Segment Information - Reconciliation of U.S. GAAP (Loss) Income Before Income Taxes to Adjusted EBITDA (Detail) - USD ($)		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting [Abstract]
Adjusted EBITDA		$ 129,138,000	$ 108,600,000	$ 85,253,000
Stock-based compensation expense		(85,581,000)	(84,787,000)	(44,549,000)
Interest expense		(6,116,000)	(4,377,000)	(12,065,000)
Depreciation and amortization		(39,124,000)	(35,504,000)	(25,644,000)
Restructuring expense		0	0	(5,053,000)
Special adjustments, interest income and other	[1]	14,302,000	(12,145,000)	1,770,000
Income (loss) before income taxes		$ 12,619,000	$ (28,213,000)	$ (288,000)

[1] The year ended December 31, 2023, includes $3.2 million currency gains on acquisition-related intercompany loans, $5.7 million losses from the mark-to-market adjustment of contingent consideration associated with the World Programming acquisition and $16.9 million of interest income. The year ended December 31, 2022, includes $16.6 million expense on repurchase of convertible senior notes, $6.8 million currency losses on acquisition-related intercompany loans, $7.2 million gains from the mark-to-market adjustment of contingent consideration associated with the World Programming acquisition and $4.1 million of interest income. The year ended December 31, 2021, includes $1.2 million currency gains on acquisition-related intercompany loans and $0.5 million of interest income.