Compuware said it was selling the company to private equity firm Thoma Bravo in a deal valued at $2.5 billion. The enterprise software company, which primarily offers mainframe operating software, has been retooling, divesting units and fending off activist investors. Compuware also spun off its Covisint unit recently. Those moves refocused Compuware on its mainframe and application performance monitoring software. As a private company Compuware and Thoma Bravo said they will be able to take a long-term strategic view and focus on returns.