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Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2019	Aug. 06, 2019
Document and Entity Information [Abstract]
Amendment Flag	false
Document Type	10-Q
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Document Quarterly Report	true
Entity Central Index Key	0001567514
Document Transition Report	false
Current Fiscal Year End Date	--12-31
Document Period End Date	Jun. 30, 2019
Entity Registrant Name	Intra-Cellular Therapies, Inc.
Trading Symbol	ITCI
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	001-36274
Entity Tax Identification Number	36-4742850
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	430 East 29th Street
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10016
City Area Code	646
Local Phone Number	440-9333
Title of 12(b) Security	Common Stock
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		55,173,222

Condensed Consolidated Balance Sheets - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 91,763,368	$ 54,947,502
Investment securities, available-for-sale	193,536,800	292,583,046
Prepaid expenses and other current assets	3,041,730	7,908,133
Total current assets	288,341,898	355,438,681
Property and equipment, net	2,082,933	1,159,766
Right of use assets, net	18,822,482
Deferred tax asset, net	529,218	529,218
Other assets	86,083	78,833
Total assets	309,862,614	357,206,498
Current liabilities:
Accounts payable	5,632,783	13,961,060
Accrued and other current liabilities	18,801,485	20,044,866
Lease liabilities, short-term	2,262,977
Accrued employee benefits	5,829,242	2,293,259
Total current liabilities	32,526,487	36,299,185
Deferred rent	0	3,192,432
Lease liabilities	20,567,765
Total liabilities	53,094,252	39,491,617
Stockholders' equity:
Common stock, $.0001 par value: 100,000,000 shares authorized; 55,186,745 and 54,895,295 shares issued and outstanding at June 30, 2019 and December 31, 2018, respectively	5,519	5,490
Additional paid-in capital	891,183,518	880,753,339
Accumulated deficit	(634,653,119)	(562,376,191)
Accumulated comprehensive gain/(loss)	232,444	(667,757)
Total stockholders' equity	256,768,362	317,714,881
Total liabilities and stockholders' equity	$ 309,862,614	$ 357,206,498

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	55,186,745	54,895,295
Common stock, shares outstanding	55,186,745	54,895,295

Condensed Consolidated Statements of Operations - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Revenues
Costs and expenses:
Research and development	23,728,464	$ 32,439,270	$ 48,719,321	$ 63,142,268
General and administrative	15,442,650	6,728,987	27,147,634	13,110,215
Total costs and expenses	39,171,114	39,168,257	75,866,955	76,252,483
Loss from operations	(39,171,114)	(39,168,257)	(75,866,955)	(76,252,483)
Interest income	1,731,550	1,793,474	3,591,627	3,397,622
Loss before provision for income taxes	(37,439,564)	(37,374,783)	(72,275,328)	(72,854,861)
Income tax expense	1,600	1,600	1,600	1,600
Net loss	$ (37,441,164)	$ (37,376,383)	$ (72,276,928)	$ (72,856,461)
Net loss per common share:
Basic & Diluted	$ (0.68)	$ (0.68)	$ (1.31)	$ (1.33)
Weighted average number of common shares:
Basic & Diluted	55,145,901	54,696,698	55,129,654	54,686,550

Condensed Consolidated Statements of Comprehensive Loss - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net loss	$ (37,441,164)	$ (37,376,383)	$ (72,276,928)	$ (72,856,461)
Other comprehensive income/(loss):
Unrealized gain/(loss) on investment securities	299,894	210,326	900,201	(230,200)
Comprehensive loss	$ (37,141,270)	$ (37,166,057)	$ (71,376,727)	$ (73,086,661)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Condensed Consolidated Statements of Stockholders' Equity - USD ($)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Comprehensive Loss [Member]
Balance at Dec. 31, 2017	$ 454,436,961	$ 5,460	$ 862,479,505	$ (407,248,780)	$ (799,224)
Balance, shares at Dec. 31, 2017		54,597,679
Exercise of stock options and issuances of restricted stock	343,926	$ 10	343,916
Exercise of stock options and issuances of restricted stock, shares		97,935
Stock issued for services	95,408		95,408
Stock issued for services, shares		4,966
Share-based compensation	8,597,808		8,597,808
Net loss	(72,856,461)			(72,856,461)
Other comprehensive income (loss)	(230,200)				(230,200)
Balance at Jun. 30, 2018	390,387,442	$ 5,470	871,516,637	(480,105,241)	(1,029,424)
Balance, shares at Jun. 30, 2018		54,700,580
Balance at Mar. 31, 2018	423,188,955	$ 5,469	867,152,094	(442,728,858)	(1,239,750)
Balance, shares at Mar. 31, 2018		54,694,718
Exercise of stock options and issuances of restricted stock	6,130	$ 1	6,129
Exercise of stock options and issuances of restricted stock, shares		3,162
Stock issued for services	47,709		47,709
Stock issued for services, shares		2,700
Share-based compensation	4,310,705		4,310,705
Net loss	(37,376,383)			(37,376,383)
Other comprehensive income (loss)	210,326				210,326
Balance at Jun. 30, 2018	390,387,442	$ 5,470	871,516,637	(480,105,241)	(1,029,424)
Balance, shares at Jun. 30, 2018		54,700,580
Balance at Dec. 31, 2018	317,714,881	$ 5,490	880,753,339	(562,376,191)	(667,757)
Balance, shares at Dec. 31, 2018		54,895,295
Exercise of stock options and issuances of restricted stock	290,447	$ 28	290,419
Exercise of stock options and issuances of restricted stock, shares		283,722
Stock issued for services	97,120	$ 1	97,119
Stock issued for services, shares		7,728
Share-based compensation	10,042,641		10,042,641
Net loss	(72,276,928)			(72,276,928)
Other comprehensive income (loss)	900,201				900,201
Balance at Jun. 30, 2019	256,768,362	$ 5,519	891,183,518	(634,653,119)	232,444
Balance, shares at Jun. 30, 2019		55,186,745
Balance at Mar. 31, 2019	288,614,426	$ 5,513	885,888,318	(597,211,955)	(67,450)
Balance, shares at Mar. 31, 2019		55,131,125
Exercise of stock options and issuances of restricted stock	259,211	$ 5	259,206
Exercise of stock options and issuances of restricted stock, shares		51,878
Stock issued for services	48,571	$ 1	48,570
Stock issued for services, shares		3,742
Share-based compensation	4,987,424		4,987,424
Net loss	(37,441,164)			(37,441,164)
Other comprehensive income (loss)	299,894				299,894
Balance at Jun. 30, 2019	$ 256,768,362	$ 5,519	$ 891,183,518	$ (634,653,119)	$ 232,444
Balance, shares at Jun. 30, 2019		55,186,745

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Condensed Consolidated Statements of Cash Flows - USD ($)	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows used in operating activities
Net loss	$ (72,276,928)	$ (72,856,461)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	206,409	178,276
Share-based compensation	10,042,641	8,597,808
Stock issued for services	97,120	95,408
Amortization of premiums and discounts on investment securities, net	(646,583)	(234,256)
Changes in operating assets and liabilities:
Prepaid expenses and other assets	4,737,440	(1,015,358)
Accounts payable	(8,328,277)	(794,669)
Accrued liabilities and other	3,230,143	5,451,351
Deferred rent		(20,139)
Net cash used in operating activities	(62,938,035)	(60,598,040)
Cash flows provided by investing activities
Purchases of investments	(25,777,875)	(183,657,067)
Maturities of investments	126,370,905	276,204,604
Purchases of property and equipment	(1,129,576)	(316,492)
Net cash provided by investing activities	99,463,454	92,231,045
Cash flows provided by financing activities
Proceeds from exercise of stock options	290,447	343,926
Net cash provided by financing activities	290,447	343,926
Net increase in cash and cash equivalents	36,815,866	31,976,931
Cash and cash equivalents at beginning of period	54,947,502	37,790,114
Cash and cash equivalents at end of period	91,763,368	$ 69,767,045
Non-cash investing and financing activities
Right of use assets under operating leases	$ 219,703

Organization	6 Months Ended
Organization	Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	1. Organization Intra-Cellular Therapies, Inc. (the “Company”), through its wholly-owned operating subsidiaries, ITI, Inc. (“ITI”) and ITI Limited, is a biopharmaceutical company focused on the discovery and clinical development of innovative, small molecule drugs that address underserved medical needs in neuropsychiatric and neurological disorders by targeting intracellular signaling mechanisms within the central nervous system (“CNS”). The Company’s lead product candidate, lumateperone, is in Phase 3 clinical development as a novel treatment for schizophrenia and bipolar depression. The Company was incorporated in the State of Delaware in August 2012 under the name “Oneida Resources Corp.” Prior to a reverse merger that occurred on August 29, 2013 (the “Merger”), Oneida Resources Corp. was a “shell” company registered under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), with no specific business plan or purpose until it began operating the business of ITI, through the Merger transaction on August 29, 2013. The Company was incorporated in Delaware and focuses primarily on the development of novel drugs for the treatment of neuropsychiatric and neurologic diseases and other disorders of the CNS. In September 2016, the Company licensed certain intellectual property rights to its wholly-owned subsidiary, ITI Limited, which was formed in the third quarter of 2016. Although the license of intellectual property rights did not result in any gain or loss in the consolidated statements of operations, the $125 million of gain related to the transaction helped generate net taxable income for tax purposes in the U.S. and the Company utilized a significant portion of its available federal and state net operating loss carryforwards to offset the majority of this gain. Any taxes incurred related to intercompany transactions were treated as tax expense in the Company’s consolidated statement of operations. In addition to the license, the Company also entered into a research and development agreement with ITI Limited pursuant to which the Company will conduct research and development services related to the license agreement and charge ITI Limited for these services. In order to further its research projects and support its collaborations, the Company will require additional financing until such time, if ever, that revenue streams are sufficient to generate consistent positive cash flow from operations. The Company currently projects that its cash, cash equivalents and investments will be sufficient to fund operating expenses and capital expenditures for a minimum of twelve months from the date that this Quarterly Report was filed. Possible sources of funds include public or private sales of the Company’s equity securities, sales of debt securities, the incurrence of debt from commercial lenders, strategic collaborations, licensing a portion or all of the Company’s product candidates and technology and, to a lesser extent, grant funding. On September 2 , 2016 , the Company filed a universal shelf registration statement on Form S-3, which was declared effective by the Securities and Exchange Commission (the “SEC”) on September 14 , 2016 , on which the Company registered for sale up to $ 350 million of any combination of its common stock, preferred stock, debt securities, warrants, rights, purchase contracts and/or units from time to time and at prices and on terms that the Company may determine. After the public offering in October 2017 , approximately $ 178 million of securities remain available for issuance under this shelf registration statement. This registration statement will remain in effect until September 14 , 2019 . In the third quarter of 2018, the Company completed the rolling submission of its New Drug Application (“NDA”) to the U.S. Food and Drug Administration (“FDA”) for lumateperone, a once-daily, oral investigational medicine with a novel mechanism of action for the treatment of schizophrenia. In the fourth quarter of 2018, the FDA accepted for review the Company’s NDA and assigned a Prescription Drug User Fee Act, or PDUFA, goal date of September 27, 2019, which has been extended to December 27, 2019 . The NDA submission is supported by data from 20 clinical trials and more than 1,900 subjects exposed to lumateperone. Lumateperone received Fast Track designation from the FDA in November 2017 for the treatment of schizophrenia.

Summary of Significant Accounting Policies

6 Months Ended

Jun. 30, 2019

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Basis of Presentation

The accompanying consolidated financial statements of Intra-Cellular Therapies, Inc. and its wholly own subsidiaries have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles set forth in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”). All intercompany accounts and transactions have been eliminated in consolidation. The Company currently operates in one operating segment. Operating segments are defined as components of an enterprise about which separate discrete information is available for the chief operating decision maker, or decision making group, in deciding how to allocate resources and assessing performance. The Company views its operations and manages its business in one segment, which is discovering and developing drugs for the treatment of neurological and psychiatric disorders.

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Although actual results could differ from those estimates, management does not believe that such differences would be material.

Cash and Cash Equivalents

The Company considers all highly liquid investments with a maturity of three months or less from the date of purchase to be cash equivalents. Cash and cash equivalents consist of checking accounts, money market accounts, money market mutual funds, and certificates of deposit with a maturity date of three months or less. The carrying values of cash and cash equivalents approximate the fair market value. Certificates of deposit, commercial paper, corporate notes and corporate bonds with a maturity date of more than three months are classified separately on the balance sheet.

Investment Securities

Investment securities consisted of the following (in thousands):


	June 30, 2019
	Amortized Cost		Unrealized Gains		Unrealized (Losses)			Estimated Fair Value
	(Unaudited)
U.S. Government Agency Securities	$	72,880	$	89	$	(26	)	$	72,943
Certificates of Deposit		3,000		—		—			3,000
Commercial Paper		22,923		11		(2	)		22,932
Corporate Notes/Bonds		94,501		174		(13	)		94,662

	$	193,304	$	274	$	(41	)	$	193,537


	December 31, 2018
	Amortized Cost		Unrealized Gains		Unrealized (Losses)			Estimated Fair Value
U.S. Government Agency Securities	$	124,691	$	24	$	(289	)	$	124,426
FDIC Certificates of Deposit (1)		245		—		—			245
Certificates of Deposit		1,000		—		—			1,000
Commercial Paper		41,317		—		(45	)		41,272
Corporate Notes/Bonds		125,998		7		(365	)		125,640

	$	293,251	$	31	$	(699	)	$	292,583


(1)	“FDIC Certificates of Deposit” consist of deposits that are less than $250,000.

The Company has classified all of its investment securities

available-for-sale,

including those with maturities beyond one year, as current assets on the consolidated balance sheets based on the highly liquid nature of the investment securities and because these investment securities are considered available for use in current operations. As of June 30, 2019 and December 31, 2018, the Company held $12.9 million and $64.6 million, respectively, of

available-for-sale

investment securities with contractual maturity dates more than one year and less than two years.

The Company monitors its investment portfolio for impairment quarterly or more frequently if circumstances warrant. In the event that the carrying value of an investment exceeds its fair value and the decline in value is determined to be other-than-temporary, the Company records an impairment charge within earnings attributable to the estimated loss. In determining whether a decline in the value of an investment is other-than-temporary, the Company evaluates currently available factors that may include, among others: (1) general market conditions; (2) the duration and extent to which fair value has been less than the carrying value; (3) the investment issuer’s financial condition and business outlook; and (4) the Company’s assessment as to whether it is more likely than not that the Company will be required to sell a security prior to recovery of its amortized cost basis. As of June 30, 2019, the aggregate related fair value of investments with unrealized losses was

million and the aggregate amount of unrealized losses was approximately

41,000

. Of the $71 million, $

million has been held in a continuous unrealized loss position for less than 12 months and

million has been held in a continuous loss position for 12 months or longer. The total continuous unrealized loss for investments held for 12 months or longer is approximatel

y $

39,000

as of June 30, 2019. As of December 31, 2018, the Company had approximately

92.1

million of investments with a continuous unrealized loss for 12 months or longer of approximately

345,000

The Company attributes the unrealized gains and losses on the

available-for-sale

securities as of June 30, 2019 and December 31, 2018 to the changes in related market interest rates. The Company does not intend to sell these securities, nor is it more likely than not that the Company will be required to sell them prior to the end of their contractual terms. Furthermore, the Company does not believe that these securities expose the Company to undue market risk or counterparty credit risk. As such, the Company does not consider these securities to be other-than-temporarily impaired.

Fair Value Measurements

The Company applies the fair value method under ASC Topic 820,

Fair Value Measurements and Disclosures

. ASC Topic 820 defines fair value, establishes a fair value hierarchy for assets and liabilities measured at fair value and requires expanded disclosures about fair value measurements. The ASC Topic 820 hierarchy ranks the quality and reliability of inputs, or assumptions, used in the determination of fair value and requires assets and liabilities carried at fair value to be classified and disclosed in one of the following categories based on the lowest level input used that is significant to a particular fair value measurement:

•

Level 1—Fair value is determined by using unadjusted quoted prices that are available in active markets for identical assets and liabilities.

•

Level 2—Fair value is determined by using inputs other than Level 1 quoted prices that are directly or indirectly observable. Inputs can include quoted prices for similar assets and liabilities in active markets or quoted prices for identical assets and liabilities in inactive markets. Related inputs can also include those used in valuation or other pricing models, such as interest rates and yield curves that can be corroborated by observable market data.

•

Level 3—Fair value is determined by inputs that are unobservable and not corroborated by market data. Use of these inputs involves significant and subjective judgments to be made by a reporting entity—e.g., determining an appropriate adjustment to a discount factor for illiquidity associated with a given security.

The Company evaluates financial assets and liabilities subject to fair value measurements on a recurring basis to determine the appropriate level at which to classify them each reporting period. This determination requires the Company to make subjective judgments as to the significance of inputs used in determining fair value and where such inputs lie within the ASC Topic 820 hierarchy.

The Company has no assets or liabilities that were measured using quoted prices for significant unobservable inputs (Level 3 assets and liabilities) as of June 30, 2019 and December 31, 2018. The carrying value of cash held in money market funds of approximately $54.1 million as of June 30, 2019 and $39.6 million as of December 31, 2018 is included in cash and cash equivalents and approximates market value based on quoted market prices (Level 1 inputs). The carrying value of cash held in certificates of deposit of approximately $31.5 million and $7.5 million as of June 30, 2019 and December 31, 2018, respectively, is included in cash and cash equivalents and approximates market value based on quoted market prices (Level 2 inputs).

The fair value measurements of the Company’s cash equivalents and

available-for-sale

investment securities are identified in the following tables (in thousands):


			Fair Value Measurements at Reporting Date Using
	June 30, 2019		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Money Market Funds	$	54,146	$	54,146	$	—	$	—
U.S. Government Agency Securities		72,943		—		72,943		—
FDIC Certificates of Deposit		—		—		—		—
Certificates of Deposit		34,500		—		34,500		—
Commercial Paper		22,932		—		22,932		—
Corporate Notes/Bonds		94,662		—		94,662		—

	$	279,183	$	54,146	$	225,037	$	—


			Fair Value Measurements at Reporting Date Using
	December 31, 2018		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Money Market Funds	$	39,591	$	39,591	$	—	$	—
U.S. Government Agency Securities		124,426		—		124,426		—
FDIC Certificates of Deposit		245		—		245		—
Certificates of Deposit		8,500		—		8,500		—
Commercial Paper		41,272		—		41,272		—
Corporate Notes/Bonds		125,640		—		125,640		—

	$	339,674	$	39,591	$	300,083	$	—

Financial Instruments

The Company considers the recorded costs of its financial assets and liabilities, which consist of certain cash equivalents, prepaid expenses, accounts payable

right of use asset, net,

accrued liabilities

and lease liabilities

, to approximate their fair value because of their relatively short maturities at June 30, 2019 and December 31, 2018. Management believes that the risks associated with its financial instruments are minimal as the counterparties are various corporations, financial institutions and government agencies of high credit standing.

Concentration of Credit Risk

Cash equivalents are held with major financial institutions in the United States. Certificates of deposit, cash and cash equivalents held with banks may exceed the amount of insurance provided on such deposits. Generally, these deposits may be redeemed upon demand and, therefore, bear minimal risk.

Accounts Receivable

Accounts receivable that management has the intent and ability to collect are reported in the balance sheets at outstanding amounts, less an allowance for doubtful accounts. The Company writes off uncollectible receivables when the likelihood of collection is not probable.

The Company evaluates the collectability of accounts receivable on a regular basis. The allowance, if any, is based upon various factors including the financial condition and payment history of customers, an overall review of collections experience on other accounts and economic factors or events expected to affect future collections experience. No allowance was recorded as of June 30, 2019 and December 31, 2018, as the Company has a history of collecting on all its accounts including from government agencies and collaborations funding its research. As of June 30, 2019 and December 31, 2018, the Company did not have accounts receivable.

Property and Equipment

Property and equipment is stated at cost and depreciated on a straight-line basis over estimated useful lives ranging from three to five years. Leasehold improvements are amortized using the straight-line method over the shorter of the estimated useful life of the assets or the term of the related lease. Expenditures for maintenance and repairs are charged to operations as incurred.

When indicators of possible impairment are identified, the Company evaluates the recoverability of the carrying value of its long-lived assets based on the criteria established in ASC Topic 360,

Property, Plant and Equipment

. The Company considers historical performance and anticipated future results in its evaluation of potential impairment. The Company evaluates the carrying value of those assets in relation to the operating performance of the business and undiscounted cash flows expected to result from the use of those assets. Impairment losses are recognized when carrying value exceeds the undiscounted cash flows, in which case management must determine the fair value of the underlying asset. No such impairment losses have been recognized to date.

Research and Development

Except for payments made in advance of services, the Company expenses its research and development costs as incurred. For payments made in advance, the Company recognizes research and development expense as the services are rendered. Research and development costs primarily consist of salaries and related expenses for personnel and resources and the costs of clinical trials. Other research and development expenses include preclinical analytical testing, manufacturing of drug product, outside service providers, materials and consulting fees.

Costs for certain development activities, such as clinical trials, are recognized based on an evaluation of the progress to completion of specific tasks using data such as subject enrollment, clinical site activations or information provided to the Company by its vendors with respect to their actual costs incurred. Payments for these activities are based on the terms of the individual arrangements, which may differ from the pattern of costs incurred, and are reflected in the financial statements as prepaid or accrued research and development expense, as the case may be.

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 flows 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 clinical trial 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 progress of the clinical trial as measured by subject progression and the timing of various aspects of the trial. The Company determines accrual estimates through financial models taking into account various clinical information provided by vendors and discussion with applicable personnel and external service providers as to the progress toward or state of completion of 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, clinical sites 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 three and six months ended June 30, 2019 and 2018, there were no material adjustments to the Company’s prior period estimates of accrued expenses for clinical trials.

Income Taxes

Income taxes are accounted for using the liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the year in which those temporary differences are expected to be recovered or settled.

The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. Valuation allowances are established when necessary to reduce net deferred tax assets to the amount expected to be realized. Income tax expense is the tax payable for the period and the change during the period in deferred tax assets and liabilities. The Company accounts for uncertain tax positions pursuant to ASC Topic 740. Financial statement recognition of a tax position taken or expected to be taken in a tax return is determined based on a

more-likely-than-not

threshold of that position being sustained. If the tax position meets this threshold, the benefit to be recognized is measured as the tax benefit having the highest likelihood of being realized upon ultimate settlement with the taxing authority. The Company recognizes interest accrued related to unrecognized tax benefits and penalties in the provision for income taxes.

On December 22, 2017, President Trump signed into law the “Tax Cuts and Jobs Act” (“TCJA”) that significantly reforms the Internal Revenue Code of 1986, as amended (the “Code”). The TCJA, among other things, includes changes to U.S. federal tax rates, imposes significant additional limitations on the deductibility of interest and net operating loss carryforwards, allows for the expensing of capital expenditures, and puts into effect the migration from a “worldwide” system of taxation to a territorial system. In addition, the TCJA repealed the alternative minimum tax (“AMT”) and provides for a refund of taxes paid between 2018 and 2021. With the passing of the TCJA, the Company will receive refunds in future periods for AMT paid in prior years. The Company therefore recognized a benefit of approximately $1.1 million for these taxes for the year ended December 31, 2017.

As of June 30, 2019 and December 31, 2018, approximately $529,000 is classified as current within prepaid expenses and other current assets and approximately $529,000 is classified as long term within deferred tax assets, net.

The Company’s effective tax rate for the six months ended June 30, 2019 and 2018 was approximately 0% for both periods, respectively. The Company’s annual effective tax rate of approximately 0% is substantially lower than the U.S. statutory rate of 21% due to valuation allowances recorded on current year losses where the Company is not at more-likely than not to recognize a future tax benefit.

Comprehensive Income (Loss)

All components of comprehensive income (loss), including net income (loss), are reported in the financial statements in the period in which they are incurred. Comprehensive income (loss) is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from

non-owner

sources. In accordance with accounting guidance, the Company presents the impact of any unrealized gains or (losses) on its investment securities in a separate statement of comprehensive income (loss) for each period.

Share-Based Compensation

Share-based payments are accounted for in accordance with the provisions of ASC Topic 718,

Compensation—Stock Compensation

. The fair value of share-based payments is estimated, on the date of grant, using the Black-Scholes-Merton option-pricing model (the “Black-Scholes model”). The resulting fair value is recognized ratably over the requisite service period, which is generally the vesting period of the option.

For all awards granted with time based vesting conditions, expense is amortized using the straight-line attribution method. Share-based compensation expense recognized in the statements of operations for the three and six months ended June 30, 2019 and 2018 is based on share-based awards ultimately expected to vest.

The Company utilizes the Black-Scholes model for estimating fair value of its stock options granted. Option valuation models, including the Black-Scholes model, require the input of subjective assumptions, and changes in the assumptions used can materially affect the grant date fair value of an award. These assumptions include the risk-free rate of interest, expected dividend yield, expected volatility and the expected life of the award.

Expected volatility rates are based on a combination of the historical volatility of the common stock of comparable publicly traded entities and the historical information about the Company’s common stock. The expected life of stock options is the period of time for which the stock options are expected to be outstanding. Given the limited historical exercise data, the expected life is determined using the “simplified method,” which defines expected life as the midpoint between the vesting date and the end of the contractual term.

The risk-free interest rates are based on the U.S. Treasury yield for a period consistent with the expected term of the option in effect at the time of the grant. The Company has not paid dividends to its stockholders since its inception and does not plan to pay cash dividends in the foreseeable future. Therefore, the Company has assumed an expected dividend rate of zero. For stock options granted, the exercise price was determined by using the closing market price of the Company’s common stock on the date of grant. The Company recognizes the effect of forfeitures when they occur.

A restricted stock unit (“RSU”) is a stock-based award that entitles the holder to receive shares of the Company’s common stock as the award vests. The fair value of each RSU is based on the fair market value of the Company’s common stock on the date of grant. The Company has granted RSUs that vest in three equal annual installments provided that the employee remains employed with the Company on the applicable vesting date.

In the first quarter of each fiscal year beginning in 2016, the Company granted time based RSUs that vest in three equal annual installments. In the first quarter of 2017, the Company granted performance-based RSUs, which vest based on the achievement of certain milestones that include (i) the submission of a new drug application (“NDA”) with the U.S. Food and Drug Administration (the

“FDA”), (ii) the approval of the NDA by the FDA (together, the “Milestone RSUs”) and (iii) the achievement of certain comparative

shareholder returns against the Company’s peers (the “TSR RSUs”). The Milestone RSUs were valued at the closing price on March 8, 2017. The Milestone RSUs related to the NDA submission have been fully amortized through December 31, 2018. The NDA submission milestone was achieved in the third quarter of 2018, so the Milestone RSUs related to the NDA submission vested on December 31, 2018. The amortization of the expenses for RSUs related to the approval of the NDA will commence if and when the NDA submission has been approved through the last day of the calendar year in which the milestone is achieved

and expires on December 31, 2019 if not achieved

. The TSR RSUs were valued using the Monte Carlo Simulation method and will be amortized over the life of the RSU agreements which ends December

2019

. The Milestone RSUs and TSR RSUs are target based and the ultimate awards, if attained, could be the target amount or higher or lower than the target amount, depending on the timing or achievement of the goal.

Under ASC Topic 718, the cumulative amount of compensation cost recognized for instruments classified as equity that ordinarily would result in a future tax deduction under existing tax law shall be considered to be a deductible difference in applying ASC Topic 740,

Income Taxes

. The deductible temporary difference is based on the compensation cost recognized for financial reporting purposes; however, these provisions currently do not impact the Company, as all the deferred tax assets have a full valuation allowance.

Since the Company had net operating loss carryforwards as of June 30, 2019 and 2018, no excess tax benefits for the tax deductions related to share-based awards were recognized in the statements of operations.

Loss Per Share

Basic net loss per common share is determined by dividing the net loss by the weighted-average number of common shares outstanding during the period, without consideration of common stock equivalents. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common stock equivalents outstanding for the period. The treasury stock method is used to determine the dilutive effect of the Company’s stock option grants and RSUs.

The following common stock equivalents were excluded in the calculation of diluted loss per share because their effect would be anti-dilutive as applied to the loss from operations for the three and six months ended June 30, 2019 and 2018:


	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
Stock options		355,963		797,638		355,963		797,560
RSUs		520,822		353,672		497,682		347,373
TSR RSUs		104,481		67,924		104,481		67,924

Recently Issued Accounting Standards

In May 2014, the FASB issued ASC Update No.

2014-09,

Revenue from Contracts with Customers (Topic 606), which has been subsequently updated (as updated, “ASC Topic 606”). The purpose of ASC Topic 606 is to provide enhancements to the quality and consistency of how revenue is reported while also improving comparability in the financial statements of companies using GAAP and International Financial Reporting Standards. The core principle requires entities to recognize revenue in a manner that depicts the transfer of goods or services to customers in amounts that reflect the consideration to which an entity expects to be entitled in exchange for those goods or services. ASC Topic 606 became effective for annual periods beginning after December 15, 2017.

The Company adopted this standard using the “modified retrospective method,” which did not result in an impact to its financial statements as the Company has not had product sales to date. Upon commercializing a product or executing any revenue generating contracts, the Company will provide additional disclosures in the notes to the consolidated financial statements related to the relevant aspects of any revenue generating contracts that the Company has or into which the Company expects to enter.

In February 2016, the FASB issued ASU No.

2016-02,

Leases (“ASU

2016-02”).

ASU

2016-02

requires the recognition of lease assets and lease liabilities by lessees for those leases classified as operating leases under previous GAAP. The classification criteria for distinguishing between finance leases and operating leases are substantially similar to the classification criteria for distinguishing between capital leases and operating leases in the previous leases guidance. ASU

2016-02

is effective for annual reporting periods beginning after December 15, 2018 and early adoption is permitted. The Company adopted the standard on January 1, 2019 using the simplified transition method, allowing the Company to not restate comparative periods and apply ASC 842 on a prospective basis, resulting in a balance sheet presentation that is not comparable to the prior period in the first year of adoption. The Company elected the package of practical expedients permitted under the transition guidance within the new standard, which among other things, allowed the Company to carry forward the historical lease classification. The Company has not elected the hindsight practical expedient. The Company made an accounting policy election to keep leases with an initial term of 12 months or less off the balance sheet. The Company recognizes those lease payments in the consolidated statements of operations on a straight-line basis over the lease term.

The adoption of the standard resulted in recognition of additional net lease assets and lease liabilities of approximately $20.2 million and $23.4 million, respectively, as of January 1, 2019. The difference between these amounts represents the net deferred rent as of January 1, 2019 with no impact on the accumulated deficit. The adoption of the new lease standard was a

non-cash

transaction. The Company concluded the new standard did not have a material impact on its liquidity and income tax position.

In February 2018, the FASB issued ASU

2018-02,

Income Statement-Reporting Comprehensive Income (Topic 220)—Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income, to address a specific consequence of the TCJA by allowing a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the TCJA’s reduction of the U.S. federal corporate income tax rate. ASU

2018-02

is effective for all entities for fiscal years beginning after December 15, 2018, with early adoption permitted, and is to be applied either in the period of adoption or retrospectively to each period in which the effect of the change in the U.S. federal corporate income tax rate in the TCJA is recognized. The Company does not have any stranded tax effects to which this ASU would apply. Therefore, there is no impact to the Company’s consolidated financial statements.

In August 2018, the SEC issued a final rule Release No.

33-10532,

“Disclosure Update and Simplification,” to amend certain disclosure requirements now seen as redundant, duplicative, overlapping, outdated or superseded in wake of recent accounting pronouncements. The amended rules became effective November 5, 2018. We analyzed the release in preparation of this Form

10-Q,

which resulted in the additional disclosure of changes to stockholders’ equity during interim periods, as presented within this Form

10-Q

within the condensed consolidated statements of stockholders’ equity. We note that many of the amended requirements under this Release are not applicable to the Company, as we do not make dividend payments to stockholders, currently report our activities under a single business segment, and already provided all other significant disclosure requirements.

In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” (ASU 2016-13) This guidance applies to all entities and impacts how entities account for credit losses for most financial assets and other instruments. For available-for-sale debt securities, entities will be required to recognize an allowance for credit losses rather than a reduction to the carrying value of the asset. For trade receivables, loans and held-to-maturity debt securities, entities will be required to estimate lifetime expected credit losses. This guidance is effective for fiscal years beginning after December 15, 2019 and interim periods therein. Early adoption is permitted for annual periods beginning after December 15, 2018 and interim periods therein. We are currently analyzing the impact of ASU 2016-13 on the condensed consolidated financial statements.

Property and Equipment

6 Months Ended

Jun. 30, 2019

Property, Plant and Equipment [Abstract]

Property and Equipment

3. Property and Equipment

Property and equipment consist of the following:


	June 30, 2019			December 31, 2018
Computer equipment	$	60,377		$	44,427
Furniture and fixtures		402,800			341,582
Scientific equipment		3,831,304			3,658,209
Leasehold improvements		1,026,170			149,470

		5,320,651			4,193,688
Less accumulated depreciation		(3,237,718	)		(3,033,922	)

	$	2,082,933		$	1,159,766

Depreciation expense for the six months ended June 30, 2019 and 2018 was $206,409 and $178,276, respectively.

Right Of Use Assets and Lease Liabilities

6 Months Ended

Jun. 30, 2019

Leases [Abstract]

Right Of Use Assets and Lease Liabilities

4. Right Of Use Assets and Lease Liabilities

In 2014, the Company entered into a long-term lease with a related party which, as amended, provided for a lease of 16,753 square feet of useable laboratory and office space located at 430 East 29th Street, New York, New York 10016. A member of the Company’s board of directors is the Executive Chairman of the parent company to the landlord under this lease. Concurrent with this lease, the Company entered into a license agreement to occupy certain vivarium related space in the same facility for the same term and rent escalation provisions as the lease. This license has the primary characteristics of a lease and is characterized as a lease in accordance with ASU 2016-02

for accounting purposes. In

September 2018

, the Company further amended the lease to obtain an additional

15,534 square feet of office space beginning October 1, 2018 and to extend the term of the lease for previously acquired space. The lease, as amended, has a term of 14.3 years ending in May 2029. The Company expects that its facility related costs will increase significantly as a result of leasing this additional space. In February 2019, the Company entered into a long-term lease for 3,164 square feet of office space in Towson, Maryland beginning March 1, 2019. The lease has a term of 3.2 years ending in April 2022 and includes a limited rent abatement and escalation provisions. The Company has no other significant leases. In addition, no identified leases require allocations between lease and

non-lease components.

In adopting ASU

2016-02

as of January 1, 2019, the Company elected the package of practical expedients, which permit the Company not to reassess under the new standard the historical lease classification. The Company has not elected the hindsight practical expedient. The Company made an accounting policy election to keep leases with an initial term of 12 months or less off of the balance sheet. The Company also elected the lessee component election, allowing the Company to account for the lease and non-lease components as a single lease component. In determining whether a contract contains a lease, asset and service agreements are assessed at onset and upon modification for criteria of specifically identified assets, control and economic benefit. The Company recognized those lease payments in the consolidated statements of operations on a straight-line basis over the lease term. The Company uses the rate implicit in the contract whenever possible when determining the applicable discount rate. As the majority of the Company’s leases do not provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at the lease commencement date in determining the present value of lease payments. On the lease commencement dates, the Company estimated the lease liabilities and the right of use assets at present value using its applicable incremental borrowing rates of its two long term leases of 7.21% for the Company’s Maryland lease of 3.2

years

and

9.1

for

the Company’s

New

York leases of

14.3

years. On January

2019

, upon adoption of ASU

2016-02,

the Company recorded right of use assets of approximately $

20.2

million, lease liabilities of $

23.4

million and eliminated deferred rent of $

3.2

million.

Right of use assets and lease liabilities for operating leases were $18.8 million and $22.8 million as of June 30, 2019, respectively.

Maturity analysis under the lease agreements are as follows:


Six months December 31, 2019	$	754,321
Year ended December 31, 2020		3,346,376
Year ended December 31, 2021		3,448,323
Year ended December 31, 2022		3,491,166
Year ended December 31, 2023		3,566,466
Thereafter		21,302,235

Total		35,908,887
Less: Present value discount		(13,078,145	)

Total Lease liability	$	22,830,742

Less: current portion		(2,262,977	)

Long-term lease liabilities	$	20,567,765

Lease expense for the three and six months ended June 30, 2019 was approximately $1.8 million and $956,000, respectively, as compared to approximately $360,000 and $719,000 for the three and six month period ended June 30, 2018.

Share-Based Compensation

6 Months Ended

Jun. 30, 2019

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Share-Based Compensation

5. Share-Based Compensation

On June 18, 2018, the Company’s stockholders approved the 2018 Equity Incentive Plan (the “2018 Plan”). The 2018 Plan provides for the granting of stock-based awards, such as stock options, restricted common stock, RSUs and stock appreciation rights to employees, directors and consultants as determined by the Board of Directors. The 2018 Plan replaced the Company’s Amended and Restated 2013 Equity Incentive Plan (the “2013 Plan”). The Company will grant no further stock options or other awards under the 2013 Plan. Any options or other awards outstanding under the 2013 Plan remain outstanding in accordance with their terms and the terms of the 2013 Plan. As of December 31, 2018, the total number of shares reserved under all equity plans was 10,287,390 and the Company had 4,807,323 shares available for future issuance under the 2018 Plan. Stock options granted under the 2018 Plan may be either incentive stock options (“ISOs”) as defined by the Code, or

non-qualified

stock options. The Board of Directors determines who will receive options, the vesting periods (which are generally one to three years) and the exercise prices of such options. Options have a maximum term of 10 years. The exercise price of ISOs granted under the 2018 Plan must be at least equal to the fair market value of the common stock on the date of grant.

Total stock-based compensation expense related to all of the Company’s share-based awards, including stock options and RSUs to employees, directors and consultants, recognized during the three and six months ended June 30, 2019 and 2018, was comprised of the following:


	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
Research and development	$	2,353,936	$	1,877,536	$	4,761,580	$	3,795,267
General and administrative		2,633,488		2,433,169		5,281,061		4,802,541

Total share-based compensation expense	$	4,987,424	$	4,310,705	$	10,042,641	$	8,597,808

The following table describes the weighted-average assumptions used for calculating the value of options granted during the six months ended June 30, 2019 and 2018:


	2019		2018
Dividend yield		0%		0%
Expected volatility		83.7%-85.7%		85.2%-85.8%
Weighted-average risk-free interest rate		2.33%		2.4%
Expected term (in years)		6.0		6.0

Information regarding the stock options activity, including with respect to grants to employees, directors and consultants as of June 30, 2019, and changes during the six-month period then ended, are summarized as follows:


	Number of Shares			Weighted-Average Exercise Price		Weighted-Average Contractual Life
Outstanding at December 31, 2018		4,748,391		$	18.75		7.0 years
Options granted		1,771,154		$	12.80		9.7 years
Options exercised		(34,900	)	$	8.32		5.3 years
Options canceled or expired		(78,436	)	$	20.91		7.5 years

Outstanding at June 30, 2019		6,406,209		$	16.78		7.4 years

Vested or expected to vest at June 30, 2019		6,406,209		$	16.78

Exercisable at June 30, 2019		3,450,350		$	19.47		5.8 years

The fair value of the time based RSUs and the Milestone RSUs is based on the closing price of the Company’s common stock on the date of grant. The fair value of the TSR RSUs was determined using the Monte Carlo simulation method.

Information regarding the time based RSU activity and changes during the

six-month

period ended June 30, 2019 are summarized as follows:


	Number of Shares			Weighted-Average Grant Date Fair Value Per Share
Outstanding at December 31, 2018		647,411		$	18.16
RSU’s granted in 2019		914,812		$	12.74
RSU’s vested in 2019		(251,955	)	$	21.85
RSU’s cancelled in 2019		(14,002	)	$	14.97

Outstanding at June 30, 2019		1,296,266		$	13.65

Information related to the Company’s Milestone RSUs and TSR RSUs during the

six-month

period ended June 30, 2019 are summarized as follows:


	Number of Shares			Weighted-Average Grant Date Fair Value Per Share
Outstanding at December 31, 2018		278,592		$	15.64
RSU’s granted in 2019		—		$	—
RSU’s cancelled in 2019		(9,463	)	$	15.64

Outstanding at June 30, 2019		269,129		$	15.64

The weighted average estimated fair value per share of the TSR RSUs granted in 2017 was $17.08, which was derived from a Monte Carlo simulation. Significant assumptions utilized in estimating the value of the awards granted include an expected dividend yield of 0%, a risk free rate of 1.6%, and expected volatility of 95.4%. The TSR RSUs granted in 2017 will entitle the grantee to receive a number of shares of the Company’s common stock determined over a three-year performance period ending and vesting on December 31, 2019, provided the grantee remains in the service of the Company on the settlement date. The Company expenses the cost of these awards ratably over the requisite service period. The number of shares for which the TSR RSUs will be settled will be a percentage of shares for which the award is targeted and will depend on the Company’s total shareholder return (as defined below), expressed as a percentile ranking of the Company’s total shareholder return as compared to the Company’s peer group (as defined below). The number of shares for which the TSR RSUs will be settled vary depending on the level of achievement of the goal. Total shareholder return is determined by dividing the average share value of the Company’s common stock over the 30 trading days preceding January 1, 2020 by the average share value of the Company’s common stock over the 30 trading days beginning on January 1, 2017, with a deemed reinvestment of any dividends declared during the performance period. The Company’s peer group includes 223 companies at December 31, 2018 which comprise the Nasdaq Biotechnology Index, which was selected by the Compensation Committee of the Company’s Board of Directors and includes a range of biotechnology companies operating in several business segments.

The Company recognized

non-cash

stock-based compensation expense related to time based RSU’s for the three and six months ended June 30, 2019 of approximately $1.9 million and $3.8 million, respectively, as compared to $1.2 million and $2.3 million for the three and six months ended June, 30, 2018, respectively. Total expense for all RSUs, including the time based and performance based RSUs, is $2.1 million and $4.2 million for the three and six months ended June 30, 2019, respectively, as compared to $1.5 million and $3.0 million for the three and six months ended June 30, 2018, respectively. As of June 30, 2019, there was $14.2 million of unrecognized compensation costs related to unvested time based RSUs. As of June 30, 2019, there was $1.9 million and $0.4 million of unrecognized compensation costs related to unvested Milestone RSUs and TSR RSUs, respectively.

Collaborations and License Agreements	6 Months Ended
Collaborations and License Agreements	Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaborations and License Agreements	6. Collaborations and License Agreements The Bristol-Myers Squibb License Agreement On May 31, 2005, the Company entered into a worldwide, exclusive License Agreement with Bristol-Myers Squibb Company (“BMS”), pursuant to which the Company holds a license to certain patents and know-how of BMS relating to lumateperone and other specified compounds. The agreement was amended on November 3, 2010. The licensed rights are exclusive, except BMS retains rights in specified compounds in the fields of obesity, diabetes, metabolic syndrome and cardiovascular disease. However, BMS has no right to use, develop or commercialize lumateperone and other specified compounds in any field of use. The Company has the right to grant sublicenses of the rights conveyed by BMS. The Company is obliged under the agreement to use commercially reasonable efforts to develop and commercialize the licensed technology. The Company is also prohibited from engaging in the clinical development or commercialization of specified competitive compounds. Under the agreement, the Company made an upfront payment of $1.0 million to BMS, a milestone payment of $1.25 million in December 2013, and a milestone payment of $1.5 million in December 2014 following the initiation of the Company’s first Phase 3 clinical trial for lumateperone for patients with exacerbated schizophrenia. Upon FDA acceptance for review of an NDA submission for lumateperone, the Company was obligated to pay BMS a $2.0 million milestone payment. This milestone was achieved in the third quarter of 2018. The Company accrued the $ 2.0 million milestone payment obligation in 2018 and paid it in January 2019. Possible milestone payments remaining total $10.0 million, including a $5.0 million milestone payment payable upon an NDA approval. Under the agreement, the Company may be obliged to make other milestone payments to BMS for each licensed product of up to an aggregate of approximately $14.75 million. The Company is also obliged to make tiered single digit percentage royalty payments ranging between 5 – 9% on sales of licensed products. The Company is obliged to pay to BMS a percentage of non-royalty payments made in consideration of any sublicense. The agreement extends, and royalties are payable, on a country-by-country and product-by-product basis, through the later of 10 years after first commercial sale of a licensed product in such country, expiration of the last licensed patent covering a licensed product, its method of manufacture or use, or the expiration of other government grants providing market exclusivity, subject to certain rights of the parties to terminate the agreement on the occurrence of certain events. On termination of the agreement, the Company may be obliged to convey to BMS rights in developments relating to a licensed compound or licensed product, including regulatory filings, research results and other intellectual property rights. In September 2016, the Company transferred certain of its rights under the BMS agreement to its wholly owned subsidiary, ITI Limited. In connection with the transfer, the Company guaranteed ITI Limited’s performance of its obligations under the BMS agreement.

Summary of Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2019

Accounting Policies [Abstract]

Basis of Presentation

Use of Estimates

Cash and Cash Equivalents

Investment Securities

Investment securities consisted of the following (in thousands):


	June 30, 2019
	Amortized Cost		Unrealized Gains		Unrealized (Losses)			Estimated Fair Value
	(Unaudited)
U.S. Government Agency Securities	$	72,880	$	89	$	(26	)	$	72,943
Certificates of Deposit		3,000		—		—			3,000
Commercial Paper		22,923		11		(2	)		22,932
Corporate Notes/Bonds		94,501		174		(13	)		94,662

	$	193,304	$	274	$	(41	)	$	193,537


	December 31, 2018
	Amortized Cost		Unrealized Gains		Unrealized (Losses)			Estimated Fair Value
U.S. Government Agency Securities	$	124,691	$	24	$	(289	)	$	124,426
FDIC Certificates of Deposit (1)		245		—		—			245
Certificates of Deposit		1,000		—		—			1,000
Commercial Paper		41,317		—		(45	)		41,272
Corporate Notes/Bonds		125,998		7		(365	)		125,640

	$	293,251	$	31	$	(699	)	$	292,583


(1)	“FDIC Certificates of Deposit” consist of deposits that are less than $250,000.

The Company has classified all of its investment securities

available-for-sale,

available-for-sale

investment securities with contractual maturity dates more than one year and less than two years.

million and the aggregate amount of unrealized losses was approximately

41,000

. Of the $71 million, $

million has been held in a continuous unrealized loss position for less than 12 months and

million has been held in a continuous loss position for 12 months or longer. The total continuous unrealized loss for investments held for 12 months or longer is approximatel

y $

39,000

as of June 30, 2019. As of December 31, 2018, the Company had approximately

92.1

million of investments with a continuous unrealized loss for 12 months or longer of approximately

345,000

The Company attributes the unrealized gains and losses on the

available-for-sale

Fair Value Measurements

The Company applies the fair value method under ASC Topic 820,

Fair Value Measurements and Disclosures

•

Level 1—Fair value is determined by using unadjusted quoted prices that are available in active markets for identical assets and liabilities.

•

The fair value measurements of the Company’s cash equivalents and

available-for-sale

investment securities are identified in the following tables (in thousands):


			Fair Value Measurements at Reporting Date Using
	June 30, 2019		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Money Market Funds	$	54,146	$	54,146	$	—	$	—
U.S. Government Agency Securities		72,943		—		72,943		—
FDIC Certificates of Deposit		—		—		—		—
Certificates of Deposit		34,500		—		34,500		—
Commercial Paper		22,932		—		22,932		—
Corporate Notes/Bonds		94,662		—		94,662		—

	$	279,183	$	54,146	$	225,037	$	—


			Fair Value Measurements at Reporting Date Using
	December 31, 2018		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Money Market Funds	$	39,591	$	39,591	$	—	$	—
U.S. Government Agency Securities		124,426		—		124,426		—
FDIC Certificates of Deposit		245		—		245		—
Certificates of Deposit		8,500		—		8,500		—
Commercial Paper		41,272		—		41,272		—
Corporate Notes/Bonds		125,640		—		125,640		—

	$	339,674	$	39,591	$	300,083	$	—

Financial Instruments

The Company considers the recorded costs of its financial assets and liabilities, which consist of certain cash equivalents, prepaid expenses, accounts payable

right of use asset, net,

accrued liabilities

and lease liabilities

Concentration of Credit Risk

Accounts Receivable

Property and Equipment

When indicators of possible impairment are identified, the Company evaluates the recoverability of the carrying value of its long-lived assets based on the criteria established in ASC Topic 360,

Property, Plant and Equipment

Research and Development

Income Taxes

more-likely-than-not

Comprehensive Income (Loss)

non-owner

Share-Based Compensation

Share-based payments are accounted for in accordance with the provisions of ASC Topic 718,

Compensation—Stock Compensation

“FDA”), (ii) the approval of the NDA by the FDA (together, the “Milestone RSUs”) and (iii) the achievement of certain comparative

and expires on December 31, 2019 if not achieved

. The TSR RSUs were valued using the Monte Carlo Simulation method and will be amortized over the life of the RSU agreements which ends December

2019

Income Taxes

Loss Per Share


	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
Stock options		355,963		797,638		355,963		797,560
RSUs		520,822		353,672		497,682		347,373
TSR RSUs		104,481		67,924		104,481		67,924

Recently Issued Accounting Standards

In May 2014, the FASB issued ASC Update No.

2014-09,

In February 2016, the FASB issued ASU No.

2016-02,

Leases (“ASU

2016-02”).

ASU

2016-02

non-cash

transaction. The Company concluded the new standard did not have a material impact on its liquidity and income tax position.

In February 2018, the FASB issued ASU

2018-02,

2018-02

In August 2018, the SEC issued a final rule Release No.

33-10532,

10-Q,

which resulted in the additional disclosure of changes to stockholders’ equity during interim periods, as presented within this Form

10-Q

Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2019

Accounting Policies [Abstract]

Schedule of Investment Securities

Investment securities consisted of the following (in thousands):


	June 30, 2019
	Amortized Cost		Unrealized Gains		Unrealized (Losses)			Estimated Fair Value
	(Unaudited)
U.S. Government Agency Securities	$	72,880	$	89	$	(26	)	$	72,943
Certificates of Deposit		3,000		—		—			3,000
Commercial Paper		22,923		11		(2	)		22,932
Corporate Notes/Bonds		94,501		174		(13	)		94,662

	$	193,304	$	274	$	(41	)	$	193,537


	December 31, 2018
	Amortized Cost		Unrealized Gains		Unrealized (Losses)			Estimated Fair Value
U.S. Government Agency Securities	$	124,691	$	24	$	(289	)	$	124,426
FDIC Certificates of Deposit (1)		245		—		—			245
Certificates of Deposit		1,000		—		—			1,000
Commercial Paper		41,317		—		(45	)		41,272
Corporate Notes/Bonds		125,998		7		(365	)		125,640

	$	293,251	$	31	$	(699	)	$	292,583


(1)	“FDIC Certificates of Deposit” consist of deposits that are less than $250,000.

Schedule of Fair Value Measurements of Cash Equivalents and Available-for-Sale Investment Securities

The fair value measurements of the Company’s cash equivalents and

available-for-sale

investment securities are identified in the following tables (in thousands):


			Fair Value Measurements at Reporting Date Using
	June 30, 2019		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Money Market Funds	$	54,146	$	54,146	$	—	$	—
U.S. Government Agency Securities		72,943		—		72,943		—
FDIC Certificates of Deposit		—		—		—		—
Certificates of Deposit		34,500		—		34,500		—
Commercial Paper		22,932		—		22,932		—
Corporate Notes/Bonds		94,662		—		94,662		—

	$	279,183	$	54,146	$	225,037	$	—


			Fair Value Measurements at Reporting Date Using
	December 31, 2018		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Money Market Funds	$	39,591	$	39,591	$	—	$	—
U.S. Government Agency Securities		124,426		—		124,426		—
FDIC Certificates of Deposit		245		—		245		—
Certificates of Deposit		8,500		—		8,500		—
Commercial Paper		41,272		—		41,272		—
Corporate Notes/Bonds		125,640		—		125,640		—

	$	339,674	$	39,591	$	300,083	$	—

Common Stock Equivalents Excluded in Calculation of Diluted Loss Per Share


	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
Stock options		355,963		797,638		355,963		797,560
RSUs		520,822		353,672		497,682		347,373
TSR RSUs		104,481		67,924		104,481		67,924

Property and Equipment (Tables)

6 Months Ended

Jun. 30, 2019

Property, Plant and Equipment [Abstract]

Property and Equipment

Property and equipment consist of the following:


	June 30, 2019			December 31, 2018
Computer equipment	$	60,377		$	44,427
Furniture and fixtures		402,800			341,582
Scientific equipment		3,831,304			3,658,209
Leasehold improvements		1,026,170			149,470

		5,320,651			4,193,688
Less accumulated depreciation		(3,237,718	)		(3,033,922	)

	$	2,082,933		$	1,159,766

Right Of Use Assets and Lease Liabilities (Tables)

6 Months Ended

Jun. 30, 2019

Leases [Abstract]

Schedule Of Maturity Analysis Under Lease Agreements

Maturity analysis under the lease agreements are as follows:


Six months December 31, 2019	$	754,321
Year ended December 31, 2020		3,346,376
Year ended December 31, 2021		3,448,323
Year ended December 31, 2022		3,491,166
Year ended December 31, 2023		3,566,466
Thereafter		21,302,235

Total		35,908,887
Less: Present value discount		(13,078,145	)

Total Lease liability	$	22,830,742

Less: current portion		(2,262,977	)

Long-term lease liabilities	$	20,567,765

Share-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2019

Total Stock-Based Compensation Expense


	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
Research and development	$	2,353,936	$	1,877,536	$	4,761,580	$	3,795,267
General and administrative		2,633,488		2,433,169		5,281,061		4,802,541

Total share-based compensation expense	$	4,987,424	$	4,310,705	$	10,042,641	$	8,597,808

Assumptions Used for Calculating Value of Options Granted

The following table describes the weighted-average assumptions used for calculating the value of options granted during the six months ended June 30, 2019 and 2018:


	2019		2018
Dividend yield		0%		0%
Expected volatility		83.7%-85.7%		85.2%-85.8%
Weighted-average risk-free interest rate		2.33%		2.4%
Expected term (in years)		6.0		6.0

Stock Option Activity


	Number of Shares			Weighted-Average Exercise Price		Weighted-Average Contractual Life
Outstanding at December 31, 2018		4,748,391		$	18.75		7.0 years
Options granted		1,771,154		$	12.80		9.7 years
Options exercised		(34,900	)	$	8.32		5.3 years
Options canceled or expired		(78,436	)	$	20.91		7.5 years

Outstanding at June 30, 2019		6,406,209		$	16.78		7.4 years

Vested or expected to vest at June 30, 2019		6,406,209		$	16.78

Exercisable at June 30, 2019		3,450,350		$	19.47		5.8 years

Time Based Restricted Stock Units [Member]

Summary of Information Regarding RSU Activity

Information regarding the time based RSU activity and changes during the

six-month

period ended June 30, 2019 are summarized as follows:


	Number of Shares			Weighted-Average Grant Date Fair Value Per Share
Outstanding at December 31, 2018		647,411		$	18.16
RSU’s granted in 2019		914,812		$	12.74
RSU’s vested in 2019		(251,955	)	$	21.85
RSU’s cancelled in 2019		(14,002	)	$	14.97

Outstanding at June 30, 2019		1,296,266		$	13.65

Milestone and Total Shareholder Return Restricted Stock Units [Member]

Summary of Information Regarding RSU Activity

Information related to the Company’s Milestone RSUs and TSR RSUs during the

six-month

period ended June 30, 2019 are summarized as follows:


	Number of Shares			Weighted-Average Grant Date Fair Value Per Share
Outstanding at December 31, 2018		278,592		$	15.64
RSU’s granted in 2019		—		$	—
RSU’s cancelled in 2019		(9,463	)	$	15.64

Outstanding at June 30, 2019		269,129		$	15.64

Organization - Additional Information (Detail)		6 Months Ended
Organization - Additional Information (Detail)	Aug. 08, 2019	Jun. 30, 2019 USD ($)	Oct. 31, 2017 USD ($)	Sep. 14, 2016 USD ($)
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Securities remained available for issuance under the Company's shelf registration			$ 178,000,000
Scenario, Plan [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Duration Of Time Essential For The Cash,Cash Equivalents And Other Investments Thereof For Funding The Operating Expenses And Capital Expenditure	12 months
Lumateperone [member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Number of clinical trials		20
ITI Limited [Member] \| Intellectual Property [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Finite lived intangible assets transactional gain		$ 125,000,000
Maximum [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Universal shelf registration statement, effective date value				$ 350,000,000
Minimum [Member] \| Lumateperone [member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Number of subjects exposed medicine		1,900

Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended	6 Months Ended		12 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2019 USD ($) Segment	Jun. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jan. 01, 2019 USD ($)	Dec. 31, 2018 USD ($)
Significant Accounting Policies [Line Items]
Number of operating segments \| Segment		1
Maturity of highly liquid investments		3 months
Maturity of certificates of deposit, commercial paper, corporate notes and corporate bonds		more than three months
Investment securities, available-for-sale	$ 193,536,800	$ 193,536,800				$ 292,583,046
Aggregate related fair value of investments with unrealized losses	71,000,000	71,000,000
Investment securities aggregate amount of unrealized loss	41,000	41,000
Investment securities, held in continuous unrealized loss position for less than 12 months	13,000,000	13,000,000				92,100,000
Investment securities, held in continuous unrealized loss position for 12 months or longer	58,000,000	58,000,000				345,000
Total continuous unrealized loss for investments held for 12 months or longer	39,000	39,000
Carrying value of cash held in money market funds	54,100,000	54,100,000
Impairment losses recognized		$ 0
Recognized tax benefit				$ 1,100,000
Effective tax rate		0.00%	0.00%
Annual effective tax rate		0.00%
US statutory rate		21.00%
Assumed expected dividend rate		0.00%	0.00%
Excess tax benefits for tax deductions		$ 0	$ 0
Net lease assets	18,822,482	18,822,482
Net lease liabilities	$ 22,830,742	22,830,742
Date Of Expiry Of Result Based Restricted Stock Units If Targets Are Not Achieved	Dec. 31, 2019
Deferred Tax Assets, Net, Noncurrent	$ 529,218	529,218				529,218
Cash and Cash Equivalents [Member]
Significant Accounting Policies [Line Items]
Carrying value of cash held in money market funds						39,600,000
Carrying value of cash held in certificates of deposit	31,500,000	31,500,000				7,500,000
Prepaid Expenses and Other Current Assets [Member]
Significant Accounting Policies [Line Items]
Deferred Tax Assets, Net, Current	529,000,000	529,000,000				529,000,000
Deferred Tax Assets, Net, Noncurrent	529,000,000	529,000,000				529,000,000
Significant Unobservable Inputs (Level 3) [Member]
Significant Accounting Policies [Line Items]
Assets measured using quoted prices	0	0				0
Liabilities measured using quoted prices	0	0				0
Accounting Standards Update 2016-02 [Member]
Significant Accounting Policies [Line Items]
Net lease assets					$ 20,200,000
Net lease liabilities					$ 23,400,000
Contractual Maturity Dates More Than One Year and Less Than Two Years [Member]
Significant Accounting Policies [Line Items]
Investment securities, available-for-sale	$ 12,900,000	$ 12,900,000				$ 64,600,000
RSUs [Member]
Significant Accounting Policies [Line Items]
Service period for granted RSUs, vest in annual installment		3 years
Minimum [Member]
Significant Accounting Policies [Line Items]
Property and equipment, estimated useful life		3 years
Maximum [Member]
Significant Accounting Policies [Line Items]
Property and equipment, estimated useful life		5 years

Summary of Significant Accounting Policies - Schedule of Investment Securities (Detail) - USD ($)

Jun. 30, 2019

Dec. 31, 2018

Schedule of Available-for-sale Securities [Line Items]

Amortized Cost

$ 193,304,000

$ 293,251,000

Unrealized Gains

274,000

31,000

Unrealized (Losses)

(41,000)

(699,000)

Estimated Fair Value

193,536,800

292,583,046

U.S. Government Agency Securities [Member]

Schedule of Available-for-sale Securities [Line Items]

Amortized Cost

72,880,000

124,691,000

Unrealized Gains

89,000

24,000

Unrealized (Losses)

(26,000)

(289,000)

Estimated Fair Value

72,943,000

124,426,000

FDIC Certificates of Deposit [Member]

Schedule of Available-for-sale Securities [Line Items]

Amortized Cost

^[1]

245,000

Estimated Fair Value

^[1]

245,000

Certificates of Deposit [Member]

Schedule of Available-for-sale Securities [Line Items]

Amortized Cost

3,000,000

1,000,000

Estimated Fair Value

3,000,000

1,000,000

Commercial Paper [Member]

Schedule of Available-for-sale Securities [Line Items]

Amortized Cost

22,923,000

41,317,000

Unrealized Gains

11,000

Unrealized (Losses)

(2,000)

(45,000)

Estimated Fair Value

22,932,000

41,272,000

Corporate Notes/Bonds [Member]

Schedule of Available-for-sale Securities [Line Items]

Amortized Cost

94,501,000

125,998,000

Unrealized Gains

174,000

7,000

Unrealized (Losses)

(13,000)

(365,000)

Estimated Fair Value

$ 94,662,000

$ 125,640,000

[1]	“FDIC Certificates of Deposit” consist of deposits that are less than $250,000.

Summary of Significant Accounting Policies - Schedule of Investment Securities (Parenthetical) (Detail)	Dec. 31, 2018 USD ($)
FDIC Certificates of Deposit [Member] \| Maximum [Member]
Schedule of Available-for-sale Securities [Line Items]
Deposits under FDIC Certificates of Deposit	$ 250,000

Summary of Significant Accounting Policies - Schedule of Fair Value Measurements of Cash Equivalents and Available-for-Sale Investment Securities (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available-for-sale investment securities	$ 279,183	$ 339,674
Money Market Funds [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available-for-sale investment securities	54,146	39,591
U.S. Government Agency Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available-for-sale investment securities	72,943	124,426
FDIC Certificates of Deposit [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available-for-sale investment securities		245
Certificates of Deposit [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available-for-sale investment securities	34,500	8,500
Commercial Paper [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available-for-sale investment securities	22,932	41,272
Corporate Notes/Bonds [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available-for-sale investment securities	94,662	125,640
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available-for-sale investment securities	54,146	39,591
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Money Market Funds [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available-for-sale investment securities	54,146	39,591
Significant Other Observable Inputs (Level 2) [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available-for-sale investment securities	225,037	300,083
Significant Other Observable Inputs (Level 2) [Member] \| U.S. Government Agency Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available-for-sale investment securities	72,943	124,426
Significant Other Observable Inputs (Level 2) [Member] \| FDIC Certificates of Deposit [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available-for-sale investment securities		245
Significant Other Observable Inputs (Level 2) [Member] \| Certificates of Deposit [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available-for-sale investment securities	34,500	8,500
Significant Other Observable Inputs (Level 2) [Member] \| Commercial Paper [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available-for-sale investment securities	22,932	41,272
Significant Other Observable Inputs (Level 2) [Member] \| Corporate Notes/Bonds [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available-for-sale investment securities	$ 94,662	$ 125,640

Summary of Significant Accounting Policies - Common Stock Equivalents Excluded in Calculation of Diluted Loss Per Share (Detail) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Stock options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of anti-dilutive securities excluded from computation of earnings per share	355,963	797,638	355,963	797,560
RSUs [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of anti-dilutive securities excluded from computation of earnings per share	520,822	353,672	497,682	347,373
Total Shareholder Return Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of anti-dilutive securities excluded from computation of earnings per share	104,481	67,924	104,481	67,924

Property and Equipment - Property and Equipment (Detail) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	$ 5,320,651	$ 4,193,688
Less accumulated depreciation	(3,237,718)	(3,033,922)
Property Plant and Equipment Net	2,082,933	1,159,766
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	60,377	44,427
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	402,800	341,582
Scientific Equipment [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	3,831,304	3,658,209
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	$ 1,026,170	$ 149,470

Property and Equipment - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 206,409	$ 178,276

Right Of Use Assets and Lease Liabilities - Additional Information (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Feb. 28, 2019 ft²	Jan. 01, 2019 USD ($)	Sep. 30, 2018 ft²	Jan. 01, 2014 ft²
Right of use assets, net	$ 18,822,482		$ 18,822,482
Net lease liabilities	22,830,742		22,830,742
Operating lease expense	$ 1,800,000	$ 360,000,000	$ 956,000,000	$ 719,000,000
Accounting Standards Update 2016-02 [Member]
Right of use assets, net						$ 20,200,000
Net lease liabilities						23,400,000
Eliminated deferred rent						$ 3,200,000
NEW YORK
Area of usable laboratory and office space \| ft²							15,534	16,753
Term of long term lease							14 years 3 months 18 days
NEW YORK \| Accounting Standards Update 2016-02 [Member]
Operating lease discount rate						7.21%
Operating Lease, Weighted Average Remaining Lease Term						3 years 2 months 12 days
MARYLAND
Area of usable laboratory and office space \| ft²					3,164
Term of long term lease					3 years 2 months 12 days
MARYLAND \| Accounting Standards Update 2016-02 [Member]
Operating lease discount rate						9.10%
Operating Lease, Weighted Average Remaining Lease Term						14 years 3 months 18 days

Right Of Use Assets and Lease Liabilities - Maturity analysis under the lease agreements (Detail)	Jun. 30, 2019 USD ($)
Operating Lease Liabilities, Payments Due [Abstract]
Six months December 31, 2019	$ 754,321
Year ended December 31, 2020	3,346,376
Year ended December 31, 2021	3,448,323
Year ended December 31, 2022	3,491,166
Year ended December 31, 2023	3,566,466
Thereafter	21,302,235
Total	35,908,887
Less: Present value discount	(13,078,145)
Total Lease liability	22,830,742
Less: current portion	(2,262,977)
Long-term lease liabilities	$ 20,567,765

Share-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2017	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for issuance						10,287,390
Expected dividend yield				0.00%	0.00%
Risk free interest rate				2.33%	2.40%
2018 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for issuance						4,807,323
Total Shareholder Return Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, vesting term				3 years
Weighted average grant date fair value of stock options granted			$ 17.08
Unrecognized compensation costs related to unvested RSUs	$ 1.9			$ 1.9
Expected dividend yield			0.00%
Risk free interest rate			1.60%
Expected volatility			95.40%
Vesting date			Dec. 31, 2019
Terms of award				Total shareholder return is determined by dividing the average share value of the Company’s common stock over the 30 trading days preceding January 1, 2020 by the average share value of the Company’s common stock over the 30 trading days beginning on January 1, 2017, with a deemed reinvestment of any dividends declared during the performance period.
Time Based Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs related to unvested RSUs	14.2			$ 14.2
Non-cash stock-based compensation expense recognized	1.9	$ 1.2		3.8	$ 2.3
RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs related to unvested RSUs	0.4			0.4
Non-cash stock-based compensation expense recognized	$ 2.1	$ 1.5		$ 4.2	$ 3.0
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, maximum term						10 years
Stock Options [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, vesting term				1 year
Stock Options [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, vesting term				3 years

Share-Based Compensation - Total Stock-Based Compensation Expense (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	$ 4,987,424	$ 4,310,705	$ 10,042,641	$ 8,597,808
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	2,353,936	1,877,536	4,761,580	3,795,267
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	$ 2,633,488	$ 2,433,169	$ 5,281,061	$ 4,802,541

Share-Based Compensation - Assumptions Used for Calculating Value of Options Granted (Detail)	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Dividend yield	0.00%	0.00%
Expected volatility, minimum	83.70%	85.20%
Expected volatility, maximum	85.70%	85.80%
Weighted-average risk-free interest rate	2.33%	2.40%
Expected term (in years)	6 years	6 years

Share-Based Compensation - Stock Options Activity (Detail) - $ / shares	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Outstanding at beginning of period, Number of Shares	4,748,391
Options granted, Number of Shares	1,771,154
Options exercised, Number of Shares	(34,900)
Options canceled or expired, Number of Shares	(78,436)
Outstanding at end of period, Number of Shares	6,406,209	4,748,391
Vested or expected to vest at end of period, Number of Shares	6,406,209
Exercisable at end of period, Number of Shares	3,450,350
Outstanding at beginning of period, Weighted-Average Exercise Price	$ 18.75
Options granted, Weighted-Average Exercise Price	12.80
Options exercised, Weighted-Average Exercise Price	8.32
Options canceled or expired, Weighted-Average Exercise Price	20.91
Outstanding at end of period, Weighted-Average Exercise Price	16.78	$ 18.75
Vested or expected to vest at end of period, Weighted-Average Exercise Price	16.78
Exercisable at end of period, Weighted-Average Exercise Price	$ 19.47
Options granted, Weighted-Average Contractual Life	9 years 8 months 12 days
Options exercised, Weighted-Average Contractual Life	5 years 3 months 18 days
Options canceled or expired, Weighted-Average Contractual Life	7 years 6 months
Outstanding at end of period, Weighted-Average Contractual Life	7 years 4 months 24 days	7 years
Exercisable at end of period, Weighted-Average Contractual Life	5 years 9 months 18 days

Share-Based Compensation - Summary of Information Regarding the Time Based RSU Activity and Changes (Detail) - RSUs [Member]	6 Months Ended
	Jun. 30, 2019 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding at beginning of period, Number of Shares \| shares	647,411
RSU's granted, Number of Shares \| shares	914,812
RSU's vested, Number of Shares \| shares	(251,955)
RSU's cancelled, Number of Shares \| shares	(14,002)
Outstanding at end of period, Number of Shares \| shares	1,296,266
Outstanding at beginning of period, Weighted-Average Grant Date Fair Value \| $ / shares	$ 18.16
RSU's granted, Weighted-Average Grant Date Fair Value \| $ / shares	12.74
RSU's vested, Weighted-Average Grant Date Fair Value \| $ / shares	21.85
RSU's cancelled, Weighted-Average Grant Date Fair Value \| $ / shares	14.97
Outstanding at end of period, Weighted-Average Grant Date Fair Value \| $ / shares	$ 13.65

Share-Based Compensation - Summary of Information Regarding Milestone RSU grants and TSR RSU grants (Detail) - Milestone and Total Shareholder Return Restricted Stock Units [Member]	6 Months Ended
	Jun. 30, 2019 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding at beginning of period, Number of Shares \| shares	278,592
RSU's cancelled, Number of Shares \| shares	(9,463)
Outstanding at end of period, Number of Shares \| shares	269,129
Outstanding at beginning of period, Weighted-Average Grant Date Fair Value \| $ / shares	$ 15.64
RSU's cancelled, Weighted-Average Grant Date Fair Value \| $ / shares	15.64
Outstanding at end of period, Weighted-Average Grant Date Fair Value \| $ / shares	$ 15.64

Collaborations and License Agreements - Additional Information (Detail) - Collaborative Arrangement, Product [Member] - Bristol-Myers Squibb Company [Member] - USD ($)		1 Months Ended		6 Months Ended
	May 31, 2005	Dec. 31, 2014	Dec. 31, 2013	Jun. 30, 2019
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Company made an upfront payment	$ 1,000,000.0
Company made milestone payment		$ 1,500,000	$ 1,250,000
Obliged to make milestone payments				$ 14,750,000
Company remaining milestone payment				$ 10,000,000.0
License expiration period				through the later of 10 years after first commercial sale of a licensed product in such country, expiration of the last licensed patent covering a licensed product
Minimum [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Royalty payment, percentage				5.00%
Maximum [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Royalty payment, percentage				9.00%
Food and Drug Administration [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Obliged to make milestone payments				$ 2,000,000.0