Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Thousands	6 Months Ended
Mar. 31, 2023	Mar. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Total Fees Waived Based on Contractual Obligations	$ 80	$ 50

Total fees waived based on contractual obligations.

No definition available.

Name:	hnna_TotalFeesWaivedBasedOnContractualObligations
Namespace Prefix:	hnna_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration