Note 3 - Revenue by Product Group, by Significant Customer and by Geographic Location; Geographic Information - Product Revenue by Product Group (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue	$ 26,956	$ 26,787	$ 30,548	$ 21,264	$ 29,388	$ 27,184	$ 33,462	$ 23,386	$ 105,555	$ 113,420	$ 103,379
Orthobiologics [Member]
Revenue									$ 93,556	$ 93,816	$ 89,695
Percentage of Product Revenue									89.00%	87.00%	87.00%
Dermal [Member]
Revenue									$ 396	$ 2,755	$ 2,759
Percentage of Product Revenue									0.00%	3.00%	3.00%
Surgical [Member]
Revenue									$ 5,514	$ 5,262	$ 5,427
Percentage of Product Revenue									5.00%	5.00%	5.00%
Manufactured Product, Other [Member]
Revenue									$ 6,065	$ 5,950	$ 5,051
Percentage of Product Revenue									6.00%	5.00%	5.00%
Product [Member]
Revenue	$ 26,950	$ 26,781	$ 30,542	$ 21,258	$ 28,884	$ 27,178	$ 28,340	$ 23,381	$ 105,531	$ 107,783	$ 102,932
Percentage of Product Revenue									100.00%	100.00%	100.00%