One of this month's biggest winners is Roku (NASDAQ: ROKU), soaring 16% last week and 89% for all of November. The stock's been on fire since the company posted game-changing third-quarter results in its first financial report as a public company.Some reports earlier in the week credited the rally to a short squeeze, which is a possibility since 4.8 million shares of Roku, or roughly 30% of the public float, were sold short by the end of October.