Note 8 - Common Stock Reserved for Future Issuance (Details) - shares	Dec. 31, 2015	Dec. 31, 2014
Performance Shares [Member]
Common Stock, Capital Shares Reserved for Future Issuance	2,419,901	1,807,349
The 2014 Employee Stock Purchase Plan [Member]
Common Stock, Capital Shares Reserved for Future Issuance	297,359	140,500
Common Stock, Capital Shares Reserved for Future Issuance	2,717,260	1,947,849