A Portland biotechnology company has decided to expand its operation to Scarborough rather than be the first tenant of a major development proposed by John Cacoulidis on the South Portland waterfront.Binax, which develops and manufactures diagnostic tools, was unable to reach an agreement with Cacoulidis to build a new office and laboratory building at the Spring Point site, said Gregory Boulos of CB Richard Ellis/The Boulos Company.Binax has outgrown its location on Read Street in Portland and company officials said the Cacoulidis project would be an ideal location, especially for its view of Portland Harbor.Binax has signed an agreement to move into the Enterprise Center at 10 South Gate Road in Scarborough, where an existing building is being renovated in anticipation of the company’s arrival in April.South Portland officials said they are disappointed that Binax decided to move to Scarborough, but they are confident that Cacoulidis will move ahead with his plans to build a hotel and marina with office and retail space.