Commitments - Narrative (Details) - USD ($) $ in Thousands			12 Months Ended
	Jul. 20, 2015	Dec. 01, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Leased Assets [Line Items]
Rent expense			$ 1,530	$ 870	$ 829
Non-cancellable purchase orders			2,499
Asset retirement obligation			388
Non-cancellable purchase orders outstanding			1,253
Amended Lease Agreement [Member]
Operating Leased Assets [Line Items]
Additional renewal term	5 years
San Diego [Member]
Operating Leased Assets [Line Items]
Rent abatements			332
Additional rent abatements			36
Improvement allowance			$ 382
San Diego [Member] | Building [Member]
Operating Leased Assets [Line Items]
Base rent percent increase			3.30%
Abatement period		4 months 15 days
Emeryville [Member] | Building [Member]
Operating Leased Assets [Line Items]
Base rent percent increase			3.00%