Preferred Stock - Narrative (Details)		1 Months Ended		12 Months Ended
	Oct. 24, 2017 USD ($) $ / shares shares	Feb. 28, 2018 shares	Jan. 31, 2018 USD ($) $ / shares	Dec. 31, 2017 USD ($) $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Mar. 07, 2018 shares
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)				5,000,000
Accrued dividends on Series A-2 Preferred Stock | $				$ 59,000	$ 47,000
Proceeds from issuance of preferred stock gross | $				2,280,000	0
Issuance of stock | $				$ 2,280,000	$ 204,000
Conversion price below this fair value of the common stock (in dollars per share) | $ / shares				$ 1.16
Common Stock
Class of Stock [Line Items]
Issuance of stock (in shares)					600,000
Stock issued for conversion of convertible preferred stock, shares (in shares)				8,392,857
Perpetual Series B-1 Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)				100
Preferred stock, shares issued (in shares)				0
Preferred stock, shares outstanding (in shares)				0
Series A-2 Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)				7,500	7,500
Preferred stock, shares issued (in shares)				32	32
Preferred stock, stated value | $				$ 7,500	$ 7,500
Stock issued during period, conversion of convertible securities, price (in dollars per share) | $ / shares				$ 2.40	$ 2.98
Convertible preferred stock, shares issued upon conversion (in shares)				3,128
Beneficial conversion feature | $				$ 58,000
Preferred stock, cumulative dividend percentage rate, per annum				5.00%
Accrued dividends on Series A-2 Preferred Stock | $				$ 59,000	$ 47,000
Preferred stock, convertible, par value (in dollars per share) | $ / shares				$ 0.0001	$ 0.0001
Preferred stock, shares outstanding (in shares)				32	32
Derivative liability | $				$ 0
Series B Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)				2,800	2,800
Preferred stock, shares issued (in shares)				450	0
Preferred stock, stated value | $				$ 1,000	$ 1,000
Stock issued during period, conversion of convertible securities, price (in dollars per share) | $ / shares	$ 0.28
Preferred stock, cumulative dividend percentage rate, per annum	0.00%
Preferred stock, convertible, par value (in dollars per share) | $ / shares	$ 1,000			$ 0.0001	$ 0.0001
Proceeds from issuance of preferred stock gross | $	$ 2,800,000
Preferred stock, shares outstanding (in shares)				450	0
Participation rights, future offerings, max percentage	100.00%
Participation rights, future offerings, period of time following closing date	24 months
Expansion of board of director members | $ / shares	6
Minimum number of shares outstanding and unconverted	333
Series B Preferred Stock | Preferred Stock
Class of Stock [Line Items]
Issuance of stock (in shares)	2,800			2,800
Issuance of stock | $	$ 2,280,000
Stock issued for conversion of convertible preferred stock, shares (in shares)				(2,350)
Series D Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)				4,000
Preferred stock, shares issued (in shares)				0
Preferred stock, shares outstanding (in shares)				0
Perpetual Series B Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)				100
Preferred stock, shares issued (in shares)				0
Preferred stock, shares outstanding (in shares)				0
Subsequent Event | Series A-2 Preferred Stock
Class of Stock [Line Items]
Stock issued during period, conversion of convertible securities, price (in dollars per share) | $ / shares			$ 2.16
Beneficial conversion feature | $			$ 24,000
Subsequent Event | Series B Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares issued (in shares)						400
Preferred stock, shares outstanding (in shares)						400
Subsequent Event | Series B Preferred Stock | Preferred Stock
Class of Stock [Line Items]
Stock issued for conversion of convertible preferred stock, shares (in shares)		(50)
Subsequent Event | Series B Preferred Stock | Common Stock
Class of Stock [Line Items]
Stock issued for conversion of convertible preferred stock, shares (in shares)		178,571