Fair Value of Financial Instruments - Financial Assets Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Marketable securities:
Fair value, Marketable securities	$ 1,427,859	$ 640,085
Municipal bonds [Member]
Marketable securities:
Fair value, Marketable securities		3,044
Fair Value, Measurements, Recurring [Member]
Cash equivalents and Marketable securities:
Assets, Fair Value	1,532,557	738,940
Fair Value, Measurements, Recurring [Member] | Municipal bonds [Member]
Marketable securities:
Fair value, Marketable securities		3,044
Fair Value, Measurements, Recurring [Member] | Corporate Notes and Bonds [Member]
Marketable securities:
Fair value, Marketable securities	135,134	125,604
Fair Value, Measurements, Recurring [Member] | Commercial Paper [Member]
Cash equivalents:
Fair value, Cash equivalents		4,999
Marketable securities:
Fair value, Marketable securities	36,514	10,995
Fair Value, Measurements, Recurring [Member] | U.S. Agency Obligations [Member]
Cash equivalents:
Fair value, Cash equivalents	3,993
Marketable securities:
Fair value, Marketable securities	98,480	54,007
Fair Value, Measurements, Recurring [Member] | U.S. Treasury Securities [Member]
Cash equivalents:
Fair value, Cash equivalents	93,922	69,999
Marketable securities:
Fair value, Marketable securities	1,157,731	446,435
Fair Value, Measurements, Recurring [Member] | Money Market Funds [Member]
Cash equivalents:
Fair value, Cash equivalents	6,783	23,857
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Cash equivalents and Marketable securities:
Assets, Fair Value	6,783	23,857
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Municipal bonds [Member]
Marketable securities:
Fair value, Marketable securities		0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Corporate Notes and Bonds [Member]
Marketable securities:
Fair value, Marketable securities	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Commercial Paper [Member]
Cash equivalents:
Fair value, Cash equivalents		0
Marketable securities:
Fair value, Marketable securities	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | U.S. Agency Obligations [Member]
Cash equivalents:
Fair value, Cash equivalents	0
Marketable securities:
Fair value, Marketable securities	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | U.S. Treasury Securities [Member]
Cash equivalents:
Fair value, Cash equivalents	0	0
Marketable securities:
Fair value, Marketable securities	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Money Market Funds [Member]
Cash equivalents:
Fair value, Cash equivalents	6,783	23,857
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Cash equivalents and Marketable securities:
Assets, Fair Value	1,525,774	715,083
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Municipal bonds [Member]
Marketable securities:
Fair value, Marketable securities		3,044
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Corporate Notes and Bonds [Member]
Marketable securities:
Fair value, Marketable securities	135,134	125,604
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Commercial Paper [Member]
Cash equivalents:
Fair value, Cash equivalents		4,999
Marketable securities:
Fair value, Marketable securities	36,514	10,995
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | U.S. Agency Obligations [Member]
Cash equivalents:
Fair value, Cash equivalents	3,993
Marketable securities:
Fair value, Marketable securities	98,480	54,007
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | U.S. Treasury Securities [Member]
Cash equivalents:
Fair value, Cash equivalents	93,922	69,999
Marketable securities:
Fair value, Marketable securities	1,157,731	446,435
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Money Market Funds [Member]
Cash equivalents:
Fair value, Cash equivalents	$ 0	$ 0