Geographic and Segment Information Segment Info (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) geographic_region	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) segment geographic_region	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Segment Reporting Information [Line Items]
Reportable segments | segment			2
Number of geographic regions in which entity operates | geographic_region	3		3
Net sales	$ 182,206	$ 277,169	$ 424,603	$ 527,970
Merger and integration expenses	2,048	4,378	5,522	7,629
Restructuring expenses	794	1,332	2,374	3,865
Amortization of intangibles	9,394	9,228	19,661	18,544
Operating loss from continuing operations	(15,237)	(29,876)	(14,629)	(50,655)
Interest income	287	224	435	473
Interest expense	5,715	4,054	10,564	5,716
Foreign exchange and other losses	(999)	(1,851)	(2,913)	(1,122)
Loss from continuing operations before tax	(21,664)	(35,557)	(27,671)	(57,020)
Assets	2,502,663		2,502,663		$ 2,411,797
Operating Segments | Cardiovascular
Segment Reporting Information [Line Items]
Net sales	124,535	172,244	276,604	327,735
Restructuring expenses	570	316	1,256	738
Operating Segments | Neuromodulation
Segment Reporting Information [Line Items]
Net sales	57,212	104,269	146,869	198,918
Restructuring expenses	305	53	808	485
Other
Segment Reporting Information [Line Items]
Net sales	459	656	1,130	1,317
Restructuring expenses	(81)	963	310	2,642
Continuing Operations
Segment Reporting Information [Line Items]
Total reportable segment (loss) income from continuing operations	(3,001)	(14,938)	12,928	(20,617)
Merger and integration expenses	2,048	4,378	5,522	7,629
Restructuring expenses	794	1,332	2,374	3,865
Amortization of intangibles	9,394	9,228	19,661	18,544
Operating loss from continuing operations	(15,237)	(29,876)	(14,629)	(50,655)
Capital expenditures	6,645	5,913	19,019	10,796
Continuing Operations | Operating Segments | Cardiovascular
Segment Reporting Information [Line Items]
Total reportable segment (loss) income from continuing operations	(9,407)	10,120	(726)	11,109
Assets	1,428,992		1,428,992		1,546,520
Capital expenditures	5,445	4,835	10,737	8,386
Continuing Operations | Operating Segments | Neuromodulation
Segment Reporting Information [Line Items]
Total reportable segment (loss) income from continuing operations	27,282	619	61,140	22,250
Assets	655,611		655,611		749,069
Capital expenditures	836	127	6,075	530
Continuing Operations | Other
Segment Reporting Information [Line Items]
Total reportable segment (loss) income from continuing operations	(20,876)	(25,677)	(47,486)	(53,976)
Assets	418,060		418,060		$ 116,208
Capital expenditures	364	951	2,207	1,880
United States
Segment Reporting Information [Line Items]
Net sales	78,187	134,576	201,770	262,974
United States | Operating Segments | Cardiovascular
Segment Reporting Information [Line Items]
Net sales	33,972	54,025	84,279	105,537
United States | Operating Segments | Neuromodulation
Segment Reporting Information [Line Items]
Net sales	44,215	80,551	117,491	157,437
Europe
Segment Reporting Information [Line Items]
Net sales	35,361	58,180	90,077	115,032
Europe | Operating Segments | Cardiovascular
Segment Reporting Information [Line Items]
Net sales	28,945	45,184	73,078	91,377
Europe | Operating Segments | Neuromodulation
Segment Reporting Information [Line Items]
Net sales	6,416	12,996	16,999	23,655
Rest of World
Segment Reporting Information [Line Items]
Net sales	68,658	84,413	132,756	149,964
Rest of World | Operating Segments | Cardiovascular
Segment Reporting Information [Line Items]
Net sales	61,618	73,035	119,247	130,821
Rest of World | Operating Segments | Neuromodulation
Segment Reporting Information [Line Items]
Net sales	6,581	10,722	12,379	17,826
Cardiopulmonary
Segment Reporting Information [Line Items]
Net sales	101,056	130,579	217,423	252,149
Cardiopulmonary | United States
Segment Reporting Information [Line Items]
Net sales	25,816	41,403	62,674	80,526
Cardiopulmonary | Europe
Segment Reporting Information [Line Items]
Net sales	23,294	34,320	57,528	69,881
Cardiopulmonary | Rest of World
Segment Reporting Information [Line Items]
Net sales	51,946	54,856	97,221	101,742
Heart Valves
Segment Reporting Information [Line Items]
Net sales	17,466	33,351	42,677	59,024
Heart Valves | United States
Segment Reporting Information [Line Items]
Net sales	2,488	4,678	5,861	9,034
Heart Valves | Europe
Segment Reporting Information [Line Items]
Net sales	5,348	10,672	14,877	21,185
Heart Valves | Rest of World
Segment Reporting Information [Line Items]
Net sales	9,630	18,001	21,939	28,805
Advanced Circulatory Support
Segment Reporting Information [Line Items]
Net sales	6,013	8,314	16,504	16,562
Advanced Circulatory Support | United States
Segment Reporting Information [Line Items]
Net sales	5,668	7,944	15,744	15,977
Advanced Circulatory Support | Europe
Segment Reporting Information [Line Items]
Net sales	303	192	673	311
Advanced Circulatory Support | Rest of World
Segment Reporting Information [Line Items]
Net sales	$ 42	$ 178	$ 87	$ 274