Shares of Roku (ROKU) - Get Report have been pummeled over the last few weeks.

On Thursday, Roku stock was set for even more losses, down more than 5% in pre-market trading. That followed the near-14% drumming it took in Wednesday's session. However, shares actually rallied on the day, climbing 2.99% after the company unveiled new streaming products

At the pre-market lows, shares were down 30% from the highs made earlier this month. Because of this recent volatility, Roku stock has become a very difficult name to trade.

Consider that shares were trading for about $100 before the company reported earnings in early August. The stock promptly gapped higher on the results and ran to a high of $176.55 about a month later. The ~75% gain came within a month's time, marking the name as "overheated" in many traders' minds -- and rightfully so. 

Then remember that the stock was already up 230% before the post-earnings move! So to say that this one has been a volatile ride would be an understatement.

RealMoney's Eric Jhonsa made a compelling case for why Comcast (CMCSA) - Get Report and Facebook (FB) - Get Report are unlikely to displace Roku, but nevertheless, shares have been under recent pressure due to this news.

Comcast and Facebook are holdings in Jim Cramer's Action Alerts PLUS member club. Want to be alerted before Jim Cramer buys or sells CMCSA or FB? Learn more now.

Trading Roku Stock

Daily chart of Roku stock.

When stocks like Roku hit "runaway" mode, predicting where they rallies to and knowing when they are done is difficult. For this name, though, there were clues.

First, Roku stock put in a bearish engulfing candle (purple arrow) on the same day that it hit new all-time highs. That was the first sign that more downside was likely. After consolidating at its 20-day moving average, Roku stock again plunged and is now finding support at its 50-day moving average.

The next few days of price action will be key in determining what's next for Roku.

Investors will first need to determine what is support and what is resistance. Right now, the 50-day is the major support level to keep an eye on. There's a trendline there as well (blue line), and a close below this area would usher in more selling.

It's getting a bounce so far on Thursday, but will it be a tepid bounce that peters out over the next few days, sort of like what we saw with the 20-day moving average?

If the 50-day ultimately fails, Roku stock has the 38.2% retracement down near $119. That's also near the gap-up open from the post-earnings rally in August. Below that, Roku stock has the 100-day moving average at $109 and trending higher (not shown) and the 50% retracement at $101.43.

If the 50-day holds as support, traders need to see if Roku stock quickly reclaims the 20-day moving average and the 23.6% retracement at $141. If these metrics act as resistance, it may force Roku stock into an important test of 50-day support vs. 20-day resistance.

It's very important to remember to go level by level with names like Roku. Knowing upside targets and downside levels helps, but ultimately investors need to go day by day and step by step. Let's see how the 50-day does. 

This article is commentary by an independent contributor. At the time of publication, the author had no positions in the stocks mentioned.