Selected Balance Sheet Components - Inventory (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Inventory:
Raw materials	$ 3,130	$ 3,532
Work-in-process	456	226
Finished goods	52	35
Inventory	$ 3,638	$ 3,793

Amount before valuation and LIFO reserves of completed merchandise or goods expected to be sold within one year or operating cycle, if longer.

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Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

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Amount before valuation and LIFO reserves of raw materials expected to be sold, or consumed within one year or operating cycle, if longer.

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Amount before valuation and LIFO reserves of merchandise or goods in the production process expected to be completed within one year or operating cycle, if longer.

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