Consolidated Statements of Comprehensive Income (Loss) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss) from consolidated operations	$ 506,239,000	$ 214,310,000	$ (411,000)
Other comprehensive income (loss):
Foreign currency translation gain (loss)	456,000	20,000	(17,000)
Net unrealized (loss) gain on available-for-sale debt securities, net of tax	(1,548,000)	272,000	198,000
Comprehensive income (loss) from consolidated operations	505,147,000	214,602,000	(230,000)
Net loss attributable to noncontrolling interests	1,125,000
Foreign currency translation gain attributable to noncontrolling interest	(105,000)
Comprehensive loss attributable to noncontrolling interest	1,020,000
Comprehensive income (loss) attributable to Fulgent	$ 506,167,000	$ 214,602,000	$ (230,000)