Note 4 - Stockholders' Equity (Details) - Stock Options, Valuation Assumptions (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Note 4 - Stockholders' Equity (Details) - Stock Options, Valuation Assumptions [Line Items]
Weighted average fair value per share of options granted during the period (in Dollars per share)			$ 7.44
Employee Stock Option [Member]
Note 4 - Stockholders' Equity (Details) - Stock Options, Valuation Assumptions [Line Items]
Expected life (in years)	4 years 211 days	4 years 284 days	4 years 211 days	4 years 284 days
Volatility	44.88%	50.30%	43.45%	55.83%
Risk-free interest rate	1.63%	1.31%	1.55%	0.94%
Weighted average fair value per share of options granted during the period (in Dollars per share)	$ 7.54	$ 9.13	$ 7.44	$ 7.55
Employee Stock Purchase Plan [Member]
Note 4 - Stockholders' Equity (Details) - Stock Options, Valuation Assumptions [Line Items]
Expected life (in years)			1 year 3 months	1 year 3 months
Volatility			33.46%	45.29%
Risk-free interest rate			0.21%	0.19%
Weighted average fair value per share of options granted during the period (in Dollars per share)			$ 6.44	$ 5.56