Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ (1,387)	$ (19,712)	$ 12,161
Other comprehensive income (loss), net of tax:
Change in foreign currency translation	(922)	(147)	(352)
Change in fair value of marketable securities	(3)	1,428	(1,000)
Total other comprehensive income (loss)	(925)	1,281	(1,352)
Comprehensive income (loss)	(2,312)	(18,431)	10,809
Comprehensive (income) loss attributable to redeemable noncontrolling interests	(2,523)
Comprehensive income (loss) attributable to common stockholders	$ (4,835)	$ (18,431)	$ 10,809