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Fair Value Measurements (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale	$ 897,316	$ 1,090,058
Fair Value, Inputs, Level 1
Debt Securities, Available-for-sale	49,106	25,019
Fair Value, Inputs, Level 2
Debt Securities, Available-for-sale	848,210	1,065,039
Cash Equivalents
Cash Equivalents	135,954	268,349
Cash Equivalents | Fair Value, Inputs, Level 1
Cash Equivalents	49,106	25,019
Cash Equivalents | Fair Value, Inputs, Level 2
Cash Equivalents	86,848	243,330
Cash Equivalents | Money Market Funds
Cash Equivalents	49,106	25,019
Cash Equivalents | Money Market Funds | Fair Value, Inputs, Level 1
Cash Equivalents	49,106	25,019
Cash Equivalents | Money Market Funds | Fair Value, Inputs, Level 2
Cash Equivalents	0	0
Cash Equivalents | Commercial paper
Cash Equivalents	70,450	179,455
Cash Equivalents | Commercial paper | Fair Value, Inputs, Level 1
Cash Equivalents	0	0
Cash Equivalents | Commercial paper | Fair Value, Inputs, Level 2
Cash Equivalents	70,450	179,455
Cash Equivalents | Municipal debt securities
Cash Equivalents	16,398	63,875
Cash Equivalents | Municipal debt securities | Fair Value, Inputs, Level 1
Cash Equivalents	0	0
Cash Equivalents | Municipal debt securities | Fair Value, Inputs, Level 2
Cash Equivalents	16,398	63,875
Short-term Investments
Debt Securities, Available-for-sale	761,362	819,478
Short-term Investments | Fair Value, Inputs, Level 1
Debt Securities, Available-for-sale	0	0
Short-term Investments | Fair Value, Inputs, Level 2
Debt Securities, Available-for-sale	761,362	819,478
Short-term Investments | Commercial paper
Debt Securities, Available-for-sale	450,529	419,469
Short-term Investments | Commercial paper | Fair Value, Inputs, Level 1
Debt Securities, Available-for-sale	0	0
Short-term Investments | Commercial paper | Fair Value, Inputs, Level 2
Debt Securities, Available-for-sale	450,529	419,469
Short-term Investments | Municipal debt securities
Debt Securities, Available-for-sale	20,965	165,573
Short-term Investments | Municipal debt securities | Fair Value, Inputs, Level 1
Debt Securities, Available-for-sale	0	0
Short-term Investments | Municipal debt securities | Fair Value, Inputs, Level 2
Debt Securities, Available-for-sale	20,965	165,573
Short-term Investments | Federal agency debt securities
Debt Securities, Available-for-sale	92,906	0
Short-term Investments | Federal agency debt securities | Fair Value, Inputs, Level 1
Debt Securities, Available-for-sale	0	0
Short-term Investments | Federal agency debt securities | Fair Value, Inputs, Level 2
Debt Securities, Available-for-sale	92,906	0
Short-term Investments | Corporate debt securities
Debt Securities, Available-for-sale	196,962	234,436
Short-term Investments | Corporate debt securities | Fair Value, Inputs, Level 1
Debt Securities, Available-for-sale	0	0
Short-term Investments | Corporate debt securities | Fair Value, Inputs, Level 2
Debt Securities, Available-for-sale	196,962	234,436
Long Term Investments
Debt Securities, Available-for-sale	0	2,231
Long Term Investments | Fair Value, Inputs, Level 1
Debt Securities, Available-for-sale	0	0
Long Term Investments | Fair Value, Inputs, Level 2
Debt Securities, Available-for-sale	0	2,231
Long Term Investments | US Treasury Bond Securities
Debt Securities, Available-for-sale	0	2,231
Long Term Investments | US Treasury Bond Securities | Fair Value, Inputs, Level 1
Debt Securities, Available-for-sale	0	0
Long Term Investments | US Treasury Bond Securities | Fair Value, Inputs, Level 2
Debt Securities, Available-for-sale	$ 0	$ 2,231

X

- Definition

Amount 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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(6))
-URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=124260329&loc=d3e26610-111562

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (aa)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27161-111563

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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

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