Convertible Debentures (Details) $ / shares in Units, $ in Thousands			3 Months Ended		6 Months Ended	9 Months Ended
	Jun. 06, 2017 USD ($) shares $ / shares	Jul. 21, 2014 USD ($) shares $ / shares	Sep. 30, 2017 USD ($) $ / shares	Sep. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) shares $ / shares	Sep. 30, 2017 USD ($) $ / shares	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($) $ / shares
Debt Instrument [Line Items]
Total convertible debt			$ 0			$ 0		$ 12,028
Aggregate principal amount of debt					$ 40,465
Common stock, par value (in dollars per share) | $ / shares			$ 0.001			$ 0.001		$ 0.001
Change in fair value of warrant liability			$ (81)	$ (132)		$ (77)	$ (5,316)
Debentures converted in shares of common stock, value						262	248
Debentures outstanding amount					$ 40,465
Loss on extinguishment of debentures			$ (11,799)	$ 0		$ (11,799)	$ 0
Series C Convertible Preferred Stock [Member]
Debt Instrument [Line Items]
Aggregate principal amount of debt	$ 40,465
Debt conversion, converted instrument, issued (in shares) | shares	40,482
Debentures outstanding amount	$ 40,465
Preferred stock, stated value (in dollars per share) | $ / shares			$ 0.10			$ 0.10		$ 0.10
Senior Secured 2.25% Convertible Debentures [Member]
Debt Instrument [Line Items]
Total convertible debt								$ 7,174
Debt instrument, unamortized discount								24,314
Deferred financing costs								524
Interest rate					2.25%
Aggregate principal amount of debt					$ 32,500
Number of shares debt convertible (in shares) | shares					8,666,668
Senior secured convertible debentures conversion price (in dollars per share) | $ / shares					$ 3.75
Maturity period					5 years
Maturity date					Jun. 30, 2021
Debt instrument, convertible, beneficial conversion feature					$ 27,300
Debentures outstanding amount					$ 32,500
Senior Secured 2.25% Convertible Debentures [Member] | Maximum [Member]
Debt Instrument [Line Items]
Senior secured convertible debentures conversion price (in dollars per share) | $ / shares					$ 6.90
Senior Secured 2.25% Convertible Debentures [Member] | Minimum [Member]
Debt Instrument [Line Items]
Senior secured convertible debentures conversion price (in dollars per share) | $ / shares					$ 3.75
Senior Secured 4% Convertible Debentures [Member]
Debt Instrument [Line Items]
Total convertible debt								4,854
Debt instrument, unamortized discount		$ 10,353						3,469
Deferred financing costs								$ 392
Interest rate					4.00%			4.00%
Aggregate principal amount of debt		$ 15,000			$ 15,000
Number of shares debt convertible (in shares) | shares		1,169,595
Senior secured convertible debentures conversion price (in dollars per share) | $ / shares		$ 12.825
Maturity period					5 years
Maturity date					Jul. 30, 2021
Debt instrument, convertible, beneficial conversion feature		$ 4,565
Fair value of warrants		5,296
Change in fair value of warrant liability		491
Debt instrument initial carrying amount		4,647
Debentures converted in shares of common stock, value					$ 262
Debt conversion, converted instrument, issued (in shares) | shares					70,000
Interest expense on debt					$ 197
Debentures outstanding amount		$ 15,000			$ 15,000
Senior Secured 4% Convertible Debentures [Member] | Series A Warrants [Member]
Debt Instrument [Line Items]
Number of warrants to purchase common stock (in shares) | shares		1,239,769
Exercise price of warrants (in dollars per share) | $ / shares		$ 12.25
Common stock, par value (in dollars per share) | $ / shares		$ 0.001
Warrants expiration date						Jul. 31, 2019
Senior Secured 2.25% Convertible Debentures and Senior Secured 4% Convertible Debentures [Member]
Debt Instrument [Line Items]
Debt instrument, interest payment	$ 4,000
Number of years for interest payments					4 years
Senior Secured 2.25% Convertible Debentures and Senior Secured 4% Convertible Debentures [Member] | Series C Convertible Preferred Stock [Member]
Debt Instrument [Line Items]
Number of shares debt convertible (in shares) | shares	15,049,000
Senior secured convertible debentures conversion price (in dollars per share) | $ / shares	$ 2.69
Debt conversion, converted instrument, issued (in shares) | shares	40,482
Preferred stock, stated value (in dollars per share) | $ / shares	$ 1,000
Each share of preferred stock to common stock (in shares) | shares	372
Senior Secured 2.25% Convertible Debentures and Senior Secured 4% Convertible Debentures [Member] | Series C Convertible Preferred Stock [Member] | Maximum [Member]
Debt Instrument [Line Items]
Beneficial ownership percentage	9.99%