Commitments and Contingencies (Details)	1 Months Ended			12 Months Ended
	Oct. 31, 2015 USD ($) ft² item	Sep. 30, 2015 USD ($)	Apr. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Mar. 21, 2014 USD ($)	Jan. 31, 2013 USD ($)
Future minimum lease payments
2016				$ 3,212,000
2017				5,442,000
2018				5,976,000
2019				6,140,000
2020				6,304,000
2021 and thereafter				25,922,000
Total future minimum lease payment				52,996,000
Rent expense				$ 2,700,000	$ 1,500,000	$ 1,300,000
Corporate Headquarters Lease
Operating Leases
Restricted cash							$ 300,000	$ 800,000
Monthly base rent	$ 200,000
Security deposit	500,000
Allowance for leasehold improvements	$ 400,000
Number of office spaces | item	2
Office space | ft²	88,000
Renewal term of lease	5 years
Redwood City Lease
Operating Leases
Monthly base rent			$ 100,000
Security deposit			$ 100,000
Austin TX, Long-term Lease
Operating Leases
Term of lease		132 months
Monthly base rent		$ 100,000
Security deposit		400,000
Maximum monthly base rent after escalation		200,000
Allowance for leasehold improvements		$ 7,800,000
Austin TX, Short-term Lease
Operating Leases
Term of lease	1 year
Monthly base rent	$ 12,900
Security deposit	12,900
Maximum | Corporate Headquarters Lease
Operating Leases
Monthly base rent	$ 400,000