Related Party Transactions - Narrative (Details)			6 Months Ended	12 Months Ended
	Oct. 17, 2018 USD ($)	Aug. 01, 2018 USD ($) day	Jun. 30, 2019 USD ($) day	Dec. 31, 2018 USD ($)
Related Party Transaction [Line Items]
Monthly retainer for advisory services		$ 35,000
Maximum days to cure material breach (days) | day		5
Severance expense				$ 300,000
Epi-Cure Pharmaceuticals, Inc. | Affiliated Entity
Related Party Transaction [Line Items]
Amount paid for transaction			$ 0
Expenses from transactions with related party			100,000
Epi-Cure Pharmaceuticals, Inc. | Affiliated Entity | Agreement With Head Of Research And Development
Related Party Transaction [Line Items]
Purchases from related party	$ 100,000
Maximum funding amount			500,000
License payment if option is exercised			2,000,000
Milestone payments			$ 63,000,000
Minimum days notice to terminate prior to written notice (days) | day			60
Epi-Cure Pharmaceuticals, Inc. | Affiliated Entity | Development Costs And Profits
Related Party Transaction [Line Items]
Cost and revenue split (percent)			50.00%