What: March was a solid month for stocks related to 3D printing. Even Proto Labs (NYSE:PRLB), which only generates about 10% of its revenue from 3D printing activities, rose nearly 15%.

So what: Aside from a press release highlighting that Proto Labs won Frost & Sullivan's 2016 manufacturing leadership award for customer value, March was an otherwise light news month for the company. More broadly, the S&P 500 rose 4.3% and other 3D printing stocks reported better-than-expected earnings during the month. It's possible that investor optimism toward stocks in general and the 3D printing sector specifically may have driven Proto Labs higher.

Image source: Proto Labs.

However, whenever a stock moves higher absent of any apparent development, investors should revisit the underlying fundamentals of the business to see if it can support the stock's rise. Last month, Proto Labs reported solid fourth-quarter growth in what's proven to be a challenging growth environment for many industrial-facing companies. During the quarter, Proto Labs served 12,414 product developers, a 22% increase year over year, which suggests that its rapid manufacturing and 3D printing services are faring well in the marketplace.

Overall, Proto Labs' fourth-quarter revenue rose 32% year over year to $73.8 million, which translated to 15.3% increase in earnings to $0.45 per share. By segment and geography, Proto Labs experienced growth across the board. European sales increased 22.3% year over year to $12.2 million, while sales originating from Japan increased 45.9% to $2.6 million.

Now what: For about 27 times forward earnings, investors get the opportunity to buy a $2 billion company with a long-term goal of reaching $1 billion in annual sales. For reference, Proto Labs generated $264.1 million in revenue during 2015, and the fourth-quarter marked the 14th consecutive quarter it reported record revenue.

Ultimately, if Proto Labs continues to execute the way it has been and increasing the number of product developers it serves, history may reflect favorably on today's stock price.