Fair Value of Financial Assets and Liabilities - Derivative Instruments (Valuation Assumptions for November 2016 Warrants) (Details) - $ / shares		1 Months Ended	12 Months Ended
	Apr. 08, 2016	Sep. 30, 2017	Dec. 31, 2017		Dec. 31, 2016		Sep. 19, 2017	Apr. 30, 2017
Fair Value Assumptions and Methodology for Assets and Liabilities [Line Items]
Common stock closing price			$ 1.01		$ 4.40		$ 0.99
Common Stock Issuance Agreement [Member]
Fair Value Assumptions and Methodology for Assets and Liabilities [Line Items]
Shares issued per agreement	85,346	523,210
November 2016 Warrant Derivative Liability [Member]
Fair Value Assumptions and Methodology for Assets and Liabilities [Line Items]
Volatility			107.00%		112.00%
Expected term (years)			3 years 10 months 21 days		4 years 10 months 21 days
Risk-free interest rate			2.08%		1.91%
Dividend yield			0.00%		0.00%
Exercise price			$ 0.57	[1]	$ 7.50	[1]		$ 1.00
Common stock closing price			$ 1.01		$ 4.40

[1] In connection with the Company's April 2017 1-for-10 reverse stock split, the exercise price of the warrants was adjusted downward to $1.00 per share. In September 2017, the exercise price of the warrants was further adjusted downward to $0.57 per share in connection with the issuance of 523,210 shares of the Company's common stock to the shareholders who were party to the Common Stock Issuance Agreement. The exercise price of the warrants is subject to further adjustment upon future dilutive issuances of the Company's common stock and stock combination events as defined in the warrant agreements (see Note 10)