| (Unaudited) | ||||||||||||||||
|
Three Months Ended
December 31, |
Twelve Months Ended
December 31, | |||||||||||||||
| (in thousands) | 2022 | 2021 | 2022 | 2021 | ||||||||||||
| Total operating expense | $ | 121,963 | $ | 103,353 | $ | 456,269 | $ | 390,174 | ||||||||
| Stock-based compensation expense | (20,177 | ) | (11,492 | ) | (76,436 | ) | (38,930 | ) | ||||||||
| Amortization | (8,828 | ) | (4,433 | ) | (27,510 | ) | (18,357 | ) | ||||||||
| Gain on mark-to-market adjustment of contingent consideration | (329 | ) | — | 7,153 | — | |||||||||||
| Restructuring expense | — | — | — | (4,028 | ) | |||||||||||
| Non-GAAP operating expense | $ | 92,629 | $ | 87,428 | $ | 359,476 | $ | 328,859 | ||||||||
The following table provides a reconciliation of Billings to revenue, the most comparable GAAP financial measure:
