Stockholders' Equity (Details 2) (USD $)			12 Months Ended				0 Months Ended		12 Months Ended				12 Months Ended				1 Months Ended	12 Months Ended
	Dec. 31, 2013 Stock options	Dec. 31, 2012 Stock options	Dec. 31, 2013 Restricted stock units	Dec. 31, 2013 1989 Stock Option Plan Stock options	Dec. 31, 2013 1989 Stock Option Plan - Options Granted Before May 26, 2004 Stock options	Dec. 31, 2013 1989 Stock Option Plan - Options Granted After May 26, 2004 Stock options	Jan. 31, 2000 2000 Broad Based Equity Incentive Plan Stock options	Dec. 31, 2013 2000 Broad Based Equity Incentive Plan Stock options	Dec. 31, 2013 2000 Broad Based Equity Incentive Plan Stock options Minimum	Dec. 31, 2013 2000 Broad Based Equity Incentive Plan Stock options Maximum	Dec. 31, 2013 2011 Equity Incentive Plan	Dec. 31, 2013 2011 Equity Incentive Plan Stock options	Dec. 31, 2013 2011 Equity Incentive Plan Stock options Minimum	Dec. 31, 2013 2011 Equity Incentive Plan Restricted stock units	Dec. 31, 2013 2011 Equity Incentive Plan Restricted stock units Minimum	Dec. 31, 2013 2002 Nonemployee Directors Stock Option Plan Stock options	Jun. 30, 2009 Employee Stock Purchase Plan (ESPP)	Dec. 31, 2013 Employee Stock Purchase Plan (ESPP)
Stock Plans
Number of shares authorized				20,000,000			5,990,000				5,500,000					1,200,000		2,424,596
Annual increase in reserve of common shares																	150,000	150,000
Vesting period			4 years	4 years			4 years						2 years	4 years	3 years	4 years
Annual vesting percentage				25.00%			25.00%
Award term					10 years	7 years			7 years	10 years						10 years
Number of options outstanding (in shares)	7,279	10,823		6,211,169				630,086				407,738				459,373
Options exercisable (in shares)	3,948			3,033,298				630,086				0				285,002
Number of shares available for grant				93,378				0				5,046,148				311,375		264,275
Percentage of employee compensation, maximum																		10.00%
Percentage of fair market value as a purchase price																		85.00%
Period for purchase of common stock																		6 months
Minimum holding period of purchased stock																		6 months
Shares issued for stock option exercises and ESPP purchases																		102,812
Exercise price (in dollars per share)																		$ 9.04