Select Condensed Consolidated Balance Sheet Details - Property and Equipment, Net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 67,728		$ 68,648
Less accumulated depreciation and amortization	(52,320)		(53,572)
Property and equipment, net	15,408		15,076
Depreciation	$ 1,600	$ 2,300
Surgical instruments
Property, Plant and Equipment [Line Items]
Useful lives	4 years
Property and equipment, gross	$ 54,364		53,095
Machinery and equipment
Property, Plant and Equipment [Line Items]
Useful lives	7 years
Property and equipment, gross	$ 5,492		5,435
Capital leased assets, gross	$ 2,100		2,100
Computer equipment
Property, Plant and Equipment [Line Items]
Useful lives	3 years
Property and equipment, gross	$ 3,512		3,511
Office furniture and equipment
Property, Plant and Equipment [Line Items]
Useful lives	5 years
Property and equipment, gross	$ 2,707		2,695
Leasehold improvements
Property, Plant and Equipment [Line Items]
Various useful lives of leasehold improvements	various
Property and equipment, gross	$ 1,653		3,467
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross			$ 445