Marketable Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 17,146	$ 25,141
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	17,146	25,141
Money market mutual funds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	17,146	20,142
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	$ 17,146	20,142
United States treasuries
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		4,999
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Fair Value		$ 4,999

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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