Note 10 - Common Stock (Tables)

12 Months Ended

Dec. 31, 2014

Stockholders' Equity Note [Abstract]

Common Stock Reserve for Future Issuance [Table Text Block]

	As of December 31,
	2014		2013
Conversion of Series A Preferred Stock		-		1,426,482
Conversion of Series A-1 Preferred Stock		-		687,395
Conversion of Series B Preferred Stock		-		1,307,771
Conversion of Series C Preferred Stock		-		1,105,907
Stock-based compensation awards		1,807,349		623,111
Employee Stock Purchase Plan		140,500		-
Warrants to purchase Common Stock		-		659,806
Total		1,947,849		5,810,472