Shelf Registration Statement (Textual) (Details) - USD ($) $ / shares in Units, shares in Thousands	1 Months Ended	12 Months Ended
	Aug. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Nov. 16, 2017
Stock Offering [Line Items]
Aggregate amount of common stock				$ 125,000,000
Proceeds from issuance of common stock, net		$ 22,950,000
Stock issued in public offering, shares	7,590
Price per share	$ 3.25
Proceeds from sale of common stock, net of offering costs	$ 23,000,000	22,950,000	$ 0
Securities issued under the shelf registration statement		24,700,000
Value remaining for future issuance		100,300,000
Common Stock
Stock Offering [Line Items]
Proceeds from issuance of common stock, net		$ 759,000
Stock issued in public offering, shares		7,590