Segment Reporting and Foreign Operations - Sales by Business Segment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue from External Customer [Line Items]
% Change	21.00%				11.00%				21.00%	11.00%	6.00%
Net Sales	$ 190,897	$ 179,337	$ 186,549	$ 171,069	$ 157,715	$ 156,975	$ 151,071	$ 138,077	$ 727,852	$ 603,838	$ 542,149
Cardiovascular Segment
Revenue from External Customer [Line Items]
% Change	21.00%				11.00%				21.00%	11.00%	6.00%
Net Sales									$ 700,613	$ 580,151	$ 520,915
Cardiovascular Segment | Stand-alone devices
Revenue from External Customer [Line Items]
% Change	44.00%				23.00%				44.00%	23.00%	8.00%
Net Sales									$ 275,431	$ 191,148	$ 155,414
Cardiovascular Segment | Custom kits and procedure trays
Revenue from External Customer [Line Items]
% Change	6.00%				2.00%				6.00%	2.00%	5.00%
Net Sales									$ 126,114	$ 119,226	$ 116,368
Cardiovascular Segment | Inflation devices
Revenue from External Customer [Line Items]
% Change	8.00%				1.00%				8.00%	1.00%	1.00%
Net Sales									$ 79,875	$ 73,916	$ 73,373
Cardiovascular Segment | Catheters
Revenue from External Customer [Line Items]
% Change	13.00%				17.00%				13.00%	17.00%	11.00%
Net Sales									$ 127,747	$ 113,367	$ 96,833
Cardiovascular Segment | Embolization devices
Revenue from External Customer [Line Items]
% Change	8.00%				2.00%				8.00%	2.00%	3.00%
Net Sales									$ 49,532	$ 46,035	$ 45,025
Cardiovascular Segment | CRM/EP
Revenue from External Customer [Line Items]
% Change	15.00%				8.00%				15.00%	8.00%	3.00%
Net Sales									$ 41,914	$ 36,459	$ 33,902
Endoscopy Segment
Revenue from External Customer [Line Items]
Net Sales									$ 27,239	$ 23,687	$ 21,234
Endoscopy Segment | Endoscopy devices
Revenue from External Customer [Line Items]
% Change	15.00%				12.00%				15.00%	12.00%	18.00%
Net Sales									$ 27,239	$ 23,687	$ 21,234