I'm involved with a startup that's specifically tackling this very problem -- how do you learn the theory & application of machine learning quickly (especially if you already know programming well). We teach using diagrams and interactive coding exercises in the browser: www.dataquest.io

If you already know Python, you could dive straight into machine learning (https://www.dataquest.io/course/machine-learning-fundamental...) and work your way upto calc / lin al, linear regression, decision trees, neural nets, etc.

If you want to get a taste without signing up, you can check out our blog posts that preview the course (like this one: https://www.dataquest.io/blog/machine-learning-tutorial/)

Happy to answer any questions over DM or email (srini@ourdomain).