p <- ggplot(data = df, aes(x = Date, y = Revenue, group = 1,
            text = paste("Date: ", Date,
                         "
Revenue: $", Revenue,
                         "
Target: $", Target)
)) +
   geom_line(colour = "grey", aes(Date, Target)) +
   geom_line(colour = "#408FA6")
ggplotly(p, tooltip = "text")