Sunnyvale-based Good Technology, the developer of enterprise mobility and management software, said yesterday that it has acquired Copiun, a developer of mobile file sharing and document synchronization software. FInancial terms of the buy were not disclosed. Copiun was based in Marlborough, Mass. Good Technology said the buy will extend its collaboration solution. Copiun's software lets users on mobile devices access files, PowerPoint presentations, and other documents without the need for a VPN connection. The firm will remain in Massachusetts, which will become an office for Good Technolgoy.