Revenue Disaggregation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Revenue	$ 28,510	$ 35,606
United States
Disaggregation of Revenue [Line Items]
Revenue	18,629	22,786
International
Disaggregation of Revenue [Line Items]
Revenue	9,881	12,820
Implant-based
Disaggregation of Revenue [Line Items]
Revenue	21,316	26,270
Implant-based | United States
Disaggregation of Revenue [Line Items]
Revenue	18,324	22,463
Implant-based | International
Disaggregation of Revenue [Line Items]
Revenue	2,992	3,807
Shipment-based
Disaggregation of Revenue [Line Items]
Revenue	7,194	9,336
Shipment-based | United States
Disaggregation of Revenue [Line Items]
Revenue	305	323
Shipment-based | International
Disaggregation of Revenue [Line Items]
Revenue	$ 6,889	$ 9,013