BELMONT, Calif.--(BUSINESS WIRE)--RingCentral, Inc. (NYSE: RNG), a leading provider of cloud business communications solutions, today announced financial results for the first quarter ended March 31, 2015. First Quarter Highlights: Revenue increased 35% year-over-year to $65.3 million; subscription revenue increased 37% year-over-year to $60.0 million. Total annualized exit monthly recurring subscriptions grew 35% year-over-year to $253.7 million. RingCentral Office® annualized exit monthly rec