Quarterly report pursuant to Section 13 or 15(d)

Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Schedule of Amortized Cost (Details)

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Fair Value Measurements - Schedule of Amortized Cost (Details) - USD ($)
3 Months Ended
Mar. 31, 2021
Mar. 31, 2022
Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Amortized Cost   $ 178,808,000 $ 199,464,000
Gross Unrealized Gains   1,000 22,000
Gross Unrealized Losses   (3,275,000) (923,000)
Fair Value   175,534,000 198,563,000
Accrued interest receivable   400,000 600,000
Realized gains (losses) on marketable securities $ 0    
U.S. Treasury securities      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Amortized Cost   51,190,000 52,791,000
Gross Unrealized Gains   0 11,000
Gross Unrealized Losses   (610,000) (138,000)
Fair Value   50,580,000 52,664,000
Yankee bonds      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Amortized Cost   8,031,000 6,175,000
Gross Unrealized Gains   0 1,000
Gross Unrealized Losses   (76,000) (16,000)
Fair Value   7,955,000 6,160,000
Agency bonds      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Amortized Cost   7,020,000 17,546,000
Gross Unrealized Gains   0 0
Gross Unrealized Losses   (49,000) (16,000)
Fair Value   6,971,000 17,530,000
Municipal bonds      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Amortized Cost   12,403,000 12,440,000
Gross Unrealized Gains   0 0
Gross Unrealized Losses   (711,000) (211,000)
Fair Value   11,692,000 12,229,000
Commercial paper      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Amortized Cost   9,185,000 17,694,000
Gross Unrealized Gains   0 0
Gross Unrealized Losses   0 (4,000)
Fair Value   9,185,000 17,690,000
Asset-backed securities      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Amortized Cost   28,364,000 27,620,000
Gross Unrealized Gains   0 1,000
Gross Unrealized Losses   (311,000) (86,000)
Fair Value   28,053,000 27,535,000
Corporate bonds      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Amortized Cost   62,615,000 65,198,000
Gross Unrealized Gains   1,000 9,000
Gross Unrealized Losses   (1,518,000) (452,000)
Fair Value   $ 61,098,000 $ 64,755,000