Balance Sheet Components - Property and Equipment, net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 143,299	$ 126,093
Less: accumulated depreciation	(69,020)	(49,132)
Property and equipment, net	74,279	76,961
Depreciation	20,200	19,400	$ 13,400
Equipment and machinery
Property, Plant and Equipment [Line Items]
Property and equipment, gross	47,711	40,721
Computer hardware and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	22,124	17,420
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	3,020	2,879
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	30,548	29,498
Building
Property, Plant and Equipment [Line Items]
Property and equipment, gross	35,154	35,154
Construction-in-process
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 4,742	$ 421