| Short-term and Long-term Investments |
The Company's short-term and long-term investments as of December 31, 2023 were as follows (in thousands): | | | | | | | | | | | | | | | | | | | | | | | | | Amortized Cost | | Gross Unrealized Gains | | Gross Unrealized Losses | | Fair Value | | Short-term debt securities: | | | | | | | | | U.S. agency securities | $ | 68,778 | | | $ | — | | | $ | (1,263) | | | $ | 67,515 | | | Corporate bonds | 216,864 | | | 96 | | | (1,733) | | | 215,227 | | | Commercial paper | 15,159 | | | — | | | — | | | 15,159 | | | Municipal securities | 9,396 | | | — | | | (231) | | | 9,165 | | | Certificates of deposit | 3,856 | | | — | | | — | | | 3,856 | | | U.S. government securities | 544,145 | | | 210 | | | (4,357) | | | 539,998 | | | Foreign government securities | 1,000 | | | — | | | (19) | | | 981 | | | Total | $ | 859,198 | | | $ | 306 | | | $ | (7,603) | | | $ | 851,901 | | | | | | | | | | | Long-term debt securities: | | | | | | | | | | | | | | | | | Corporate bonds | $ | 94,564 | | | $ | 809 | | | $ | (45) | | | $ | 95,328 | | | Municipal securities | 2,495 | | | 55 | | | (138) | | | 2,412 | | | U.S. government securities | 152,549 | | | 875 | | | (37) | | | 153,387 | | | | | | | | | | | Total | $ | 249,608 | | | $ | 1,739 | | | $ | (220) | | | $ | 251,127 | |
The Company's short-term and long-term investments as of December 31, 2022 are as follows (in thousands): | | | | | | | | | | | | | | | | | | | | | | | | | Amortized Cost | | Gross Unrealized Gains | | Gross Unrealized Losses | | Fair Value | | Short-term debt securities: | | | | | | | | | U.S. agency securities | $ | 96,545 | | | $ | 16 | | | $ | (2,120) | | | $ | 94,441 | | | Corporate bonds | 368,110 | | | 2 | | | (7,475) | | | 360,637 | | | Commercial paper | 31,503 | | | — | | | — | | | 31,503 | | | Municipal securities | 9,884 | | | — | | | (191) | | | 9,693 | | | Certificates of deposit | 6,400 | | | — | | | — | | | 6,400 | | | U.S. government securities | 580,568 | | | 6 | | | (8,937) | | | 571,637 | | | Foreign government securities | 7,795 | | | — | | | (255) | | | 7,540 | | | Total | $ | 1,100,805 | | | $ | 24 | | | $ | (18,978) | | | $ | 1,081,851 | | | | | | | | | | | Long-term debt securities: | | | | | | | | | U.S. agency securities | $ | 74,097 | | | $ | — | | | $ | (3,782) | | | $ | 70,315 | | | Corporate bonds | 245,891 | | | 6 | | | (9,171) | | | 236,726 | | | Municipal securities | 10,415 | | | 3 | | | (664) | | | 9,754 | | | U.S. government securities | 268,902 | | | — | | | (13,210) | | | 255,692 | | | Foreign government securities | 1,000 | | | — | | | (58) | | | 942 | | | Total | $ | 600,305 | | | $ | 9 | | | $ | (26,885) | | | $ | 573,429 | |
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| Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value |
The Company's gross unrealized losses and fair values for those investments that were in an unrealized loss position as of December 31, 2023 and 2022, aggregated by investment category and the length of time that individual securities have been in a continuous loss position were as follows (in thousands): | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | December 31, 2023 | | Less than 12 months | | Greater than 12 months | | Total | | Fair Value | | Gross Unrealized Losses | | Fair Value | | Gross Unrealized Losses | | Fair Value | | Gross Unrealized Losses | | Short-term debt securities: | | | | | | | | | | | | | U.S. agency securities | $ | 9,770 | | | $ | (10) | | | $ | 57,745 | | | $ | (1,253) | | | $ | 67,515 | | | $ | (1,263) | | | Corporate bonds | 61,054 | | | (60) | | | 110,706 | | | (1,673) | | | 171,760 | | | (1,733) | | | Municipal securities | — | | | — | | | 9,165 | | | (231) | | | 9,165 | | | (231) | | | U.S. government securities | 80,724 | | | (113) | | | 207,183 | | | (4,243) | | | 287,907 | | | (4,356) | | | Foreign government securities | — | | | — | | | 981 | | | (19) | | | 981 | | | (19) | | | Total | $ | 151,548 | | | $ | (183) | | | $ | 385,780 | | | $ | (7,419) | | | $ | 537,328 | | | $ | (7,602) | | | | | | | | | | | | | | | Long-term debt securities: | | | | | | | | | | | | | | | | | | | | | | | | | Corporate bonds | 11,819 | | | (31) | | | 2,274 | | | (14) | | | 14,093 | | | (45) | | | Municipal securities | 976 | | | (24) | | | 383 | | | (112) | | | 1,359 | | | (136) | | | U.S. government securities | 28,474 | | | (37) | | | — | | | — | | | 28,474 | | | (37) | | | | | | | | | | | | | | | Total | $ | 41,269 | | | $ | (92) | | | $ | 2,657 | | | $ | (126) | | | $ | 43,926 | | | $ | (218) | |
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | December 31, 2022 | | Less than 12 months | | Greater than 12 months | | Total | | Fair Value | | Gross Unrealized Losses | | Fair Value | | Gross Unrealized Losses | | Fair Value | | Gross Unrealized Losses | | Short-term debt securities: | | | | | | | | | | | | | U.S. agency securities | $ | 8,572 | | | $ | (24) | | | $ | 84,628 | | | $ | (2,096) | | | $ | 93,200 | | | $ | (2,120) | | | Corporate bonds | 34,795 | | | (423) | | | 320,748 | | | (7,052) | | | 355,543 | | | (7,475) | | | Municipal securities | 587 | | | (13) | | | 5,811 | | | (178) | | | 6,398 | | | (191) | | | U.S. government securities | 146,974 | | | (839) | | | 394,880 | | | (8,098) | | | 541,854 | | | (8,937) | | | Foreign government securities | — | | | — | | | 7,540 | | | (255) | | | 7,540 | | | (255) | | | Total | $ | 190,928 | | | $ | (1,299) | | | $ | 813,607 | | | $ | (17,679) | | | $ | 1,004,535 | | | $ | (18,978) | | | | | | | | | | | | | | | Long-term debt securities: | | | | | | | | | | | | | U.S. agency securities | $ | 11,501 | | | $ | (20) | | | $ | 58,814 | | | $ | (3,762) | | | $ | 70,315 | | | $ | (3,782) | | | Corporate bonds | 33,862 | | | (262) | | | 201,791 | | | (8,909) | | | 235,653 | | | (9,171) | | | Municipal securities | 467 | | | (33) | | | 8,784 | | | (631) | | | 9,251 | | | (664) | | | U.S. government securities | 54,405 | | | (590) | | | 201,288 | | | (12,620) | | | 255,693 | | | (13,210) | | | Foreign government securities | — | | | — | | | 942 | | | (58) | | | 942 | | | (58) | | | Total | $ | 100,235 | | | $ | (905) | | | $ | 471,619 | | | $ | (25,980) | | | $ | 571,854 | | | $ | (26,885) | |
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