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CASH, CASH EQUIVALENTS AND INVESTMENTS - Amortized Costs, Unrealized Gains and Losses, and Estimated Fair Value (Details) - USD ($) $ in Thousands | Sep. 30, 2024 | Dec. 31, 2023
--- | --- | ---
Total cash and equivalents |  |
Amortized Cost Basis | $ 284,397 | $ 263,320
Unrealized Gains | 37 | 31
Unrealized Losses | 0 | 0
Estimated Fair Value | 284,434 | 263,351
Short-term investments: |  |
Amortized Cost Basis | 581,632 | 734,332
Unrealized Gains | 433 | 249
Unrealized Losses | (9) | (88)
Short-term investments | 582,056 | 734,493
Amortized Cost Basis | 866,029 | 997,652
Unrealized Gains | 470 | 280
Unrealized Losses | (9) | (88)
Total cash, cash equivalents and short-term investments | 866,490 | 997,844
U.S. agency securities |  |
Short-term investments: |  |
Amortized Cost Basis | 2,240 | 118,370
Unrealized Gains | 0 | 0
Unrealized Losses | (1) | (78)
Short-term investments | 2,239 | 118,292
U.S. Treasury securities |  |
Short-term investments: |  |
Amortized Cost Basis | 562,072 | 615,962
Unrealized Gains | 429 | 249
Unrealized Losses | (8) | (10)
Short-term investments | 562,493 | 616,201
Commercial paper |  |
Short-term investments: |  |
Amortized Cost Basis | 17,320 | 0
Unrealized Gains | 4 | 0
Unrealized Losses | 0 | 0
Short-term investments | 17,324 | 0
Demand deposits |  |
Total cash and equivalents |  |
Amortized Cost Basis | 5,406 | 2,795
Unrealized Gains | 0 | 0
Unrealized Losses | 0 | 0
Estimated Fair Value | 5,406 | 2,795
Total cash equivalents |  |
Total cash and equivalents |  |
Amortized Cost Basis | 278,991 | 260,525
Unrealized Gains | 37 | 31
Unrealized Losses | 0 | 0
Estimated Fair Value | 279,028 | 260,556
Money market funds |  |
Total cash and equivalents |  |
Amortized Cost Basis | 118,774 | 61,166
Unrealized Gains | 0 | 0
Unrealized Losses | 0 | 0
Estimated Fair Value | 118,774 | 61,166
U.S. Treasury securities |  |
Total cash and equivalents |  |
Amortized Cost Basis | 68,669 | 92,113
Unrealized Gains | 13 | 14
Unrealized Losses | 0 | 0
Estimated Fair Value | 68,682 | 92,127
Commercial paper |  |
Total cash and equivalents |  |
Amortized Cost Basis | 84,626 | 93,447
Unrealized Gains | 23 | 15
Unrealized Losses | 0 | 0
Estimated Fair Value | 84,649 | 93,462
Certificates of deposit |  |
Total cash and equivalents |  |
Amortized Cost Basis | 6,672 | 13,799
Unrealized Gains | 1 | 2
Unrealized Losses | 0 | 0
Estimated Fair Value | 6,673 | 13,801
Municipal securities |  |
Total cash and equivalents |  |
Amortized Cost Basis | 250 | 0
Unrealized Gains | 0 | 0
Unrealized Losses | 0 | 0
Estimated Fair Value | $ 250 | $ 0

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- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(1)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-2 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479130/326-30-45-1 + Details
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- Definition Cash includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the customer may deposit additional funds at any time and effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid Investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Short-term investments, exclusive of cash equivalents, generally consist of marketable securities intended to be sold within one year (or the normal operating cycle if longer) and may include trading securities, available-for-sale securities, or held-to-maturity securities (if maturing within one year), as applicable. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(9)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 + Details
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