Financial Instruments - Summary of Financial assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2021	Dec. 31, 2020
Available-for-sale [Abstract]
Cash	$ 2,503
Adjusted Cost	477,751
Unrealized Losses	(81)
Fair Value	477,670
Cash and cash equivalents	107,456	$ 24,624
Marketable Securities	370,214	$ 0
Financial liabilities, Fair value
Fair Value, Inputs, Level 1 [Member] \| Money Market Funds [Member]
Available-for-sale [Abstract]
Adjusted Cost	45,955
Fair Value	45,955
Cash and cash equivalents	45,955
Fair Value, Inputs, Level 2 [Member]
Available-for-sale [Abstract]
Adjusted Cost	429,293
Unrealized Losses	(81)
Fair Value	429,212
Cash and cash equivalents	58,998
Marketable Securities	370,214
Fair Value, Inputs, Level 2 [Member] \| U.S. Government Securities [Member]
Available-for-sale [Abstract]
Adjusted Cost	25,019
Unrealized Losses	(12)
Fair Value	25,007
Marketable Securities	25,007
Fair Value, Inputs, Level 2 [Member] \| U.S. Treasury Securities [Member]
Available-for-sale [Abstract]
Adjusted Cost	118,502
Unrealized Losses	(6)
Fair Value	118,496
Cash and cash equivalents	58,998
Marketable Securities	59,498
Fair Value, Inputs, Level 2 [Member] \| Commercial Paper [Member]
Available-for-sale [Abstract]
Adjusted Cost	130,030
Unrealized Losses	(9)
Fair Value	130,039
Marketable Securities	130,039
Fair Value, Inputs, Level 2 [Member] \| Corporate Bonds [Member]
Available-for-sale [Abstract]
Adjusted Cost	154,715
Unrealized Losses	(72)
Fair Value	154,643
Marketable Securities	154,643
Fair Value, Inputs, Level 2 [Member] \| Muncipal Securities [Member]
Available-for-sale [Abstract]
Adjusted Cost	1,027
Fair Value	1,027
Marketable Securities	1,027
Fair Value, Inputs, Level 3 [Member] \| Warrant Liabilities [Member]
Available-for-sale [Abstract]
Financial liabilities, Adjusted cost	1,110
Financial liabilities, Fair value	$ 1,110

Financial Liabilities Adjusted Cost

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Amount of unrealized loss before deducting unrealized gain on investments in available-for-sale securities.

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Amount 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. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Fair value of financial obligations, including, but not limited to, debt instruments, derivative liabilities, federal funds purchased and sold under agreements to repurchase, securities loaned or sold under agreements to repurchase, financial instruments sold not yet purchased, guarantees, line of credit, loans and notes payable, servicing liability, and trading liabilities.

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Amount of investment in marketable security.

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