For eight years now, the stock market has been soaring, and major market benchmarks continue to set new record highs. But for some particularly impressive stocks, gains have come a lot more quickly. If you had invested in Wayfair (NYSE:W), Omeros (NASDAQ:OMER), or AgroFresh Solutions (NASDAQ:AGFS) as recently as the beginning of 2017, then you could have doubled your money. But are they still good buys at current levels? Read on to find out more about these three stock winners and their future prospects.

W Chart

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Wayfair brings e-commerce home

Wayfair has accomplished a feat that many people thought impossible: finding a way to translate the home furnishings business to an online format. Given the challenges in transporting bulky items, many believed that handling furniture and other home furnishings would be impossible for a retailer without any brick-and-mortar presence. But Wayfair is seeing booming sales, and the fact that the company managed to lose less money than expected points to a future in which the retailer might actually become profitable.

Most of Wayfair's gains have come in the past couple of months, in the aftermath of a strong first quarter and strong anticipated sales growth for the near future. Investors need to be prepared for the possibility that Wayfair will emphasize expanding its scope and boosting its top-line results at the expense of short-term profits, and it could be a while before the bottom line gets into the black. However, for investors in other leading e-commerce players, that concept won't be a surprise, and it could bolster Wayfair's growth trajectory going forward.

Wayfair couch and pillows.

Image source: Wayfair.

Omeros looks healthier

Small biotech companies constantly aim to improve patients' lives and make money in the process. Omeros has aimed to do that with its approved drug Omidria, which is designed to prevent pupil constriction during and after cataract surgery. The company expects to bring in about $128 million in sales from the drug next year, but many investors are even more excited about its OMS721 candidate treatment for autoimmune-related diseases such as atypical hemolytic uremic syndrome.

Earlier this month, Omeros got word that the U.S. Food and Drug Administration had given OMS721 breakthrough therapy designation. That should accelerate the potential path to approval for the drug, and that in turn would help Omeros gain sales and profits from OMS721 more quickly if it passes clinical trial muster. With prospects looking bright, further good news could keep lifting Omeros higher.

AgroFresh's turnaround bears fruit

Along among these stocks, AgroFresh Solutions had suffered dramatically coming into 2017. The agricultural technology company had seen rising competition for its SmartFresh system for fruit quality management, and investors weren't certain whether the company had a viable growth strategy going forward. However, AgroFresh met the challenge by presenting its vision of the future in March, and by concentrating on its core post-harvest business as it works to figure out a better pre-harvest operational strategy, the company hopes that it can integrate its products to address fruit producers' needs throughout the supply cycle.

In May, AgroFresh's first-quarter financial results reflected the near-term success of the company's efforts. Sales jumped 15%, as growth in Brazil, Chile, and Argentina was instrumental in keeping AgroFresh moving forward during the Northern Hemisphere's winter season. Investors will have to wait until the second half of 2017 to see the full impact of the company's turnaround efforts, but early results have them optimistic about AgroFresh's future.

For stocks to double in less than six months doesn't happen that often, and investors shouldn't take further gains for granted. Yet if AgroFresh, Omeros, and Wayfair keep moving forward with their respective growth efforts, then further share-price increases could well follow.