Fair Value Measurements of Financial Instruments - Summary of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 25,373	$ 21,935
Gross Unrealized Gain	85	1
Gross Unrealized Loss	(1)	(16)
Estimated Fair Values	25,457	21,920
Money Market Funds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	2,544	2,027
Estimated Fair Values	2,544	2,027
Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	1,749	6,965
Gross Unrealized Loss		(3)
Estimated Fair Values	1,749	6,962
Corporate Bonds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	21,080	12,943
Gross Unrealized Gain	85	1
Gross Unrealized Loss	(1)	(13)
Estimated Fair Values	21,164	12,931
Cash and Cash Equivalents
Schedule Of Available For Sale Securities [Line Items]
Estimated Fair Values	2,544	4,275
Short-term Investments
Schedule Of Available For Sale Securities [Line Items]
Estimated Fair Values	18,183	9,475
Other Assets
Schedule Of Available For Sale Securities [Line Items]
Estimated Fair Values	$ 4,730	$ 8,170

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on 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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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on 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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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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