Agreements With Endospan (Narrative) (Details)		1 Months Ended		3 Months Ended	12 Months Ended
	Sep. 11, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2021 USD ($) item	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Variable Interest Entity [Line Items]
Securities purchase option agreement, expiration period					90 days
Number of tranches | item					3
Endospan [Member]
Variable Interest Entity [Line Items]
Securities purchase option agreement	$ 1,000,000.0		$ 1,000,000.0
Per three tranches of funding	$ 5,000,000.0
Funded second tranche payment		$ 5,000,000.0
Required percentage of number of patients before third tranche of loan funding can be acquired	50.00%
Investment in VIE	$ 15,000,000.0				$ 20,000,000.0
Additional amounts		$ 5,000,000.0
Endospan loan, fair value						$ 409,000	$ 358,000
Distribution agreements, fair value				$ 5,500,000	5,500,000	8,000,000.0
Expense from fair value adjustment					$ 409,000
Asset impairment				$ 4,900,000
Value of option purchase						$ 4,900,000
Endospan [Member] | Minimum [Member]
Variable Interest Entity [Line Items]
Option to purchase outstanding securities			350,000,000.0
Endospan [Member] | Maximum [Member]
Variable Interest Entity [Line Items]
Option to purchase outstanding securities			$ 450,000,000.0
Secured Debt [Member] | Endospan [Member]
Variable Interest Entity [Line Items]
Loan provided	15,000,000.0
JOTEC GmbH [Member] | Endospan [Member]
Variable Interest Entity [Line Items]
Distribution fee	$ 9,000,000.0