The Boston office of IntraLinks, a provider of online workspaces for secure document exchange, is expanding its local presence.

The firm has signed a lease for 20,000 square feet of space at the Schrafft Center in Charlestown. The company will be moving from a 12,000-square-foot office on Bedford Street in Boston.

William Bush represented the landlord, The Flatley Co., in the transaction, while The Stevens Group represented the tenant.