Hate to be the bearer of bad tidings but any door manufactured after 1980 requires the utilization of safety glazing meeting Z97.1 and CPSC requirements. Current IBC code requires that you must bring entire door into compliance when replacing glass. Meaning all panes must be re-glazed with tempered glass, laminated glass, plexiglass (not recommended) polycarbonate (coated if possible. This is a legal obligation, if anyone gets hurt from non-complying glazing even after you sell the home, you could be held liable . Have been in the construction and window business for over 45 years, I know of what I speak. Check general condition of door, may be less expensive to purchase new door.