Stock-based Compensation and Awards Narrative (Details) (USD $) In Millions, except Share data, unless otherwise specified				9 Months Ended
	Sep. 30, 2012	Sep. 30, 2012 Stock Options	Dec. 31, 2011 Stock Options	Sep. 30, 2012 2012 Stock Option Plan Stock Options	Sep. 30, 2012 2012 Employee Stock Purchase Plan ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity incentive plans	3
Vesting period of options granted				4 years
Percent vested at the end of one year				25.00%
Options granted exercisable period				10 years
Shares held by employees subject to repurchase		63,472	112,967
Shares held by employees subject to repurchase, aggregate price		$ 0.2	$ 0.4
Limit on payroll deductions used to purchase shares					15.00%
ESPP offering period					6 months
ESPP first offering period					11 months
Employee discount to purchase shares					85.00%