Investments - Narrative (Details) - USD ($)	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Proceeds from sales of marketable securities	$ 0	$ 0	$ 0	$ 0
Realized gains or losses from debt securities available-for-sale	0	0	0	0
Unrealized loss position of debt securities	0		0		$ 0
Fair value of equity securities	700,000		700,000		$ 400,000
Unrealized losses on equity securities	0	0	0	0
Debt securities available-for-sale
Debt Securities, Available-for-sale [Line Items]
Reclassified from accumulated OCI	$ 0	$ 0	$ 0	$ 0

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position without allowance for credit loss.

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Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), classified as current.

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Amount of cash inflow from sale, maturity, prepayment and call 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 after tax of reclassification adjustments of other comprehensive income (loss).

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