Summary of Significant Accounting Policies - Segment Information - Additional Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) segment	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of segments | segment	1
Property, plant and equipment, net	$ 119,244		$ 112,674
Total revenues	39,666	$ 53,747
Foreign Countries
Segment Reporting Information [Line Items]
Property, plant and equipment, net	23,019		$ 21,837
Total revenues	$ 4,203	$ 3,714