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Stockholders' Equity - Preferred Stock (Details) - USD ($)				3 Months Ended				6 Months Ended	12 Months Ended
	Aug. 02, 2019	Jul. 25, 2018	Jul. 17, 2018	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Dec. 31, 2018	Aug. 06, 2019	Aug. 05, 2019	May 24, 2018	May 23, 2018
Preferred Stock [Abstract]
Preferred stock, shares authorized (in shares)				5,000,000				5,000,000	5,000,000			5,000,000	5,000,000
Preferred stock, par value (in dollars per share)				$ 0.001				$ 0.001	$ 0.001
Preferred stock, shares issued (in shares)				30,233				30,233	30,233
Preferred stock, shares outstanding (in shares)				4,540				4,540	4,606
Number of shares callable by warrants (in shares)												2,300,000	23,400,000
Common stock issued (in shares)		6,723
Subsequent Event [Member]
Preferred Stock [Abstract]
Preferred stock, shares authorized (in shares)										5,000,000	5,000,000
Common Stock [Member]
Preferred Stock [Abstract]
Number of shares callable by warrants (in shares)		141,183
Warrant exercise price (in dollars per share)		$ 39.93
Common stock issued (in shares)		6,723		5,000	139,855	192	202
2018 Rights Offering [Member]
Preferred Stock [Abstract]
Number of shares callable by warrants (in shares)			1
Warrant exercise price (in dollars per share)			$ 39.93
Period exercisable from the date of issuance								30 months
Common stock issued (in shares)		6,723
Gross proceeds from private placement of stock		$ 5,700,000
Redemption price of warrant prior to expiration				$ 0.01				$ 0.01
Common stock price per share for warrant redemption								$ 3.63
Common stock price for warrant redemption								$ 181.50
Number of consecutive trading days for warrant redemption								20 days
Warrants liability fair value				$ 400,000				$ 400,000	$ 3,100,000
2018 Rights Offering [Member] \| Warrant [Member]
Preferred Stock [Abstract]
Number of shares callable by warrants (in shares)			1,050
Warrant exercise price (in dollars per share)			$ 1,000
2018 Rights Offering [Member] \| Common Stock [Member]
Preferred Stock [Abstract]
Number of shares callable by warrants (in shares)			141,183
Series A Convertible Preferred Stock [Member]
Preferred Stock [Abstract]
Preferred stock, shares issued (in shares)				13,500				13,500	13,500
Convertible preferred stock								3.60%	3.60%
Preferred stock, shares outstanding (in shares)				0				0	0
Series B Convertible Preferred Stock [Member]
Preferred Stock [Abstract]
Preferred stock, shares issued (in shares)				10,000				10,000	10,000
Preferred stock, shares outstanding (in shares)				1,112				1,112	1,112
Series C Convertible Preferred Stock [Member]
Preferred Stock [Abstract]
Preferred stock, shares authorized (in shares)		7,000
Preferred stock, par value (in dollars per share)		$ 0.001
Preferred stock, shares issued (in shares)				6,723				6,723	6,723
Preferred stock, shares outstanding (in shares)				3,428				3,428	3,494
Number of shares callable by warrants (in shares)		7,059,150
Number of share converted into common stock for each share (in shares)		25
Series C Convertible Preferred Stock [Member] \| Dividend Paid [Member]
Preferred Stock [Abstract]
Dividends payable									$ 2,500,000
Series C Convertible Preferred Stock [Member] \| 2018 Rights Offering [Member]
Preferred Stock [Abstract]
Number of shares callable by warrants (in shares)			20,000
Series C Convertible Preferred Stock [Member] \| 2018 Rights Offering [Member] \| Subsequent Event [Member]
Preferred Stock [Abstract]
Preferred stock conversion price (in dollars per share)	$ 0.7986
Preferred stock conversion price reduced (in dollars per share)	0.15
Common Stock and Series B Convertible Preferred Stock [Member] \| 2018 Rights Offering [Member]
Preferred Stock [Abstract]
Charge on Non Transferable Subscription Rights			$ 0
Series T Warrants [Member] \| 2018 Rights Offering [Member] \| Subsequent Event [Member]
Preferred Stock [Abstract]
Warrant exercise price (in dollars per share)	0.7986
Warrant exercise price reduced (in dollars per share)	$ 0.15