Select Condensed Consolidated Balance Sheet Details - Intangible Assets, Net (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Mar. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	$ 54,394		$ 54,394			$ 32,835
Less accumulated amortization	(28,012)		(28,012)			(27,587)
Intangible assets, net	26,382		26,382			5,248
Amortization of intangible assets	100	$ 300	$ 400	$ 500
Developed technology
Finite-Lived Intangible Assets [Line Items]
Useful lives			12 years
Intangible assets, Gross	26,975		$ 26,975			13,876
Intellectual property
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	1,004		1,004			1,004
License agreements
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	5,738		5,738			5,738
Trademarks and trade names
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	792		$ 792			732
Customer-related
Finite-Lived Intangible Assets [Line Items]
Useful lives			2 years
Intangible assets, Gross	7,458		$ 7,458			7,458
Distribution network
Finite-Lived Intangible Assets [Line Items]
Useful lives			4 years
Intangible assets, Gross	4,027		$ 4,027			$ 4,027
In process research and development
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	8,400		8,400
SafeOp Surgical, Inc.
Finite-Lived Intangible Assets [Line Items]
Business acquisition, intangible assets recorded					$ 21,600
SafeOp Surgical, Inc. | Developed technology
Finite-Lived Intangible Assets [Line Items]
Business acquisition, intangible assets recorded	13,100		$ 13,100
Useful lives			20 years
SafeOp Surgical, Inc. | In process research and development
Finite-Lived Intangible Assets [Line Items]
Business acquisition, intangible assets recorded	$ 8,400		$ 8,400