| Schedule of available-for-sale securities |
| | | | | | | | | | | | | | | | | | | | | | | | | | | March 31, 2024 | | December 31, 2023 | | | Amortized
Cost | | Gross
Unrealized
Gain | | Gross
Unrealized
(Loss) | | Estimated Fair Value | | Amortized
Cost | | Gross
Unrealized
Gain | | Gross
Unrealized
(Loss) | | Estimated Fair Value | | | | (in thousands) | | | | Cash, cash equivalents and restricted cash (2) | | $ | 813,817 | | $ | — | | $ | — | | $ | 813,817 | | $ | 642,095 | | $ | — | | $ | — | | $ | 642,095 | U.S. Treasury securities (1) | | | 34,996 | | | — | | | (531) | | | 34,465 | | | 201,522 | | | 14 | | | (1,118) | | | 200,418 | Municipal securities (1) | | | 36,013 | | | 1 | | | (1,358) | | | 34,656 | | | 38,091 | | | — | | | (1,627) | | | 36,464 | Total | | $ | 884,826 | | $ | 1 | | $ | (1,889) | | $ | 882,938 | | $ | 881,708 | | $ | 14 | | $ | (2,745) | | $ | 878,977 | | | | | | | | | | | | | | | | | | | | | | | | | | Classified as: | | | | | | | | | | | | | | | | | | | | | | | | | Cash, cash equivalents and restricted cash (2) | | | | | | | | | | | | 813,817 | | | | | | | | | | | | 642,095 | Short-term investments | | | | | | | | | | | | 69,121 | | | | | | | | | | | | 236,882 | Total | | | | | | | | | | | $ | 882,938 | | | | | | | | | | | $ | 878,977 |
| (1) | Per the Company’s investment policy, all debt securities are classified as short-term investments irrespective of holding period. |
| (2) | Cash equivalents includes liquid demand deposits, money market funds, and other liquid investments having an original maturity of less than three months. |
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