Note 13 - Segment Reporting - Revenue by Geographic Region (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue	$ 42,553	$ 36,389	$ 76,678	$ 65,688
Products [Member]
Revenue	35,291	30,115	62,530	53,107
Hand Piece Refills [Member]
Revenue	1,057	649	1,826	1,148
Skincare [Member]
Revenue	1,302	963	2,558	1,947
Total Product Revenue [Member]
Revenue	37,650	31,727	66,914	56,202
Service [Member]
Revenue	4,903	4,662	9,764	9,486
UNITED STATES
Revenue	28,132	24,239	49,268	40,783
JAPAN
Revenue	3,946	3,710	7,501	7,590
Asia, Excluding Japan [Member]
Revenue	4,231	2,830	7,074	6,014
Europe [Member]
Revenue	1,803	1,219	4,373	3,445
Rest of World [Member]
Revenue	$ 4,441	$ 4,391	$ 8,462	$ 7,856