Balance Sheet Components Accrued Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Accrued Liabilities, Current [Abstract]
Payroll and related expenses	$ 4,868	$ 4,424
Uninvoiced purchases	1,562	1,741
Preferred stock warrant liability	0	1,853
Deferred rent	550	500
Exercise of unvested stock options	299	373
Customer prepayments	836	387
Sales and use tax payable	442	343
Other	544	522
Total accrued payroll and other accruals	$ 9,101	$ 10,143