Note 4 - Stockholders' Equity (Details) - Stock Options, Valuation Assumptions (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Employee Stock Option [Member]
Note 4 - Stockholders' Equity (Details) - Stock Options, Valuation Assumptions [Line Items]
Expected life (in years)	4 years 284 days	4 years 317 days	4 years 284 days	4 years 306 days
Volatility	55.00%	59.50%	56.10%	59.60%
Risk-free interest rate	1.33%	0.78%	0.93%	0.78%
Expected dividend	0.00%	0.00%	0.00%	0.00%
Weighted average fair value per share of options granted during the period (in Dollars per share)	$ 8.50	$ 4.32	$ 7.77	$ 4.21
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			46.10%	51.10%
Risk-free interest rate			0.19%	0.16%
Expected dividend			0.00%	0.00%
Weighted average fair value per share of options granted during the period (in Dollars per share)			$ 5.28	$ 2.33