CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Ordinary Shares	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Balance at Dec. 31, 2015	$ 250,820		$ 640,406	$ (1,505)	$ (388,081)
Balance (in shares) at Dec. 31, 2015		83,778,581
Share-based compensation to employees	21,441		21,441
Exercise of options and warrants	993		993
Exercise of options and warrants (in shares)		3,195,477
Issuance of shares in connection with employee stock purchase plan	616		616
Issuance of shares in connection with employee stock purchase plan(in shares)		92,388
Tax benefit from share-based award activity	698		698
Other comprehensive income (loss), net of tax benefit of $38 and $57 for the years December 2016 and September 2017	(378)			(378)
Net loss	(131,845)				(131,845)
Balance at Dec. 31, 2016	142,345		664,154	(1,883)	(519,926)
Balance (in shares) at Dec. 31, 2016		87,066,446
Share-based compensation to employees	20,760		20,760
Exercise of options and warrants	3,095		3,095
Exercise of options and warrants (in shares)		2,172,266
Cumulative effect adjustment resulting from ASU2016-09 adoption (see Note 1)			670		(670)
Issuance of shares in connection with employee stock purchase plan	781		781
Issuance of shares in connection with employee stock purchase plan(in shares)		116,967
Other comprehensive income (loss), net of tax benefit of $38 and $57 for the years December 2016 and September 2017	421			421
Net loss	(50,717)				(50,717)
Balance at Sep. 30, 2017	$ 116,685		$ 689,460	$ (1,462)	$ (571,313)
Balance (in shares) at Sep. 30, 2017		89,355,679