If you receive the error message Violation: ''extensionTaxonomyLineItemNotLinkedToAnyHypercube'' when validating an ESEF file, it means a line item is not linked to a hypercube in the extension taxonomy’s definition linkbase.
You can read more about hypercubes from the Workiva Support page What is a hypercube?.
There are items which do not use any dimensions, but they still need to be added to the definition linkbase. These items are placed in the section titled "[999999] Line items not dimensionally qualified".
False error messages
We've experienced an issue where the validators used by some OAM's (Officially Appointed Mechanism) incorrectly state that certain items located in section "[999999] Line items not dimensionally qualified" are incorrectly placed, because they do in fact use dimensions.
This is not the case, however. So far we haven't had a single case with a customer where an item was incorrectly placed in in the [999999] section, it has instead been an issue with the validator in question.
If you receive a message from your OAM that items are incorrectly placed in the [999999] section, contact our support team at wkrt.support@workiva.com.