Calculating lapsed consumers - table with no transaction info

Hello everyone! 

I am well aware that some posts already exist on this topic, however, I am having issues adapating the solutions to my situation: 

The definition of a lapsed consumer: # of consumers who have purchased within last 12 months, but have not done so in over the previous 3 months. After 12 months of no purchases, the user is no longer considered to be lapsed.

I have a DimDate table. 

The other table is the customer table. Where I have a specific customer ID. This table is populated each time a customers is making a purchase (same customer will get the same customer ID). There is a Date column (connected to my date table). 

This table do not have any other transactional information (order, value, etc.)

I believe I need to translate this into DAX (or calculated columns?):

"If a customer ID is present within the last 12 months, but is no present within the last 3 months, then count as "Lapsed" (or add Lapsed in a calculated column? and then add a count measure?) But, if the customer ID is not present in the last 12 months show "Not Lapsed" (or do not count as Lapsed)". 

Fields names: 
Date: DimDate[Date]

Customer ID: Customer_table[customerID]

The main goal is to: COUNT the number of Lapsed customers over the selected period (typical date filters) 

Thank you for your help and guidance!

Bt.