Note 6 - Stockholders' Equity (Detail) - Valuation Assumptions	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Two Thousand Four Equity Incentive Plan [Member]
Expected term (years)	4 years 36 days	4 years 36 days	4 years 36 days
Expected volatility	53.40%	52.90%	55.90%
Risk-free interest rate	0.60%	1.10%	1.80%
Dividend yield	0.00%	0.00%
Two Thousand Four Employee Stock Purchase Plan [Member]
Expected term (years)	6 months	6 months	6 months
Expected volatility	45.80%	39.20%	39.50%
Risk-free interest rate	0.10%	0.10%	0.20%
Dividend yield	0.00%	0.00%