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Short-Term Investments | 9 Months Ended
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Sep. 30, 2024
Short-Term Investments |
Short-Term Investments | 4.Short-Term Investments The following table summarizes the short-term investments held at September 30, 2024 and December 31, 2023 (in thousands): ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ |  | ​ | ​ |  | Gross Unrealized |  | Gross Unrealized |  | ​ | ​
​ | ​ | Amortized Cost | ​ | Gains | ​ | Losses | ​ | Fair Value
September 30, 2024 | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Treasury notes | ​ | $ | 103,813 | ​ | ​ | 260 | ​ | ​ | — | ​ | $ | 104,073
Reverse repurchase agreements | ​ | ​ | 100,000 | ​ | ​ | — | ​ | ​ | — | ​ | ​ | 100,000
Treasury bills | ​ | ​ | 59,240 | ​ | ​ | 71 | ​ | ​ | — | ​ | ​ | 59,311
Total | ​ | $ | 263,053 | ​ | $ | 331 | ​ | $ | — | ​ | $ | 263,384
​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | ​ | ​ | ​ | Gross Unrealized | ​ | Gross Unrealized | ​ | ​ | ​
​ |  | Amortized Cost |  | Gains |  | Losses |  | Fair Value
December 31, 2023 | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Reverse repurchase agreements | ​ | $ | 71,000 | ​ | $ | — | ​ | $ | — | ​ | $ | 71,000
Total | ​ | $ | 71,000 | ​ | $ | — | ​ | $ | — | ​ | $ | 71,000
​ The contractual maturities of all short-term investments held at September 30, 2024 and December 31, 2023 were one year or less. There were no short-term investments in an unrealized loss position as of September 30, 2024 and December 31, 2023. The Company is required to determine whether a decline in the fair value below the amortized cost basis of short-term investments is due to credit-related factors. At each reporting date, the Company performs an evaluation of impairment to determine if any unrealized losses are the result of credit losses. Impairment is assessed at the individual security level. Factors considered in determining whether a loss resulted from a credit loss or other factors include the Company’s intent and ability to hold the investment until the recovery of its amortized cost basis, the extent to which the fair value is less than the amortized cost basis, the length of time and extent to which fair value has been less than the amortized cost basis, the financial condition of the issuer, any historical failure of the issuer to make scheduled interest or principal payments, any changes to the rating of the security by a rating agency, any adverse legal or regulatory events affecting the issuer or issuer’s industry, and any significant deterioration in economic conditions. Unrealized losses on short-term investments presented in the previous table have not been recognized in the condensed consolidated statements of operations because the securities are high credit quality, investment grade securities that the Company does not intend to sell and will not be required to sell prior to their anticipated recovery, and the decline in fair value is attributable to factors other than credit losses. Based on its evaluation, the Company determined it does not have any credit losses related to its short-term investments as of September 30, 2024 and December 31, 2023. Gross realized gains and losses on the sales of short-term investments are included in other income, net. Unrealized holding gains or losses for the period that have been included in accumulated other comprehensive income, as well as gains and losses reclassified out of accumulated other comprehensive income into other income, net, were not material to the Company’s condensed consolidated statements of operations. The cost of investments sold or the amount reclassified out of the accumulated other comprehensive income into other income, net is based on the specific identification method for purposes of recording realized gains and losses. All proceeds in the three- and nine-month periods ended September 30, 2024 and 2023 related to maturities of underlying investments. The gains on proceeds from maturities of short-term investments were not material to the Company’s condensed consolidated statements of operations for the three and nine months ended September 30, 2024 and 2023.

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