Commitments - Narrative (Details) - USD ($) $ in Thousands			12 Months Ended
	Jul. 20, 2015	Dec. 01, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Leased Assets [Line Items]
Rent expense			$ 1,925	$ 1,530	$ 870
Non-cancellable purchase orders			2,706
Asset retirement obligation			308
Non-cancellable purchase orders outstanding			336
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
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%