Summary of Significant Accounting Policies - Intellectual Property (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Summary of Significant Accounting Policies
Intellectual property-related expenses	$ 1.3	$ 1.1

Represents the amount of expenses associated with intellectual property.

No definition available.

Name:	atre_IntellectualPropertyExpenses
Namespace Prefix:	atre_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration