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Fair Value Measurement (Tables) | 9 Months Ended
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Sep. 30, 2021
Fair Value Measurement |
Schedule of financial assets and liabilities measured at fair value on a recurring basis | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | ​ | September 30, 2021
(in thousands) |  | Level 1 | ​ | Level 2 | ​ | Level 3 | ​ | Total
Financial Assets | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Cash | ​ | $ | 10,874 | ​ | $ | — | ​ | $ | — | ​ | $ | 10,874
Money market funds | ​ | ​ | 14,723 | ​ | ​ | — | ​ | ​ | — | ​ | ​ | 14,723
Corporate bonds | ​ | ​ | — | ​ | ​ | 3,019 | ​ | ​ | — | ​ | ​ | 3,019
Commercial paper | ​ |  | — | ​ | ​ | 198,626 | ​ | ​ | — | ​ | ​ | 198,626
U.S. government treasury bills | ​ | ​ | 17,001 | ​ | ​ | — | ​ | ​ | — | ​ | ​ | 17,001
Government-sponsored enterprise securities | ​ |  | — | ​ | ​ | 61,711 | ​ | ​ | — | ​ | ​ | 61,711
Total | ​ | $ | 42,598 | ​ | $ | 263,356 | ​ | $ | — | ​ | $ | 305,954
Schedule of financial assets reconciliation | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | September 30, 2021
​ |  | ​ | ​ |  | Gross |  | Gross |  | ​ | ​
​ | ​ | Amortized | ​ | Unrealized | ​ | Unrealized | ​ | Estimated
(in thousands) |  | Cost | ​ | Gains | ​ | Losses | ​ | Fair Value
Financial Assets | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Cash and cash equivalents | ​ | $ | 25,597 | ​ | $ | — | ​ | $ | — | ​ | $ | 25,597
Short-term marketable securities (<12 months to maturity) | ​ | ​ | 245,169 | ​ | ​ | 20 | ​ | ​ | (6) | ​ | ​ | 245,183
Long-term marketable securities (>12 months to maturity) | ​ |  | 35,173 | ​ |  | 4 | ​ |  | (3) | ​ | ​ | 35,174
Total | ​ | $ | 305,939 | ​ | $ | 24 | ​ | $ | (9) | ​ | $ | 305,954

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- Definition Tabular disclosure of the reconciliation of available-for-sale securities from cost basis to fair value. + References No definition available. + Details
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- Definition Tabular disclosure of assets and liabilities, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
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