Entity Wide Disclosures - Summary of Revenue by Major Source (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation Of Revenue [Line Items]
Total revenue	$ 192,115	$ 179,253	$ 170,144	$ 163,077	$ 112,682	$ 110,643	$ 106,216	$ 106,611	$ 704,589	$ 436,152	$ 421,582
Oncology
Disaggregation Of Revenue [Line Items]
Total revenue									189,026
Other
Disaggregation Of Revenue [Line Items]
Total revenue									161,194
Metabolic
Disaggregation Of Revenue [Line Items]
Total revenue									94,128
Cardiology
Disaggregation Of Revenue [Line Items]
Total revenue									91,824
AVAI
Disaggregation Of Revenue [Line Items]
Total revenue									76,739
Central Nervous System
Disaggregation Of Revenue [Line Items]
Total revenue									53,904
Endocrine
Disaggregation Of Revenue [Line Items]
Total revenue									26,002
Medical Devices
Disaggregation Of Revenue [Line Items]
Total revenue									11,772
Revenue Net
Disaggregation Of Revenue [Line Items]
Total revenue									$ 704,589	$ 0	$ 0