Condensed Statements of Changes in Convertible Preferred Stock and 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, 2015		$ 12			$ (12,392)		$ (12,380)
Balance at beginning of period (shares) at Dec. 31, 2015		3,758,488
Increase (Decrease) in Stockholders' Equity
Redemption value adjustment - Series A preferred stock				$ (123)	(26)		(149)
Share-based compensation - employee				46			46
Share-based compensation - non-employee				77			77
Net loss					(2,103)		(2,103)
Balance at end of period at Mar. 31, 2016		$ 12			(14,521)		(14,509)
Balance at end of period (shares) at Mar. 31, 2016		3,758,488
Balance at beginning of period at Dec. 31, 2016		$ 17		47,674	(27,059)		20,632
Balance at beginning of period (shares) at Dec. 31, 2016		9,270,255
Increase (Decrease) in Stockholders' Equity
Issuance of common stock	$ 1		$ 8,978			$ 8,979
Issuance of common stock (shares)	1,324,256
Issuance of detachable stock warrants in connection with private placement offering			3,562			3,562
Issuance costs of offering			$ (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 end of period (shares) at Mar. 31, 2017		10,596,838