Stock Quotes in this Article: GDP, GMCR, HALO, IDRA, AXDX

DELAFIELD, Wis. (Stockpickr) -- Corporate insiders sell their own companies' stock for a number of reasons.

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They might need the cash for a big personal purchase such as a new house or yacht, or they might need the cash to fund a charity. Sometimes they sell as part of a planned selling program that they have put in place for diversification purposes, which allows them to sell stock in stages instead of selling all at one price.

Other times they sell because they think their stock is overvalued and the risk/reward is no longer attractive. Some even dump their own stock because they have inside knowledge that a competitor is eating their lunch and stealing market share.

But insiders usually buy their own shares for one reason: They think the stock is a bargain and has tremendous upside.

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The key word in that last statement is "think." Just because a corporate insider thinks his or her stock is going to trade higher, that doesn't mean it will play out that way. Insiders can have all the conviction in the world that their stock is a buy, but if the market doesn't agree with them, the stock could end up going nowhere. Also, I say "usually" because sometimes insiders are loaned money by the company to buy their own stock. Those loans are often sweetheart deals and shouldn't be viewed as organic insider buying.

At the end of the day, its large institutional money managers running big mutual funds and hedge funds that drive stock prices, not insiders. That said, many of these savvy stock operators will follow insider buying activity when they agree with the insider that the stock is undervalued and has upside potential. This is why it's so important to always be monitoring insider activity, but it's twice as important to make sure the trend of the stock coincides with the insider buying.

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Recently, a number of companies' corporate insiders have bought large amounts of stock. These insiders are finding some value in the market, which warrants a closer look at these stocks. Here's a look at some stocks where insiders have been doing some big buying in per SEC filings.

Halozyme Therapeutics

One biopharmaceutical stock that insiders are active in here is Halozyme Therapeutics (HALO), which is develops and commercializes innovative products that advance patient care. Insiders are buying this stock into modest strength, since shares are up 5% so far in 2013.

Halozyme Therapeutics has a market cap of $802 million and an enterprise value of $720 million. This stock trades at a premium valuation, with a price-to-sales of 14.95 and a price-to-book of 71.72. Its estimated growth rate for this year is -41.7%, and for next year it's pegged at 33.8%. This is a cash-rich company, since the total cash position on its balance sheet is $76.01 million and its total debt is $31.82 million.

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A director just bought 100,000 shares, or about $681,000 worth of stock, at $6.72 to $6.91 a share.

From a technical perspective, HALO is currently trending just below its 50-day moving average and above its 200-day moving average, which is neutral trendwise. This stock recently gapped down sharply from $8.75 to $6.92 a share with heavy downside volume. Following that gap down, shares of HALO have gone on to hit a recent low of $6.51 a share, which occurred right above its 200-day moving average at $6.53 share. Shares of HALO have now started to rebound off that recent lows and it's moving within range of triggering a near-term breakout trade.

If you're bullish on HALO, then I would look for long-biased trades as long as this stock is trending above some near-term support levels at $6.51 or $5.88 a share and then once it breaks out above some near-term overhead resistance levels at $7.32 to its 50-day at $7.41 a share high volume. Look for a sustained move or close above that level with volume that hits near or above its three-month average action of 1.44 million shares. If that breakout hits soon, then HALO will set up to re-fill some of its previous gap down zone that started at $8.75 a share. Any high-volume move above $8.75 will then give HALO a chance to tag its next major overhead resistance level at around $10 a share.

Accelerate Diagnostics

Another health care player that insiders are loading up on here is Accelerate Diagnostics (AXDX), engages in the research and development and commercialization of proprietary surface chemistry formulation and quantitative bio-analytical measurement instruments. Insiders are buying this stock into big time strength, since shares are up sharply in 2013 by 118%.

Accelerate Diagnostics has a market cap of $342 million and an enterprise value of $286 million. This stock trades at a premium valuation, with a price-to-book of 12.19. This is a cash-rich company, since the total cash position on its balance sheet is $27.17 million and its total debt is zero.

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A director just bought 78,494 shares, or about $618,000 worth of stock, at $7.72 to $8 per share. That same director also just bought 413,090 shares, or about $3.32 million worth of stock, at $8.04 per share.

From a technical perspective, AXDX is currently trending above both its 50-day and 200-day moving averages, which is bullish. This stock has been uptrending strong for the last few weeks, with shares moving higher from its low of $6.86 to its intraday high of $8.86 a share. During that move, shares of AXDX have been consistently making higher lows and higher highs, which is bullish technical price action. That move has started to push shares of AXDX within range of triggering a major breakout trade.

If you're in the bull camp on AXDX, then look for long-biased trades as long as this stock is trending above its 50-day at $8.22 or above more near-term support at $7.25, and then once it breaks out above some near-term overhead resistance levels at $8.95 to its 52-week high at $9.22 a share with high volume. Look for a sustained move or close above those levels with volume that registers near or above its three-month average action of 96,009 shares. If that breakout triggers soon, then AXDX will set up to enter new 52-week-high territory, which is bullish technical price action. Some possible upside targets off that move are $12 to $15 a share.

Green Mountain Coffee Roasters

One consumer goods player that insiders are in love with here is Green Mountain Roasters (GMCR), which is engaged in the specialty coffee and coffee maker businesses. Insiders are buying this stock into major strength, since shares are up a whopping 100% so far in 2013.

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Green Mountain Coffee Roasters has a market cap of $12.5 billion and an enterprise value of $11.4 billion. This stock trades at a reasonable valuation, with a trailing price-to-earnings of 28.71 and a forward price-to-earnings of 22.30. Its estimated growth rate for this year is 35.4%, and for next year it's pegged at 15.1%. This is barely a cash-rich company, since the total cash position on its balance sheet is $352.20 million and its total debt is $323.60 million.

A director just bought 14,000 shares, or about $1.05 million worth of stock, at $75.14 per share.

From a technical perspective, GMCR is currently trending above both its 50-day and 200-day moving averages, which is bullish. This stock has been uptrending strong for the last two months, with shares moving higher from its low of $67.51 to its intraday high of $84.41 a share. During that uptrend, shares of GMCR have been making mostly higher lows and higher highs, which is bullish technical price action. That move has now started to push shares of GMCR into breakout territory above some past resistance levels at $82.51 to $82.95 a share.

If you're bullish on GMCR, then look for long-biased trades as long as this stock is trending above $80 or above its 50-day at $76 and then once it breaks out above its new 52-week high at $84.40 a share with high volume. Look for a sustained move or close above that level with volume that hits near or above its three-month average volume of 3.80 million shares. If that breakout triggers soon, then GMCR will set up to enter new 52-week-high territory, which is bullish technical price action. Some possible upside targets off that move are $100 to $110 a share.

Goodrich Petroleum

One energy player that insiders are finding value in here is Goodrich Petroleum (GDP), which explores, exploits, develops and produces oil and natural gas properties in East Texas and Northwest Louisiana. Insiders are buying this stock into major strength, since shares are up a whopping 130% so far in 2013.

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Goodrich Petroleum has a market cap of $786 million and an enterprise value of $1.40 billion. This stock trades at a reasonable valuation, with a price-to-sales of 4.48 and a price-to-book of 7.25. Its estimated growth rate for this year is -190%, and for next year it's pegged at 37.9%. This is not a cash-rich company, since the total cash position on its balance sheet is $2.65 million and its total debt is $554.11 million.

The chairman of the board just bought 40,000 shares, or about $1 million worth of stock, at $25 per share. Another director also just bought shares 70,000, or about $1.75 million worth of stock, at $25 per share.

From a technical perspective, GDP is currently trending above both its 50-day and 200-day moving averages, which is bullish. This stock has been uptrending very strong for the last two months, with shares soaring higher from its low of $11.16 to its recent high of $24 a share. During that uptrend, shares of GDP have been consistently making higher lows and higher highs, which is bullish technical price action. That move now has GDP trending within range of triggering a near-term breakout trade.

If you're bullish on GDP, then look for long-biased trades as long as this stock is trending some near-term support levels at $20.10 or above $19, and then once it breaks out above some near-term overhead resistance levels at $23 to its 52-week high at $24.01 a share high volume. Look for a sustained move or close above those levels with volume that hits near or above its three-month average volume of 1.07 million shares. If that breakout hits, then GDP will set up to enter new 52-week-high territory, which is bullish technical price action. Some possible upside targets off that move are $30 to $33 a share.

Idera Pharmaceuticals

One more stock with some decent insider buying is Idera Pharmaceuticals (IDRA), a clinical stage biotechnology company engaged in the discovery and development of novel synthetic DNA- and RNA- based drug candidates. Insiders are buying this stock into big time strength, since shares are up sharply by 83% so far in 2013.

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Idera Pharmaceuticals has a market cap of $74 million and an enterprise value of $51 million. This stock trades at a premium valuation, with a price-to-book of 24.92. Its estimated growth rate for this year is 34.6%, and for next year it's pegged at 1.9%. This is a cash-rich company, since the total cash position on its balance sheet is $16.30 million and its total debt is zero.

A director just bought 300,000 shares, or about $525,000 worth of stock, at $1.75 per share.

From a technical perspective, IDRA is currently trending above both its 50-day and 200-day moving averages, which is bullish. This stock has been uptrending strong for the last four months, with shares ripping higher from its low of 52 cents per share to its recent high of $2.13 a share. During that move, shares of IDRA have been consistently making higher lows and higher highs, which is bullish technical price action. That move has now pushed shares of IDRA within range of triggering a big breakout trade.

If you're bullish on IDRA, then look for long-biased trades as long as this stock is trending above some key near-term support levels at $1.47 to $1.45, and then once it breaks out above its 52-week high at $2.13 a share and then above some past resistance at $2.19 a share with high volume. Look for a sustained move or close above those levels with volume that hits near or above its three-month average action of 231,742 shares. If that breakout triggers soon, then IDRA will set up to enter new 52-week-high territory, which is bullish technical price action. Some possible upside targets off that breakout are $3 to $3.75 a share.

To see more stocks with notable insider buying, check out the Stocks With Big Insider Buying portfolio on Stockpickr.

-- Written by Roberto Pedone in Delafield, Wis.

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At the time of publication, author had no positions in stocks mentioned.

Roberto Pedone, based out of Delafield, Wis., is an independent trader who focuses on technical analysis for small- and large-cap stocks, options, futures, commodities and currencies. Roberto studied international business at the Milwaukee School of Engineering, and he spent a year overseas studying business in Lubeck, Germany. His work has appeared on financial outlets including CNBC.com and Forbes.com. You can follow Pedone on Twitter at www.twitter.com/zerosum24 or @zerosum24.