CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Statement [Abstract]
Net revenues	$ 64,756	$ 50,109	$ 178,395	$ 123,365	$ 177,026
Cost of revenues	18,949	15,153	57,020	39,969	55,609
Gross profit	45,807	34,956	121,375	83,396	121,417
Operating costs and expenses:
Research, development and clinical trials	13,074	9,273	35,540	28,055	38,103
Sales and marketing	19,124	16,387	56,455	47,503	63,528
General and administrative	18,855	15,215	54,388	42,660	59,114
Total operating costs and expenses	51,053	40,875	146,383	118,218	160,745
Operating income (loss)	(5,246)	(5,919)	(25,008)	(34,822)	(39,328)
Financial expenses (income), net	2,397	2,156	10,110	6,785	9,169
Income (loss) before income taxes	(7,643)	(8,075)	(35,118)	(41,607)	(48,497)
Income taxes	4,051	3,423	12,810	9,110	13,165
Net income (loss)	$ (11,694)	$ (11,498)	$ (47,928)	$ (50,717)	$ (61,662)
Basic and diluted net income (loss) per ordinary share	$ (0.13)	$ (0.13)	$ (0.52)	$ (0.57)	$ (0.70)
Weighted average number of ordinary shares used in computing basic and diluted net income (loss) per share	92,911,375	89,125,646	91,409,619	88,265,835	88,546,719