Short-Term Investments - Summary of Estimated Fair Value of Short-Term Investments (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Cash Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	$ 446,744	$ 390,254
Gross Unrealized Gain	37	86
Gross Unrealized Loss	(57)	(17)
Estimated Fair Value	446,724	390,323
Commercial paper
Cash Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	222,319	108,892
Gross Unrealized Gain	11	5
Gross Unrealized Loss	(2)	(1)
Estimated Fair Value	$ 222,328	$ 108,896
Commercial paper | Maximum
Cash Cash Equivalents And Short Term Investments [Line Items]
Maturity (in years)	1 year	1 year
U.S. Government-sponsored enterprise
Cash Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	$ 63,175	$ 52,330
Gross Unrealized Gain	18	21
Gross Unrealized Loss	(19)	(1)
Estimated Fair Value	$ 63,174	$ 52,350
U.S. Government-sponsored enterprise | Maximum
Cash Cash Equivalents And Short Term Investments [Line Items]
Maturity (in years)	2 years	2 years
U.S. Treasury securities
Cash Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	$ 104,937	$ 143,244
Gross Unrealized Gain	2	12
Gross Unrealized Loss	(23)	(2)
Estimated Fair Value	$ 104,916	$ 143,254
U.S. Treasury securities | Maximum
Cash Cash Equivalents And Short Term Investments [Line Items]
Maturity (in years)	2 years	2 years
Corporate debt securities
Cash Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	$ 53,303	$ 85,788
Gross Unrealized Gain	6	48
Gross Unrealized Loss	(13)	(13)
Estimated Fair Value	$ 53,296	$ 85,823
Corporate debt securities | Maximum
Cash Cash Equivalents And Short Term Investments [Line Items]
Maturity (in years)	2 years	2 years
Supranational bonds
Cash Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	$ 3,010
Gross Unrealized Gain	0
Gross Unrealized Loss	0
Estimated Fair Value	$ 3,010
Supranational bonds | Maximum
Cash Cash Equivalents And Short Term Investments [Line Items]
Maturity (in years)	1 year