Fair Value of Financial Instruments - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Impairments		$ 0
Realized gain or loss on available-for-sale securities	$ 0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Money Market Funds
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Investments	61,600,000	94,600,000
Significant Other Observable Inputs (Level 2) | Short-term investments
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Marketable securities	236,700,000	218,200,000
Accrued interest receivable	$ 800,000	$ 1,100,000