Note 11 - Stock Options Activity (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Outstanding at beginning of period (in shares)	3,342,015
Outstanding at beginning of period (in dollars per share)	$ 7.67
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	695,698
Granted (in dollars per share)	$ 9	$ 11.20
Exercised (in shares)	(104,339)
Exercised (in dollars per share)	$ 5.30
Expired or cancelled (in shares)	(45,541)
Expired or cancelled (in dollars per share)	$ 8.94
Outstanding at end of period (in shares)	3,887,833	3,342,015
Outstanding at end of period (in dollars per share)	$ 7.96	$ 7.67
Outstanding at end of period	6 years 73 days
Outstanding at end of period	$ 877,383
Vested or expected to vest at end of period (in shares)	3,831,985
Vested or expected to vest at end of period (in dollars per share)	$ 7.93
Vested or expected to vest at end of period	6 years 58 days
Vested or expected to vest at end of period	$ 877,383
Options exercisable at end of period (in shares)	2,715,043
Options exercisable at end of period (in dollars per share)	$ 7.10
Options exercisable at end of period	5 years 21 days
Options exercisable at end of period	$ 877,383