Statements of Changes In Shareholders' Equity - USD ($) $ in Thousands		Ordinary Share		Additional paid-in capital		Accumulated deficit	Total
Balance at Dec. 31, 2015		$ 33		$ 94,876		$ (73,989)	$ 20,920
Balance, shares at Dec. 31, 2015		12,222,583
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		$ 1		17			18
Issuance of ordinary shares upon exercise of options to purchase ordinary shares and RSUs by employees and non-employees, shares		128,496
Issuance of ordinary shares in at-the-market offering, net of issuance expenses in the amount of $468		$ 2		4,097			4,099
Issuance of ordinary shares in at-the-market offering, net of issuance expenses in the amount of $468, shares		692,062
Issuance of warrants to purchase ordinary shares				1,239			1,239
Cashless exercise of warrants into ordinary shares			[1]		[1]
Cashless exercise of warrants into ordinary shares, shares		45,116
Issuance of ordinary shares and warrants to purchase ordinary shares in follow-on public offering, net of issuance expenses in an amount of $1,099		$ 9		11,080			11,089
Issuance of ordinary shares and warrants to purchase ordinary shares in follow-on public offering, net of issuance expenses in an amount of $1,099, shares		3,250,000
Net loss						(32,503)	(32,503)
Balance at Dec. 31, 2016		$ 45		114,707		(106,492)	8,260
Balance, shares at Dec. 31, 2016		16,338,257
Share-based compensation to employees and non-employees				3,654			3,654
Issuance of ordinary shares upon exercise of options to purchase ordinary shares and RSUs by employees and non-employees		$ 1		37			38
Issuance of ordinary shares upon exercise of options to purchase ordinary shares and RSUs by employees and non-employees, shares		166,748
Issuance of ordinary shares in at-the-market offering, net of issuance expenses in the amount of $467		$ 16		9,293			9,309
Issuance of ordinary shares in at-the-market offering, net of issuance expenses in the amount of $467, shares		5,613,084
Issuance of ordinary shares in follow-on public offering, net of issuance expenses in an amount of $1,117		$ 22		7,141			7,163
Issuance of ordinary shares in follow-on public offering, net of issuance expenses in an amount of $1,117, shares		7,885,550
Cumulative effect to stock based compensation from adoption of a new accounting standard				11		(11)
Net loss						(24,717)	(24,717)
Balance at Dec. 31, 2017		$ 84		134,843		(131,220)	3,707
Balance, shares at Dec. 31, 2017		30,003,639
Share-based compensation to employees and non-employees				2,766			2,766
Issuance of ordinary shares upon exercise of options to purchase ordinary shares and RSUs by employees and non-employees			[1]
Issuance of ordinary shares upon exercise of options to purchase ordinary shares and RSUs by employees and non-employees, shares		429,515
Issuance of ordinary shares in investing agreement, net of issuance expenses in an amount of $830	[2]	$ 12		4,283			4,295
Issuance of ordinary shares in investing agreement, net of issuance expenses in an amount of $830, shares	[2]	4,117,891
Issuance of ordinary shares in at-the-market offering, net of issuance expenses in the amount of $236	[2]	$ 4		1,113			1,117
Issuance of ordinary shares in at-the-market offering, net of issuance expenses in the amount of $236, shares	[2]	1,247,172
Issuance of ordinary shares, warrants and pre-funded warrants in follow-on public offering, net of issuance expenses in an amount of $1,505	[2]	$ 49		11,528			11,577
Issuance of ordinary shares, warrants and pre-funded warrants in follow-on public offering, net of issuance expenses in an amount of $1,505, shares	[2]	18,200,498
Modification of warrants to purchase ordinary shares	[3]			18			18
Exercise of pre-funded warrants	[2]	$ 44		119			163
Exercise of pre-funded warrants, shares	[2]	16,328,950
Cumulative effect to accumulated deficit from adoption of a new accounting standard						(23)	(23)
Net loss						(21,675)	(21,675)
Balance at Dec. 31, 2018		$ 193		$ 154,670		$ (152,918)	$ 1,945
Balance, shares at Dec. 31, 2018		70,327,665

[1] Represents an amount lower than $1.

[2] See note 8b.

[3] See note 8e.