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Balance Sheet Components - Summary of Amortized Cost, Gross Unrealized Holding Gains or Losses, and Fair Value of Available-for-Sale Investments (Detail) - USD ($) $ in Thousands | Mar. 31, 2021 | Dec. 31, 2020
--- | --- | ---
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized Cost | $ 204,341 | $ 8,272
Gross Unrealized Holding Gains | 129 | 119
Gross Unrealized Holding Losses | (67) | (3)
Fair Value | 204,403 | 8,388
Corporate bonds [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized Cost | 75,503 |
Gross Unrealized Holding Gains | 4 |
Gross Unrealized Holding Losses | (54) |
Fair Value | 75,453 |
Commercial paper [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized Cost | 59,536 |
Gross Unrealized Holding Gains | 4 |
Gross Unrealized Holding Losses | (1) |
Fair Value | 59,539 |
U.S. government bonds [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized Cost | 30,060 |
Gross Unrealized Holding Gains | 2 |
Gross Unrealized Holding Losses | (3) |
Fair Value | 30,059 |
Agency bonds [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized Cost | 14,349 |
Gross Unrealized Holding Gains | 1 |
Gross Unrealized Holding Losses | (3) |
Fair Value | 14,347 |
Asset-backed securities [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized Cost | 12,573 |
Gross Unrealized Holding Gains | 0 |
Gross Unrealized Holding Losses | (4) |
Fair Value | 12,569 |
Foreign government bonds [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized Cost | 12,195 |
Gross Unrealized Holding Gains | 1 |
Gross Unrealized Holding Losses | (2) |
Fair Value | 12,194 |
Bond and mutual funds [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized Cost |  | 8,147
Gross Unrealized Holding Gains |  | 0
Gross Unrealized Holding Losses |  | (3)
Fair Value |  | 8,144
Equity investments [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized Cost | 125 | 125
Gross Unrealized Holding Gains | 117 | 119
Gross Unrealized Holding Losses | 0 | 0
Fair Value | $ 242 | $ 244

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- Definition Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27161-111563 + Details
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