Complex sentence: James founded DP in his basement and, over the next 15 years, the company ultimately grew to employ 1,500 people with plants in Opelika, AL, Los Angeles, and Toronto, with sales of about $1 billion annually.
Split into simpler sentences: James founded DP in his basement and, over the next 15 years, the company experienced tremendous growth. It ultimately grew to employ 1,500 people with plants in Opelika, AL, Los Angeles, and Toronto, and the sales grew to about $1 billion annually.