Revenue from Contract with Customer - Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Revenue recognized	$ 347,821	$ 162,043
Precision Oncology
Disaggregation of Revenue [Line Items]
Revenue recognized	128,369	0
Precision Oncology | Medicare Parts B & C
Disaggregation of Revenue [Line Items]
Revenue recognized	47,034	0
Precision Oncology | Commercial
Disaggregation of Revenue [Line Items]
Revenue recognized	59,605	0
Precision Oncology | International Sales
Disaggregation of Revenue [Line Items]
Revenue recognized	20,936	0
Precision Oncology | Other
Disaggregation of Revenue [Line Items]
Revenue recognized	794	0
Screening
Disaggregation of Revenue [Line Items]
Revenue recognized	219,452	162,043
Screening | Medicare Parts B & C
Disaggregation of Revenue [Line Items]
Revenue recognized	98,159	82,917
Screening | Commercial
Disaggregation of Revenue [Line Items]
Revenue recognized	109,369	73,351
Screening | Other
Disaggregation of Revenue [Line Items]
Revenue recognized	$ 11,924	$ 5,775