Entity Wide Disclosures - Summary of Revenue by Major Source (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation Of Revenue [Line Items]
Total revenue	$ 230,879	$ 200,741
Oncology
Disaggregation Of Revenue [Line Items]
Total revenue	69,212	55,962
Other
Disaggregation Of Revenue [Line Items]
Total revenue	50,569	46,869
Metabolic
Disaggregation Of Revenue [Line Items]
Total revenue	36,075	35,001
Cardiology
Disaggregation Of Revenue [Line Items]
Total revenue	25,899	22,650
AVAI
Disaggregation Of Revenue [Line Items]
Total revenue	25,147	19,924
Central Nervous System
Disaggregation Of Revenue [Line Items]
Total revenue	23,977	20,335
Revenue Net
Disaggregation Of Revenue [Line Items]
Total revenue	$ 230,879	$ 200,741