Financial Instruments - Summary of Investments (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Schedule of Available-for-sale Securities [Line Items]
Total short-term investments (available for sale), Fair value	$ 174,213	$ 300,676
Short-term, Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Total short-term investments (available for sale), Cost	5,028	139
Total short-term investments (available for sale), Gross Unrealized Gain		1
Total short-term investments (available for sale), Gross Unrealized (Loss)	(1)
Total short-term investments (available for sale), Fair value	5,027	140
Short-term, Non-governmental Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total short-term investments (available for sale), Cost	168,623	288,578
Total short-term investments (available for sale), Gross Unrealized Gain	27	331
Total short-term investments (available for sale), Gross Unrealized (Loss)	(184)	(176)
Total short-term investments (available for sale), Fair value	168,466	288,733
Short-term, Treasury and Federal Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Total short-term investments (available for sale), Cost	720	11,799
Total short-term investments (available for sale), Gross Unrealized Gain		6
Total short-term investments (available for sale), Gross Unrealized (Loss)		(2)
Total short-term investments (available for sale), Fair value	720	11,803
Short-term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Total short-term investments (available for sale), Cost	174,371	300,516
Total short-term investments (available for sale), Gross Unrealized Gain	27	338
Total short-term investments (available for sale), Gross Unrealized (Loss)	(185)	(178)
Total short-term investments (available for sale), Fair value	$ 174,213	$ 300,676