Cost of Goods of 30% of factory gate price is fairly standard for electronics, a bit lower in small market professional kit (You have NRE costs to amortise over a smaller volume), quite a bit higher in mass market consumer where you are basically competing on price, and are doing big volumes. I generally warn my management if I see COG exceeding about 25% of factory gate, then they can take a view.
Remember that all the engineering (including software) is an NRE cost, which has to be recouped, and you have things like buildings, and management, QA, sales, marketing (Different functions!), admin and janitorial staff to pay for that are not generally accounted in the COG.
Also remember that the metalwork, and assembly costs factor into the COG, so your BOM should be significantly lower then the COG, I usually try to keep the electronics BOM < 50% of target COG.
Seriously this stuff is business 101, it follows on from the "Sell things for more then they cost you" lesson.
Regards, Dan.