| Fair Value of Assets and Liabilities Measured on Recurring Basis |
| | | | | | | | | | | | | | | | | | | | | | | | | | (In thousands) | | Balance at
June 30,
2024 | | Level 1 | | Level 2 | | Level 3 | Assets: | | | | | | | | | | | | | Cash equivalents | | $ | 243,685 | | $ | 243,685 | | $ | — | | $ | — | Municipal bonds | | | 13,841 | | | — | | | 13,841 | | | — | Corporate debt securities | | | 52,748 | | | — | | | 52,748 | | | — | Asset-backed securities | | | 12,676 | | | — | | | 12,676 | | | — | Government, federal agency, and other sovereign obligations | | | 31,039 | | | — | | | 31,039 | | | — | 2025 Hedge | | | 471 | | | — | | | 471 | | | — | Liabilities: | | | | | | | | | | | | | Senior Convertible Notes due 2025 | | | 432,159 | | | 432,159 | | | — | | | — | Bifurcated Conversion Option of the Senior Convertible Notes due 2025 | | | 471 | | | — | | | 471 | | | — | Business acquisition liabilities | | | 121,332 | | | — | | | — | | | 121,332 |
| | | | | | | | | | | | | | | | | | | | | | | | | | (In thousands) | | Balance at
December 31,
2023 | | Level 1 | | Level 2 | | Level 3 | Assets: | | | | | | | | | | | | | Cash equivalents | | $ | 203,689 | | $ | 203,689 | | $ | — | | $ | — | Municipal bonds | | | 18,057 | | | — | | | 18,057 | | | — | Corporate debt securities | | | 58,838 | | | — | | | 58,838 | | | — | Asset-backed securities | | | 17,161 | | | — | | | 17,161 | | | — | Government, federal agency, and other sovereign obligations | | | 31,869 | | | 2,928 | | | 28,941 | | | — | 2025 Hedge | | | 687 | | | — | | | 687 | | | — | | | | | | | | | | | | | | Liabilities: | | | | | | | | | | | | | Senior Convertible Notes due 2025 | | | 417,363 | | | 417,363 | | | — | | | — | Bifurcated Conversion Option of the Senior Convertible Notes due 2025 | | | 687 | | | — | | | 687 | | | — | Business acquisition liabilities | | | 139,358 | | | — | | | — | | | 139,358 |
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| Changes in Carrying Value of Business Acquisition Liabilities |
| | | | | | | | | | | | | | | | | | | | | | | | | Three Months Ended | | Six Months Ended | | June 30, | | June 30, | (In thousands) | 2024 | | 2023 | | 2024 | | 2023 | Beginning balance | $ | 111,310 | | $ | 64,882 | | $ | 139,358 | | $ | 68,258 | Purchase price contingent consideration | | 1,923 | | | — | | | 21,066 | | | — | Changes resulting from foreign currency fluctuations | | 3 | | | — | | | 246 | | | — | Contingent cash payments | | (4,296) | | | (2,832) | | | (50,886) | | | (5,524) | Contingent RSU grants | | (181) | | | (340) | | | (517) | | | (559) | Changes in fair value of business acquisition liabilities | | 12,898 | | | 3,726 | | | 12,739 | | | 3,280 | Contractual payable reclassification | | (325) | | | (84) | | | (674) | | | (103) | Ending balance | $ | 121,332 | | $ | 65,352 | | $ | 121,332 | | $ | 65,352 |
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