UNDOCUMENTED MECHANICS
The wave advances every 17 frames, about 0.7s.
0.6s cast delay. Not shown in the tooltip; it caps how often the skill can be cast and is unaffected by faster cast rate.
"Width" above follows a diminishing curve, not a flat gain per level; the other numbers in the same block do not: 9yards at level 1, 11yards at 5, 13yards at 10, 13yards at 20, 15yards at the limit. Reaching the limit takes skill level 60, gear bonuses included, so the first few points are worth far more than the last ones.
On impact it spawns a second missile; that damage is not included in the figure above.