Marketable Securities - Marketable Available-for-Sale Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 8,067
Estimated Fair Value	60,729	$ 118,130
Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	85,638	22,415
Estimated Fair Value	85,638	22,415
Cash and Cash Equivalents [Member] \| Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	85,638	22,415
Estimated Fair Value	85,638	22,415
Current marketable securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	60,742	118,122
Gross Unrealized Gains	1	13
Gross Unrealized Losses	(14)	(5)
Estimated Fair Value	60,729	118,130
Current marketable securities [Member] \| U.S. and Foreign Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	28,760	38,561
Estimated Fair Value	28,760	38,561
Current marketable securities [Member] \| U.S. and Foreign Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	15,476	29,186
Gross Unrealized Gains		7
Gross Unrealized Losses	(8)	(4)
Estimated Fair Value	15,468	29,189
Current marketable securities [Member] \| Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	8,524	7,883
Gross Unrealized Gains	1	2
Gross Unrealized Losses	(3)
Estimated Fair Value	8,522	7,885
Current marketable securities [Member] \| U.S. Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	7,982	23,991
Gross Unrealized Gains		3
Gross Unrealized Losses	(3)
Estimated Fair Value	7,979	23,994
Current marketable securities [Member] \| US Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		15,498
Gross Unrealized Gains		1
Estimated Fair Value		15,499
Current marketable securities [Member] \| Supranational Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		3,003
Gross Unrealized Losses		(1)
Estimated Fair Value		3,002
Maketable Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	154,447	140,537
Gross Unrealized Gains	3	13
Gross Unrealized Losses	(16)	(5)
Estimated Fair Value	154,434	$ 140,545
Non-current marketable securities [Member] \| U.S. and Foreign Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Gains	2
Gross Unrealized Losses	(2)
Estimated Fair Value	$ 8,067

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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-Topic 320
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-Section 50
-Paragraph 2
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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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