Hi: I am only guessing that this is a perennial - - it overwintered outdoors here in Orange County, CA, with ease. Now that it's in full bloom I can see adding a few more of them would be nice. Thanks for any input.
It looks like a Nierembergia. 'Mont Blanc' and 'White Robe' are older white varieties, but your plant could also be this newer one which appears to have a bit less yellow in the center: