CONDENSED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands		Total	Ordinary Share		Additional paid-in capital	Accumulated deficit	ATM Offering Program	ATM Offering Program Ordinary Share	ATM Offering Program Additional paid-in capital	Follow On Public Offering	Follow On Public Offering Ordinary Share	Follow On Public Offering Additional paid-in capital
Beginning Balance at Dec. 31, 2015		$ 20,920	$ 33		$ 94,876	$ (73,989)
Beginning Balance (in shares) at Dec. 31, 2015			12,222,583
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation to employees and non-employees		3,398			3,398
Issuance of ordinary shares upon exercise of options to purchase ordinary shares and RSUs by employees and non-employees		18	$ 1		17
Issuance of ordinary shares upon exercise of options to purchase ordinary shares and RSUs by employee and non-employees (in shares)			128,496
Issuance of ordinary shares and warrants in an offering, net of issuance expenses							$ 4,099	$ 2	$ 4,097	$ 11,089	$ 9	$ 11,080
Issuance of ordinary shares and warrants in an offering, net of issuance expenses (in shares)								692,062			3,250,000
Issuance of warrants to purchase ordinary shares		1,239			1,239
Cashless exercise of warrants into ordinary shares (in shares)			45,116
Net loss		(32,503)				(32,503)
Ending Balance (in shares) at Dec. 31, 2016			16,338,257
Ending Balance at Dec. 31, 2016		8,260	$ 45		114,707	(106,492)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect to stock based compensation from adoption of a new accounting standard		0			11	(11)
Share-based compensation to employees and non-employees		2,597			2,597
Issuance of ordinary shares upon exercise of options to purchase ordinary shares and RSUs by employees and non-employees	[1]	$ 28			28
Issuance of ordinary shares upon exercise of options to purchase ordinary shares and RSUs by employee and non-employees (in shares)		87,795	105,606	[1]
Issuance of ordinary shares and warrants in an offering, net of issuance expenses	[2]						$ 9,010	$ 15	$ 8,995
Issuance of ordinary shares and warrants in an offering, net of issuance expenses (in shares)	[2]							5,379,908
Net loss		$ (18,555)
Ending Balance (in shares) at Sep. 30, 2017			21,823,771
Ending Balance at Sep. 30, 2017		$ 1,340	$ 60		$ 126,338	$ (125,058)

[1] (1) See Note 8b to the condensed consolidated financial statements

[2] (2) See Note 8e to the condensed consolidated financial statements