The offices in Cambridge didn't shutdown. Approximately Samsung bought one building (WiFi), and a year later Qualcomm bought the other (BT + audio). Both Samsung and Qualcomm had rounds of redundancies but have also both hired lots of people. My guess is both offices are about the same fullness as they were ten years ago.
I know a few people who joined ARM after CSR closed down but that could be just some offices shutting down.
(not an arm employee, btw)