| Summary of Financial Assets Measured at Fair Value on Recurring Basis |
The following tables set forth our financial assets that are measured at fair value on a recurring basis, excluding publicly traded equity securities, as of December 31, 2023 and 2022: | | | | | | | | | | | | | | | | | | | | | | | | | December 31, 2023 | | Cost or
Amortized Cost | | Gross
Unrealized
Gains | | Gross
Unrealized
Losses | | Total Estimated
Fair Value | | | | | | | | | | (in thousands) | | Cash | $ | 1,780,402 | | | $ | — | | | $ | — | | | $ | 1,780,402 | | | Level 1 securities: | | | | | | | | | U.S. government securities | 1,295,918 | | | 894 | | | (3,919) | | | 1,292,893 | | | U.S. government agency securities | 138,420 | | | 31 | | | (188) | | | 138,263 | | | Level 2 securities: | | | | | | | | | Corporate debt securities | 234,336 | | | 577 | | | (99) | | | 234,814 | | | Commercial paper | 65,380 | | | — | | | — | | | 65,380 | | | Certificates of deposit | 18,725 | | | — | | | — | | | 18,725 | | | Total | $ | 3,533,181 | | | $ | 1,502 | | | $ | (4,206) | | | $ | 3,530,477 | |
| | | | | | | | | | | | | | | | | | | | | | | | | December 31, 2022 | | Cost or
Amortized Cost | | Gross
Unrealized
Gains | | Gross
Unrealized
Losses | | Total Estimated
Fair Value | | | | | | | | | | (in thousands) | | Cash | $ | 1,325,946 | | | $ | — | | | $ | — | | | $ | 1,325,946 | | | Level 1 securities: | | | | | | | | | U.S. government securities | 1,630,224 | | | 109 | | | (9,484) | | | 1,620,849 | | | U.S. government agency securities | 175,269 | | | 19 | | | (188) | | | 175,100 | | | Level 2 securities: | | | | | | | | | Corporate debt securities | 309,942 | | | 32 | | | (1,462) | | | 308,512 | | | Commercial paper | 290,589 | | | — | | | — | | | 290,589 | | | Certificates of deposit | 157,965 | | | — | | | (1) | | | 157,964 | | | Total | $ | 3,889,935 | | | $ | 160 | | | $ | (11,135) | | | $ | 3,878,960 | |
|
| Summary of Gain (Loss) on Strategic Investments |
Gains and losses recognized during the periods presented were as follows: | | | | | | | | | | | | | | | | | | | Year Ended December 31, | | 2023 | | 2022 | | 2021 | | | | | | | | (in thousands) | | Gains (losses) recognized on strategic investments sold during the period, net | $ | — | | | $ | 45,935 | | | $ | 27,820 | | | Unrealized gains on strategic investments still held at the reporting date | 1,368 | | | 19,946 | | | 145,010 | | | Unrealized losses, including impairments, on strategic investments still held at the reporting date | (28,423) | | | (1,421) | | | (2,854) | | | Gains (losses) on strategic investments, net | $ | (27,055) | | | $ | 64,460 | | | $ | 169,976 | |
Gains and losses recognized during the periods presented, which are included within other income (expense), net on our consolidated statements of operations, were as follows: | | | | | | | | | | | | | | | | | | | Year Ended December 31, | | 2023 | | 2022 | | 2021 | | (in thousands) | | Gains (losses) recognized on publicly traded equity securities sold during the period, net | $ | 11,046 | | | $ | (22,095) | | | $ | — | | | Unrealized gains (losses) on publicly traded equity securities still held at the reporting date, net | (17,731) | | | (79,214) | | | 122,064 | | | Gains (losses) on publicly traded equity securities, net | $ | (6,685) | | | $ | (101,309) | | | $ | 122,064 | |
|