Consolidated Statements of Changes in Convertible Preferred Stock and Stockholders' Equity (Deficiency) (USD $) In Thousands, except Share data		Convertible Preferred Stock [Member]	Common Stock [Member]		Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Total
Balance at Dec. 31, 2013		$ 43,775	$ 4		$ 4,741		$ (47,753)	$ (43,008)
Balance (in Shares) at Dec. 31, 2013		15,082,141	3,953,314
Issuance of common stock upon initial public offering (net of issuance costs of $2,376)			5		106,066			106,071
Issuance of common stock upon initial public offering (net of issuance costs of $2,376) (in Shares)			5,300,436
Conversion of preferred stock to common stock upon initial public offering		(43,775)	15		43,760			43,775
Conversion of preferred stock to common stock upon initial public offering (in Shares)		(15,082,141)	15,082,141
Conversion of warrants to purchase preferred stock into warrants to purchase common stock					2,866			2,866
Exercise of warrants to purchase common stock	[1]
Exercise of warrants to purchase common stock (in Shares)			107,217
Stock-based compensation expense					4,664			4,664
Exercise of stock options				[1]	381			382
Exercise of stock options (in Shares)			238,951
Exercise of restricted stock units	[1]
Exercise of restricted stock units (in Shares)			3,545
Unrealized loss on derivative instruments						(326)		(326)
Net loss							(19,398)	(19,398)
Balance at Dec. 31, 2014			25		162,478	(326)	(67,151)	95,026
Balance (in Shares) at Dec. 31, 2014			24,685,604
Stock-based compensation expense					1,685			1,685
Exercise of stock options				[1]	548			548
Exercise of stock options (in Shares)			156,382					140,716
Exercise of restricted stock units	[1]
Exercise of restricted stock units (in Shares)			2,660
Unrealized loss on derivative instruments						(120)		(120)
Net loss							(12,670)	(12,670)
Balance at Mar. 31, 2015			$ 25		$ 164,711	$ (446)	$ (79,821)	$ 84,469
Balance (in Shares) at Mar. 31, 2015			24,844,646

[1] Represents an amount lower than $ 1.