Selected Balance Sheet Components - Schedule of inventory (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Inventory:
Raw materials	$ 6,576	$ 6,085
Work-in-process	617	541
Finished goods	89	190
Inventory	$ 7,282	$ 6,816

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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