Balance Sheet Details - Property and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 68,648	$ 77,668
Less accumulated depreciation and amortization	(53,572)	(61,587)
Property and equipment, net	15,076	16,081
Depreciation	$ 7,400	10,800	$ 9,500
Surgical instruments
Property, Plant and Equipment [Line Items]
Useful lives	4 years
Property and equipment, gross	$ 53,095	52,404
Machinery and equipment
Property, Plant and Equipment [Line Items]
Useful lives	7 years
Property and equipment, gross	$ 5,435	14,416
Capital leased assets, gross	$ 2,100	2,600
Computer equipment
Property, Plant and Equipment [Line Items]
Useful lives	3 years
Property and equipment, gross	$ 3,511	3,816
Office furniture and equipment
Property, Plant and Equipment [Line Items]
Useful lives	5 years
Property and equipment, gross	$ 2,695	3,426
Leasehold improvements
Property, Plant and Equipment [Line Items]
Various useful lives of leasehold improvements	various
Property and equipment, gross	$ 3,467	3,467
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 445	139
Capital leased assets, gross		$ 100