 to 43.4%, a 50-basis-point improvement for the comparable period. Non-GAAP gross margin for the quarter was 49.2%, compared to 47.5% for the comparable period, a 170-basis-point improvement.
We picked up 30 basis points of our 165- to 240-basis-point improvement we are looking from our 2018 full-year baseline of 48.9%, so pretty strong start there. Opex, Q1 2019. Total operating expenses as a percentage of revenue on a non-GAAP basis were approximately 37%, which is in line with our expectations for the quarter. And that's -- we guided that higher expenses, Fred mentioned it in his opening statement, sales meetings and shows, and it's just a -- it's a heavy operating-expense quarter for us.
Tax rate on a GAAP basis for the quarter was 10% and 17% -- compared to the 17% for the prior-year period. Tax rate on a non-GAAP basis for the quarter was 21%, compared to 23%. And we continue to benefit from stock-option exercise and the tax reform. EPS.
GAAP earnings were $0.11, compared to $0.10 for the comparable period. Non-GAAP earnings were $0.37 for Q1, compared to $0.31 for the comparable period, a 19% increase over the same period. A few other items of interest for everyone. Debt balance was $384 million.
A leverage ratio of 2.2 on a gross basis and 1.97 on a net basis. We paid our debt down by $11 million. Working capital was $243 million, capex for the quarter came in at $18.3 million, DNA of approximately $22.4 million, and stock comp expense of $1.8 million. So overall, we have three quarters left, but I think we're off to a good start.
Fred?
Fred Lampropoulos -- Chairman and Chief Executive Officer
Well, Raul, thank you very much. Listen, I know there are other calls going on today. I think that gives you the core of what you wanted to talk about. We continue to be enthused about the business and the opportunities.
As I mentioned, the pipeline is full. We've recently received a number of regulatory approvals. We don't generally talk about those and I won't go into those specifically, but the business is poised to, I think, respond and to take advantage of the marketplace and the opportunities. So with that said, I think that pretty well covers it.
So we'll get to the questions and try to keep this at a minimum. But the lines will be open. And as a reminder that after this call and the questions, for clarification, Raul and I will be around for an hour or two to answer questions that you may have and to clarify points for you. That being said, with that being done, then we'll wait and turn the time back over to our administrator, and we'll start answering your questions to the best of our ability.
Thank you again for attending.
Questions and Answers:
Operator
Thank you, sir. [Operator instructions] Our first question comes from the line of Jim Sidoti of Sidoti & Company. Your line is open.
Jim Sidoti -- Sidoti and Company -- Analyst
Good afternoon. Can you hear me?
Fred Lampropoulos -- Chairman and Chief Executive Officer
Yes, we can, Jim.
Jim Sidoti -- Sidoti and Company -- Analyst
Great. Fred, when you were talking about products that compete against Terumo being up 44%, you said that excluded the Prelude Ideal, I think? Can you give us a little more color on how the Prelude Ideal is doing?
Fred Lampropoulos -- Chairman and Chief Executive Officer
Yes. You know, Mike -- Jim, it's been one of the most successful products we've done in years. I was looking at some numbers earlier today. Again, it was a product that we just launched last year, in March of '18.
And in that month, we did $57,000 worth of revenue for the month of March. This year, we did $570,000 in revenue. And the reason it's so successful is that we're selling in Japan. We've got -- recently got approval in Japan.
It's on U.S., Canada, Australia. And this is this metal-reinforced sheet for radial procedures. So Jim, it's -- when you do these R&D projects, it's nice when you have one like this, they don't come along very often, but to be able to essentially pick up about a 10% market share in your first year is, I think, extraordinary. And we just have a lot of high hopes for this product line as we go forward.
Jim Sidoti -- Sidoti and Company -- Analyst
Right. And my second question has to do with the deal announced last week Medline acquiring Namic, positives and negatives to that. And I think Medline might have been a customer of yours. Can you give us some sense on how you think this all plays out?
Fred Lampropoulos -- Chairman and Chief Executive Officer
Yes. Well, first of all, Medline is one of our customers as well. We work with Cardinal and Medline and Avid, Owens & Minor, through distribution where hospitals require or have agreements and Merit provides certain parts of kits or stand-alone products. So that's kind of ongoing.
I would generally say this that, first of all, I think it's interesting to note, Jim, that when we started this company, it was to emulate Namic. They have great products. But whenever you have disruption and you have a product moving from a noncompetitor to a competitor, and by that I mean you've got it moving out of AngioDynamics and then into a company that competes with several other companies in that distribution and in that front-line manufacturing, it creates opportunities both on the national accounts level and in that sort of thing. I can tell you that there are a number of conversations going on as people try to figure this whole thing out.
The net of it all, Jim, is that I believe that it's a net plus-plus to Merit. And of course, now all this has to -- you've got, first of all, this deal sitting out here. It's going to take several months for it to close, but we view it as a big opportunity for the company not just in the U.S. but globally because no one really knows what's going to happen with all of those relationships.
And it creates doubt. Whenever you have doubt and you have disruption, there's opportunity there. So I think that's best way for me to answer your question. Raul, do you have a different idea? Would you -- do have any other thoughts on that?
Raul Parra -- Chief Financial Officer
No. I think this is --
Fred Lampropoulos -- Chairman and Chief Executive Officer
No. OK. All right. OK, Jimmy, go ahead, please.
Jim Sidoti -- Sidoti and Company -- Analyst
All right. And then the last for me. You didn't make any comments regarding your guidance you gave for '19 and '20, so I assume based on your results today that everything you were thinking three months ago is pretty much intact?
Fred Lampropoulos -- Chairman and Chief Executive Officer
Yes. I mean, I think our business is -- I don't see that anything has changed. I think that there are a number -- if I were to -- again, let me restate that. No, I do think there have been some positives that are over and above some of the things we talked about.
There are always headwinds, but I think there are more tailwinds. We're feeling a freeze to our back. And I'll just kind of leave it at that, Jim, without going in any detail. But I think I am -- I would be more positive about our business, just kind of looking at it today from what I did just because of some recent developments and opportunities.
Jim Sidoti -- Sidoti and Company -- Analyst
Right. I think historically, you've always kind of maintained outlook after the first quarter. It takes you at least to the back half of the year before you make any changes. So I assume that -- I didn't expect you to make any big changes this afternoon.
Fred Lampropoulos -- Chairman and Chief Executive Officer
Yes. No. We wouldn't do that, especially as you pointed out as we expanded these years in that core growth. I think it's prudent for us to watch this next quarter.
We will then be ending the summer quarter. But based on what we see and how we feel about the business and our optimism, we'll play it by year, and we'll see where we are in another 90 days or so.
Jim Sidoti -- Sidoti and Company -- Analyst
All right. Thank you.
Fred Lampropoulos -- Chairman and Chief Executive Officer
All right, Jim. Thank you. Nice to hear your voice, Jim.
Operator
Thank you. Our next question comes from the line of Larry Biegelsen of Wells Fargo. Your line is open.
Adam Maeder -- Wells Fargo -- Analyst
Hi, guys. It's Adam Maeder on for Larry. I wanted to start with one on the top line and ask about the cadence of growth for the remainder of the year. You did 10% organic in Q1.
To hit your full-year guidance, 8% to 10% implies high-single-digit growth in the second half of the year against more challenging prior-year comp. So what