Stockholders' Equity (Details 2) (USD $)	12 Months Ended		12 Months Ended										12 Months Ended				12 Months Ended
	Dec. 31, 2011 1989 Stock Option Plan	Jun. 30, 2009 1989 Stock Option Plan Maximum	Dec. 31, 2011 1989 Stock Option Plan - Options Granted Before May 26, 2004	Dec. 31, 2011 1989 Stock Option Plan - Options Granted After May 26, 2004	Dec. 31, 2011 2000 Broad Based Equity Incentive Plan	Dec. 31, 2011 2000 Broad Based Equity Incentive Plan Minimum	Dec. 31, 2011 2000 Broad Based Equity Incentive Plan Maximum	Jan. 31, 2000 2000 Broad Based Equity Incentive Plan Maximum	Dec. 31, 2011 2011 Equity Incentive Plan	Mar. 31, 2011 2011 Equity Incentive Plan	Dec. 31, 2011 2011 Equity Incentive Plan - stock options	Dec. 31, 2010 2011 Equity Incentive Plan - stock options	Dec. 31, 2011 2011 Equity Incentive Plan - stock options Minimum	Dec. 31, 2011 2011 Equity Incentive Plan-restricted stock units Minimum	Dec. 31, 2011 2002 Nonemployee Directors Stock Option Plan	Sep. 30, 2000 2002 Nonemployee Directors Stock Option Plan Maximum	Dec. 31, 2011 Employee Stock Purchase Plan (ESPP) month	Dec. 31, 2010 Employee Stock Purchase Plan (ESPP)	Dec. 31, 2011 Employee Stock Purchase Plan (ESPP) Minimum	Dec. 31, 2011 Employee Stock Purchase Plan (ESPP) Maximum
Stock Option Plans
Number of shares authorized		20,000,000						5,990,000		2,000,000						1,000,000	2,124,596
Annual increase in reserve of common shares																	150,000	150,000
Annual vesting percentage	25.00%				25.00%
Vesting period (in years)	4 years				4 years										4 years
Award term (in years)			10 years	7 years		7 years	10 years						2 years	3 years	10 years
Number of options outstanding (in shares)	7,520,400				2,556,537						10,722,000	9,811,000			645,000
Options exercisable (in shares)	4,442,537				2,258,342						7,158,000				457,500
Number of shares available for grant	3,277,145								2,000,000						199,500		191,088
Percentage of employee compensation, maximum																	10.00%
Percentage of fair market value as a purchase price																	85.00%
Period for purchase of common stock (in months)																	6
Minimum holding period of purchased stock (in months)																	6
Shares issued for stock option exercises and ESPP purchases																	98,218
Exercise price (in dollars per share)																			$ 7.79	$ 7.91