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Base rent and management fees.

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Convertible notes payable interest rate.

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Deferred rent.

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Lease termination date

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Payment To Related Party

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Promissory note issued.

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Related party administrative expense percentage.

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Related party transaction agreement notice period.

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Stock issued during period shares conversion rate of convertible securities per shares.

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Termination Date

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Exercise price per share or per unit of warrants or rights outstanding.

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Number of securities into which each warrant or right may be converted. For example, but not limited to, each warrant may be converted into two shares.

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Carrying value as of the balance sheet date of the portion of long-term debt due within one year or the operating cycle if longer identified as Convertible Notes Payable. Convertible Notes Payable is a written promise to pay a note which can be exchanged for a specified amount of another, related security, at the option of the issuer and the holder.

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Carrying amount as of the balance sheet date of obligations due all related parties. For classified balance sheets, represents the current portion of such liabilities (due within one year or within the normal operating cycle if longer).

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Portion of the carrying amount as of the balance sheet date of obligations due all related parties that is payable after one year or beyond the normal operating cycle if longer.

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Date which lease or group of leases is set to expire, in CCYY-MM-DD format.

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Description of lessee's operating lease.

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The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

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The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

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Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income.

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Amount of transactions with related party during the financial reporting period.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

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Number of shares issued during the period as a result of the conversion of convertible securities.

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Related Party Transactions - Additional Information (Detail)				5 Months Ended	12 Months Ended
	Nov. 02, 2017 USD ($) $ / shares shares	May 01, 2017 USD ($)	Apr. 24, 2015	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($)	Dec. 31, 2017 GBP (£)	Oct. 31, 2020 USD ($)	Oct. 31, 2020 GBP (£)	Jun. 05, 2018 $ / shares	Oct. 26, 2017 USD ($)	Sep. 21, 2017 $ / shares
Related Party Transaction [Line Items]
Amount due under services agreement					$ 0	$ 861,030
Related party transaction amounts of work orders issued					570,525	593,933
Research and development expenses					33,620,223	22,359,712
Aggregate future minimum rental payments under operating lease					$ 4,615,675
Promissory note issued											$ 1,442,009
Convertible notes payable, interest rate		10.00%
Conversion of note payable into convertible preferred shares \| shares	238,579
Conversion rate of note payable into convertible preferred shares \| $ / shares	$ 2.70
Accrued interest cancelled	$ 145,833
Warrant to purchase preferred shares \| shares					900,000
Warrant exercise price \| $ / shares					$ 2.70					$ 10.48		$ 10.48
ARE [Member]
Related Party Transaction [Line Items]
Note payable to related party, amount		$ 2,500,000
Transition Services Agreement with Related Party [Member] \| Kadmon [Member]
Related Party Transaction [Line Items]
Percentage of administrative fees			7.00%
Services termination date			Apr. 24, 2018
Ownership percentage by related party			12.90%
Cash payment					$ 1,431,555	275,941
July 2016 Lease [Member]
Related Party Transaction [Line Items]
Operating lease expiration date					Dec. 31, 2021
Operating leases rent expense payment description					The Company records monthly rent expense on a straight-line basis from July 1, 2016 through December 31, 2021.
Deferred rent					$ 201,264	231,276
Operating lease rent expenses					487,555	487,559
Aggregate future minimum rental payments under operating lease					1,663,952
Letter of credit outstanding amount					$ 122,866
December 2016 [Member]
Related Party Transaction [Line Items]
Operating lease expiration date					Oct. 31, 2032
Operating leases rent expense payment description					The Company recorded monthly rent expense on a straight-line basis from December 15, 2016 through October 31, 2032.
Operating lease rent expenses					$ 0	1,660,806
Operating lease termination date					Mar. 31, 2018
Base rent and management fees				$ 563,507
Promissory note issued											$ 1,442,009
UCL Consultants Limited [Member] \| Research Agreement [Member]
Related Party Transaction [Line Items]
Amount due under services agreement					$ 389,101	775,315
Related party transaction amounts of work orders issued						1,885,000	£ 1,402,202
Agreement termination notice period					30 days
Research and development expenses					$ 636,000	538,000
UCL Consultants Limited [Member] \| Manufacturing Agreement [Member]
Related Party Transaction [Line Items]
Amount due under services agreement					0	2,466,142
Research and development expenses					$ 0	$ 1,904,352
Agreement termination date					2018-01
UCL Consultants Limited [Member] \| Scenario, Forecast [Member] \| Research Agreement [Member]
Related Party Transaction [Line Items]
Future obligations under agreement								$ 779,685	£ 612,382