Commitments and Contingencies (Details) $ in Thousands	1 Months Ended			6 Months Ended	12 Months Ended
	Jul. 31, 2017 USD ($)	Apr. 30, 2017 USD ($)	Mar. 31, 2017 CAD ($)	Jun. 30, 2018	Dec. 31, 2017 USD ($)	Dec. 31, 2015 USD ($)	Aug. 31, 2015 USD ($)
Asset Purchase Agreement [Member] | 1st Order Pharmaceuticals, Inc. [Member]
Commitments and Contingencies [Line Items]
Upfront fee paid		$ 350
Milestone payments paid					$ 700
Asset Purchase Agreement [Member] | 1st Order Pharmaceuticals, Inc. and Valeant Pharmaceuticals International, Inc. [Member] | Clinical Development Milestones [Member]
Commitments and Contingencies [Line Items]
Future potential payments		1,000
Asset Purchase Agreement [Member] | 1st Order Pharmaceuticals, Inc. and Valeant Pharmaceuticals International, Inc. [Member] | Regulatory Milestone [Member]
Commitments and Contingencies [Line Items]
Future potential payments		13,000
Asset Purchase Agreement [Member] | 1st Order Pharmaceuticals, Inc. and Valeant Pharmaceuticals International, Inc. [Member] | Sales-based and Other Milestones [Member]
Commitments and Contingencies [Line Items]
Future potential payments		33,600
Asset Purchase Agreement [Member] | 1st Order Pharmaceuticals, Inc. and Valeant Pharmaceuticals International, Inc. [Member] | Pre-commercial and Single Digit Percentage Royalty on Commercial Sales Milestone [Member]
Commitments and Contingencies [Line Items]
Future potential payments		$ 1,500
License Agreement [Member]
Commitments and Contingencies [Line Items]
Upfront fee paid	$ 1,000
License Agreement [Member] | Clinical Development Milestones [Member]
Commitments and Contingencies [Line Items]
Future potential payments	2,000
License Agreement [Member] | Regulatory Milestone [Member] | Maximum [Member]
Commitments and Contingencies [Line Items]
Future potential payments	$ 7,000
Medpace Clinical Development Service Agreement [Member]
Commitments and Contingencies [Line Items]
Service agreement, term				5 years
Committed service obligation							$ 7,000
Contractual obligation paid						$ 3,000
License, Manufacture and Supply Agreement [Member]
Commitments and Contingencies [Line Items]
Upfront fee paid			$ 500