The following table provides a reconciliation of Adjusted EBITDA to net income, the most comparable GAAP financial measure:
| (Unaudited) | ||||||||
| Three Months Ended March 31, | ||||||||
| (in thousands) | 2020 | 2019 | ||||||
| Net income | $ | 6,030 | $ | 13,019 | ||||
| Income tax expense | 4,652 | 4,088 | ||||||
| Stock-based compensation expense | 3,171 | 1,212 | ||||||
| Interest expense | 2,813 | 270 | ||||||
| Interest income and other (1) | (654 | ) | 201 | |||||
| Depreciation and amortization | 5,660 | 5,194 | ||||||
| Adjusted EBITDA | $ | 21,672 | $ | 23,984 | ||||
(1) Includes $0.2 million impairment charge for royalty contracts for the three months ended March 31, 2019.
The following table provides a recompilation of Free Cash Flow to net cash provided by operating activities, the most comparable GAAP financial measure:
| (Unaudited) | ||||||||
| Three Months Ended March 31, | ||||||||
| (in thousands) | 2020 | 2019 | ||||||
| Net cash provided by operating activities | $ | 28,036 | $ | 25,315 | ||||
| Capital expenditures | (1,644 | ) | (4,583 | ) | ||||
| Free Cash Flow | $ | 26,392 | $ | 20,732 | ||||
