Note 6 - Common Stock - Reserved for Future Issuances Shares of Common Stock (Details) - shares	Sep. 30, 2015	Dec. 31, 2014
Performance Shares [Member]
Reserved for Future Issuance (in shares)	2,440,127	1,807,349
The 2014 Employee Stock Purchase Plan [Member]
Reserved for Future Issuance (in shares)	299,127	140,500
Reserved for Future Issuance (in shares)	2,739,254	1,947,849