Note 15 - Product Revenue by Geographic Location (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
UNITED STATES
Total Revenue	$ 21,895	$ 19,218	$ 39,906	$ 31,809
Percentage of Revenue	82.00%	84.00%	82.00%	83.00%
Europe [Member]
Total Revenue	$ 2,977	$ 2,331	$ 5,542	$ 4,317
Percentage of Revenue	11.00%	10.00%	11.00%	11.00%
Other Location [Member]
Total Revenue	$ 1,709	$ 1,355	$ 3,416	$ 2,298
Percentage of Revenue	7.00%	6.00%	7.00%	6.00%
Total Revenue	$ 26,581	$ 22,904	$ 48,864	$ 38,424
Percentage of Revenue	100.00%	100.00%	100.00%	100.00%