An under-the-radar stock that could double By: CNBC.com News August 05, 2014 at 13:36 PM EDT AlphaOne's Dan Niles says the next big "disruptor" stock is RingCentral, a cloud-based phone system, with 1% penetration in a potential market of $75 billion. Read More >> Related Stocks: AT&T Inc Atlantic Power Corp Google, Inc. Microsoft Ringcentral Inc Vonage Holdings