Revenue Recognition (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended				6 Months Ended		12 Months Ended
	Jul. 31, 2021	Feb. 28, 2019	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020	Sep. 30, 2019	Aug. 31, 2019
Refunds of revenues previously deferred							$ 10,000
Deferred revenue, Long-term			$ 23,562				23,562				$ 22,805
Other assets			12,847				12,847				14,743
Deferred revenue			34,209				34,209				72,930
Deferred revenue, current portion			10,647				10,647				50,125
Total revenues			142,026		$ 86,472		294,342	$ 180,484
Deferred revenue, long-term portion			23,562				23,562				22,805
Revenue recognized during the period that was included in deferred revenues at the beginning of the period							30,839
Product
Revenue recognized			1,700		600		3,000	1,600
Cost of revenues			73,227		42,731		134,549	84,251
Total revenues			137,232		80,414		$ 255,614	167,460
Product | Minimum
Billing collection period (in months)							9 months
Product | Maximum
Billing collection period (in months)							12 months
Licensing and other
Cost of revenues			2,885		4,208		$ 8,376	7,666
Total revenues			4,794		$ 6,058		38,728	$ 13,024
Genetic testing services
Revenue recognized during the period that was included in deferred revenues at the beginning of the period							$ 200
Qiagen
Proceeds from license agreement										$ 5,000
Agreement term							10 years
Revenue, remaining performance obligation										40,000
Revenue recognized during the period that was included in deferred revenues at the beginning of the period							$ 28,600
Qiagen | Volume, regulatory and commercial milestones
Revenue, remaining performance obligation										$ 10,000
Qiagen | Other licensing and other revenue
Refunds of revenues previously deferred				$ 10,000
Deferred revenue				$ 28,600
Laboratory distribution partners | Product | Minimum
Billing collection period (in months)							2 months
Laboratory distribution partners | Product | Maximum
Billing collection period (in months)							3 months
BGI Genomics
Proceeds from license agreement		$ 50,000				$ 35,600
Receivable						$ 2,500
Agreement term		10 years
Deferred revenue, current portion			3,200				$ 3,200
BGI Genomics | Sequencing services
Other assets												$ 6,000
BGI Genomics | Sequencing products
Other assets												4,000
BGI Genomics | Sequencing products and services
Other assets												$ 10,000
Foundation Medicine ("FMI")
Proceeds from license agreement									$ 16,300
Deferred revenue, current portion			5,100				5,100
Prepaid royalties											$ 2,500
Foundation Medicine ("FMI") | Milestone payments
Deferred revenue, current portion			1,000				1,000
Foundation Medicine ("FMI") | Milestone payments | Subsequent Event
Proceeds from license agreement	$ 1,000
Foundation Medicine ("FMI") | Upfront licensing fees and prepaid revenues
Initial transaction price													$ 13,300
Foundation Medicine ("FMI") | Developmental, regulatory, and commercial milestones
Initial transaction price													$ 32,000
Foundation Medicine ("FMI") | Developmental performance milestones
Proceeds from license agreement									3,000
Foundation Medicine ("FMI") | Licensing fees and prepaid revenue
Proceeds from license agreement									$ 13,300
Foundation Medicine ("FMI") | Clinical trial studies
Revenue recognized			$ 0
BGI and FMI | Genetic testing services
Revenue recognized during the period that was included in deferred revenues at the beginning of the period							$ 2,000