Revenue Recognition - Deferred Revenues (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenue recognized during the period that was included in deferred revenues at the beginning of the period	$ 7,246
Deferred revenue, current portion	50,125	$ 56,016
Deferred revenue, Long-term	22,805	23,808
Deferred revenue	72,930	$ 79,824
BGI Genomics
Deferred revenue, current portion	3,900
Foundation Medicine ("FMI")
Deferred revenue, current portion	6,200
BGI Genomics and Foundation Medicine (including genetic testing services)
Revenue recognized during the period that was included in deferred revenues at the beginning of the period	7,200
BGI Genomics and Foundation Medicine ("FMI")
Revenue recognized during the period that was included in deferred revenues at the beginning of the period	6,800
Revenue recognized	1,200
Genetic testing services and provision of IVD kits
Revenue recognized during the period that was included in deferred revenues at the beginning of the period	$ 400