Equity - Preferred Stock (Details) $ / shares in Units, $ in Thousands				12 Months Ended
	Jan. 06, 2018 $ / shares shares	Mar. 08, 2017 USD ($)	Mar. 07, 2017 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) $ / shares shares	Mar. 31, 2017 shares
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares) | shares				5,000,000	5,000,000
Preferred stock, par value (in dollars per share) | $ / shares				$ 0.001	$ 0.001
Number of units issued (shares) | shares	409,091
Purchase price per unit (in usd per share) | $ / shares	$ 3.80
Preferred shares issued (in shares) | shares				8,000	8,000
Deemed dividend on preferred stock				$ 513	$ 4,099
Dividend paid in-kind to preferred stockholders				336	264
2017 Private Placement
Class of Stock [Line Items]
Preferred stock, par value (in dollars per share) | $ / shares			$ 1,000
Preferred shares issued (in shares) | shares			1
Conversion price (usd per share) | $ / shares			$ 11.6355
Number of common shares authorized for purchase as a percent of conversion shares			100.00%
Series A Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares) | shares						8,000
Dividend paid in-kind to preferred stockholders				300	300
Series A Convertible Preferred Stock | 2017 Private Placement
Class of Stock [Line Items]
Shares issued upon conversion (in shares) | shares			85
Proceeds for issuance of preferred stock, gross		$ 8,000	$ 1,300
Dividend rate, preferred stock			4.00%
Dividend rate, period of initial rate			5 years
Increased dividend rate, preferred stock			8.00%
Proceeds from beneficial conversion feature			$ 3,700
Deemed dividend on preferred stock				500	4,100
Ownership percentage, convertible preferred stock			70.00%
Units | 2017 Private Placement
Class of Stock [Line Items]
Number of units issued (shares) | shares			8,000
Purchase price per unit (in usd per share) | $ / shares			$ 1,000
Warrants
Class of Stock [Line Items]
Discount on shares, preferred stock			$ 3,000
Deemed dividend on preferred stock				$ 500	$ 300
Risk-free interest rate (term structure) | Series A Convertible Preferred Stock | 2017 Private Placement
Class of Stock [Line Items]
Risk-free interest rate			0.0315
Credit Spread | Series A Convertible Preferred Stock | 2017 Private Placement
Class of Stock [Line Items]
Risk-free interest rate			0.3127
Measurement Input, Market Yield | Series A Convertible Preferred Stock | 2017 Private Placement
Class of Stock [Line Items]
Risk-free interest rate			0.3442