We should always keep in mind that the best strategy for stocks is to pick good ones and hold them for a long time. That said, it's highly encouraging and very attractive when a company delivers a solid, estimates-beating quarter, or gets a glowing recommendation from an influential investment bank.

That was the case on Tuesday with a tech stock still relatively new to the market and a veteran biotech company. Here's a look at what made both pop, and whether the pair can sustain the upward momentum.

Two women celebrating while looking at a laptop screen.

Image source: Getty Images.

Slack Technologies

Have you gotten the message?

The stock of corporate e-communications specialist Slack Technologies (NYSE:WORK) received a badly needed boost of nearly 5% on Tuesday. The company has Piper Jaffray to thank, as the investment bank launched coverage of the stock that day with a positive analyst note.

Piper Jaffray's recommendation on Slack is overweight (buy, in simpler words), and its price target for the shares is $30. That's some distance from the $21.48 price the stock closed at on Monday.

The bank believes that the stock is oversold at this point, and as such its risk-versus-reward profile has improved. To a point that's understandable, as Slack has really slacked since its June IPO, with a share price that's plummeted by over 40%.

There is one clear and direct reason why: Microsoft (NASDAQ:MSFT), which has developed a very Slack-looking corporate messaging app of its own called Microsoft Teams. Not long after said IPO, Microsoft Teams pulled ahead in terms of daily average users (DAUs), an ominous sign for Slack so early in the race.

Microsoft versus Slack is hardly a fair fight. The monster IT company has not only gobs of capital and armies of talented software developers, it also possesses a huge installed base among enterprise clients. Once upon a time it actually considered buying Slack, but maybe direct and determined competition is a better way to grab hold of this market.

I'm a regular user of Slack's app and I like it. The problem from an investment standpoint is that the company is basically a one-trick pony racing a very powerful and aggressive horse. For me, Slack stock is not a buy no matter what kind of reviews it gets from analysts.

Incyte

Biotech stock Incyte (NASDAQ:INCY) rose by over 4% on Tuesday, on the back of strong and encouraging quarterly figures.

The company released its Q3 of fiscal 2019 results, which showed that its sales increased a robust 23% year over year to nearly $552 million. The driving force behind this growth was Incyte's cancer drug Jakafi, which also treats an affliction called graft-versus-host disease that can result from organ transplants. Jakafi sales rose 25% to $433 million in Q3.

On the bottom line, non-GAAP (adjusted) net profit more than doubled to $179 million ($0.82 per share).

Both headline results trounced analyst estimates. On average, prognosticators were expecting only $539 million in revenue and a per-share net profit of $0.65.

More encouragingly, Incyte upped its guidance for annual sales of the crucial Jakafi. The company now believes it will take in $1.65 billion to $1.68 billion from the drug. The previous forecast was for $1.61 billion to $1.65 billion.

Jakafi has obviously found its market, and Incyte has other weapons in this arsenal. Its leukemia drug Iclusig isn't at the level of Jakafi, but it still brought in over $20 million in sales during the quarter. Meanwhile, the company has a new cancer treatment in the pipeline, as well as another drug for graft-versus-host disease.

Although Incyte shares have risen precipitously over the last few years, I think the stock still has room to grow higher. Cancer is a scourge, and any drug that effectively helps treat any form of it should find a place on the market. I'd still be a buyer of Incyte stock.