Revenue Recognition - Disaggregation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Total revenues	$ 86,472	$ 74,355	$ 180,484	$ 141,179
United States
Disaggregation of Revenue [Line Items]
Total revenues	80,757	62,393	167,488	122,676
Americas, excluding U.S.
Disaggregation of Revenue [Line Items]
Total revenues	721	767	1,503	1,585
Europe, Middle East, India, Africa
Disaggregation of Revenue [Line Items]
Total revenues	3,584	4,318	7,060	8,322
Asia Pacific and Other
Disaggregation of Revenue [Line Items]
Total revenues	1,410	6,877	4,433	8,596
Insurance carriers
Disaggregation of Revenue [Line Items]
Total revenues	67,630	50,777	138,302	100,978
Laboratory and other partners
Disaggregation of Revenue [Line Items]
Total revenues	13,041	15,132	28,724	25,155
Patients
Disaggregation of Revenue [Line Items]
Total revenues	5,801	8,446	13,458	15,046
Product
Disaggregation of Revenue [Line Items]
Total revenues	80,414	65,099	167,460	128,463
Licensing and other
Disaggregation of Revenue [Line Items]
Total revenues	$ 6,058	$ 9,256	$ 13,024	$ 12,716