Financial Instruments - Summary of Cash and Cash Equivalents, Money Market Funds and Short-term Investments by Significant Investment Category (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
Jun. 30, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Adjusted Cost	$ 233,812	$ 263,729
Unrealized Gains	17	15
Unrealized Losses	(47)	(47)
Market Value	233,782	263,697
Level 1 \| Money Market Funds
Debt Securities, Available-for-sale [Line Items]
Adjusted Cost	23,568	27,686
Unrealized Gains	0	0
Unrealized Losses	0	0
Market Value	23,568	27,686
Level 2 \| Corporate debt securities included in cash and cash equivalents and short-term investments
Debt Securities, Available-for-sale [Line Items]
Adjusted Cost	183,684	118,759
Unrealized Gains	11	1
Unrealized Losses	(47)	(46)
Market Value	183,648	118,714
Level 2 \| U.S. Treasury securities included in short-term investments
Debt Securities, Available-for-sale [Line Items]
Adjusted Cost	7,532	63,101
Unrealized Gains	1	4
Unrealized Losses	0	(1)
Market Value	7,533	63,104
Level 2 \| U.S. government agency securities included in cash and cash equivalents and short-term investments
Debt Securities, Available-for-sale [Line Items]
Adjusted Cost	19,028	54,183
Unrealized Gains	5	10
Unrealized Losses	0	0
Market Value	$ 19,033	$ 54,193

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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