The microcontroller in question is a Teensy 3.2. My understanding is that the most current that you can get from a standard computer USB port is ~180mA; how much of that will current devices attached to the Teensy's Vin (+5V in the case of USB power) receive?
A USB port can supply at least 100 mA without USB enumeration, and 500 mA or more after successful enumeration. Most PCs (and laptops) don't actually restrict the current in either mode, and you can often draw more than 500 mA, but that is not recommended (or guaranteed).
Check this post. It seems many computers don't monitor it, and you can draw 500mA without a problem.