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Short-Term and Long-Term Investments - Summary of Investment (Detail) - USD ($)
$ in Thousands
Mar. 31, 2021
Dec. 31, 2020
Cash and Cash Equivalents [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Debt Securities, Available-for-sale $ 127,411 $ 161,742
Short-term Investments [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Debt Securities, Available-for-sale 95,719 50,166
Other Long-term Investments [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Debt Securities, Available-for-sale 2,541 2,517
Estimate of Fair Value Measurement [Member] | Cash and Cash Equivalents [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Debt Securities, Available-for-sale 43,728 89,491
Estimate of Fair Value Measurement [Member] | Short-term Investments [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Debt Securities, Available-for-sale 95,719 50,166
Estimate of Fair Value Measurement [Member] | Other Long-term Investments [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Debt Securities, Available-for-sale 2,541 2,517
Estimate of Fair Value Measurement [Member] | Auction Rate Securities [Member] | Other Long-term Investments [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Debt Securities, Available-for-sale 2,541 2,517
Estimate of Fair Value Measurement [Member] | Money Market Funds [Member] | Cash and Cash Equivalents [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Debt Securities, Available-for-sale 43,728 69,493
Estimate of Fair Value Measurement [Member] | US Treasury Obligations [Member] | Cash and Cash Equivalents [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Debt Securities, Available-for-sale   19,998
Estimate of Fair Value Measurement [Member] | US Treasury Obligations [Member] | Short-term Investments [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Debt Securities, Available-for-sale 95,719 50,166
Portion at Other than Fair Value Measurement [Member] | Cash [Member] | Cash and Cash Equivalents [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Debt Securities, Available-for-sale $ 83,683 $ 72,251