message:positive - Reported value is below 0

A positive number was expected by the XBRL taxonomy but the number provided in the report is negative. XBRL taxonomy expects a positive number here and not a negative.

This could be a false positive, if you are reporting an exceptional situation, for example a negative value for a reserve. However, it could also mean that the value is not tagged correctly.

In XBRL, the fact value should always be relative to the balance of the concept that is chosen for the fact.

For example, the concept ifrs-full:CostOfSales is a debit concept in the IFRS taxonomy. So while you are likely to report this as a negative value in your readable version of the income statement, the underlying fact value in the iXBRL should be positive.

In most cases this is handled automatically. However, if you find out that for some of your line items this is not done correctly, you can correct this by setting the Concept is negative property on either the table row or a specific table cell to set it explicitly.

To find where these negative values are in your report you can use the preview feature and step through the financial statement values using the arrows in the top right. Check for negative values here, and review if they indeed should be negative.