestone payments to Jenrin totaling up to $18.4 million for each compound it elects to develop based upon the achievement of specified development and regulatory milestones. In addition, Corbus is obligated to pay Jenrin royalties in the mid, single digits based on net sales of any Licensed Products, subject to specified reductions. In January 2017, the FASB issued ASU 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Property and Equipment	5. PROPERTY AND EQUIPMENT Property and Equipment consisted of the following: December 31, 2018 2017 Computer hardware and software $ 431,637 $ 136,522 Office furniture and equipment 914,742 287,048 Leasehold improvements 2,025,410 191,244 Construction in progress — 1,181,730 Property and equipment, gross 3,371,789 1,796,544 Less: accumulated depreciation (666,583 ) (363,889 ) Property and equipment, net $ 2,705,206 $ 1,432,655 Depreciation expense was approximately $494,000 and $256,000 for the years ended December 31, 2018 and 2017, respectively. In the first quarter of 2018, the Company wrote off $191,244 of fully amortized leasehold improvements related to the termination of the September 2016 Amendment in February 2018 as discussed in Note 6. At December 31, 2017, construction in progress consisted of purchased property and equipment not placed in service until the Company’s relocation into 32,733 square feet of office space in February 2018 (See Note 6). On December 30, 2015, the Company entered into a lease agreement for a copier machine. The cost of the machine was approximately $12,000 and is included in office furniture and equipment category in the table above. The lease payments commenced when the machine was placed in service in January 2016. The machine is being amortized over the life of the lease, which is for a three-year term and includes a bargain purchase option at the end of the term. See Note 6 for details of this capital lease commitment.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	6. COMMITMENTS AND CONTINGENCIES Operating Lease Commitment In September 2016, the Company amended its commercial lease for office space to expand into an additional 4,088 square feet of office space within the same building for an aggregate total of 10,414 square feet of leased office space (“September 2016 Amendment”). The Company began occupying this space in early November 2016 and the final lease payment was to be due in January 2021. The September 2016 Amendment required an increase in the standby letter of credit to $50,000 (See Note 3). The September 2016 Amendment was terminated upon the commencement date of the August 2017 Lease Agreement discussed below. On August 21, 2017, the Company entered into a lease agreement (“August 2017 Lease Agreement”) with the same landlord, pursuant to which the Company agreed to lease 32,733 square feet of office space (“Leased Premises”). The initial term of the August 2017 Lease Agreement is for a period of seven years which began with the Company’s occupancy of the Leased Premises in February 2018. The base rent for the Leased Premises ranges from approximately $470,000 for the first year to approximately $908,000 for the seventh year. Per the terms of the August 2017 Lease Agreement, the landlord agreed to reimburse the Company for $1,080,189 of leasehold improvements. The reimbursements have been deferred and will be recognized as a reduction of rent expense over the term of the lease. Additionally, the August 2017 Lease Agreement required a standby irrevocable letter of credit of $400,000, which may be reduced, if the Company is not in default under the August 2017 Lease Agreement, to $300,000 and $200,000 on the third and fourth anniversary of the commencement date, respectively, The Company entered into an unsecured letter of credit for $400,000 in connection with the August 2017 Lease Agreement for which it incurred interest expense of $7,431 and $9,743 in year ended December 31, 2018 and 2017, respectively. The Company records the total rent payable during the lease term on a straight-line basis over the term of the lease and records the difference between the rents paid and the straight-line rent as deferred rent, which is classified in deferred rent, current and deferred rent, noncurrent in the Company’s balance sheet as of December 31, 2018 and 2017. Pursuant to the terms of the Company’s non-cancelable lease agreements in effect at December 31, 2018, the future minimum rent commitments are as follows: 2019 $ 623,958 2020 784,243 2021 830,600 2022 855,150 2023 879,699 Thereafter 1,055,639 Total $ 5,029,289 Total rent expense for the years ended December 31, 2018 and 2017 was $587,963 and $356,547, respectively. On February 26, 2019, the Company amended its lease (“February 2019 Lease Agreement”) pursuant to which an additional 30,023 square feet of office space (“New Premises”) will be leased by the Company in the same building for an aggregate total of 62,756 square feet of leased office space (“Total Premises”). The commencement date for the New Premises is expected to occur no later than August 1, 2019 and the lease term for the Total Premises is October 31, 2026. The future minimum rent commitments for the Total Premises are estimated to be approximately as follows: 2019 $ 678,000 2020 1,288,000 2021 1,592,000 2022 1,640,000 2023 1,687,000 Thereafter 5,036,000 Total $ 11,921,000 Capital Lease Commitment The lease payments commenced when the machine was placed in service in January 2016. The lease is for a three-year term and includes a bargain purchase option at the end of the term. In the accompanying balance sheet as of December 31, 2017 and 2016, the current portion of this capital lease obligation is classified in accrued expenses and the long-term portion of the capital lease obligation is classified in other long-term liabilities. Pursuant to the terms of this capital lease agreement, the future minimum capital lease commitments are as follows as of December 31, 2018: Total future minimum lease payments – end in 2019 $ 378 Less: interest (3 ) Future capital lease obligations 375 Less: current portion (375 ) Long-term portion $ — For commitments under the Company’s development award agreements- see Note 9.

Notes Payable

Notes Payable	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Notes Payable	7. NOTES PAYABLE In October 2016, the Company entered into a loan agreement with a financing company for $348,750 to finance one of the Company’s insurance policies. The terms of the loan stipulate equal monthly payments of principal and interest payments of $39,114 over a nine-month period. Interest on this loan was accrued at an annual rate of 2.25%. This loan was fully repaid in July 2017. In November 2017, the Company entered into a loan agreement with a financing company for $415,265 to finance one of the Company’s insurance policies. The terms of the loan stipulate equal monthly payments of principal and interest payments of $41,975 over a ten-month period. Interest accrued on this loan at an annual rate of 2.35%. This loan was fully repaid in August 2018. In November 2018, the Company entered into a loan agreement with a financing company for $491,629 to finance one of the Company’s insurance policies. The terms of the loan stipulated equal monthly payments of principal and interest payments of $49,857 over a ten-month period. Interest accrues on this loan was accrued at an annual rate of 3.07%. Prepaid expenses and other current assets as of December 31, 2018 and 2017 included $441,875 and $368,976, respectively, related to these insurance policies.

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2018
Payables and Accruals [Abstract]
Accrued Expenses	8. ACCRUED EXPENSES Accrued expenses consisted of the following: December 31, 2018 2017 Accrued clinical operations and trials costs $ 4,914,881 $ 2,003,799 Accrued product development costs 2,222,093 1,255,439 Accrued compensation 2,253,621 1,335,672 Accrued other 460,596 146,609 Total $ 9,851,191 $ 4,741,519

Development Awards and Deferred

Development Awards and Deferred Revenue	12 Months Ended
	Dec. 31, 2018
Development Awards And Deferred Revenue
Development Awards and Deferred Revenue	9. DEVELOPMENT AWARDS AND DEFERRED REVENUE 2015 CFFT Award On April 20, 2015, the Company entered into an award agreement (the “2015 CFFT Award Agreement “) with the Cystic Fibrosis Foundation Therapeutics, Inc (“CFFT”), a non-profit drug discovery and development affiliate of the Cystic Fibrosis Foundation (“CFF”) pursuant to which the Company received a development award (the “2015 CFFT Award”) for up to $5 million in funding. The funding from the 2015 CFFT Award supported a first-in-patient Phase 2 clinical trial of the Company’s oral anti-inflammatory drug lenabasum in adults with cystic fibrosis (“CF”). The Company received $5.0 million in payments under the 2015 CFFT Award as outlined below. The payments received under the 2015 CFFT Award were recorded as deferred revenue when the triggering event to receive those amounts had occurred and were amortized on a straight-line basis over the expected duration of the remaining performance period under the 2015 CFFT Award which concluded in the third quarter of 2017. Upon the execution of the 2015 CFFT Award Agreement, the Company received a payment of $1,250,000 in May 2015. In November 2015, the Company received a second payment of $1,250,000 upon the achievement of a milestone for dosing the first patient. In August 2016, the Company received a third payment from the CFFT in the amount of $1,000,000 for achieving a milestone in July 2016 related to dosing the median clinical trial patient. In January 2017, the Company received a fourth payment from the CFFT in the amount of $1,000,000 for achieving a milestone in December 2016 related to completing the final visit for the final patient, which was billed by the Company to CFFT in December 2016 and was classified in grants receivable as of December 31, 2016. The Company received the final payment from CFFT in the amount of $500,000 in November 2017 for achieving the final milestone in September 2017 related to the issuance to CFFT of the final integrated statistical report for to the Phase 2 CF clinical trial. At that time the Company had completed all its performance obligations under the contract and therefore the performance period had concluded. In accordance with ASC 605, the Company recorded $2,440,195 of revenue during the year ended December 31, 2017 under the 2015 CFFT Award Agreement. No revenue was recorded under the 2015 CFFT Award Agreement during the year ended December 31, 2018 as the final performance period concluded in the third quarter of 2017. Under ASC 605, milestone payments were initially recognized only in the period that the payment-triggering event occurred or was achieved. Effective January 1, 2018, ASC 605 was superseded by ASC 606 (See Note 3). The Company adopted ASC 606 in the first quarter of 2018 using the modified retrospective method according to which the cumulative effect of initially applying ASC 606 is recognized at the date of initial application. Since the Company concluded its performance obligations and completed recognizing revenue under the 2015 CFFT Award Agreement in the third quarter of 2017, there was no cumulative effect to record at the date of the Company’s adoption of ASC 606. Pursuant to the terms of the 2015 CFFT Award Agreement, the Company is obligated to make royalty payments to CFFT contingent upon commercialization of lenabasum in the Field of Use (as defined in the 2015 CFFT Award Agreement) as follows: (i) a royalty payment equal to five times the amount the Company receives under the 2015 CFFT Award Agreement, up to $25 million, payable in three equal annual installments following the first commercial sale of lenabasum, the first of which is due within 90 days following the first commercial sale of lenabasum, (ii) a royalty payment to CFFT equal to the amount the Company receives under the 2015 CFFT Award Agreement, up to $5 million, due in the first calendar year in which the aggregate cumulative net sales of lenabasum in the Field of Use exceed $500 million, and (iii) royalty payment(s) to CFFT of up to approximately $15 million if the Company transfers, sells or licenses lenabasum in the Field of Use other than for certain clinical or development purposes, or if the Company enters into a change of control transaction, with such payment(s) to be credited against the royalty payments due upon commercialization. The Field of Use is defined in the 2015 CFFT Award as the treatment in humans of CF, asbestosis, bronchiectasis, byssinosis, chronic bronchitis/COPD hypersensitivity pneumonitis, pneumoconiosis, primary ciliary dyskinesis, sarcoidosis and silicosis. Either CFFT or the Company may terminate the agreement for cause, which includes the Company’s material failure to achieve certain commercialization and development milestones. The Company’s payment obligations, if any, would survive the termination of the 2015 CFFT Award Agreement. 2018 CFF Award On January 26, 2018, the Company entered into the Cystic Fibrosis Program Related Investment Agreement with the CFF (“Investment Agreement”), a non-profit drug discovery and development corporation, pursuant to which the Company received an award for up to $25 million in funding (the “2018 CFF Award”) to support a Phase 2b Clinical Trial (the “Phase 2b Clinical Trial”) of lenabasum in patients with cystic fibrosis, of which the Company has received $12.5 million during the year ended December 31, 2018 upon the Company’s achievement of milestones related to the progress of the Phase 2b Clinical Trial, as set forth in the Investment Agreement. The Company expects that the remainder of the 2018 CFF Award will be paid incrementally upon the Company’s achievement of the remaining milestones related to the progress of the Phase 2b Clinical Trial, as set forth in the Investment Agreement. Pursuant to the terms of the Investment Agreement, the Company is obligated to make certain royalty payments to CFF, including a royalty payment of one and one-half times the amount of the 2018 CFF Award, payable in cash within sixty days upon the first receipt of approval of lenabasum in the United States and a second royalty payment of one and one-half times the amount of the 2018 CFF Award upon approval in another major market, as set forth in the Investment Agreement (the “Approval Royalty”). At the Company’s election, the Company may satisfy the first of the two Approval Royalties in registered shares of the Company’s common stock. Additionally, the Company is obligated to make (i) royalty payments to CFF of two and one-half percent of net sales from lenabasum due within sixty days after any quarter in which such net sales occur in the Field, as defined in the Investment Agreement, (ii) royalty payments to CFF of one percent of net sales of Non-Field Products, as defined in the Investment Agreement due within sixty days after any quarter in which such net sales occur, and (iii) royalty payments to CFF of ten percent of any amount the Company and its stockholders receive in connection with the license, sale, or other transfer to a third party of lenabasum, if indicated for the treatment or prevention of CF, or a change of control transaction, except that such payment shall not exceed five times the amount of the 2018 CFF Award, with such payments to be credited against any other net sales royalty payments due. Accordingly, we will owe to CFF a royalty payment equal to 10% of any amounts we receive as payment under the collaboration agreement with Kaken, provided that the total royalties that we will be required to pay under the Investment Agreement resulting from income from licenses or sales subject to the Investment Agreement are capped at five times the total amount of the 2018 CFF Award, and we may credit such royalties against any royalties on net sales otherwise owed to CFF under the Investment Agreement. Accordingly, we will be required to pay CFF $2,700,000 within 60 days of our receipt of the $27,000,000 upfront cash payment from Kaken. Either CFF or the Company may terminate the Investment Agreement for cause, which includes the Company’s material failure to achieve certain commercialization and development milestones. The Company’s payment obligations survive the termination of the Investment Agreement. Pursuant to the terms of the Investment Agreement, the Company issued a warrant to CFF to purchase an aggregate of 1,000,000 shares of the Company’s common stock (the “CFF Warrant”). The CFF Warrant is exercisable at a price equal to $13.20 per share and is immediately exercisable for 500,000 shares of the Company’s common stock. Upon completion of the final milestone set forth in the Investment Agreement and receipt of the final payment from CFF to the Company pursuant to the Investment Agreement, the CFF Warrant will be exercisable for the remaining 500,000 shares of the Company’s common stock. The CFF Warrant expires on January 26, 2025. Any shares of the Company’s common stock issued upon exercise of the CFF Warrant will be unregistered and subject to a one-year lock-up. The Company recorded $4,822,272 of revenue during the year ended December 31, 2018 under the Investment Agreement. The Company assessed the 2018 CFF Award for accounting under ASC 606, which it adopted in the first quarter of 2018 (Note 3). To determine revenue recognition for arrangements that an entity determines are within the scope of ASC 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company assessed this arrangement in accordance with ASC 606 and concluded that the contract counterparty, CFF, is a customer. The Company identified the following material promise under the arrangement: research and development activities and related services under the Phase 2b Clinical Trial. Based on these assessments, the Company identified one performance obligation at the outset of the Investment Agreement, which consists of: Phase 2b Clinical Trial research and development activities and related services. To determine the transaction price, the Company included the total aggregate payments under the Investment Agreement which amount to $25 million and reduced the revenue to be recognized by the payment to the customer of $6,215,225 in the form of the CFF Warrant representing its fair value, leaving the remaining $18,784,775 as the transaction price as of the outset of the arrangement, which will be recognized as revenue over the performance period as discussed below. The $6,215,225 fair value of the warrant was also recorded as an increase to additional paid in capital. The Company billed and collected $12,500,000 in milestone payments during the year ended December 31, 2018 which was recorded as an increase to deferred revenue. A roll forward of deferred revenue for the year ended December 31, 2018 is presented below: December 31, 2018 Beginning balance $ — Billing to CFF upon achievement of milestones 12,500,000 Fair value of CFF Warrant (6,215,225 ) Recognition of revenue (4,822,272 ) Ending balance $ 1,462,503 The CFF Warrant is accounted for as a payment to the customer under ASC 606. See Note 13 for further information related to the CFF Warrant. The Company notes that the Investment Agreement contains an initial payment that was received upon contract execution and subsequent milestone payments, which are a form of variable consideration that require evaluation for constraint considerations. The Company concluded that the related performance milestones are generally within the Company’s control and as result are considered probable. Revenue associated with the performance obligation is being recognized as revenue as the research and development services are provided using an input method, according to the costs incurred as related to the research and development activities on each program and the costs expected to be incurred in the future to satisfy the performance obligation. The transfer of control occurs over this time period and, in management’s judgment, is the best measure of progress towards satisfying the performance obligation. The research and development services related to this performance obligation are expected to be performed over an approximately two and a half year period expected to be completed in the second quarter of 2020. The amounts received that have not yet been recognized as revenue are recorded in deferred revenue and the amounts recognized as revenue, but not yet received or invoiced are generally recognized as contract assets on the Company’s condensed consolidated balance sheet.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	10. INCOME TAXES No provision or benefit for federal or state income taxes has been recorded, as the Company has incurred a net loss for all of the periods presented, and the Company has provided a full valuation allowance against its deferred tax assets. At December 31, 2018 and 2017, the Company had federal net operating loss carryforwards of approximately $82,545,000 and $56,536,000, respectively, of which federal carryforwards will expire in varying amounts beginning in 2029. At December 31, 2018 and 2017, the Company had Massachusetts net operating loss carryforwards of approximately $78,152,000 and $53,110,000, respectively. In the first quarter of 2017, the Company adopted ASU 2016-09, which removed the requirement to recognize the deferred tax assets on excess tax benefits in respect of share based payments only when realized. As such, during the year ended December 31, 2017, the Company’s gross deferred tax assets and corresponding valuation allowance each included a one-time increase in respect of an additional federal and state net operating losses of $1,432,000. The adoption of ASU 2016-09 did not have an impact on the Company’s balance sheet, results of operations, cash flows or statement of stockholders’ equity because the Company has a full valuation allowance on its deferred tax assets. Utilization of net operating losses may be subject to substantial annual limitations due to the “change in ownership” provisions of the Internal Revenue Code, and similar state provisions. The annual limitations may result in the expiration of net operating losses before utilization. The Company has not yet conducted a study to determine if any such changes have occurred that could limit the Company’s ability to use the net operating losses and tax credit carryforwards. The Company also had research and development tax credit carryforwards at December 31, 2018 and 2017 of approximately $2,926,000 and $1,283,000, respectively. Significant components of the Company’s net deferred tax asset are as follows: December 31, 2018 2017 NOL carryforward $ 22,273,661 $ 15,229,127 Foreign net operating loss carryforward 3, 616,502 — Tax credits 2,793,247 1,213,347 Stock based compensation 3,381,969 1,724,248 Accrued expenses 660,427 45,654 Other temporary differences 186,069 116,292 Subtotal 32,911,875 18,328,668 Valuation allowance (32,911,875 ) (18,328,668 ) Net deferred tax asset $ — $ — The Company has maintained a full valuation allowance against its deferred tax assets in all periods presented. A valuation allowance is required to be recorded when it is not more likely than not that some portion or all of the net deferred tax assets will be realized. Since the Company cannot determine that it is more likely than not that it will generate taxable income, and thereby realize the net deferred tax assets, a full valuation allowance has been provided. The valuation allowance increased by $14,583,207 and $5,088,343 in 2018 and 2017, respectively, due to the increase in deferred tax assets, primarily due to net operating loss carryforwards. The Company has no uncertain tax positions at December 31, 2018 and 2017 that would affect its effective tax rate. Since the Company is in a loss carryforward position, the Company is generally subject to U.S. federal and state income tax examinations by tax authorities for all years for which a loss carryforward is available. Income tax benefits computed using the federal statutory income tax rate differs from the Company’s effective tax rate primarily due to the following: December 31, 2018 2017 Tax provision at statutory rate % 21.00 % 34.00 % State taxes, net of federal benefit % 5.42 % 5.66 % Permanent differences % -2.00 % -2.05 % Foreign expected tax 9.85 % — % Tax credits % 4.31 % 1.59 % Income tax rate change % — % -24.11 % Other % 1.14 % 0.60 % Increase in valuation reserve % -39.72 % -15.69 % Total % 0.00 % 0.00 % The Tax Cut and Jobs Act of 2017 On December 22, 2017, the legislation commonly referred to as the Tax Cut and Jobs Act (the “Tax Act”) was enacted into law. The Tax Act, among other things, contains significant changes to corporate taxation, including reduction of the corporate tax rate from a top marginal rate of 35% to a flat rate of 21%; limitation of the tax deduction for interest expense to 30% of adjusted earnings (except for certain small businesses); limitation of the deduction of net operating losses generated in tax years beginning after December 31, 2017 to 80% of taxable income, indefinite carryforward of net operating losses generated in tax years after 2018 and elimination of net operating loss carrybacks; changes in the treatment of offshore earnings regardless of whether they are repatriated; current inclusion in U.S. federal taxable income of certain earnings of controlled foreign corporations, mandatory capitalization of research and development expenses beginning in 2022; immediate deductions for certain new investments instead of deductions for depreciation expense over time; further deduction limits on executive compensation; and modifying, repealing and creating many other business deductions and credits, including the reduction in the orphan drug credit from 50% to 25% of qualifying expenditures. As of December 31, 2017, we made a reasonable estimate of the effects of the Tax Act on our existing deferred taxes and related disclosures by reducing our net federal and state deferred tax assets by $7,815,832 for the reduction in corporate tax rate. This adjustment to our deferred tax assets was offset against the valuation allowance. Additionally, the SEC staff has issued SAB 118, which allows to record provisional amounts during a measurement period not to extend beyond one year of the enactment date. On December 22, 2017, Staff Accounting Bulletin No. 118 (“SAB 118”) was issued to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Act. The Company finalized its estimates during the fourth quarter of 2018.

Common Stock

Common Stock	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Common Stock	11. COMMON STOCK The Company has authorized 150,000,000 shares of common stock, $0.0001 par value per share, of which 57,247,496 shares, and 55,603,427 shares were issued and outstanding as of December 31, 2018, and 2017, respectively. On February 28, 2017, the Company entered into a securities purchase agreement providing for the issuance and sale by the Company of 3,887,815 shares of its common stock in a registered direct offering to institutional and accredited investors at a purchase price of $7.00 per share with gross proceeds to the Company totaling $27,214,705 less issuance costs of $36,291. On October 26, 2017, the Company consummated an underwritten public offering of shares of its common stock pursuant to which the Company sold an aggregate of 4,650,000 shares of its common stock at a purchase price of $7.00 per share with gross proceeds to the Company totaling $32,550,000, less estimated issuance costs incurred of approximately $2,184,000. The Company also granted the underwriters a 30-day option to purchase up to an additional 697,500 shares of common stock on the same terms as the underwriters were purchasing the base number of shares, which they exercised in November 2017 with net proceeds to the Company totaling $4,589,550. On January 5, 2018, the Company entered into a sales agreement with Cantor Fitzgerald under which the Company had the ability to direct Cantor Fitzgerald as its sales agent to sell common stock up to an aggregate offering of up to $50 million under an “At the Market Offering” (“January 2018 Sales Agreement”). Sales of common stock under the January 2018 Sales Agreement were made pursuant to an effective registration statement for an aggregate offering of up to $50 million. During the first quarter of 2018, the Company sold 1,500,000 shares of its common stock to an institutional investor under the January 2018 Sales Agreement for which the Company received net proceeds of approximately $11.2 million. The Company did not sell any shares under the January 2018 Sales Agreement in remainder of 2018 and through February 8, 2019, the effective date of the Company’s termination of the January 2018 Sales Agreement (see Note 15). During the year ended December 31, 2017, the Company sold 1,413,633 shares of its common stock under a sales agreement that the Company entered into in November 2016 with Cantor Fitzgerald (“Sales Agreement”) for net proceeds of $13,268,208. The Sales Agreement was terminated in October 2017. During the year ended December 31, 2018, the Company issued 144,069 shares of common stock upon the exercise of stock options and warrants to purchase common stock and the Company received net proceeds of $352,645 from these exercises. During the year ended December 31, 2017, the Company issued 272,734 shares of common stock upon the exercise of stock options and warrants to purchase common stock and the Company received net proceeds of $189,490 from these exercises. On January 30, 2019, the Company consummated an underwritten public offering of shares of its common stock. See Note 15.

Stock Options

Stock Options	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Options	12. STOCK OPTIONS In April 2014, the Company adopted the Corbus Pharmaceuticals Holdings, Inc. 2014 Equity Incentive Plan (the “2014 Plan”). Pursuant to the 2014 Plan, the Company’s Board of Directors may grant incentive and nonqualified stock options and restricted stock to employees, officers, directors, consultants and advisors. Pursuant to the terms of an annual evergreen provision in the 2014 Plan, the number of shares of common stock available for issuance under the 2014 Plan shall automatically increase on January 1 of each year by at least seven percent (7%) of the total number of shares of common stock outstanding on December 31st of the preceding calendar year, or, pursuant to the terms of the 2014 Plan, in any year, the Board of Directors may determine that such increase will provide for a lesser number of shares. On January 1, 2018, pursuant to an annual evergreen provision contained in the 2014 Plan, the number of shares reserved for future grants was increased by 2,500,000 shares, which was less than seven percent (7%) of the outstanding shares of common stock on December 31, 2017. As of December 31, 2018, there was a total of 15,543,739 shares reserved for issuance under the 2014 Plan and there were 5,072,241 shares available for future grants. Options issued under the 2014 Plan generally vest over 4 years from the date of grant in multiple tranches and are exercisable for up to 10 years from the date of issuance. In accordance with the terms of the 2014 Plan, effective as of January 1, 2019, the number of shares of common stock available for issuance under the 2014 Plan increased by 3,000,000 shares, which was less than seven percent (7%) of the outstanding shares of common stock on December 31, 2018. As of January 1, 2019, the 2014 Plan had a total reserve of 18,543,739 shares and there were 8,072,241 shares available for future grants. Share-based Compensation For stock options issued and outstanding for the years ended December 31, 2018 and 2017, the Company recorded non-cash, stock-based compensation expense of $7,609,508 ($7,500,888 for employees and $108,620 for non-employees) and $5,694,489 ($4,640,646 for employees and $1,053,843 for non-employees), respectively, net of estimated forfeitures. The fair value of each option award for employees is estimated on the date of grant and for non-employees is estimated at the end of each reporting period until vested using the Black-Scholes option pricing model that uses the assumptions noted in the following table. The Company uses historical data, as well as subsequent events occurring prior to the issuance of the financial statements, to estimate option exercises and employee terminations in order to estimate its forfeiture rate. The expected term of options granted under the 2014 Plan, all of which qualify as “plain vanilla” per SEC Staff Accounting Bulletin 107, is determined based on the simplified method due to the Company’s limited operating history, and is 6.25 years based on the average between the vesting period and the contractual life of the option. For non-employee options, the expected term is the contractual term. The risk-free rate is based on the yield of a U.S. Treasury security with a term consistent with the option. The weighted average assumptions used principally in determining the fair value of options granted to employees were as follows: 2018 2017 Risk free interest rate % 2.53 % 2.12 % Expected dividend yield % 0 % 0 % Expected term in years 6.25 6.25 Expected volatility % 87.70 % 86.01 % Estimated forfeiture rate % 5.00 % 5.00 % For the year ended December 31, 2017, the assumptions used in determining the fair value of options granted to nonemployees included risk free interest rate ranging from 2.12%-2.38%, no expected dividend yield, expected term ranging from 4.91 years to 9.91 years, expected volatility ranging from 85.58% to 89.58%, and estimated forfeiture rate of 5%. A summary of option activity for years ended December 31, 2018 and 2017 is presented below: Options Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term in Years Intrinsic Value Outstanding at December 31, 2016 6,610,179 $ 2.54 Granted 1,681,500 $ 8.28 Exercised (272,734 ) $ 0.67 Forfeited (173,979 ) $ 6.53 Outstanding at December 31, 2017 7,844,966 $ 3.75 Granted 2,378,500 $ 7.58 Exercised (139,069 ) $ 2.50 Forfeited (490,407 ) $ 7.85 Outstanding at December 31, 2018 9,593,990 $ 4.51 7.23 $ 22,510,816 Exerciseable at December 31, 2018 5,967,701 $ 2.87 6.43 $ 20,691,512 The weighted average grant-date fair value of options granted during the years ended December 31, 2018 and 2017 was $5.63 and $6.22 per share, respectively. The aggregate intrinsic value of options exercised during the years ended December 31, 2018 and 2017 was approximately $543,060 and $2,092,964, respectively. As of December 31, 2018, there was approximately $15,400,414 of total unrecognized compensation expense, related to non-vested share-based compensation arrangements. The unrecognized compensation expense is estimated to be recognized over a period of 2.55 years at December 31, 2018. As summary of non-vested stock options for the years ended December 31, 2018 and 2017 is presented below: Options Shares Weighted Average Fair Value Non-vested at December 31, 2016 3,826,274 $ 2.86 Granted 1,681,500 $ 6.22 Vested (2,003,806 ) $ 2.60 Forfeited (173,979 ) $ 5.03 Nonvested at December 31, 2017 3,329,989 $ 4.61 Granted 2,378,500 $ 5.63 Vested (1,643,772 ) $ 3.98 Forfeited (438,428 ) $ 5.91 Non-vested at December 31, 2018 3,626,289 $ 5.32

Warrants

Warrants	12 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Warrants	13. WARRANTS During the year ended December 31, 2018, warrants to purchase 5,000 shares of common stock were exercised for proceeds of $5,000. No warrants were exercised during the year ended December 31, 2017. At December 31, 2018, there were warrants outstanding to purchase 2,283,500 shares of common stock with a weighted average exercise price of $6.34 and a weighted average remaining life of 2.89 years, including the warrant issued to CFF pursuant to the terms of the Investment Agreement (Note 8). The Company issued a warrant to CFF to purchase an aggregate of 1,000,000 shares of the Company’s common stock (the “CFF Warrant”). The CFF Warrant is exercisable at a price equal to $13.20 per share and is immediately exercisable for 500,000 shares of the Company’s common stock. Upon completion of the final milestone set forth in the Investment Agreement and receipt of the final payment from CFF to the Company pursuant to the Investment Agreement, the CFF Warrant will be exercisable for the remaining 500,000 shares of the Company’s common stock. The CFF Warrant expires on January 26, 2025. Any shares of the Company’s common stock issued upon exercise of the CFF Warrant will be unregistered and subject to a one-year lock-up. The CFF Warrant is classified as equity as it meets all the conditions under GAAP for equity classification. In accordance with GAAP, the Company has calculated the fair value of the warrant for initial measurement and will reassess whether equity classification for the warrant is appropriate upon any changes to the warrants or capital structure, at each balance sheet date. The weighted average assumptions used in determining the $6,215,225 fair value of the CFF Warrant were as follows: Risk free interest rate 2.60 % Expected dividend yield 0 % Expected term in years 7.00 Expected volatility 83.5 %

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2018
Related Party Transactions [Abstract]
Related Party Transactions	14. RELATED PARTY TRANSACTIONS On September 20, 2016, the Company entered into a consulting agreement (the “2016 Consulting Agreement”) with Orchestra Medical Ventures, LLC (“Orchestra”), of which a member of the Company’s Board of Directors, David Hochman, is Managing Partner. Under this agreement, Orchestra rendered a variety of consulting and advisory services relating principally to identifying and evaluating strategic relationships, licensing opportunities, and business strategies. The term of the 2016 Consulting Agreement commenced on September 20, 2016 and expired on March 20, 2017. Pursuant to the terms of the 2016 Consulting Agreement, the Company paid to Orchestra cash compensation in an aggregate amount of $100,000. In connection with this agreement, the Company granted an equity incentive award to Mr. Hochman consisting of options to purchase 50,000 shares (“Option Shares”) of common stock (the “Option Award”) pursuant to the Company’s 2014 Equity Compensation Plan, of which fifty percent (50%) vested on the three (3) month anniversary of the date of grant of the Option Award and the remainder of the Option Shares vested on the six (6) month anniversary of the date of grant of the Option Award. The Option Shares were granted with an exercise price of $7.14 per share. The Company recorded stock-based compensation expense of approximately $222,000 during the year ended December 31, 2016 and $171,000 during the first quarter of 2017 in respect of the Option Award. No stock-based compensation expense was recorded after the first quarter of 2017 related to the Option Shares as they were fully vested in March 2017.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	15. SUBSEQUENT EVENTS Evergreen Provision Pursuant to the terms of an annual evergreen provision in the 2014 Plan, the number of shares of common stock available for issuance under the 2014 Plan shall automatically increase on January 1 of each year by at least seven percent (7%) of the total number of shares of common stock outstanding on December 31st of the preceding calendar year, or, pursuant to the terms of the 2014 Plan, in any year, the Board of Directors may determine that such increase will provide for a lesser number of shares. In accordance with the terms of the 2014 Plan, effective as of January 1, 2019, the number of shares of common stock available for issuance under the 2014 Plan increased by 3,000,000 shares, such amount being less than seven percent (7%) of the outstanding shares of common stock on December 31, 2018. As of January 1, 2019, the 2014 Plan had a total reserve of 18,543,739 shares and there were 8,072,2414 shares available for future grants. Collaboration with Kaken On January 3, 2019, Corbus Pharmaceuticals Holdings, Inc. the Company entered into a Collaboration and License Agreement (the “Agreement”) with Kaken Pharmaceutical Co., Ltd., a company organized under the laws of Japan (“Kaken”). Pursuant to the Agreement, Corbus granted Kaken an exclusive license to commercialize pharmaceutical preparations containing lenabasum (the “Licensed Products”) for the prevention or treatment of dermatomyositis and systemic sclerosis (together, the “Initial Indications”) in Japan (the “Territory”). Pursuant to the terms of the Agreement, Corbus will bear the cost of, and be responsible for, among other things, conducting the clinical studies and other developmental activities for the Licensed Products in the Initial Indications in the Territory, and Kaken will bear the cost of, and be responsible for, among other things, preparing and filing applications for regulatory approval in the Territory and for commercializing Licensed Products in the Territory, and will use commercially reasonable efforts to commercialize Licensed Products and obtain pricing approval for Licensed Products in the Territory. In consideration of the license and other rights granted by Corbus, Kaken will pay Corbus a $27,000,000 upfront cash payment and is obligated to pay potential milestone payments to Corbus totaling up to approximately $173,000,000 for the achievement of certain development, sales and regulatory milestones, with part of the milestone payments being calculated in Japanese Yen, and therefore subject to change based on the conversion rate to U.S. Dollars in effect at the time of payment. In addition, during the Royalty Term (as defined below), Kaken is obligated to pay Corbus royalties on sales of Licensed Products in the Territory, under certain conditions, in the double digits, which royalty shall be reduced in certain circumstances. In particular, for so long as Corbus supplies Licensed Products to Kaken pursuant to a supply agreement to be entered into by the parties, royalty payments shall be payable for each unit of Licensed Product that Corbus supplies as a percentage of the Japanese National Health Insurance price of the Licensed Product. During any time in which a supply agreement is not in effect, royalty payments shall be changed to a rate to be agreed upon by the parties in good faith. The Agreement will remain in effect on a Licensed Product-by-Licensed product basis and will expire upon the expiration of the Royalty Term for the final Licensed Product. The “Royalty Term” means the period beginning on the date of the first commercial sale of the Licensed Product in Japan and ends on the latest of (i) the expiration of the last valid claim of the royalty patents covering such Licensed Product in Japan, (ii) the expiration of regulatory exclusivity for such Licensed Product for such Initial Indication in Japan, or (iii) ten (10) years after the first commercial sale of such Licensed Product for such Initial Indication in Japan. The Agreement may be terminated by either party for material breach, upon a party’s insolvency or bankruptcy or upon a challenge by one party of any patents of the other party, and Kaken may terminate in specified situations, including for a safety concern or clinical failure, or at its convenience following the second anniversary of the first commercial sale of a Licensed Product in either of the Initial Indications in the Territory, with 180 days’ notice. Pursuant to the Agreement, the parties agreed to develop a joint steering committee to provide strategic oversight of the parties’ activities under the Agreement, as well as a joint development committee to coordinate the development of Licensed Products in Japan. Additionally, the parties will establish a joint commercialization committee to review and confirm commercialization activities with respect to Licensed Products in Japan upon regulatory approval of such Licensed Product. The Agreement also contains customary representations, warranties and covenants by both parties, as well as customary provisions relating to indemnification, confidentiality and other matters. The Company is evaluating the terms of the Agreement and believes it is within the scope of ASC 606. Accordingly, the Company expects that the $27 million upfront payment will be recognized in the first quarter of 2019. Termination of January 2018 Sales Agreement On January 29, 2019, the Company provided notice of its termination of the January 2018 Sales Agreement. The termination of the January 2018 Sales Agreement was effective on February 8, 2019. Public Offering On January 30, 2019, the Company consummated an underwritten public offering of shares of its common stock pursuant to which the Company sold an aggregate of 6,198,500 shares of its common stock, including 808,500 shares sold pursuant to the full exercise of the underwriters’ option to purchase additional shares, at a purchase price of $6.50 per share with gross proceeds to the Company totaling $40,290,250, less estimated issuance costs incurred of approximately $2,667,000. Office Space Lease Amendment On February 26, 2019, the Company amended its lease (“February 2019 Lease Agreement”) pursuant to which an additional 30,023 square feet of office space (“New Premises”) will be leased by the Company in the same building for an aggregate total of 62,756 square feet of leased office space (See Note 6).

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates The process of preparing financial statements in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates and changes in estimates may occur. The most significant estimates are related to stock-based compensation expense, the accrual of research, product development and clinical obligations, the recognition of revenue under the Investment Agreement (see Note 9) and the valuation of the CFF Warrant discussed in Note 9).
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers only those investments which are highly liquid, readily convertible to cash, and that mature within three months from date of purchase to be cash equivalents. Marketable investments are those with original maturities in excess of three months. At December 31, 2018 and 2017, cash equivalents were comprised of money market funds. The Company had no marketable investments at December 31, 2018 and 2017. Restricted cash as of December 31, 2017 in the amount of $108,991 was classified in current assets and included a collateral account for the Company’s corporate credit cards. The collateral account was closed in the first quarter of 2018 and accordingly the cash became unrestricted. Additionally, as of December 31, 2017, restricted cash included a stand-by letter of credit issued in favor of a landlord for $50,000 which was classified in current assets as of December 31, 2017. This stand-by letter of credit was terminated in the first quarter of 2018 in connection with the August 2017 Lease Agreement discussed in Note 6, and accordingly, the cash became unrestricted. Cash, cash equivalents, and restricted cash consists of the following: December 31, 2018 2017 Cash $ 808,943 $ 206,510 Money market fund 40,939,525 62,330,985 Cash and cash equivalents 41,748,468 62,537,495 Restricted cash — 158,991 Total cash, cash equivalents, and restricted cash shown in the statement of cash flows $ 41,748,468 $ 62,696,486 As of December 31, 2018, all of the Company’s cash was held in the United States, except for approximately $702,000 of cash which was held in our subsidiary in the United Kingdom. As of December 31, 2017, all of the Company’s cash was held in the United States.
Financial Instruments	Financial Instruments The carrying amounts reported in the consolidated balance sheet for cash and cash equivalents, receivables, accounts payable and accrued expenses approximate their fair value based on the short-term nature of these instruments. The carrying values of the notes payable approximate their fair value due to the fact that they are at market terms.
Property and Equipment	Property and Equipment The estimated life for the Company’s property and equipment is as follows: three years for computer hardware and software and three to five years for office furniture and equipment. The Company’s leasehold improvements and assets under capital lease are amortized over the shorter of their useful lives or the respective leases. See Note 5 for details of property and equipment and Note 6 for operating and capital lease commitments.
Research and Development Expenses	Research and Development Expenses Costs incurred for research and development are expensed as incurred. Nonrefundable advance payments for goods or services that have the characteristics that will be used or rendered for future research and development activities pursuant to executory contractual arrangements with third party research organizations are deferred and recognized as an expense as the related goods are delivered or the related services are performed.
Accruals for Research and Development Expenses and Clinical Trials	Accruals for Research and Development Expenses and Clinical Trials As part of the process of preparing its financial statements, the Company is required to estimate its expenses resulting from its obligations under contracts with vendors, clinical research organizations and consultants and under clinical site agreements in connection with conducting clinical trials. The financial terms of these contracts are subject to negotiations, which vary from contract to contract and may result in payment terms that do not match the periods over which materials or services are provided under such contracts. The Company’s objective is to reflect the appropriate expenses in its financial statements by matching those expenses with the period in which services are performed and efforts are expended. The Company accounts for these expenses according to the timing of various aspects of the expenses. The Company determines the accrual estimates by taking into account discussion with applicable personnel and outside service providers as to the progress of clinical trials, or the services completed. During the course of a clinical trial, the Company adjusts its clinical expense recognition if actual results differ from its estimates. The Company makes estimates of its accrued expenses as of each balance sheet date based on the facts and circumstances known to it at that time. The Company’s clinical trial accruals are dependent upon the timely and accurate reporting of contract research organizations and other third-party vendors. Although the Company does not expect its estimates to be materially different from amounts actually incurred, its understanding of the status and timing of services performed relative to the actual status and timing of services performed may vary and may result in it reporting amounts that are too high or too low for any particular period. For the years ended December 31, 2018 and 2017, there were no material adjustments to the Company’s prior period estimates of accrued expenses for clinical trials.
Leases and Deferred Rent	Leases and Deferred Rent The Company leases its office space. Leases are evaluated and classified as operating or capital leases for financial reporting purposes. The Company’s office space leases qualify as operating leases. For operating leases that contain rent escalations and rent holidays, the Company records the total rent payable during the lease term on a straight-line basis over the term of the lease and records the difference between the rents paid and the straight-line rent as deferred rent. Additionally, any tenant improvement allowances received from the lessor are recorded as a reduction to rent expense over the term of the lease.
Concentrations of Credit Risk	Concentrations of Credit Risk The Company has no significant off-balance-sheet concentration of credit risk such as foreign exchange contracts, option contracts or other hedging arrangements. The Company may from time to time have cash in banks in excess of Federal Deposit Insurance Corporation insurance limits. However, the Company believes the risk of loss is minimal as these banks are large financial institutions.
Segment Information	Segment Information Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker, or decision-making group, in making decisions regarding resource allocation and assessing performance. To date, the Company has viewed its operations and manages its business as principally one operating segment, which is developing and commercializing therapeutics to treat rare life-threatening inflammatory and fibrotic diseases. As of December 31, 2018 and 2017, all of the Company’s assets were located in the United States, except for approximately $702,000 of cash, $1,183,000 of prepaid expenses, $28,000 of other assets, and $54,000 of property and equipment, net which were held in our subsidiary in the United Kingdom as of December 31, 2018.
Income Taxes	Income Taxes For federal and state income taxes, deferred tax assets and liabilities are recognized based upon temporary differences between the financial statement and the tax basis of assets and liabilities. Deferred income taxes are based upon prescribed rates and enacted laws applicable to periods in which differences are expected to reverse. A valuation allowance is recorded to reduce a net deferred tax benefit when it is not more likely than not that the tax benefit from the deferred tax assets will be realized. Accordingly, given the cumulative losses since inception, the Company has provided a valuation allowance equal to 100% of the deferred tax assets in order to eliminate the deferred tax assets amounts. Tax positions taken or expected to be taken in the course of preparing the Company’s tax returns are required to be evaluated to determine whether the tax positions are “more-likely-than-not” of being sustained by the applicable tax authority. Tax positions not deemed to meet a more-likely-than-not threshold, as well as accrued interest and penalties, if any, would be recorded as a tax expense in the current year. There were no uncertain tax positions that require accrual or disclosure to the financial statements as of December 31, 2018 or 2017. On December 22, 2017, Staff Accounting Bulletin No. 118 (“SAB 118”) was issued to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Tax Act. In accordance with SAB 118, the Company had recorded a provisional estimate in these financial statements for the effect of the corporate tax rate change. The Company finalized its estimates during the fourth quarter of 2018, described more fully in Note 10.
Impairment of Long-lived Assets	Impairment of Long-lived Assets The Company continually monitors events and changes in circumstances that could indicate that carrying amounts of long-lived assets may not be recoverable. An impairment loss is recognized when expected undiscounted cash flows of an asset are less than an asset’s carrying value. Accordingly, when indicators of impairment are present, the Company evaluates the carrying value of such assets in relation to the operating performance and future undiscounted cash flows of the underlying assets. An impairment loss equal to the excess of the fair value of the asset over its carrying amount, is recorded when it is determined that the carrying value of the asset may not be recoverable. No impairment charges were recorded for the years ended December 31, 2018 and 2017.
Stock-based Payments	Stock-based Payments The Company recognizes compensation costs resulting from the issuance of stock-based awards to employees, non-employees and directors as an expense in the statement of operations over the service period based on a measurement of fair value for each stock-based award. The fair value of each option grant to employees is estimated as of the date of grant using the Black-Scholes option-pricing model, net of estimated forfeitures. The fair value is amortized as compensation cost on a straight-line basis over the requisite service period of the awards, which is generally the vesting period. Stock options granted to non-employee consultants are revalued at the end of each reporting period until vested using the Black-Scholes option-pricing model and the changes in their fair value are recorded as adjustments to expense over the related vesting period. On March 30, 2016, the FASB issued ASU No. 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting .
Net Loss Per Common Share	Net Loss Per Common Share Basic and diluted net loss per share of the Company’s common stock has been computed by dividing net loss by the weighted average number of shares outstanding during the period. For years in which there is a net loss, options and warrants are anti-dilutive and therefore excluded from diluted loss per share calculations. The following table sets forth the computation of basic and diluted earnings per share for the years ended December 31, 2018 and 2017: Years Ended December 31, 2018 2017 Basic and diluted net loss per share of common stock: Net loss $ (55,672,139 ) $ (32,421,612 ) Weighted average shares of common stock outstanding 56,999,741 50,176,953 Net loss per share of common stock-basic and diluted $ (0.98 ) $ (0.65 ) The impact of the following potentially dilutive securities outstanding as of December 31, 2018 and 2017 have been excluded from the computation of dilutive weighted average shares outstanding as the inclusion would be antidilutive. December 31, 2018 2017 Warrants 2,283,500 1,288,500 Stock options 9,593,990 7,844,966 11,877,490 9,133,466
Recent Accounting Pronouncements	Recent Accounting Pronouncements Revenue Recognition In May 2014, the FASB issued guidance codified in Accounting Standards Codification (ASC) 606, Revenue Recognition — Revenue from Contracts with Customers ASC 605, Revenue Recognition The Company adopted ASC 606 in the first quarter of 2018 using the modified retrospective method according to which the cumulative effect of initially applying ASC 606 is recognized at the date of initial application, and elected to utilize a practical expedient and did not restate contracts that were completed as of the date of adoption. Since the Company has concluded its performance obligations and has completed recognizing revenue under the 2015 CFFT Award in the third quarter of 2017 (See Note 9), there was no cumulative effect to record at the date of the Company’s adoption of ASC 606 and no revenue to recognize for the first quarter of 2018 related to the 2015 CFFT Award. Revenue for the quarter and the year ended December 31, 2018 was $1,927,306 and $4,822,272, respectively, recognized in accordance with ASC 606 and pertains only to the 2018 CFF Award discussed in Note 9. The total impact to revenue as a result of the adoption of ASC 606 was higher revenue of approximately $325,000 for the quarter ended December 31, 2018 and lower revenue of approximately $201,000 for the year ended December 31, 2018. The Company will assess any new agreements it enters into under ASC 606, including whether such agreements fall under the scope of such standard. This standard applies to all contracts with customers, except for contracts that are within the scope of other standards, such as leases, insurance, collaboration arrangements and financial instruments. Under ASC 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of ASC 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations, and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. Revenue associated with the 2018 CFF Award performance obligation is being recognized as revenue as the research and development services are provided using an input method, according to the costs incurred as related to the research and development activities and the costs expected to be incurred in the future to satisfy the performance obligation. The transfer of control occurs over this time period and, in management’s judgment, is the best measure of progress towards satisfying the performance obligation. The research and development services related to this performance obligation are expected to be performed over an approximately two and a half-year period expected to be completed in the second quarter of 2020. Amounts received prior to revenue recognition are recorded as deferred revenue. Amounts expected to be recognized as revenue within the 12 months following the balance sheet date are classified as current portion of deferred revenue in the accompanying consolidated balance sheets. Amounts not expected to be recognized as revenue within the 12 months following the balance sheet date would be classified as deferred revenue, net of current portion. Amounts recognized as revenue, but not yet received or invoiced are generally recognized as contract assets. Accounting for Leases In February 2016, the FASB issued ASU No . Leases (Topic 842), . Nonemployee Share-Based Payment Accounting In June 2018, the FASB issued ASU 2018-07, Compensation-Stock Compensation (Topic 718), Improvements to Nonemployee Share-Based Payment Accounting Collaborative Arrangements In November 2018, the FASB issued ASU 2018-08, Collaborative Arrangements (Topic 808): Clarifying the Interaction between Topic 808 and Topic 606 . ASU 2018-08 clarifies the interaction between the accounting guidance for collaborative arrangements and revenue from contracts with customers. . Early adoption, including adoption in any interim period, is permitted. The Company is currently .

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Schedule of Cash and Cash Equivalents and Restricted Cash	Cash, cash equivalents, and restricted cash consists of the following: December 31, 2018 2017 Cash $ 808,943 $ 206,510 Money market fund 40,939,525 62,330,985 Cash and cash equivalents 41,748,468 62,537,495 Restricted cash — 158,991 Total cash, cash equivalents, and restricted cash shown in the statement of cash flows $ 41,748,468 $ 62,696,486
Schedule of Computation of Basic and Diluted Earnings Per Share	The following table sets forth the computation of basic and diluted earnings per share for the years ended December 31, 2018 and 2017: Years Ended December 31, 2018 2017 Basic and diluted net loss per share of common stock: Net loss $ (55,672,139 ) $ (32,421,612 ) Weighted average shares of common stock outstanding 56,999,741 50,176,953 Net loss per share of common stock-basic and diluted $ (0.98 ) $ (0.65 )
Schedule of Potentially Dilutive Securities Excluded from Computation of Dilutive Weighted Average Shares Outstanding	The impact of the following potentially dilutive securities outstanding as of December 31, 2018 and 2017 have been excluded from the computation of dilutive weighted average shares outstanding as the inclusion would be antidilutive. December 31, 2018 2017 Warrants 2,283,500 1,288,500 Stock options 9,593,990 7,844,966 11,877,490 9,133,466

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Summary of Property and Equipment	Property and Equipment consisted of the following: December 31, 2018 2017 Computer hardware and software $ 431,637 $ 136,522 Office furniture and equipment 914,742 287,048 Leasehold improvements 2,025,410 191,244 Construction in progress — 1,181,730 Property and equipment, gross 3,371,789 1,796,544 Less: accumulated depreciation (666,583 ) (363,889 ) Property and equipment, net $ 2,705,206 $ 1,432,655

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2018
Schedule of Future Minimum Capital Lease Commitments	Pursuant to the terms of this capital lease agreement, the future minimum capital lease commitments are as follows as of December 31, 2018: Total future minimum lease payments – end in 2019 $ 378 Less: interest (3 ) Future capital lease obligations 375 Less: current portion (375 ) Long-term portion $ —
August 2017 Lease Agreement [Member]
Schedule of Future Minimum Rent Commitments	Pursuant to the terms of the Company’s non-cancelable lease agreements in effect at December 31, 2018, the future minimum rent commitments are as follows: 2019 $ 623,958 2020 784,243 2021 830,600 2022 855,150 2023 879,699 Thereafter 1,055,639 Total $ 5,029,289
February 2019 Lease Agreement [Member]
Schedule of Future Minimum Rent Commitments	The future minimum rent commitments for the Total Premises are estimated to be approximately as follows: 2019 $ 678,000 2020 1,288,000 2021 1,592,000 2022 1,640,000 2023 1,687,000 Thereafter 5,036,000 Total $ 11,921,000

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2018
Payables and Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consisted of the following: December 31, 2018 2017 Accrued clinical operations and trials costs $ 4,914,881 $ 2,003,799 Accrued product development costs 2,222,093 1,255,439 Accrued compensation 2,253,621 1,335,672 Accrued other 460,596 146,609 Total $ 9,851,191 $ 4,741,519

Development Awards and Deferr_2

Development Awards and Deferred Revenue (Tables)	12 Months Ended
	Dec. 31, 2018
Development Awards And Deferred Revenue
Schedule of Roll Forward Deferred Revenue	A roll forward of deferred revenue for the year ended December 31, 2018 is presented below: December 31, 2018 Beginning balance $ — Billing to CFF upon achievement of milestones 12,500,000 Fair value of CFF Warrant (6,215,225 ) Recognition of revenue (4,822,272 ) Ending balance $ 1,462,503

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Components of Net Deferred Tax Asset	Significant components of the Company’s net deferred tax asset are as follows: December 31, 2018 2017 NOL carryforward $ 22,273,661 $ 15,229,127 Foreign net operating loss carryforward 3, 616,502 — Tax credits 2,793,247 1,213,347 Stock based compensation 3,381,969 1,724,248 Accrued expenses 660,427 45,654 Other temporary differences 186,069 116,292 Subtotal 32,911,875 18,328,668 Valuation allowance (32,911,875 ) (18,328,668 ) Net deferred tax asset $ — $ —
Schedule of Effective Income Tax Rate Reconciliation	Income tax benefits computed using the federal statutory income tax rate differs from the Company’s effective tax rate primarily due to the following: December 31, 2018 2017 Tax provision at statutory rate % 21.00 % 34.00 % State taxes, net of federal benefit % 5.42 % 5.66 % Permanent differences % -2.00 % -2.05 % Foreign expected tax 9.85 % — % Tax credits % 4.31 % 1.59 % Income tax rate change % — % -24.11 % Other % 1.14 % 0.60 % Increase in valuation reserve % -39.72 % -15.69 % Total % 0.00 % 0.00 %

Stock Options (Tables)

Stock Options (Tables)	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Assumptions Used Principally in Determining Fair Value of Options Granted	The weighted average assumptions used principally in determining the fair value of options granted to employees were as follows: 2018 2017 Risk free interest rate % 2.53 % 2.12 % Expected dividend yield % 0 % 0 % Expected term in years 6.25 6.25 Expected volatility % 87.70 % 86.01 % Estimated forfeiture rate % 5.00 % 5.00 %
Summary of Option Activity	A summary of option activity for years ended December 31, 2018 and 2017 is presented below: Options Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term in Years Intrinsic Value Outstanding at December 31, 2016 6,610,179 $ 2.54 Granted 1,681,500 $ 8.28 Exercised (272,734 ) $ 0.67 Forfeited (173,979 ) $ 6.53 Outstanding at December 31, 2017 7,844,966 $ 3.75 Granted 2,378,500 $ 7.58 Exercised (139,069 ) $ 2.50 Forfeited (490,407 ) $ 7.85 Outstanding at December 31, 2018 9,593,990 $ 4.51 7.23 $ 22,510,816 Exerciseable at December 31, 2018 5,967,701 $ 2.87 6.43 $ 20,691,512
Summary of Non-Vested Stock Options	As summary of non-vested stock options for the years ended December 31, 2018 and 2017 is presented below: Options Shares Weighted Average Fair Value Non-vested at December 31, 2016 3,826,274 $ 2.86 Granted 1,681,500 $ 6.22 Vested (2,003,806 ) $ 2.60 Forfeited (173,979 ) $ 5.03 Nonvested at December 31, 2017 3,329,989 $ 4.61 Granted 2,378,500 $ 5.63 Vested (1,643,772 ) $ 3.98 Forfeited (438,428 ) $ 5.91 Non-vested at December 31, 2018 3,626,289 $ 5.32

Warrants (Tables)

Warrants (Tables)	12 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Weighted Average Assumption of Warrants	Risk free interest rate 2.60 % Expected dividend yield 0 % Expected term in years 7.00 Expected volatility 83.5 %

Liquidity (Details Narrative)

Liquidity (Details Narrative) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Accumulated deficit	$ (121,370,240)	$ (65,698,101)
Cash and cash equivalents	41,748,468	62,537,495
Proceeds from sale of stock	12,052,645	$ 78,891,699
Kaken Pharmaceutical Co., Ltd. [Member]
Upfront payment, recieved from related party	27,000,000
Cystic Fibrosis Foundation [Member] | Investment Agreement [Member]
Proceeds from Royalty	$ 2,700,000
Upfront payment, percentage	10.00%
Cystic Fibrosis Foundation [Member] | Investment Agreement [Member] | January 2019 Offering [Member]
Proceeds from sale of stock	$ 37,600,000

Significant Accounting Polici_4

Significant Accounting Policies (Details Narrative)	3 Months Ended	12 Months Ended
	Dec. 31, 2018USD ($)	Dec. 31, 2018USD ($)Segment	Dec. 31, 2017USD ($)
Significant Accounting Policies [Line Items]
Marketable investments
Operating segments | Segment		1
Cash	808,943	$ 808,943	206,510
Property and equipment, net	2,705,206	$ 2,705,206	1,432,655
Valuation allowance		100.00%
Uncertain tax position
Impairment charges
Revenues		4,822,272	2,440,195
ASC 606 [Member] | Higher Revenue [Member]
Significant Accounting Policies [Line Items]
Revenues	325,000
ASC 606 [Member] | Lower Revenue [Member]
Significant Accounting Policies [Line Items]
Revenues	201,000
2018 CFF Award [Member] | ASC 606 [Member]
Significant Accounting Policies [Line Items]
Revenues	1,927,306	$ 4,822,272
Computer Hardware and Software [Member]
Significant Accounting Policies [Line Items]
Estimated useful life of all property and equipment		3 years
United Kingdom [Member]
Significant Accounting Policies [Line Items]
Cash held in subsidiary	702,000	$ 702,000
Cash	702,000	702,000
Prepaid expenses	1,183,000	1,183,000
Other assets	28,000	28,000
Property and equipment, net	54,000	$ 54,000
Corporate Credit Cards [Member]
Significant Accounting Policies [Line Items]
Restricted cash			108,991
Stand-by Letter of Credit [Member]
Significant Accounting Policies [Line Items]
Restricted cash			$ 50,000
Maximum [Member]
Significant Accounting Policies [Line Items]
Cash equivalents maturity period		3 months
Maximum [Member] | January 01, 2019 [Member]
Significant Accounting Policies [Line Items]
Operating lease liability	4,200,000	$ 4,200,000
Operating lease, right of use asset	2,600,000	$ 2,600,000
Maximum [Member] | Office Furniture and Equipment [Member]
Significant Accounting Policies [Line Items]
Estimated useful life of all property and equipment		5 years
Minimum [Member]
Significant Accounting Policies [Line Items]
Marketable investments maturity period		3 months
Minimum [Member] | January 01, 2019 [Member]
Significant Accounting Policies [Line Items]
Operating lease liability	3,400,000	$ 3,400,000
Operating lease, right of use asset	$ 2,100,000	$ 2,100,000
Minimum [Member] | Office Furniture and Equipment [Member]
Significant Accounting Policies [Line Items]
Estimated useful life of all property and equipment		3 years

Significant Accounting Polici_5

Significant Accounting Policies - Schedule of Cash and Cash Equivalents and Restricted Cash (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Cash	$ 808,943	$ 206,510
Money market fund	40,939,525	62,330,985
Cash and cash equivalents	41,748,468	62,537,495
Restricted cash		158,991
Total cash, cash equivalents, and restricted cash shown in the statement of cash flows	$ 41,748,468	$ 62,696,486	$ 15,192,257

Significant Accounting Polici_6

Significant Accounting Policies - Schedule of Computation of Basic and Diluted Earnings Per Share (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Net loss	$ (55,672,139)	$ (32,421,612)
Weighted average shares of common stock outstanding	56,999,741	50,176,953
Net loss per share of common stock-basic and diluted	$ (0.98)	$ (0.65)

Significant Accounting Polici_7

Significant Accounting Policies - Schedule of Potentially Dilutive Securities Excluded from Computation of Dilutive Weighted Average Shares Outstanding (Details) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from computation of dilutive weighted average shares outstanding	11,877,490	9,133,466
Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from computation of dilutive weighted average shares outstanding	2,283,500	1,288,500
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from computation of dilutive weighted average shares outstanding	9,593,990	7,844,966

License Agreement (Details Narr

License Agreement (Details Narrative) - USD ($)	Sep. 20, 2018	Sep. 30, 2018	Dec. 31, 2018
Research and Development Expense [Member]
Upfront cash payment		$ 250,000
Potential milestone payments			$ 18,400,000
Jenrin Agreement [Member]
Upfront cash payment	$ 250,000
Potential milestone payments	$ 18,400,000

Property and Equipment (Details

Property and Equipment (Details Narrative)	1 Months Ended		3 Months Ended	12 Months Ended
	Feb. 28, 2018ft²	Sep. 30, 2016ft²	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 30, 2015USD ($)
Property, Plant and Equipment [Line Items]
Depreciation expense				$ 493,938	$ 255,652
Write off of fully amortized leasehold improvements			$ 191,244	191,244
Area of office space | ft²	32,733	4,088
Cost of machine				$ 3,371,789	$ 1,796,544
Copier Machine [Member]
Property, Plant and Equipment [Line Items]
Cost of machine						$ 12,000
Lease term						3 years

Property and Equipment - Summar

Property and Equipment - Summary of Property and Equipment (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 3,371,789	$ 1,796,544
Less: accumulated depreciation	(666,583)	(363,889)
Property and equipment, net	2,705,206	1,432,655
Computer Hardware and Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	431,637	136,522
Office Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	914,742	287,048
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	2,025,410	191,244
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross		$ 1,181,730

Commitments and Contingencies_2

Commitments and Contingencies (Details Narrative)	Aug. 21, 2017USD ($)ft²	Feb. 28, 2018ft²	Sep. 30, 2016USD ($)ft²	Dec. 31, 2018USD ($)ft²	Dec. 31, 2017USD ($)
Commitment And Contingencies [Line Items]
Area of office space | ft²		32,733	4,088
Rent expense				$ 587,963	$ 356,547
August 2017 Lease Agreement [Member]
Commitment And Contingencies [Line Items]
Area of office space | ft²	32,733
Leasehold improvements	$ 1,080,189
Irrevocable letter of credit	400,000
Unsecured letter of credit	400,000
Incurred interest expense				$ 7,431	$ 9,743
August 2017 Lease Agreement [Member] | First Year [Member]
Commitment And Contingencies [Line Items]
Rent expense	470,000
August 2017 Lease Agreement [Member] | Seventh Year [Member]
Commitment And Contingencies [Line Items]
Rent expense	908,000
August 2017 Lease Agreement [Member] | Third Anniversary [Member]
Commitment And Contingencies [Line Items]
Irrevocable letter of credit	300,000
August 2017 Lease Agreement [Member] | Fourth Anniversary [Member]
Commitment And Contingencies [Line Items]
Irrevocable letter of credit	$ 200,000
February 2019 Lease Agreement [Member] | February 26, 2019 [Member] | New Premises [Member]
Commitment And Contingencies [Line Items]
Area of office space | ft²				30,023
Lease term, description				The commencement date for the New Premises is expected to occur no later than August 1, 2019
February 2019 Lease Agreement [Member] | February 26, 2019 [Member] | Total Premises [Member]
Commitment And Contingencies [Line Items]
Area of office space | ft²				62,756
Lease term, description				The lease term for the Total Premises is October 31, 2026.
Capital Lease Agreement [Member]
Commitment And Contingencies [Line Items]
Capital lease term				3 years
September 2016 Amendment [Member]
Commitment And Contingencies [Line Items]
Area of office space | ft²			10,414
Operating lease expiration date			Jan. 31, 2021
Standby letters of credit			$ 50,000

Commitments and Contingencies -

Commitments and Contingencies - Schedule of Future Minimum Rent Commitments (Details)	Dec. 31, 2018USD ($)
August 2017 Lease Agreement [Member]
2019	$ 623,958
2020	784,243
2021	830,600
2022	855,150
2023	879,699
Thereafter	1,055,639
Total	5,029,289
February 2019 Lease Agreement [Member]
2019	678,000
2020	1,288,000
2021	1,592,000
2022	1,640,000
2023	1,687,000
Thereafter	5,036,000
Total	$ 11,921,000

Commitments and Contingencies_3

Commitments and Contingencies - Schedule of Future Minimum Capital Lease Commitments (Details) - Copier Machine [Member]	Dec. 31, 2018USD ($)
Commitment And Contingencies [Line Items]
Total future minimum lease payments - end in 2019	$ 378
Less: interest	(3)
Future capital lease obligations	375
Less: current portion	(375)
Long-term portion

Notes Payable (Details Narrativ

Notes Payable (Details Narrative) - USD ($)	1 Months Ended			12 Months Ended
	Nov. 30, 2018	Nov. 30, 2017	Oct. 31, 2016	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Proceeds from issuance of notes payable				$ 491,629	$ 415,265
Insurance Policy [Member]
Debt Instrument [Line Items]
Prepaid expenses and other current assets				$ 441,875	$ 368,976
Loan Agreement [Member]
Debt Instrument [Line Items]
Proceeds from issuance of notes payable	$ 491,629	$ 415,265	$ 348,750
Monthly principal and interest payments	$ 49,857	$ 41,975	$ 39,114
Monthly loan payments term	10 months	10 months	9 months
Annual interest rate	3.07%	2.35%	2.25%

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Payables and Accruals [Abstract]
Accrued clinical operations and trials costs	$ 4,914,881	$ 2,003,799
Accrued product development costs	2,222,093	1,255,439
Accrued compensation	2,253,621	1,335,672
Accrued other	460,596	146,609
Total	$ 9,851,191	$ 4,741,519

Development Awards and Deferr_3

Development Awards and Deferred Revenue (Details Narrative) - USD ($)	Jan. 26, 2018	Apr. 20, 2015	Dec. 31, 2018	Dec. 31, 2017	Nov. 30, 2017	Jan. 31, 2017	Aug. 31, 2016	Nov. 30, 2015	May 31, 2015
Development Award [Line Items]
Amount received upon achievement			$ 1,462,503
Revenue			$ 4,822,272	2,440,195
Warrant exercisable shares of common stock			5,000
Additional paid in capital, fair value of warrant issued			$ 6,215,225
Kaken Pharmaceutical Co., Ltd. [Member]
Development Award [Line Items]
Upfront payment, received from related party			27,000,000
Cystic Fibrosis Foundation Warrants [Member]
Development Award [Line Items]
Revenue			18,784,775
Warrant to purchase of common stock	1,000,000
Warrant exercisable price per share	$ 13.20
Warrant exercisable shares of common stock	500,000
Warrant expires date	Jan. 26, 2025
Additional paid in capital, fair value of warrant issued			6,215,225
Maximum [Member]
Development Award [Line Items]
Amount received upon achievement			12,500,000
2015 CFFT Award Agreement [Member]
Development Award [Line Items]
Amount received upon achievement					$ 500,000	$ 1,000,000	$ 1,000,000	$ 1,250,000	$ 1,250,000
Revenue				$ 2,440,195
2015 CFFT Award Agreement [Member] | Oral Anti-inflammatory Drug [Member]
Development Award [Line Items]
Amount received upon achievement		$ 5,000,000
2015 CFFT Award Agreement [Member] | Lenabasum [Member] | Upon Reaching the Sales Target [Member]
Development Award [Line Items]
Payment due period after the first commercial sale		90 days
Royalty payment, sales target		$ 500,000,000
2015 CFFT Award Agreement [Member] | Maximum [Member]
Development Award [Line Items]
Development award received		5,000,000
2015 CFFT Award Agreement [Member] | Maximum [Member] | Lenabasum [Member] | Upon Commercialization of the Product [Member]
Development Award [Line Items]
Royalty payable		25,000,000
2015 CFFT Award Agreement [Member] | Maximum [Member] | Lenabasum [Member] | Upon Reaching the Sales Target [Member]
Development Award [Line Items]
Royalty payable		5,000,000
2015 CFFT Award Agreement [Member] | Maximum [Member] | Lenabasum [Member] | Upon Transfer Sale or Licensing [Member]
Development Award [Line Items]
Royalty payable		$ 15,000,000
Cystic Fibrosis Program Related Investment Agreement [Member] | Maximum [Member]
Development Award [Line Items]
Development award received	$ 25,000,000
Investment Agreement [Member]
Development Award [Line Items]
Revenue			4,822,272
Reclassified to contract asset and classified in prepaid expenses			25,000,000
Investment Agreement [Member] | Cystic Fibrosis Foundation [Member]
Development Award [Line Items]
Proceeds from Royalty			2,700,000
Investment Agreement [Member] | Kaken Pharmaceutical Co., Ltd. [Member] | 2018 CFF Award [Member]
Development Award [Line Items]
Proceeds from Royalty			2,700,000
Upfront payment, received from related party			27,000,000
Investment Agreement [Member] | Phase 2b Clinical Trial [Member]
Development Award [Line Items]
Amount received upon achievement			$ 12,500,000
Investment Agreement [Member] | Cystic Fibrosis Foundation Warrants [Member]
Development Award [Line Items]
Warrant exercisable shares of common stock	500,000
Collaboration Agreement [Member] | Cystic Fibrosis Foundation [Member]
Development Award [Line Items]
Royalty payment percentage			10.00%

Development Awards and Deferr_4

Development Awards and Deferred Revenue - Schedule of Roll Forward Deferred Revenue (Details)	12 Months Ended
	Dec. 31, 2018USD ($)
Development Awards And Deferred Revenue
Deferred revenue, beginning balance
Billing to CFF upon achievement of milestones	12,500,000
Fair value of CFF Warrant	(6,215,225)
Recognition of revenue	(4,822,272)
Deferred revenue, ending balance	$ 1,462,503

Income Taxes (Details Narrative

Income Taxes (Details Narrative) - USD ($)	Dec. 22, 2017	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Line Items]
Net operating loss carryforwards		$ 82,545,000	$ 56,536,000
Net operating loss carryforwards excess stock-based compensation			1,432,000
Research and development tax credit carryforwards		2,926,000	1,283,000
Deferred tax assets valuation allowance increase		14,583,207	5,088,343
Uncertain tax position
Income tax description		On December 22, 2017, the legislation commonly referred to as the Tax Cut and Jobs Act (the "Tax Act") was enacted into law. The Tax Act, among other things, contains significant changes to corporate taxation, including reduction of the corporate tax rate from a top marginal rate of 35% to a flat rate of 21%; limitation of the tax deduction for interest expense to 30% of adjusted earnings (except for certain small businesses)
Corporate tax rate percentage		21.00%	34.00%
Taxable income percentage		0.00%	0.00%
Federal [Member]
Income Taxes [Line Items]
Operating loss carryforwards expiration year		2029
Massachusett [Member]
Income Taxes [Line Items]
Net operating loss carryforwards		$ 78,152,000	$ 53,110,000
The Tax Cut and Jobs Act of 2017 [Member]
Income Taxes [Line Items]
Taxable income percentage			80.00%
Deferred tax asset			$ 7,815,832
The Tax Cut and Jobs Act of 2017 [Member] | Orphan Drug Credit [Member] | Maximum [Member]
Income Taxes [Line Items]
Corporate tax rate percentage		50.00%
The Tax Cut and Jobs Act of 2017 [Member] | Orphan Drug Credit [Member] | Minimum [Member]
Income Taxes [Line Items]
Corporate tax rate percentage		25.00%
The Tax Cut and Jobs Act of 2017 [Member] | Interest Expense [Member]
Income Taxes [Line Items]
Corporate tax rate percentage	30.00%

Income Taxes - Components of Ne

Income Taxes - Components of Net Deferred Tax Asset (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Deferred Tax Assets, Net [Abstract]
NOL carryforward	$ 22,273,661	$ 15,229,127
Foreign net operating loss carryforward	3,616,502
Tax credits	2,793,247	1,213,347
Stock based compensation	3,381,969	1,724,248
Accrued expenses	660,427	45,654
Other temporary differences	186,069	116,292
Subtotal	32,911,875	18,328,668
Valuation allowance	(32,911,875)	(18,328,668)
Net deferred tax asset

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Tax provision at statutory rate	21.00%	34.00%
State taxes, net of federal benefit	5.42%	5.66%
Permanent differences	(2.00%)	(2.05%)
Foreign expected tax	9.85%
Tax credits	4.31%	1.59%
Income tax rate change		(24.11%)
Other	1.14%	0.60%
Increase in valuation reserve	(39.72%)	(15.69%)
Total	0.00%	0.00%

Common Stock (Details Narrative

Common Stock (Details Narrative) - USD ($)	Jan. 05, 2018	Oct. 26, 2017	Feb. 28, 2017	Nov. 30, 2017	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Common stock, shares authorized						150,000,000	150,000,000
Common stock, par value						$ 0.0001	$ 0.0001
Common stock, shares issued						57,247,496	55,603,427
Common stock, shares outstanding						57,247,496	55,603,427
Gross proceeds from sale of stock						$ 12,052,645	$ 78,891,699
Stock issuance cost						$ 464,680	$ 2,969,837
Issuance of common stock upon exercise of stock options, shares						139,069	272,734
Warrants [Member]
Issuance of common stock upon exercise of warrants, shares						144,069	272,734
Equity Option [Member]
Issuance of common stock upon exercise of stock options, shares						144,069	272,734
Stock Option and Warrants [Member]
Proceeds from exercise of stock options						$ 352,645	$ 189,490
At the Market Offering [Member] | Maximum [Member]
Number of common stock value sold	$ 50,000,000
Institutional Investors [Member]
Aggregate common stock sold, shares		4,650,000
Purchase price per share		$ 7
Gross proceeds from sale of stock		$ 32,550,000		$ 4,589,550
Stock issuance cost		$ 2,184,000
Options to purchase shares of common stock		697,500
Securities Purchase Agreement [Member] | Institutional and Accredited Investors [Member]
Aggregate common stock sold, shares			3,887,815
Purchase price per share			$ 7
Gross proceeds from sale of stock			$ 27,214,705
Stock issuance cost			$ 36,291
January 2018 Sales Agreement [Member] | Institutional Investor [Member]
Aggregate common stock sold, shares					1,500,000
Gross proceeds from sale of stock					$ 11,200,000
January 2018 Sales Agreement [Member] | Institutional Investor [Member] | Remainder of 2018 and Through February 8, 2019 [Member]
Aggregate common stock sold, shares
Gross proceeds from sale of stock
Sales Agreement [Member]
Aggregate common stock sold, shares							1,413,633
Gross proceeds from sale of stock							$ 13,268,208

Stock Options (Details Narrativ

Stock Options (Details Narrative) - USD ($)	1 Months Ended	12 Months Ended
	Apr. 30, 2014	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 7,609,508	$ 5,694,489
Weighted average grant-date fair value, options granted		$ 5.63	$ 6.22
Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant-date fair value, options granted		$ 5.63	$ 6.22
Average intrinsic value of options exercised		$ 543,060	$ 2,092,964
Total unrecognized compensation expense		$ 15,400,414
Share-based compensation expense, not yet recognized weighted average period of recognition		2 years 6 months 18 days
Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 7,500,888	4,640,646
Non-Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 108,620	$ 1,053,843
Option granted expected forfeiture rate			5.00%
Non-Employees [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option granted expected term			4 years 10 months 28 days
Option granted risk free interest rate			2.12%
Option granted expected dividend yield			$ 0
Option granted expected volatility			85.58%
Non-Employees [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option granted expected term			9 years 10 months 28 days
Option granted risk free interest rate			2.38%
Option granted expected dividend yield			$ 0
Option granted expected volatility			89.58%
2014 Equity Incentive Plan [Member] | Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate common stock available for stock options granted, shares		15,543,739
Shares available for grant		5,072,241
Stock option vesting term		4 years
Stock option expiration period		10 years
Option granted expected term		6 years 2 months 30 days
Evergreen Provision [Member] | 2014 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of outstanding common shares	7.00%		7.00%
Increase in number of shares of common stock available for issuance			2,500,000
Evergreen Provision [Member] | 2014 Equity Incentive Plan [Member] | January 1, 2019 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of outstanding common shares		7.00%
Increase in number of shares of common stock available for issuance		3,000,000
Aggregate common stock available for stock options granted, shares		18,543,739
Shares available for grant		8,072,241

Stock Options - Summary of Assu

Stock Options - Summary of Assumptions Used Principally in Determining Fair Value of Options Granted (Details) - Employee Stock Option [Member]	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk free interest rate	2.53%	2.12%
Expected dividend yield	0.00%	0.00%
Expected term in years	6 years 2 months 30 days	6 years 2 months 30 days
Expected volatility	87.70%	86.01%
Estimated forfeiture rate	5.00%	5.00%

Stock Options - Summary of Opti

Stock Options - Summary of Option Activity (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Shares, Outstanding, Beginning balance	7,844,966	6,610,179
Shares, Granted	2,378,500	1,681,500
Shares, Exercised	(139,069)	(272,734)
Shares, Forfeited	(490,407)	(173,979)
Shares, Outstanding, Ending balance	9,593,990	7,844,966
Shares, Exercisable	5,967,701
Weighted Average Exercise Price, Outstanding, Beginning balance	$ 3.75	$ 2.54
Weighted Average Exercise Price, Granted	7.58	8.28
Weighted Average Exercise Price, Exercised	2.50	0.67
Weighted Average Exercise Price, Forfeited	7.85	6.53
Weighted Average Exercise Price, Outstanding, Ending balance	4.51	$ 3.75
Weighted Average Exercise Price, Exercisable	$ 2.87
Weighted Average Remaining Contractual Term in Years, Outstanding	7 years 2 months 23 days
Weighted Average Remaining Contractual Term in Years, Exercisable	6 years 5 months 5 days
Average Intrinsic Value, Outstanding	$ 22,510,816
Average Intrinsic Value, Exercisable	$ 20,691,512

Stock Options - Summary of Non-

Stock Options - Summary of Non-Vested Stock Options (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Shares Non-vested , Beginning balance	3,329,989	3,826,274
Shares, Granted	2,378,500	1,681,500
Shares, Vested	(1,643,772)	(2,003,806)
Shares, Forfeited	(438,428)	(173,979)
Shares Outstanding, Ending balance	3,626,289	3,329,989
Weighted Average Fair Value Non Vested, Beginning Balance	$ 4.61	$ 2.86
Weighted Average Fair Value, Granted	5.63	6.22
Weighted Average Fair Value, Vested	3.98	2.60
Weighted Average Fair Value, Forfeited	5.91	5.03
Weighted Average Fair Value Non Vested, Ending Balance	$ 5.32	$ 4.61

Warrants (Details Narrative)

Warrants (Details Narrative) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Class of Warrant or Right [Line Items]
Warrants outstanding to purchase of common stock shares	5,000
Proceeds from exercise of warrants	$ 5,000
Fair value of warrants issued	$ 6,215,225
CFF Warrant [Member]
Class of Warrant or Right [Line Items]
Warrants outstanding to purchase of common stock shares	1,000,000
Weighted average exercise price of warrants	$ 13.20
Number of warrants exercisable for common stock	500,000
Investment Agreement [Member] | CFF Warrant [Member]
Class of Warrant or Right [Line Items]
Warrants outstanding to purchase of common stock shares	2,283,500
Weighted average exercise price of warrants	$ 6.34
Weighted average remaining life of warrants	2 years 10 months 21 days
Number of warrants exercisable for common stock	500,000
Warrants expiration term	Jan. 26, 2025

Warrants - Schedule of Weighted

Warrants - Schedule of Weighted Average Assumption of Warrants (Details) - Warrants [Member]	12 Months Ended
	Dec. 31, 2018
Class of Warrant or Right [Line Items]
Risk free interest rate	2.60%
Expected dividend yield	0.00%
Expected term in years	7 years
Expected volatility	83.50%

Related Party Transactions (Det

Related Party Transactions (Details Narrative) - USD ($)	1 Months Ended	3 Months Ended	12 Months Ended
	Sep. 20, 2016	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Options granted exercise price			$ 7.58	$ 8.28
Stock-based compensation expense		$ 171,000			$ 222,000
Stock Option [Member]
Related Party Transaction [Line Items]
Stock-based compensation expense
2014 Equity Compensation Plan [Member]
Related Party Transaction [Line Items]
Options to purchase, shares	50,000
Option vested percentage	50.00%
Options granted exercise price	$ 7.14
Orchestra Medical Ventures LLC [Member] | 2016 Consulting Agreement [Member]
Related Party Transaction [Line Items]
Agreement expiry date	Mar. 20, 2017
Cash compensation amount	$ 100,000

Subsequent Events (Details Narr

Subsequent Events (Details Narrative)	Jan. 30, 2019USD ($)$ / sharesshares	Jan. 03, 2019USD ($)	Jan. 01, 2019shares	Apr. 30, 2014	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)shares	Feb. 26, 2019ft²
Proceeds from issuance of common stock					$ 12,052,645	$ 78,891,699
Stock issuance cost					464,680	$ 2,969,837
Evergreen Provision [Member] | 2014 Equity Incentive Plan [Member]
Increased number of shares of common stock available for issuance | shares						2,500,000
Percentage of outstanding common shares				7.00%		7.00%
Kaken Pharmaceutical Co., Ltd. [Member]
Upfront payment, received from related party					$ 27,000,000
Subsequent Event [Member] | New Premises [Member]
Area of land for office space | ft²							30,023
Subsequent Event [Member] | Total Premises [Member]
Area of land for office space | ft²							62,756
Subsequent Event [Member] | Public Offering [Member]
Number of common stock share sold | shares	6,198,500
Purchase price of shares | $ / shares	$ 6.50
Proceeds from issuance of common stock	$ 40,290,250
Stock issuance cost	$ 2,667,000
Subsequent Event [Member] | Public Offering [Member] | Underwriters' Option [Member]
Number of common stock share sold | shares	808,500
Subsequent Event [Member] | Collaboration and License Agreement [Member] | First Quarter of 2019 [Member]
Upfront payment, received from related party		$ 27,000,000
Subsequent Event [Member] | Evergreen Provision [Member] | 2014 Equity Incentive Plan [Member]
Increases in number of shares of common stock available for issuance, minimum percentage of outstanding common stock			7.00%
Increased number of shares of common stock available for issuance | shares			3,000,000
Percentage of outstanding common shares			7.00%
Total reserve under the plan | shares			18,543,739
Shares available for future grants | shares			80,722,414
Subsequent Event [Member] | Kaken Pharmaceutical Co., Ltd. [Member] | Collaboration and License Agreement [Member]
Upfront payment, received from related party		27,000,000
Consideration received on milestone payments		$ 173,000,000
Royalty term description		Ten (10) years after the first commercial sale of such Licensed Product for such Initial Indication in Japan. The Agreement may be terminated by either party for material breach, upon a party's insolvency or bankruptcy or upon a challenge by one party of any patents of the other party, and Kaken may terminate in specified situations, including for a safety concern or clinical failure, or at its convenience following the second anniversary of the first commercial sale of a Licensed Product in either of the Initial Indications in the Territory, with 180 days' notice.