Balance Sheet Components - Property and Equipment, net (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 81,308,000		$ 81,308,000		$ 74,390,000
Less: accumulated depreciation	(14,317,000)		(14,317,000)		(7,186,000)
Property and equipment, net	66,991,000		66,991,000		67,204,000
Depreciation	2,700,000	1,000,000	7,400,000	2,500,000
Equipment and machinery
Property, Plant and Equipment [Line Items]
Property and equipment, gross	17,243,000		17,243,000		13,733,000
Computer hardware and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	6,890,000		6,890,000		3,688,000
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,374,000		1,374,000		1,352,000
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	19,520,000		19,520,000		19,407,000
Building
Property, Plant and Equipment [Line Items]
Property and equipment, gross	35,154,000		35,154,000		35,154,000
Construction-in-process
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,127,000		1,127,000		1,056,000
Building and improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	53,400,000		53,400,000		53,300,000
Line of Credit | Letter of Credit
Property, Plant and Equipment [Line Items]
Letter of credit	$ 4,000,000		$ 4,000,000