What: Shares of thin film equipment manufacturer Veeco Instruments (VECO -0.15%) fell as much as much as 20% on Tuesday. The decline has improved slightly to 14% at the time of this writing. The stock is down after the company's soft guidance and an analyst downgrade.

So what: Veeco's fourth-quarter non-GAAP EPS of $0.01 was slightly better than the consensus analyst estimate for a loss per share of $0.02. But despite the earnings beat, the company's weak guidance stood out most in the company's results.

Veeco guided for first-quarter revenue in the range of $70 million to $80 million -- a significant pullback from the company's year-ago first-quarter revenue of $98 million. 

Since our bookings in Q3 of 2015 were low, we see its impact in projected Q1 revenue, explained Veeco Instruments CFO Sam Maheshwari during the company's fourth-quarter earnings call (via a Reuters transcript).

Now what: Looking beyond Q1, management seemed uncertain about when revenue could begin to improve.

Metal organic chemical vapor deposition, or MOCVD investment backdrop is "expected to remain soft through the first half," based on the company's "somewhat depressed MOCVD bookings," management explained during the call.

It did say revenue will "probably" be up in Q2 versus Q1. Notably, however, a sequential increase between Q1 and Q2 would still likely represent a year-over-year decline since the company's revenue in Q2 last year was $131 million. It would take a huge jump for revenue to get from a range of $70 million to $80 million in Q1 to $131 million in Q2.