Acquisition Of JOTEC (Narrative) (Details) - USD ($)		1 Months Ended	3 Months Ended	6 Months Ended	12 Months Ended
	Dec. 01, 2017	Dec. 31, 2017	Jun. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Term loan balance		$ 228,969,000	$ 227,442,000	$ 227,442,000	$ 228,969,000
Additional goodwill from JOTEC Acquisition				$ 1,359,000
JOTEC [Member]
Business Acquisition [Line Items]
Agreement date				Dec. 01, 2017
Acquisition price	$ 225,000,000
Total consideration	221,869,000
Cash consideration	168,800,000
Common shares issued					2,682,754
Common stock value issued in business combination					$ 53,100,000
Escrow deposit, part of payments to acquire business	$ 22,500,000
Transaction and integration costs			851,000	$ 4,300,000
Revenues		4,100,000
Net loss		(1,500,000)			$ (736,000)	$ (1,966,000)
Pro forma tax rate					38.00%	38.00%
JOTEC [Member] | Common Stock [Member]
Business Acquisition [Line Items]
Common shares issued	2,682,754
Common stock value issued in business combination	$ 53,100,000
Term Loan [Member]
Business Acquisition [Line Items]
Term loan balance	225,000,000	$ 225,000,000	$ 223,875,000	$ 223,875,000	$ 225,000,000
Term Loan [Member] | JOTEC [Member]
Business Acquisition [Line Items]
Term loan balance	225,000,000
Senior Secured Credit Facility [Member] | JOTEC [Member]
Business Acquisition [Line Items]
Credit facility aggregate commitments	255,000,000
Revolving Credit Facility [Member] | JOTEC [Member]
Business Acquisition [Line Items]
Credit facility aggregate commitments	$ 30,000,000