Summary of significant accounting policies - Revenue recognition from contracts with customers (Details)	3 Months Ended
Mar. 31, 2020 item Program
Summary of significant accounting policies
Number of preclinical research programs \| Program	2
Number of combined performance obligation for each research program	1
Number of research program performance obligations	2

The number of preclinical research programs in collaborative arrangement.

No definition available.

Name:	hook_CollaborativeArrangementNumberOfPreclinicalResearchPrograms
Namespace Prefix:	hook_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration