Submitted my resume online and got an e-mail the next day to schedule a short chat on the phone. I scheduled for a few days later. That first call was with an HR rep who asked basic questions about why I wanted to work for Mathworks, what my thesis was going to be about, and how I handled conflict. Afterwards, I was scheduled for a technical phone interview the next week. The technical phone interview lasted about 45 minutes and covered math (calculus, linear algebra), programming concepts (overloading, constructors, destructors, etc), DSP (convolution, z-transform, stability, causality, etc) and MATLAB (matrix operations, etc). I answered probably 80% of the questions completely correctly and another 10% I didn't answer correctly, but gave some insight into how I would answer it if I remembered the precise equations required (a ton of this stuff I hadn't learned for over 8 years). I got an email the next day to schedule an onsite interview.