Accounting for the Transaction - Preliminary Estimate of Purchase Price (Details) - USD ($) $ / shares in Units, $ in Thousands	Apr. 12, 2019	Jun. 30, 2020	Dec. 31, 2019	Apr. 11, 2019
Business Acquisition [Line Items]
Number of shares owned by Vital stockholders (in shares)		14,968,340	10,744,806
Vital Therapies, Inc.
Business Acquisition [Line Items]
Number of shares owned by Vital stockholders (in shares)				42,369,694
Vital Therapies, Inc. | Immunic AG
Business Acquisition [Line Items]
Number of shares owned by Vital stockholders (in shares)	1,059,269
Total fully-diluted shares (in shares)	1,186,769
Multiplied by the fair value per share of Vital common stock (in USD per share)	$ 33.20
Estimated purchase price	$ 39,400
Restricted Stock Units | Vital Therapies, Inc. | Immunic AG
Business Acquisition [Line Items]
RSUs owned prior to transaction (in shares)	127,500			5,100,000