So Apple drops 6% because they're migrating to one of Cirrus's newer components? This of course is assuming the customer in question is Apple.
a decreased forecast for a high volume product as the customer migrates to one of Cirrus Logics newer components.
As you can read here:
http://www.reuters.com/article/2013/04/17/us-apple-shares-idUSBRE93G0PA20130417
Cirrus get over 90% of their revenue from Apple. If Apple is not purchasing in anticipated quantities in the next quarter, particular part(s) for a current device, but transitioning to an as yet unreleased product - say 4 months hence, then that will definitely have a knock-on effect. Cirrus was hammered to the tune of over 15% today. This would not have happened if this one customer was amongst the remaining 10% of its sales.
Simply put, Cirrus were anticipating selling X amount of part(s) to Apple but have reduced their guidance. Cirrus being very much in the supply change of Apple would have been well aware of Apple's timetable for new devices going forward.