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.

No definition available.

Name:	us-gaap_ClassOfStockLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Exchange Agreement with Immunic AG - Additional Information (Details) € in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($)	Mar. 31, 2019 EUR (€)	Jan. 31, 2019
Vital Therapies, Inc. \| Immunic, Inc.
Class of Stock [Line Items]
Expected ownership percentage			89.00%
Reverse Merger Investment
Class of Stock [Line Items]
Consideration received on transaction	$ 30.0	€ 26.7