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Related Parties - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Related Party Transaction [Line Items]
Due to related parties	$ 634,000		$ 634,000		$ 409,000
AHMC Healthcare Inc. \| Genetic Sequencing Services
Related Party Transaction [Line Items]
Revenue from related parties	762,000	$ 1,300,000	2,600,000	$ 1,300,000
Trade accounts receivable, net from related parties	724,000		724,000		1,800,000
Fulgent Pharma LLC
Related Party Transaction [Line Items]
Related party costs	0	0	0	0
Due to related parties	634,000		634,000		409,000
Fulgent Pharma LLC \| Research Development Service
Related Party Transaction [Line Items]
Expenses to transport employees and supplies	74,000	$ 0	279,000	$ 0
PTJ Associates Inc
Related Party Transaction [Line Items]
Expenses to transport employees and supplies	$ 65,000		$ 142,000
Accounts payable to related parties					$ 94,000