Note 11 - Segment Information and Revenue by Geograpy and Products - Revenue by Geographic Region (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net revenue	$ 47,632	$ 38,173	$ 36,389	$ 29,299	$ 37,875	$ 30,281	$ 27,477	$ 22,423	$ 151,493	$ 118,056	$ 94,761
Revenue mix	$ 47,632	$ 38,173	$ 36,389	$ 29,299	$ 37,875	$ 30,281	$ 27,477	$ 22,423	151,493	118,056	94,761
Product [Member]
Net revenue									125,883	92,721	71,223
Revenue mix									125,883	92,721	71,223
Hand Piece Refills [Member]
Net revenue									2,435	2,498	2,910
Revenue mix									2,435	2,498	2,910
Skincare [Member]
Net revenue									4,342	3,809	2,889
Revenue mix									4,342	3,809	2,889
Total Product Revenue [Member]
Net revenue									132,660	99,028	77,022
Revenue mix									132,660	99,028	77,022
Service [Member]
Net revenue									18,833	19,028	17,739
Revenue mix									18,833	19,028	17,739
UNITED STATES
Net revenue									94,581	65,513	48,916
Revenue mix									94,581	65,513	48,916
JAPAN
Net revenue									17,264	14,727	11,504
Revenue mix									17,264	14,727	11,504
Asia, Excluding Japan [Member]
Net revenue									13,719	13,445	15,596
Revenue mix									13,719	13,445	15,596
Europe [Member]
Net revenue									8,317	7,539	7,728
Revenue mix									8,317	7,539	7,728
Rest of World [Member]
Net revenue									17,612	16,832	11,017
Revenue mix									$ 17,612	$ 16,832	$ 11,017