Note 15 - Revenue by Product, by Significant Customer and by Geographic Region; Geographic Information - Total Revenue by Geographic Location (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Total Revenue	$ 28,726	$ 25,789	$ 26,581	$ 22,283	$ 30,894	$ 23,681	$ 22,904	$ 15,520	$ 103,379	$ 92,999	$ 105,595
Percentage of Revenue									100.00%	100.00%	100.00%
UNITED STATES
Total Revenue									$ 83,972	$ 76,621	$ 92,259
Percentage of Revenue									81.00%	82.00%	87.00%
Europe [Member]
Total Revenue									$ 10,953	$ 8,756	$ 6,215
Percentage of Revenue									11.00%	9.00%	6.00%
Other Location [Member]
Total Revenue									$ 8,454	$ 7,622	$ 7,121
Percentage of Revenue									8.00%	9.00%	7.00%