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Fair Value Measurements - Fair value hierarchy (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2023 | Dec. 31, 2022
Financial Instruments Measurements |  |
Transfers between Level 1, Level 2 and Level 3 | $ 0 | $ 0
Fair Value, Recurring [Member] |  |
Summary of assets measured at fair value on a recurring basis |  |
Total | 78,709 | 207,856
Fair Value, Recurring [Member] | Level 1 |  |
Summary of assets measured at fair value on a recurring basis |  |
Total | 7,709 | 7,924
Fair Value, Recurring [Member] | Level 2 |  |
Summary of assets measured at fair value on a recurring basis |  |
Total | 71,000 | 199,932
Fair Value, Recurring [Member] | Money market funds |  |
Summary of assets measured at fair value on a recurring basis |  |
Cash and cash equivalents | 7,709 | 1,944
Fair Value, Recurring [Member] | Money market funds | Level 1 |  |
Summary of assets measured at fair value on a recurring basis |  |
Cash and cash equivalents | 7,709 | 1,944
Fair Value, Recurring [Member] | Corporate debt securities |  |
Summary of assets measured at fair value on a recurring basis |  |
Short-term investments: |  | 16,445
Fair Value, Recurring [Member] | Corporate debt securities | Level 2 |  |
Summary of assets measured at fair value on a recurring basis |  |
Short-term investments: |  | 16,445
Fair Value, Recurring [Member] | Yankee securities |  |
Summary of assets measured at fair value on a recurring basis |  |
Short-term investments: |  | 1,999
Fair Value, Recurring [Member] | Yankee securities | Level 2 |  |
Summary of assets measured at fair value on a recurring basis |  |
Short-term investments: |  | 1,999
Fair Value, Recurring [Member] | Bonds |  |
Summary of assets measured at fair value on a recurring basis |  |
Short-term investments: |  | 2,988
Fair Value, Recurring [Member] | Bonds | Level 2 |  |
Summary of assets measured at fair value on a recurring basis |  |
Short-term investments: |  | 2,988
Fair Value, Recurring [Member] | Treasury bills |  |
Summary of assets measured at fair value on a recurring basis |  |
Short-term investments: |  | 5,980
Fair Value, Recurring [Member] | Treasury bills | Level 1 |  |
Summary of assets measured at fair value on a recurring basis |  |
Short-term investments: |  | 5,980
Fair Value, Recurring [Member] | Reverse repurchase agreements |  |
Summary of assets measured at fair value on a recurring basis |  |
Short-term investments: | 71,000 | 178,500
Fair Value, Recurring [Member] | Reverse repurchase agreements | Level 2 |  |
Summary of assets measured at fair value on a recurring basis |  |
Short-term investments: | $ 71,000 | $ 178,500

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- Definition Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 + Details
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- Definition Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. + References No definition available. + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-3 + Details
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- Definition Amount of transfer of financial instrument classified as an asset into level 3 of the fair value hierarchy. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(3) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 + Details
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- Definition Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 + Details
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