| Summary of debt securities |
The following tables summarize the amortized cost, unrealized gain and loss and estimated fair value of cash equivalents and short-term investments: | | | | | | | | | | | | | | | | | | | | | | | | | December 31, 2022 | | (in thousands) | Amortized Cost | | Unrealized Gain | | Unrealized Loss | | Estimated Fair Value | | Cash equivalents | | | | | | | | | Money market funds | $ | 201,476 | | | $ | — | | | $ | — | | | $ | 201,476 | | | Total cash equivalents | $ | 201,476 | | | $ | — | | | $ | — | | | $ | 201,476 | | | | | | | | | | | Short-term investments | | | | | | | | | Commercial paper | $ | 144,093 | | | $ | 2 | | | $ | (377) | | | $ | 143,718 | | | Corporate bonds | 37,778 | | | — | | | (194) | | | 37,584 | | | Asset backed securities | 19,723 | | | 11 | | | (161) | | | 19,573 | | | Certificates of deposit | 10,000 | | | — | | | — | | | 10,000 | | | Supranational bonds | 4,017 | | | — | | | (67) | | | 3,950 | | | U.S. Treasury and agency obligations | 52,309 | | | — | | | (565) | | | 51,744 | | | Total short-term investments | $ | 267,920 | | | $ | 13 | | | $ | (1,364) | | | $ | 266,569 | |
| | | | | | | | | | | | | | | | | | | | | | | | | December 31, 2021 | | (in thousands) | Amortized Cost | | Unrealized Gain | | Unrealized Loss | | Estimated Fair Value | | Cash equivalents | | | | | | | | | Money market funds | $ | 178,518 | | | $ | — | | | $ | — | | | $ | 178,518 | | | | | | | | | | | Total cash equivalents | $ | 178,518 | | | $ | — | | | $ | — | | | $ | 178,518 | | | | | | | | | | | Short-term investments | | | | | | | | | Commercial paper | $ | 134,165 | | | $ | — | | | $ | (47) | | | $ | 134,118 | | | Corporate bonds | 27,169 | | | — | | | (41) | | | 27,128 | | | Asset backed securities | 27,464 | | | — | | | (53) | | | 27,411 | | | Certificates of deposit | 10,000 | | | — | | | (8) | | | 9,992 | | | Supranational bonds | 8,632 | | | — | | | (33) | | | 8,599 | | | U.S. Treasury and agency obligations | 27,168 | | | — | | | (124) | | | 27,044 | | | Total short-term investments | $ | 234,598 | | | $ | — | | | $ | (306) | | | $ | 234,292 | |
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| Schedule of contractual maturities of short-term investments |
The contractual maturities of our short-term investments are as follows: | | | | | | | | | | | | | | | | | | | | | | | | | December 31, 2022 | | December 31, 2021 | | (in thousands) | Amortized Cost | | Estimated Fair Value | | Amortized Cost | | Estimated Fair Value | | Due within one year | $ | 243,430 | | | $ | 242,129 | | | $ | 195,579 | | | $ | 195,453 | | | Due between one and four years | 24,490 | | | 24,440 | | | 39,019 | | | 38,839 | | | Total short-term investments | $ | 267,920 | | | $ | 266,569 | | | $ | 234,598 | | | $ | 234,292 | |
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