Condensed Statements of Changes in Stockholders’ Equity (Deficit) - USD ($) $ in Thousands	Common Stock Private placement	Common Stock	Additional Paid-in Capital Private placement	Additional Paid-in Capital	Accumulated Deficit	Private placement	Total
Balance at beginning of period at Dec. 31, 2016		$ 17		$ 47,674	$ (27,059)		$ 20,632
Balance at end of period (shares) at Mar. 31, 2017		10,596,838
Balance at beginning of period (shares) at Dec. 31, 2016		9,270,255
Increase (Decrease) in Stockholders' Equity
Issuance of common stock from private placement	$ 1		$ 8,978			$ 8,979
Issuance of common stock from private placement (shares)	1,324,256
Issuance of detachable stock warrants in connection with private placement			3,562			3,562
Issuance costs of private placement			$ (1,219)			$ (1,219)
Exercise of stock options				3			3
Exercise of stock options (in shares)		2,327
Share-based compensation - employee				829			829
Share-based compensation - non-employee				7			7
Net loss					(7,496)		(7,496)
Balance at end of period at Mar. 31, 2017		$ 18		59,834	(34,555)		25,297
Balance at beginning of period at Dec. 31, 2016		$ 17		47,674	(27,059)		20,632
Balance at end of period (shares) at Dec. 31, 2017		10,633,042
Balance at beginning of period (shares) at Dec. 31, 2016		9,270,255
Balance at end of period at Dec. 31, 2017		$ 18		64,397	(60,474)		3,941
Balance at end of period (shares) at Mar. 31, 2018		14,232,313
Balance at beginning of period (shares) at Dec. 31, 2017		10,633,042
Increase (Decrease) in Stockholders' Equity
Issuance of common stock from private placement		$ 4		25,146			$ 25,150
Issuance of common stock from private placement (shares)		3,592,858					3,592,858
Issuance costs of private placement				(2,093)			$ (2,093)
Exercise of stock options				23			23
Exercise of stock options (in shares)		6,413
Share-based compensation - employee				1,019			1,019
Share-based compensation - non-employee				1			1
Net loss					(7,224)		(7,224)
Balance at end of period at Mar. 31, 2018		$ 22		$ 88,493	$ (67,698)		$ 20,817