Commitments - Narrative (Details)	12 Months Ended				0 Months Ended	12 Months Ended		1 Months Ended
	Dec. 31, 2012 USD ($)	Dec. 31, 2012 GBP (£)	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)	Apr. 23, 2012 Building [Member] San Diego [Member]	Dec. 31, 2012 Building [Member] San Diego [Member]	Dec. 31, 2012 Building [Member] Emeryville [Member] USD ($)	Aug. 31, 2009 Vehicles [Member] USD ($)	Aug. 31, 2009 Vehicles [Member] Maximum [Member] vehicle
Operating Leased Assets [Line Items]
Base rent percent increase					3.00%		3.00%
Period uncharged						3 months	2 months
Improvement allowance							$ 305,000
Vehicles available for lease									95
Term of lease per vehicle								36 months
Lessor required letter of credit								200,000
Rent expense	828,000		826,000	839,000
Non-cancellable purchase orders	3,327,000
Monthly manufacturing fee	502,000	311,000
Manufacturing fee, total	$ 5,025,000	£ 3,111,000
Remaining term for manufacturing fee	10 months	10 months