Note 13 - Revenue by Product Group, by Significant Customer and by Geographic Location; Geographic Information (Tables)

12 Months Ended

Dec. 31, 2020

Notes Tables

Schedule of Segment Reporting Information, by Segment [Table Text Block]

	Years Ended December 31,
	2020					2019					2018
	Revenue		Percentage of Product Revenue			Revenue		Percentage of Product Revenue			Revenue		Percentage of Product Revenue
Joint Pain Management	$	83,029		64	%	$	103,466		90	%	$	96,719		92	%
Joint Preservation and Restoration		39,368		30	%		2,070		2	%		1,127		1	%
Other		8,060		6	%		8,976		8	%		7,685		7	%
	$	130,457		100	%	$	114,512		100	%	$	105,531		100	%

Schedule of Revenue and Operating Income by Geographical Areas [Table Text Block]

	Years Ended December 31,
	2020					2019					2018
	Total		Percentage of			Total		Percentage of			Total		Percentage of
	Revenue		Revenue			Revenue		Revenue			Revenue		Revenue
Geographic Location:
United States	$	103,182		79	%	$	90,302		79	%	$	85,351		81	%
Europe		14,179		11	%		14,744		13	%		11,730		11	%
Other		13,096		10	%		9,564		8	%		8,474		8	%
Total	$	130,457		100	%	$	114,610		100	%	$	105,555		100	%

Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Table Text Block]

	Years Ended December 31,
	2020		2019
United States	$	48,611	$	48,635
Italy		2,002		2,148
Total	$	50,613	$	50,783