Transactions With Related Parties (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
On-X [Member]
Related Party Transaction [Line Items]
Purchases from related party transactions	$ 3,000,000
Member Of Board Of Directors , Retired[Member]
Related Party Transaction [Line Items]
Revenue from related parties	443,000	$ 133,000	$ 316,000
Purchases from related party transactions	23,000	34,000	39,000
Son Of Member Of Board Of Directors [Member]
Related Party Transaction [Line Items]
Revenue from related parties	745,000	793,000	479,000
President And CEO [Member]
Related Party Transaction [Line Items]
Purchases from related party transactions	55,000	$ 53,000	$ 44,000
Member Of Board Of Directors Joining 2018 [Member]
Related Party Transaction [Line Items]
Revenue from related parties	$ 296,000