Commitments - Narrative (Details)	2 Months Ended		12 Months Ended				0 Months Ended				12 Months Ended	1 Months Ended
	Dec. 31, 2013 USD ($)	Dec. 31, 2013 GBP (£)	Dec. 31, 2014 USD ($)	Dec. 31, 2014 GBP (£)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 01, 2014 San Diego [Member] USD ($)	Dec. 01, 2014 Building [Member] San Diego [Member]	Apr. 23, 2012 Building [Member] San Diego [Member]	Dec. 01, 2014 Building [Member] San Diego [Member] USD ($)	Dec. 31, 2014 Building [Member] Emeryville [Member] USD ($)	Aug. 31, 2009 Vehicles [Member] USD ($)
Operating Leased Assets [Line Items]
Term of lease							64 months					36 months
Additional renewal term								60 months
Base rent percent increase									3.00%		3.00%
Abatement period								4 months 15 days
Additional rent abatements										$ 36,000
Improvement allowance							382,000				305,000
Period uncharged											2 months
Lessor required letter of credit												200,000
Rent expense			870,000		829,000	828,000
Non-cancellable purchase orders			4,028,000
Monthly manufacturing fee	651,000	419,000
Manufacturing fee, total			10,416,000	6,704,000
Non-cancellable purchase orders outstanding			$ 2,435,000