Convertible Debentures (Details) $ / shares in Units, $ in Thousands		12 Months Ended
	Jul. 21, 2014 USD ($) shares $ / shares	Dec. 31, 2016 USD ($) shares $ / shares	Dec. 31, 2015 USD ($) $ / shares	Oct. 29, 2013 $ / shares shares
Debt Instrument [Line Items]
Total convertible debt		$ 12,028	$ 9,839
Common stock, par value (in dollars per share) | $ / shares		$ 0.001	$ 0.001
Fair value of warrants adjustment (income) expense		$ (5,396)	$ (1,814)
Debentures converted in shares of common stock, value		265	4,815
Interest expense on debt		217
Debentures outstanding amount		$ 40,727
Maximum [Member]
Debt Instrument [Line Items]
Discounted cash flow change		10.00%
Series A Warrants [Member]
Debt Instrument [Line Items]
Number of warrants to purchase common stock (in shares) | shares	6,198,832			685,715
Exercise price of warrants (in dollars per share) | $ / shares				$ 8.50
Senior Secured 2.25% Convertible Debentures [Member]
Debt Instrument [Line Items]
Total convertible debt		$ 7,174	5,489
Interest rate		2.25%
Debt instrument, unamortized discount		$ 24,314	26,267
Deferred financing costs		524	522
Aggregate principal amount of debt		$ 32,500
Number of shares debt convertible (in shares) | shares		43,333,334
Initial conversion price (in dollars per share) | $ / shares		$ 0.75
Maturity period		5 years
Maturity date		Jun. 30, 2021
Debt instrument, convertible, beneficial conversion feature		$ 27,300
Senior Secured 2.25% Convertible Debentures [Member] | Minimum [Member]
Debt Instrument [Line Items]
Initial conversion price (in dollars per share) | $ / shares		$ 0.75
Senior Secured 2.25% Convertible Debentures [Member] | Maximum [Member]
Debt Instrument [Line Items]
Initial conversion price (in dollars per share) | $ / shares		$ 1.38
Senior Secured 4% Convertible Debentures [Member]
Debt Instrument [Line Items]
Total convertible debt		$ 4,854	4,350
Interest rate		4.00%
Debt instrument, unamortized discount	$ 10,353	$ 3,469	3,922
Deferred financing costs		392	$ 443
Aggregate principal amount of debt	$ 15,000	$ 15,000
Number of shares debt convertible (in shares) | shares	5,847,955	5,847,955
Initial conversion price (in dollars per share) | $ / shares	$ 2.565	$ 2.565
Maturity period		5 years
Maturity date		Jun. 30, 2021
Debt instrument, convertible, beneficial conversion feature	$ 4,565
Fair value of warrants	5,296
Fair value of warrants adjustment (income) expense	491
Debt instrument initial carrying amount	$ 4,647
Debentures converted in shares of common stock, value		$ 265
Debt conversion, converted instrument, issued (in shares) | shares		354,411
Senior Secured 4% Convertible Debentures [Member] | Series A Warrants [Member]
Debt Instrument [Line Items]
Number of warrants to purchase common stock (in shares) | shares		6,198,832
Exercise price of warrants (in dollars per share) | $ / shares	$ 2.45
Maturity date		Jul. 01, 2019
Common stock, par value (in dollars per share) | $ / shares	$ 0.001