Note 4 - Stockholders' Equity - Outstanding Options Granted to Consultants for Sales and Pre-Marketing Services (Details) - Jun. 30, 2015 - $ / shares	Total
February 2013 [Member] | Consultants [Member]
Options for shares of common stock (in shares)	3,500
Exercise price per share (in dollars per share)	$ 12.47
Options exercisable (in shares)	1,833
Exercisable through	February 2023
August 2013 [Member] | Consultants [Member]
Options for shares of common stock (in shares)	5,000
Exercise price per share (in dollars per share)	$ 21.14
Options exercisable (in shares)	2,292
Exercisable through	August 2023
October 2013 [Member] | Consultants [Member]
Options for shares of common stock (in shares)	1,084
Exercise price per share (in dollars per share)	$ 24.23
Options exercisable (in shares)	355
Exercisable through	October 2023
March 2014 [Member] | Consultants [Member]
Options for shares of common stock (in shares)	15,575
Exercise price per share (in dollars per share)	$ 39.86
Options exercisable (in shares)	5,141
Exercisable through	March 2024
May 2014 [Member] | Consultants [Member]
Options for shares of common stock (in shares)	8,700
Exercise price per share (in dollars per share)	$ 22.01
Options exercisable (in shares)	2,356
Exercisable through	May 2024
August 2014 [Member] | Consultants [Member]
Options for shares of common stock (in shares)	1,250
Exercise price per share (in dollars per share)	$ 21
Exercisable through	August 2024
November 2014 [Member] | Consultants [Member]
Options for shares of common stock (in shares)	12,000
Exercise price per share (in dollars per share)	$ 21.66
Exercisable through	November 2024
May 2015 [Member] | Consultants [Member]
Options for shares of common stock (in shares)	6,250
Exercise price per share (in dollars per share)	$ 19.51
Exercisable through	May 2025
Consultants [Member]
Options for shares of common stock (in shares)	53,359
Options exercisable (in shares)	11,977
Exercise price per share (in dollars per share)	$ 28.253
Options exercisable (in shares)	2,649,977