Note 7 - Accrued Liabilities - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Employee related expenses	$ 6,592	$ 4,478
Royalties	4,423	3,498
Clinical trials	1,135	442
Professional services	387	333
Sales and use taxes payable	155	193
Other accrued liabilities	1,590	1,005
Total accrued liabilities	$ 14,282	$ 9,949