Note 13 - Convertible Preferred Stock - Convertible Preferred Stock (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Shares Authorized (in shares)	50,000,000	50,000,000
Shares Outstanding (in shares)	0	0
Carrying Value
Convertible Preferred Stock [Member]
Shares Authorized (in shares)		43,502,124
Shares Outstanding (in shares)		110,500,514
Liquidation Amount		$ 46,019
Carrying Value		$ 46,030
Series A Preferred Stock [Member] | Convertible Preferred Stock [Member]
Shares Authorized (in shares)		7,703,785
Shares Outstanding (in shares)		20,923,195
Liquidation Amount		$ 3,082
Carrying Value		$ 3,082
Series B Preferred Stock [Member] | Convertible Preferred Stock [Member]
Shares Authorized (in shares)		2,567,390
Shares Outstanding (in shares)		6,972,887
Liquidation Amount		$ 2,567
Carrying Value		$ 2,567
Series C Preferred Stock [Member] | Convertible Preferred Stock [Member]
Shares Authorized (in shares)		3,256,601
Shares Outstanding (in shares)		8,606,455
Liquidation Amount		$ 1,806
Carrying Value		$ 1,806
Series D Preferred Stock [Member] | Convertible Preferred Stock [Member]
Shares Authorized (in shares)		11,773,243
Shares Outstanding (in shares)		31,004,350
Liquidation Amount		$ 11,415
Carrying Value		$ 11,425
Series E Preferred Stock [Member] | Convertible Preferred Stock [Member]
Shares Authorized (in shares)		2,212,960
Shares Outstanding (in shares)		6,010,107
Liquidation Amount		$ 3,319
Carrying Value		$ 3,319
Series F Preferred Stock [Member] | Convertible Preferred Stock [Member]
Shares Authorized (in shares)		15,988,145
Shares Outstanding (in shares)		36,983,520
Liquidation Amount		$ 23,830
Carrying Value		$ 23,831