HID Headlight winks out after 15-20 minutes

Hello all,

My first little maintenance problem in 17 months of Prius ownership. I noticed the right headlight was inop after pulling into my garage the other evening. I turned the headlight switch off and on and lo and behold! On it came!

The next day, I was going into work early (4 AM, to monitor a departing early morning flight) and after about 20 minutes on the road, I noticed the right headlight go out. Once again, I flipped the headlight switch off and on and bingo! Back on it came! This seems to be the status quo at the moment.

Anyone have any experience in this? I don't have any experience with these HID lamps. It seems as though it isn't the lamp itself but probably the controller.

If the contoller, I have heard they are horribly expensive. I would hope that the warranty (or my extended warranty) would cover the replacement. I can't see how (if defective) that the controller would be considered a normal "wear and tear" item and not be covered. The lamp itself, yes.