Entity Wide Disclosures - Summary of Revenue by Major Source (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation Of Revenue [Line Items]
Total revenue	$ 229,886	$ 216,238	$ 214,104	$ 200,741	$ 192,115	$ 179,253	$ 170,144	$ 163,077	$ 860,969	$ 704,589	$ 436,152
Oncology
Disaggregation Of Revenue [Line Items]
Total revenue									256,766	189,056
Other
Disaggregation Of Revenue [Line Items]
Total revenue									222,514	163,983
Metabolic
Disaggregation Of Revenue [Line Items]
Total revenue									138,650	124,837
Cardiology
Disaggregation Of Revenue [Line Items]
Total revenue									91,258	95,213
AVAI
Disaggregation Of Revenue [Line Items]
Total revenue									86,390	77,271
Central Nervous System
Disaggregation Of Revenue [Line Items]
Total revenue									65,391	54,229
Revenue Net
Disaggregation Of Revenue [Line Items]
Total revenue									$ 860,969	$ 704,589	$ 0