Supplemental Balance Sheet Information - Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 707,003	$ 705,583
Less: Accumulated depreciation	(229,238)	(207,794)
Property, plant and equipment, net	477,765	497,789
Energy Servers
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	511,239	511,153
Computers, software and hardware
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	19,743	19,384
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	98,397	97,158
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	4,695	4,679
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	22,931	22,799
Building
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	40,512	40,512
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 9,486	$ 9,898

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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