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Short-term and Long-term Investments (Tables)
 9 Months Ended
Sep. 30, 2021
Investments, Debt and Equity Securities [Abstract]  
Summary of Amortized Cost, Gross Unrealized Gains and Losses, and Fair Value of Short-term and Long-term Investments The following table summarizes the amortized cost, gross unrealized gains and losses, and fair value of available-for-sale investments as of September 30, 2021:
Amortized
Cost		Gross
Unrealized
Gains		Gross
Unrealized
Losses		Aggregate
Fair Value
U.S. government debt securities$139,375 $5 $(35)$139,345 
Certificates of deposit265 — — 265 
Total$139,640 $5 $(35)$139,610 
The following table summarizes the amortized cost, gross unrealized gains and losses, and fair value of available-for-sale investments as of December 31, 2020:
Amortized
Cost		Gross
Unrealized
Gains		Gross
Unrealized
Losses		Aggregate
Fair Value
U.S. government debt securities$48,048 $14 $(1)$48,061 
Certificates of deposit264 — — 264 
Total$48,312 $14 $(1)$48,325 
Contractual Obligation, Fiscal Year Maturity
The estimated fair value of available-for-sale investments classified by their contractual maturities as of September 30, 2021 was:
Due within one year$72,684 
After one year through two years66,926 
Total$139,610