Income taxes (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Income taxes
Income tax benefits for the net operating losses incurred	$ 0	$ 0

Amount of income tax benefits recorded for the net operating losses incurred.

No definition available.

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Namespace Prefix:	hook_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration