Business Risk and Credit Risk Concentration Involving Cash - Additional Information (Details) - Customer	12 Months Ended
Jun. 30, 2020	Jun. 30, 2019
Risks And Uncertainties [Abstract]
Revenue from number of customers	1	2

Revenue from contract with customers, number of customers.

No definition available.

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Namespace Prefix:	astc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration