Stock Purchase (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2013 USD ($) $ / shares $ / warrant shares	Dec. 31, 2012 USD ($) $ / shares $ / warrant shares	Jun. 26, 2017 shares
Securities Financing Transactions Disclosures [Abstract]
Price per share (dollars per share) | $ / shares				$ 1.03
Stock and warrants purchase price | $				$ 14,400
Shares of common stock (shares)				14,000,000
Warrants to purchase common stock (shares)				7,000,000
Price per warrant (dollars per share) | $ / warrant			1.03	1.03
Additional warrant to purchase common stock (shares)			7,000,000	7,000,000
Price per warrant (dollars per share) | $ / warrant				2.00
Value of warrants | $				$ 5,900
Value of common stock | $				$ 8,500
Exercised warrant per purchase agreement (shares)			7,000,000
Exercised warrants (percent)			92.00%
Price per warrant (dollars per share) | $ / shares	$ 2	$ 2	$ 2
Additional exercised warrant per purchase agreement (shares)			6,400,000
Unexercised warrants (shares)		415,871	571,160		45,564
Proceeds from warrants | $	$ 741	$ 311	$ 20,100
Additional exercised warrant per purchase agreement (shares)	370,307	155,289