Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Over-Allotment	[1]	Series J Preferred Stock	[2]	Ordinary Shares	Ordinary Shares Over-Allotment	[1]	Preferred Shares	Preferred Shares Series J Preferred Stock	[2]	Additional Capital Paid-in	Additional Capital Paid-in Over-Allotment	[1]	Additional Capital Paid-in Series J Preferred Stock	[2]	Accumulated Other Comprehensive Loss	Accumulated Deficit
Balance at Dec. 31, 2014	$ 97,875											$ 374,375						$ (276,500)
Balance (in shares) at Dec. 31, 2014						13,431,414			58,676,017
Share-based compensation to employees	11,860											11,860
Exercise of options and warrants	2,038											2,038
Exercise of options and warrants (in shares)						731,665
Issuance of shares, net		$ 157,534		$ 94,599									$ 157,534		$ 94,599
Issuance of shares, net (in shares)							7,876,195			4,068,500
Issuance of shares and options in respect of settlement, net of fair value of shares provided as indemnification (Note 14c) (in shares)						(1,005,210)
Conversion of preferred shares to ordinary shares						62,744,517			(62,744,517)
Other comprehensive loss, net of tax benefit of $165, $38, and 68 for the years ended December 2015, 2016 and 2017	(1,505)																$ (1,505)
Net loss	(111,581)																	(111,581)
Balance at Dec. 31, 2015	250,820											640,406					(1,505)	(388,081)
Balance 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 employeestock 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 loss, net of tax benefit of $165, $38, and 68 for the years ended December 2015, 2016 and 2017	(378)																(378)
Net loss	(131,845)																	(131,845)
Balance at Dec. 31, 2016	142,345											664,154					(1,883)	(519,926)
Balance at Dec. 31, 2016						87,066,446
Cumulative effect adjustment resulting from ASU 2016-09 adoption (See Note 2)												670						(670)
Share-based compensation to employees	27,116											27,116
Exercise of options and warrants	3,685											3,685
Exercise of options and warrants (in shares)						2,244,153
Issuance of shares in connection with employeestock purchase plan	1,540											1,540
Issuance of shares in connection with employee stock purchase plan(in shares)						167,433
Other comprehensive loss, net of tax benefit of $165, $38, and 68 for the years ended December 2015, 2016 and 2017	540																540
Net loss	(61,662)																	(61,662)
Balance at Dec. 31, 2017	$ 113,564											$ 697,165					$ (1,343)	$ (582,258)
Balance at Dec. 31, 2017						89,478,032

[1] Net of issuance expenses (including underwriter fees) of $15,742

[2] Net of issuance expenses of $319