Cash and Cash Equivalents and Short-Term Investments - Summary of Amortized Cost, Unrealized Gain and Loss and Estimated Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Cash and Cash Equivalents [Line Items]
Amortized Cost	$ 127,666	$ 137,854
Unrealized Gain	54	52
Unrealized Loss	0	(2)
Estimated Fair Value	127,720	137,904
Commercial paper
Cash and Cash Equivalents [Line Items]
Amortized Cost	70,641	61,371
Unrealized Gain	0	0
Unrealized Loss	0	0
Estimated Fair Value	70,641	61,371
Corporate bonds
Cash and Cash Equivalents [Line Items]
Amortized Cost	11,741	23,856
Unrealized Gain	28	14
Unrealized Loss	0	(1)
Estimated Fair Value	11,769	23,869
U.S. Treasury and agency obligations
Cash and Cash Equivalents [Line Items]
Amortized Cost	45,284	52,627
Unrealized Gain	26	38
Unrealized Loss	0	(1)
Estimated Fair Value	45,310	52,664
Money market funds
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	51,409	13,588
Commercial paper
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents		8,987
Cash equivalents
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 51,409	$ 22,575