Stockholders’ Equity (Deficit) (Details) - USD ($)			1 Months Ended						3 Months Ended	6 Months Ended	12 Months Ended
	Aug. 01, 2016	Jun. 08, 2016	Oct. 31, 2017	Sep. 30, 2017	Mar. 31, 2017	Aug. 31, 2016	Jun. 30, 2016	Nov. 30, 2015	Sep. 30, 2016	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jul. 26, 2016	Sep. 30, 2015	Jan. 31, 2015	Oct. 31, 2014
Proceeds from issuance of redeemable convertible units												$ 5,500,000	$ 10,833,000
Transaction costs												3,293,000	$ 445,000
Stock issued, shares	6,250,000
Prepaid expenses											$ 1,109,000	$ 1,034,000
Issuance of units related to option exercises, shares												1,109	772
Beneficial conversion feature on convertible preferred stock											384,000	$ 7,660,000
Accrued dividends on preferred stock											$ 1,534,000	$ 642,000
Deemed dividends on preferred stock									$ 20,900,000
Common stock, par value											$ 0.001	$ 0.001		$ 0.001
Common stock, shares authorized											200,000,000	200,000,000		200,000,000
Price per share of common stock	$ 12.00
Underwriting discounts and commissions	$ 5,300,000
Offering expenses	3,700,000
Proceeds from IPO, net	$ 66,000,000											$ 69,750,000
Shares outstanding	45,078,666										78,643,954	45,078,666
Gross proceeds from common stock											$ 95,954,000
Common stock issued											78,643,954	45,078,666
Common stock and warrants issued in public offering, net											$ 75,087,000	$ 69,750,000
Third Party Investors [Member]
Transaction costs												40,000	$ 3,100,000
GoldenTree Asset Management LP [Member]
Stock issued, shares	208,333
Kadmon I, LLC [Member]
Ownership percentage											12.10%
Kadmon I, LLC [Member] | Investment Funds [Member]
Ownership percentage											80.00%
Ownership percentage after distribution											50.00%
Kadmon I, LLC [Member] | Certain Parties [Member]
Ownership percentage											20.00%
Ownership percentage after distribution											50.00%
Class A Units [Member]
Advisory agreement expense												$ 3,000,000
Issuance of units related to option exercises, shares												7,200	5,011
Shares issued for settlements												25,000
Third party obligations settlement expense												$ 100,000
Unit price															$ 32.50		$ 39.00
Class B Units [Member]
Common units outstanding											0
Class C Units[Member]
Common units outstanding											0
Class D Units [Member]
Common units outstanding											0
Class D Units [Member] | Conversion Event Threshold Three [Member]
Proceeds from conversion event											$ 4,200,000
Class E Redeemable Convertible Units [Member]
Proceeds from issuance of redeemable convertible units												$ 5,500,000
Stock issued, shares												478,266
Preferred stock issued																43,478
Redemption value											$ 85,000,000
Liquidation preference											125.00%
Liquidation preference rate increase											1.00%
Unit price							$ 11.50
Beneficial conversion feature, discount percentage						15.00%
Deemed dividends on preferred stock						$ 13,400,000
Class E Redeemable Convertible Units [Member] | Chief Executive Officer [Member]
Stock issued, shares							86,957					86,957
Class E Redeemable Convertible Units [Member] | Board of Directors Chairman [Member]
Stock issued, shares							21,740					21,740
Class E Redeemable Convertible Units [Member] | Directors [Member]
Stock issued, shares							21,740					21,740
Class E Redeemable Convertible Units [Member] | Third Party Investors [Member]
Stock issued, shares												75,875	3,438,984
Class E Redeemable Convertible Units [Member] | GoldenTree Asset Management LP [Member]
Stock issued, shares							43,479					43,479
Convertible Preferred Stock [Member]
Preferred stock, shares authorized		10,000,000									10,000,000	10,000,000		10,000,000
Preferred stock issued		30,000									30,000	30,000
Preferred stock outstanding											30,000	30,000
Issuance per share		$ 1,000
Accrued dividends added to liquidation preference										$ 1,400,000
Liquidation preference		$ 30,000,000									$ 31,400,000
Beneficial conversion feature, discount percentage	20.00%
Shares issued for conversion											3,351,717	3,191,843
Accrued dividends on preferred stock											$ 1,500,000	$ 600,000
Deemed dividends on preferred stock						$ 7,500,000					400,000	200,000
Series B And C Preferred Stock [Member] | Conversion Event Threshold Three [Member]
Proceeds from conversion event											41,700,000
License Agreement, Jinghua [Member]
Proceeds from issuance of redeemable convertible units								$ 10,000,000
Minimum [Member] | Conversion Event Threshold Three [Member]
Company valuation											$ 45,800,000
Minimum [Member] | Class E Redeemable Convertible Units [Member]
Percent of value for conversion											80.00%
Qualified IPO threshold											$ 75,000,000
Liquidation preference											5.00%
Maximum [Member] | Class E Redeemable Convertible Units [Member]
Liquidation preference											10.00%
Pre-IPO [Member] | Class E Redeemable Convertible Units [Member]
Conversion price											$ 11.50
Post-IPO [Member] | Class A Units [Member]
Percent of value for conversion											85.00%
Post-IPO [Member] | Class E Redeemable Convertible Units [Member]
Conversion price											$ 11.50
2015 Second-Lien Convertible Debt [Member]
Borrowings, face amount												$ 15,000,000			$ 92,000,000
2017 Public Offering [Member]
Transaction costs											$ 5,300,000
Stock issued, shares			4,500,000	22,275,000							26,775,000
Price per share of common stock											$ 3.001
Gross proceeds from common stock			$ 13,600,000	$ 66,800,000							$ 80,400,000
Net proceeds from common stock											$ 75,100,000
Warrants issued			1,800,000	8,910,000							10,710,000
Warrants exercise price											$ 3.35
Warrant exercise price term											5 years
Proceeds from common stock issued in public offering											$ 57,600,000
Proceeds from warrants issued in public offering											22,800,000
2017 Private Placement [Member]
Transaction costs					$ 1,800,000						$ 1,800,000
Stock issued, shares					6,767,855						6,767,855
Price per share of common stock					$ 3.36						$ 3.36
Gross proceeds from common stock					$ 22,700,000						$ 22,700,000
Net proceeds from common stock					$ 20,900,000						$ 20,900,000
Warrants issued					2,707,138						2,707,138
Warrants exercise price					$ 4.50						$ 4.50
Warrant exercise price term					13 months						13 months
Liquidation damages, as percentage of subscription amount											2.00%
2017 Private Placement [Member] | Maximum [Member]
Liquidation damages, as percentage of subscription amount											8.00%