Revenue Recognition - Disaggregation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Total revenues	$ 142,026	$ 86,472	$ 294,342	$ 180,484
United States
Disaggregation of Revenue [Line Items]
Total revenues	134,814	80,757	279,771	167,488
Americas, excluding U.S.
Disaggregation of Revenue [Line Items]
Total revenues	992	721	1,805	1,503
Europe, Middle East, India, Africa
Disaggregation of Revenue [Line Items]
Total revenues	4,265	3,584	8,724	7,060
Asia Pacific and Other
Disaggregation of Revenue [Line Items]
Total revenues	1,955	1,410	4,042	4,433
Insurance carriers
Disaggregation of Revenue [Line Items]
Total revenues	118,396	67,630	218,795	138,302
Laboratory partners
Disaggregation of Revenue [Line Items]
Total revenues	15,599	13,041	60,134	28,724
Patients
Disaggregation of Revenue [Line Items]
Total revenues	8,031	5,801	15,413	13,458
Licensing and other
Disaggregation of Revenue [Line Items]
Total revenues	$ 4,794	$ 6,058	$ 38,728	$ 13,024