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Accrued Liabilities
3 Months Ended
Mar. 31, 2019
Payables and Accruals [Abstract]  
Accrued Liabilities
Accrued Liabilities

The components of other accrued liabilities are as follows:
 
As of
 
March 31, 2019
 
December 31, 2018
Contract liabilities (Note 3)
$
902

 
$
1,234

Accrued remediation contingency (Note 14)
1,223

 

Other accrued liabilities
2,775

 
4,865

Total other accrued liabilities
$
4,900

 
$
6,099