Balance Sheet Components Accrued Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Accrued Liabilities, Current [Abstract]
Payroll and related expenses	$ 6,449	$ 4,424
Uninvoiced purchases	1,349	1,741
Preferred stock warrant liability	0	1,853
Deferred rent	571	500
Exercise of unvested stock options	242	373
Customer prepayments	105	387
Sales and use tax payable	426	343
Other	225	522
Total accrued payroll and other accruals	$ 9,367	$ 10,143