[Community Puzzle] The Dart 101

I thow darts, but I’ve never heard of losing points in x01 game.

Anyhow, I need clarification on losing more points than have been earned.

For instance: first turn: 10 X X

is the minimum 0 or is this a -40 (+10, -20, -30)

incidentally, this would make the next turn advantageous if it is miss-miss-miss and back to 0.