Quarterly report pursuant to Section 13 or 15(d)

Notes Payable (Details)

v3.10.0.1
Notes Payable (Details)
$ / shares in Units, $ in Thousands
6 Months Ended
Oct. 15, 2013
USD ($)
Jun. 30, 2018
USD ($)
$ / shares
Dec. 31, 2017
$ / shares
Oct. 23, 2013
item
Notes Payable        
Class Of Warrant Or Right, Exercise Price Of Warrants Or Rights | $ / shares   $ 0.95 $ 0.97  
Sweetwater IDR Bond [Member]        
Notes Payable        
Proceeds from Issuance of Long-term Debt $ 34,000      
Periodic payment amount   $ 17,478    
Due Quarterly Commencing From January 1, 2014 [Member] | Sweetwater IDR Bond [Member]        
Notes Payable        
Fixed interest rate (as a percent)       5.75%
Due Quarterly Commencing From January 1, 2015 [Member] | Sweetwater IDR Bond [Member]        
Notes Payable        
Number of installments | item       28