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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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+ 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

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