Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2018

Commitments and Contingencies Disclosure [Abstract]

Future Minimum Contractual Commitments under Non-cancelable Agreements

Future minimum contractual commitments as of December 31, 2018 under non-cancelable agreements having initial or remaining terms in excess of one year are as follows: 

	2019		2020		2021		2022		2023		Thereafter
Gas contract	$	1,643	$	1,647	$	680	$	—	$	—	$	—
Office leases	723		—		—		—		—		—
Automobile leases	419		223		77		—		—		—
Total	$	2,785	$	1,870	$	757	$	—	$	—	$	—