These benefits ensure that the value our customers receive from their 3D Systems solution grow substantially over the life of their ownership, which can often exceed 15 years from the initial purchase.
The 3D Systems technology provides over a 0.5 million production parts every 24 hours, 365 days a year, which is more than the rest of the industry combined.
Last summer, we announced a restructuring program that was designed to ultimately yield a $100 million of run rate cost savings with $60 million to be achieved by the end of 2020.
I'm pleased to say that we achieved our $60 million savings target by year-end and that our efforts are continuing unabated.
Looking ahead, we have detailed plans within our core additive business to deliver an additional $20 million in savings this year, with the balance of $100 million linked to our analysis of future divestitures.
Based upon our initial analysis, these new markets that Roadrunner will open for us are in excess of $400 million and we'll expand from there as the full capabilities of the new platform are adopted.
2020 revenue of $557.2 million decreased 12.4% compared to the prior year, primarily due to the impacts of COVID-19, the effects of which occurred most severely at the onset of the pandemic, with a strong rebound in activity in the second half of the year.
As such, excluding $44.4 million of revenue from businesses that were divested last year or at the beginning of this year, baseline 2020 revenue would have been approximately $512.8 million.
Gross profit margin on a GAAP basis for the full year 2020 was 40.1% compared to 44.1% in the prior year.
Non-GAAP gross profit margin was 42.6% compared to 44.8% in the prior year.
Gross profit margin decreased primarily due to the under-absorption of supply chain overhead resulting from lower production and end-of-life inventory changes of $12.4 million and mix.
Operating expenses for the full year 2020 on a GAAP basis increased 1.4% to $342.3 million compared to the prior year.
On a non-GAAP basis, operating expenses were $236.9 million, a 16.2% decrease from the prior year.
For the fourth quarter, we expect revenue of $172.7 million, an increase of 2.6% compared to the fourth quarter of 2019 and an increase of 26.8% compared to the third quarter of 2020, driven by growth in both Healthcare and Industrial.
We expect a GAAP loss of $0.16 per share in the fourth quarter of 2020 compared to a GAAP loss of $0.04 in the fourth quarter of 2019.
We expect non-GAAP income of $0.09 per share in the fourth quarter of 2020 compared to non-GAAP income of $0.05 per share in the fourth quarter of 2019.
Revenue from Healthcare increased 48% year-over-year and 42.4% quarter-over-quarter to $86.6 million, driven by all parts of the Healthcare business: dental, medical devices, simulators and regenerative medicine.
Excluding dental applications, revenue in the balance of the Healthcare business, which we refer to broadly as medical applications, increased 27.7% year-over-year.
Industrial sales decreased 21.6% year-over-year to $86 million as demand has not fully rebounded to pre-pandemic levels.
On a sequential quarter-over-quarter basis, we saw broad-based revenue improvement of approximately 14.2% in our Industrial business, with no single customer or segment responsible for the improvement.
We expect gross profit margin of 42% in the fourth quarter of 2020 compared to 44.1% in the fourth quarter of 2019.
Non-GAAP gross profit margin was 42.9%, compared to 44.3% in the same period last year.
While revenue in these two businesses were expected to decline, their divestiture is expected to negatively impact gross margins going forward by about 300 to 400 basis points, while our restructuring and transformation activities will benefit gross margins.
Net, going forward in 2021, we expect non-GAAP gross margins in a range of 40% to 44%.
Operating expenses for the fourth quarter were $71.7 million on a GAAP basis, a decrease of 9.2% compared to the fourth quarter of 2019, including an 11.2% decrease in SG&A expenses and a 3.1% decrease in R&D expenses.
Importantly, our non-GAAP operating expenses in the fourth quarter were $58 million, a 15.8% decrease from the fourth quarter of the prior year as we saw the benefits from our restructuring efforts.
The primary differences between GAAP and non-GAAP operating expenses are $6.1 million in restructuring charges as well as $4 million in amortization of intangibles and stock-based compensation and $3.7 million in legal and divestiture-related charges, consistent with our historical GAAP to non-GAAP adjustments.
Recall that in 2020 we announced a restructuring to reduce operating costs by $100 million per year, with $60 million of annualized cost reduction by the end of 2020.
As Jeff mentioned, we were pleased that we delivered on our objective of $60 million cost reduction in 2020.
In addition, we have plans for an additional $20 million of cost reductions in 2021.
Therefore, the plans to achieve the remaining $20 million toward our $100 million cost-reduction plan will be achieved by divestitures or through further cost reductions that we will implement once we have finalized our divestiture analysis.
Adjusted EBITDA, defined as non-GAAP operating profit plus depreciation, was $28.7 million or 5.2% of revenue in 2020, compared to $31.2 million in 2019 or 4.9% of revenue.
For the fourth quarter of 2020, adjusted EBITDA improved materially to $22.9 million or 13.2% of revenue, compared to $12.9 million or 7.7% of revenue in the fourth quarter of 2019.
We ended the quarter with $84.7 million of cash on hand, including restricted cash and cash and assets held for sale.
Cash on hand decreased $50 million since the beginning of 2020.
Importantly, our cash on hand increased $8.4 million from Q3 2020 to Q4 2020.
Our term loan at the end of the year was $21 million.
We have a $100 million revolver that was undrawn as of December 31, 2020, and has approximately $62 million of availability based on terms of the agreement.

Summary:
For the fourth quarter, we expect revenue of $172.7 million, an increase of 2.6% compared to the fourth quarter of 2019 and an increase of 26.8% compared to the third quarter of 2020, driven by growth in both Healthcare and Industrial.
We expect a GAAP loss of $0.16 per share in the fourth quarter of 2020 compared to a GAAP loss of $0.04 in the fourth quarter of 2019.
We expect non-GAAP income of $0.09 per share in the fourth quarter of 2020 compared to non-GAAP income of $0.05 per share in the fourth quarter of 2019.
Net, going forward in 2021, we expect non-GAAP gross margins in a range of 40% to 44%.