Summary of Business and Significant Accounting Policies (Details 1)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Stock Options [Member]
Fair value of stock option grant and stock purchase right granted under the ESPP estimated on the date of grant using Black-Scholes option pricing model
Expected volatility, minimum	54.00%	50.00%	54.00%	50.00%
Expected volatility, maximum	55.00%	56.00%	57.00%	69.00%
Expected term (in years)	6 years 15 days	6 years 26 days	6 years 15 days	6 years 22 days
Risk-free interest rate, minimum	0.90%	1.71%	0.90%	1.69%
Risk-free interest rate, maximum	1.17%	2.23%	1.18%	(2.67%)
Dividend yield
2012 ESPP [Member]
Fair value of stock option grant and stock purchase right granted under the ESPP estimated on the date of grant using Black-Scholes option pricing model
Expected volatility	41.58%		41.58%
Expected term (in years)	6 months 29 days		6 months 29 days
Risk-free interest rate	0.16%		0.16%
Dividend yield