Available-for-Sale-Securities - Schedule of Available-for-Sale Securities Reconciliation (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Cost	$ 97,042	$ 30,750
Gross Unrealized Gains	3	0
Gross Unrealized Losses	(68)	(13)
Estimated Fair Value	96,977	30,737
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Cost	60,903	8,406
Gross Unrealized Gains	3	0
Gross Unrealized Losses	(61)	(7)
Estimated Fair Value	60,845	8,399
Money market funds
Debt Securities, Available-for-sale [Line Items]
Cost	9,600	7,591
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	9,600	7,591
Municipal debt securities
Debt Securities, Available-for-sale [Line Items]
Cost	26,539	14,753
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(7)	(6)
Estimated Fair Value	$ 26,532	$ 14,747

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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Amount 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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