Shareholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended	9 Months Ended
	Jan. 25, 2018	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Class of Stock [Line Items]
Exercise of common stock options, shares		50,000	99,937
Proceeds from exercise of stock options			$ 98	$ 69
Number of warrants exercised			30,000
Proceeds from exercise of warrants			$ 46
Underwriting agreement to issue and sell common stock	9,807,105
Number of shares of common stock called by warrants	3,922,842
Warrants exercise price per share	$ 1.55
Common stock, price per share	$ 1.35
Number of shares of common stock called by each warrant	0.4
Offering close date	Jan. 29, 2018
Proceeds from underwriting agreement, net	$ 11,900		$ 12,172	$ 5,811
Over-Allotment Option [Member]
Class of Stock [Line Items]
Underwriting agreement to issue and sell common stock	1,279,187
Number of shares of common stock called by warrants	511,674
Private Placement [Member]
Class of Stock [Line Items]
Underwriting agreement to issue and sell common stock	203,708
Number of shares of common stock called by warrants	81,487
Common stock, price per share	$ 1.35
Offering close date	Feb. 15, 2018
Proceeds from underwriting agreement, net	$ 300
Series B Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares issued		5,659	5,659		5,659
Preferred stock, shares outstanding		5,659	5,659		5,659