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Short-Term and Long-Term Investments - Amortized Cost and Estimated Fair Value of Available-for-Sale Securities by Contractual Maturities (Detail)
$ in Thousands
Jun. 30, 2021
USD ($)
Schedule of Available-for-sale Securities [Line Items]  
Debt Securities, Available-for-sale, Amortized Cost $ 70,470
Available For Sale Debt Securities Estimated Fair Value 70,469
Failed Auction Security [Member]  
Schedule of Available-for-sale Securities [Line Items]  
Due in twenty to forty years, Cost 3,000
Due in twenty to forty years, Estimated Fair Value 2,561
US Treasury Obligations [Member]  
Schedule of Available-for-sale Securities [Line Items]  
Maturities greater than three months but less than one year, Cost 70,470
Maturities greater than three months but less than one year, Estimated Fair Value $ 70,469