Equity - Additional Information - Stock Issuance - Shares Issued to Terex Corporation (Detail) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Dec. 19, 2014
Dec. 31, 2014
Dec. 31, 2016
Mar. 01, 2016
Dec. 31, 2015
Class of Warrant or Right [Line Items]          
Common Stock, shares issued     16,200,294   16,072,100
Cash received   $ 12,500      
Terex Corporation [Member]          
Class of Warrant or Right [Line Items]          
Common Stock, shares issued       30,425  
Option to pay annual principal payments in equity at market value       $ 150  
Share price for transaction       $ 4.93  
Terex Corporation [Member] | Securities Purchase Agreement [Member]          
Class of Warrant or Right [Line Items]          
Common Stock, shares issued 1,108,156        
Cash received $ 12,500