Revenue from Contracts with Customers. - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Net sales	$ 255,532	$ 224,810	$ 493,881	$ 427,844
United States
Disaggregation of Revenue [Line Items]
Net sales	144,662	124,445	282,722	234,501
International
Disaggregation of Revenue [Line Items]
Net sales	110,870	100,365	211,159	193,343
Cardiovascular
Disaggregation of Revenue [Line Items]
Net sales	246,666	216,387	477,146	412,241
Cardiovascular | United States
Disaggregation of Revenue [Line Items]
Net sales	136,113	116,324	266,605	219,461
Cardiovascular | International
Disaggregation of Revenue [Line Items]
Net sales	110,553	100,063	210,541	192,780
Endoscopy
Disaggregation of Revenue [Line Items]
Net sales	8,866	8,423	16,735	15,603
Stand-alone devices | Cardiovascular
Disaggregation of Revenue [Line Items]
Net sales	103,522	92,496	198,948	175,742
Stand-alone devices | Cardiovascular | United States
Disaggregation of Revenue [Line Items]
Net sales	55,906	50,941	109,305	94,953
Stand-alone devices | Cardiovascular | International
Disaggregation of Revenue [Line Items]
Net sales	47,616	41,555	89,643	80,789
Cianna Medical | Cardiovascular
Disaggregation of Revenue [Line Items]
Net sales	11,237	0	24,085	0
Cianna Medical | Cardiovascular | United States
Disaggregation of Revenue [Line Items]
Net sales	11,230	0	24,078	0
Cianna Medical | Cardiovascular | International
Disaggregation of Revenue [Line Items]
Net sales	7	0	7	0
Custom kits and procedure trays | Cardiovascular
Disaggregation of Revenue [Line Items]
Net sales	34,343	33,992	67,286	67,264
Custom kits and procedure trays | Cardiovascular | United States
Disaggregation of Revenue [Line Items]
Net sales	23,124	23,667	45,179	45,984
Custom kits and procedure trays | Cardiovascular | International
Disaggregation of Revenue [Line Items]
Net sales	11,219	10,325	22,107	21,280
Inflation devices | Cardiovascular
Disaggregation of Revenue [Line Items]
Net sales	24,315	24,305	46,333	46,724
Inflation devices | Cardiovascular | United States
Disaggregation of Revenue [Line Items]
Net sales	8,347	8,160	16,320	15,828
Inflation devices | Cardiovascular | International
Disaggregation of Revenue [Line Items]
Net sales	15,968	16,145	30,013	30,896
Catheters | Cardiovascular
Disaggregation of Revenue [Line Items]
Net sales	45,344	39,374	88,383	73,239
Catheters | Cardiovascular | United States
Disaggregation of Revenue [Line Items]
Net sales	20,696	16,704	40,108	31,974
Catheters | Cardiovascular | International
Disaggregation of Revenue [Line Items]
Net sales	24,648	22,670	48,275	41,265
Embolization devices | Cardiovascular
Disaggregation of Revenue [Line Items]
Net sales	14,008	12,724	25,835	25,310
Embolization devices | Cardiovascular | United States
Disaggregation of Revenue [Line Items]
Net sales	5,274	5,094	9,980	10,126
Embolization devices | Cardiovascular | International
Disaggregation of Revenue [Line Items]
Net sales	8,734	7,630	15,855	15,184
CRM/EP | Cardiovascular
Disaggregation of Revenue [Line Items]
Net sales	13,897	13,496	26,276	23,962
CRM/EP | Cardiovascular | United States
Disaggregation of Revenue [Line Items]
Net sales	11,536	11,758	21,635	20,596
CRM/EP | Cardiovascular | International
Disaggregation of Revenue [Line Items]
Net sales	2,361	1,738	4,641	3,366
Endoscopy devices | Endoscopy
Disaggregation of Revenue [Line Items]
Net sales	8,866	8,423	16,735	15,603
Endoscopy devices | Endoscopy | United States
Disaggregation of Revenue [Line Items]
Net sales	8,549	8,121	16,117	15,040
Endoscopy devices | Endoscopy | International
Disaggregation of Revenue [Line Items]
Net sales	$ 317	$ 302	$ 618	$ 563