| RECONCILIATION OF OPERATING INCOME TO NON-GAAP OPERATING INCOME | ||||||||||||||||
| (Unaudited, in thousands) | ||||||||||||||||
|
Three Months Ended
December 31, |
Year Ended
December 31, | |||||||||||||||
| 2019 | 2018 | 2019 | 2018 | |||||||||||||
| Total operating income | $ | 30,694 | $ | 33,077 | $ | 102,562 | $ | 113,488 | ||||||||
| Adjustments to reconcile total operating income to non-GAAP total operating income: | ||||||||||||||||
| Stock-based compensation expense | 18,680 | 14,842 | 78,699 | 60,607 | ||||||||||||
| Amortization of acquisition-related intangible assets | - | 197 | 110 | 841 | ||||||||||||
| Deferred compensation plan expense (income) | 1,412 | (1,513 | ) | 3,995 | (591 | ) | ||||||||||
| Non-GAAP operating income | $ | 50,786 | $ | 46,603 | $ | 185,366 | $ | 174,345 | ||||||||
