Image source: II-VI.

What: Shares of engineered material and opto-electronic component manufacturer II-VI (NASDAQ:IIVI) declined on Wednesday, one day after the company's third-quarter earnings report propelled the stock higher. At 2:45 p.m. ET, shares of II-VI were down about 10%.

So what: II-VI's third-quarter results were generally positive. The company reported non-GAAP revenue of $200.9 million, up 10% year over year and about $8 million higher than the average analyst estimate. Strong 25% growth in the photonics business, as well as a 12% surge in performance products sales, more than offset a decline in the laser solutions segment. However, acquisitions in that area led total laser solutions revenue to grow slightly year over year.

Non-GAAP EPS was $0.35, up 52% year over year and $0.07 higher than analysts expected. Non-GAAP bookings totaled $233.3 million during the quarter, up 19.2% year over year, growing significantly faster than revenue.

Shares of II-VI surged on Tuesday due to the company's report, closing about 5.5% higher. That gain was more than undone on Wednesday, though, with no new news driving the decline.

Now what: One thing that could be giving investors pause is II-VI's guidance. The company expects revenue to grow during the fiscal fourth quarter, with revenue excluding acquisition effects expected between $200 million and $210 million, up from $196.7 million during the prior-year period. But non-GAAP EPS is expected to decline year over year, with the company guiding for a range of $0.22 to $0.24, compared to $0.27 in the prior-year period. Excluding acquisition effects, EPS is expected to be roughly flat year over year.

It's impossible to say exactly what caused the decline in the stock today, but II-VI CEO Francis Kramer expects a strong fourth quarter:

With our acquisitions and investments to commence next quarter, we are accelerating the build out of a scalable semiconductor VCSEL laser platform. II-VI Photonics delivered a robust quarter, particularly from the optical communication markets. Our record bookings this quarter indicate that we expect to end the fourth quarter strong.

Timothy Green has no position in any stocks mentioned. The Motley Fool recommends II-VI. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.