Axcelis Technologies' earnings have taken off in quite an impressive fashion. The sweetener is that insiders have a mountain of stock, and the CEO remuneration is quite reasonable. The drastic earnings growth indicates the business is going from strength to strength. Hopefully a trend that continues well into the future. Big growth can make big winners, so the writing on the wall tells us that Axcelis Technologies is worth considering carefully. However, before you get too excited we've discovered 1 warning sign for Axcelis Technologies that you should be aware of.