Looking at margin improvement in another way, our total cost of revenue only increased 3% year-over-year compared to the 30% increase in total revenue we realized in the same period. This illustrates the progress we are making in implementing manufacturing efficiencies and cost reductions across both products and services as well as the benefits of higher revenue, increasing production volumes and tight control of overhead costs. We are laser-focused on the activities we believe will drive significant long-term and sustainable improvement in our gross margins. Continuing down the P&L. Total operating expenses were $12.8 million in the third quarter consisting of $3.5 million in sales and marketing, $3.1 million in R&D and $6.2 million in G&A.
This compares to total operating expenses of $14.1 million in the third quarter of 2022. The decrease was largely due to nonrecurring costs incurred in the third quarter of last year associated with the strategic review process initiated by our Board of Directors in that period. Net loss was $13.4 million in Q3. This compares to a net loss of $16.3 million in Q3 last year. This improvement was largely due to higher revenue, better gross margins and lower operating expenses in Q3 this year. Net loss per share was $0.31 in Q3 compared to net loss per share of $0.38 in the prior year quarter. With respect to noncash expenses and capital expenditures, depreciation and amortization was $0.8 million, stock compensation expense was $1.3 million and capital expenditures were $0.5 million in the third quarter.
I’ll now turn to our outlook. We are once again reaffirming our previous full year 2023 revenue guidance of at least $22 million, which represents growth of at least 30% and assumes we will place at least 15 systems. Compared to Q3, we expect Q4 system revenue to be relatively consistent, consumable revenue to be slightly lower due mainly to shipment timing and service revenue to be higher due to increased validation activity. We expect to complete at least five validations in the fourth quarter, which is consistent with our prior guidance. In light of the current macroeconomic environment, our customers continue to scrutinize the timing and scale of purchase decisions. And while our guidance continues to reflect this uncertainty and our teams continue to effectively navigate this environment, we expect these headwinds to persist through the end of the year.
Shifting to gross margins. We expect sequential improvement in Q4 as we benefit from higher production volumes and cost reduction activities in consumables as well as the benefit of higher revenue and increased productivity in service. Gross margin improvement continues to be a top strategic objective for us. We are focused on driving cost reduction and increasing manufacturing efficiency and products and increasing productivity in services. We continue to expect these actions as well as the benefit of higher sales volumes to lead us to positive gross margins in 2024 with expansion to 50% to 60% as the business continues to scale over time. We expect Q4 operating expenses to be between $12 million and $13 million. Finally, we finished the third quarter with approximately $104 million in cash, cash equivalents and investments.
Cash burn was approximately $9 million in the period. In the fourth quarter, we expect cash burn to be slightly less than Q3, as we realized cash benefits from working capital management. As a result, we expect to end 2023 with cash and investments slightly below $100 million and remain confident that this will provide us with cash runway at least into 2026. That concludes my comments. So at this point, we’ll open the call up for questions. Operator?
Operator: Certainly. [Operator Instructions] Tejas Savant with Morgan Stanley. Your line is open.
Unidentified Analyst: Good morning, guys. This is Edmond on for Tejas. Thank you for taking my questions. Just to start, with five systems placed in the quarter, your guidance implies [indiscernible] the remainder in 4Q. Just wondering what underlies your confidence in being able to deliver that in 4Q? And what do you currently have baked into your guidance in terms of year-end budget flush?
