Regular expression for a positive double number in a text box?

public static boolean isDouble(String itemPrice)
{
return itemPrice.matches("^[+]?\\d{0,10}+(\\.{0,1}(\\d{0,3}))?$");
}

double values like True when

5

.5

5.

5.5

When False values like

2..2

3,2

$3

afs

a/.sdf