Stock-Based Compensation - Plan Information (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended	9 Months Ended				0 Months Ended	9 Months Ended
	Sep. 30, 2013 Stock Options	Sep. 30, 2013 Stock Options	Sep. 30, 2012 Stock Options	Sep. 30, 2013 2012 Equity Incentive Plan	Sep. 26, 2012 2012 Equity Incentive Plan	Sep. 26, 2012 2012 Equity Incentive Plan Stock Options	Sep. 30, 2013 2000 Equity Incentive Plan Stock Options	Dec. 31, 2012 2000 Equity Incentive Plan Stock Options	Sep. 30, 2013 2000 Equity Incentive Plan Stock Options Minimum	Sep. 26, 2012 Increase of Number of Shares Option	Sep. 26, 2012 Increase of Percentage of Shares Outstanding Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized					3,050,000
Equity incentive plan annual increase (shares)										3,050,000
Equity incentive plan, annual increase, percent of shares outstanding											5.00%
Award vesting period						4 years	4 years
Term of award						10 years	10 years
Expiration period				10 years
Number of shares available for grant				1,613,525
Award strike price as a percentage of market value									85.00%
Number of shares subject to repurchase (shares)							20,336	47,220
Share-based compensation arrangement by share-based payment award, number of unvested shares repurchased	125	125	60,125
Liability for options early exercised							$ 0.1	$ 0.3