Preferred Stock - Narrative (Details)		1 Months Ended		12 Months Ended
	Jan. 25, 2018 USD ($) $ / shares shares	Feb. 28, 2019 shares	Oct. 31, 2017 USD ($) member $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) $ / shares shares	Mar. 08, 2019 USD ($) shares	Sep. 30, 2018 $ / shares
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)				5,000,000
Issuance of stock | $				$ 1,527,000	$ 2,280,000
Conversion price below this fair value of the common stock (in dollars per share) | $ / shares				$ 1.16
Common Stock
Class of Stock [Line Items]
Conversion of convertible preferred stock, shares (in shares)				5,423,000	8,393,000
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				$ 2.16	$ 2.40
Convertible preferred stock, shares issued upon conversion (in shares)				3,477
Beneficial conversion feature | $				$ 24,000
Preferred stock, cumulative dividend percentage rate, per annum				5.00%
Accrued dividends on Series A-2 Preferred Stock | $				$ 71,000	$ 59,000
Redemption price per share (in dollars per share) | $ / shares							$ 8,250
Redemption price per share, multiplier (in dollars per share) | $ / shares							$ 7,500
Redemption price per share, multiplier, percentage							110.00%
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)				75	450
Preferred stock, stated value | $				$ 1,000	$ 1,000
Stock issued during period, conversion of convertible securities, price (in dollars per share) | $ / shares			$ 0.28
Proceeds from issuance of preferred stock gross | $			$ 2,800,000	$ 0	$ 2,280,000
Preferred stock, convertible, par value (in dollars per share) | $ / shares			$ 1,000	$ 0.0001	$ 0.0001
Participation rights, future offerings, max percentage			100.00%
Expansion of board of director members (up to) | member			6
Preferred stock, shares outstanding (in shares)				75	450
Series B Preferred Stock | Subsequent Event
Class of Stock [Line Items]
Preferred stock, shares issued (in shares)						0
Preferred stock, shares outstanding (in shares)						0
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
Conversion of convertible preferred stock, shares (in shares)				375	2,350
Series B Preferred Stock | Preferred Stock | Subsequent Event
Class of Stock [Line Items]
Conversion of convertible preferred stock, shares (in shares)		75
Series B Preferred Stock | Common Stock
Class of Stock [Line Items]
Conversion of convertible preferred stock, shares (in shares)				1,339,286	8,392,857
Series B Preferred Stock | Common Stock | Subsequent Event
Class of Stock [Line Items]
Conversion of convertible preferred stock, shares (in shares)		267,857
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
Series C Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)				1,750	1,750
Preferred stock, shares issued (in shares)				525	525
Preferred stock, stated value | $				$ 1,000	$ 1,000
Stock issued during period, conversion of convertible securities, price (in dollars per share) | $ / shares	$ 0.30
Proceeds from issuance of preferred stock gross | $	$ 1,750,000			$ 1,527,000	$ 0
Preferred stock, convertible, par value (in dollars per share) | $ / shares	$ 1,000			$ 0.0001	$ 0.0001
Preferred stock, shares outstanding (in shares)				525	525
Series C Preferred Stock | Subsequent Event
Class of Stock [Line Items]
Preferred stock, shares issued (in shares)						475
Preferred stock, stated value | $						$ 475,000
Preferred stock, shares outstanding (in shares)						475
Series C Preferred Stock | Preferred Stock
Class of Stock [Line Items]
Preferred stock, cumulative dividend percentage rate, per annum	0.00%
Issuance of stock (in shares)	1,750			1,750
Issuance of stock | $	$ 1,527,000
Conversion of convertible preferred stock, shares (in shares)				1,225
Participation rights, future offerings, max percentage				100.00%
Series C Preferred Stock | Preferred Stock | Subsequent Event
Class of Stock [Line Items]
Conversion of convertible preferred stock, shares (in shares)		50
Series C Preferred Stock | Common Stock
Class of Stock [Line Items]
Conversion of convertible preferred stock, shares (in shares)				4,083,333
Series C Preferred Stock | Common Stock | Subsequent Event
Class of Stock [Line Items]
Conversion of convertible preferred stock, shares (in shares)		166,667