Revenue from Contracts with Customers. - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Net sales	$ 243,049	$ 221,659	$ 736,930	$ 649,504
United States
Disaggregation of Revenue [Line Items]
Net sales	144,011	126,108	426,730	360,610
International
Disaggregation of Revenue [Line Items]
Net sales	99,038	95,551	310,200	288,894
Cardiovascular
Disaggregation of Revenue [Line Items]
Net sales	234,426	212,150	711,570	624,392
Cardiovascular | United States
Disaggregation of Revenue [Line Items]
Net sales	135,671	116,879	402,271	336,341
Cardiovascular | International
Disaggregation of Revenue [Line Items]
Net sales	98,755	95,271	309,299	288,051
Endoscopy
Disaggregation of Revenue [Line Items]
Net sales	8,623	9,509	25,360	25,112
Stand-alone devices | Cardiovascular
Disaggregation of Revenue [Line Items]
Net sales	96,326	90,975	295,275	266,717
Stand-alone devices | Cardiovascular | United States
Disaggregation of Revenue [Line Items]
Net sales	55,816	52,173	165,121	147,125
Stand-alone devices | Cardiovascular | International
Disaggregation of Revenue [Line Items]
Net sales	40,510	38,802	130,154	119,592
Cianna Medical | Cardiovascular
Disaggregation of Revenue [Line Items]
Net sales	11,638	0	35,723	0
Cianna Medical | Cardiovascular | United States
Disaggregation of Revenue [Line Items]
Net sales	11,544	0	35,622	0
Cianna Medical | Cardiovascular | International
Disaggregation of Revenue [Line Items]
Net sales	94	0	101	0
Custom kits and procedure trays | Cardiovascular
Disaggregation of Revenue [Line Items]
Net sales	33,972	33,095	101,257	100,359
Custom kits and procedure trays | Cardiovascular | United States
Disaggregation of Revenue [Line Items]
Net sales	23,115	23,199	68,292	69,184
Custom kits and procedure trays | Cardiovascular | International
Disaggregation of Revenue [Line Items]
Net sales	10,857	9,896	32,965	31,175
Inflation devices | Cardiovascular
Disaggregation of Revenue [Line Items]
Net sales	22,183	22,893	68,515	69,617
Inflation devices | Cardiovascular | United States
Disaggregation of Revenue [Line Items]
Net sales	8,156	7,819	24,475	23,647
Inflation devices | Cardiovascular | International
Disaggregation of Revenue [Line Items]
Net sales	14,027	15,074	44,040	45,970
Catheters | Cardiovascular
Disaggregation of Revenue [Line Items]
Net sales	44,426	40,591	132,809	113,830
Catheters | Cardiovascular | United States
Disaggregation of Revenue [Line Items]
Net sales	20,262	18,081	60,370	50,055
Catheters | Cardiovascular | International
Disaggregation of Revenue [Line Items]
Net sales	24,164	22,510	72,439	63,775
Embolization devices | Cardiovascular
Disaggregation of Revenue [Line Items]
Net sales	12,333	12,395	38,168	37,706
Embolization devices | Cardiovascular | United States
Disaggregation of Revenue [Line Items]
Net sales	5,254	5,145	15,234	15,272
Embolization devices | Cardiovascular | International
Disaggregation of Revenue [Line Items]
Net sales	7,079	7,250	22,934	22,434
CRM/EP | Cardiovascular
Disaggregation of Revenue [Line Items]
Net sales	13,548	12,201	39,823	36,163
CRM/EP | Cardiovascular | United States
Disaggregation of Revenue [Line Items]
Net sales	11,524	10,462	33,157	31,058
CRM/EP | Cardiovascular | International
Disaggregation of Revenue [Line Items]
Net sales	2,024	1,739	6,666	5,105
Endoscopy devices | Endoscopy
Disaggregation of Revenue [Line Items]
Net sales	8,623	9,509	25,360	25,112
Endoscopy devices | Endoscopy | United States
Disaggregation of Revenue [Line Items]
Net sales	8,340	9,229	24,459	24,269
Endoscopy devices | Endoscopy | International
Disaggregation of Revenue [Line Items]
Net sales	$ 283	$ 280	$ 901	$ 843