STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT) (USD $) In Thousands, except Share data	Total	Common stock	Additional Paid-in Capital	Accumulated Deficit
Beginning Balance at Dec. 31, 2013	$ 15,581	$ 16	$ 90,498	$ (74,933)
Beginning Balance, shares at Dec. 31, 2013		15,685,562
Issuance of common stock for cash, net of offering costs, shares		5,116,228
Issuance of common stock for cash, net of offering costs	7,866	5	7,861
Issuance of common stock upon exercise of warrants for cash, shares		209,025
Issuance of common stock upon exercise of warrants for cash, value	338		338
Issuance of common stock upon vesting of Restricted Stock Units, shares		139,671
Issuance of common stock upon vesting of Restricted Stock Units, value	(2)		(2)
Share-based compensation	647		647
Net loss	(9,689)			(9,689)
Ending Balance at Dec. 31, 2014	14,741	21	99,342	(84,622)
Ending Balance, shares at Dec. 31, 2014		21,150,486
Issuance of common stock upon vesting of Restricted Stock Units, shares		47,925
Share-based compensation	130		130
Net loss	(2,744)			(2,744)
Ending Balance at Mar. 31, 2015	$ 12,127	$ 21	$ 99,472	$ (87,366)
Ending Balance, shares at Mar. 31, 2015		21,198,411