Balance Sheet Account Details - Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Goodwill		$ 337,028	$ 83,834
Goodwill, Acquired During Period	$ 253,200
Accumulated amortization		(72,562)	(56,367)
Total		203,827
Gross assets		276,389	84,006
Net		$ 203,827	27,639
Purchased technology
Finite-Lived Intangible Assets [Line Items]
Weighted-average useful life (years)		9 years 1 month
Gross assets		$ 112,100	53,600
Accumulated amortization		(49,614)	(41,369)
Total		$ 62,486	12,231
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted-average useful life (years)		7 years 10 days
Gross assets		$ 122,404	7,157
Accumulated amortization		(10,960)	(5,928)
Total		$ 111,444	1,229
License agreements
Finite-Lived Intangible Assets [Line Items]
Weighted-average useful life (years)		9 years 10 months 10 days
Gross assets		$ 6,515	6,009
Accumulated amortization		(3,980)	(3,222)
Total		$ 2,535	2,787
Patent and trademark costs
Finite-Lived Intangible Assets [Line Items]
Weighted-average useful life (years)		10 years 9 months
Gross assets		$ 28,740	11,240
Accumulated amortization		(4,917)	(3,522)
Total		$ 23,823	7,718
Software development costs
Finite-Lived Intangible Assets [Line Items]
Weighted-average useful life (years)		5 years
Gross assets		$ 6,630	6,000
Accumulated amortization		(3,091)	(2,326)
Total		$ 3,539	$ 3,674