Summary of Significant Accounting Policies - Revenue Recognition - Condensed Statement of Cash flows (Details) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities
Net loss	$ (8,646)	$ (11,273)
Adjustments to reconcile net loss to net cash used in operating activities:
Accounts receivable	(1,391)	(524)
Inventory	940	(1,584)
Shipping term reversal	(39)
Deferred income on shipments to distributors		$ (237)
ASU 2014-09 \| Balances without the adoption of Topic 606
Cash flows from operating activities
Net loss	(9,974)
Adjustments to reconcile net loss to net cash used in operating activities:
Accounts receivable	(532)
Inventory	939
Shipping term reversal	431
ASU 2014-09 \| Adjustments
Cash flows from operating activities
Net loss	(1,328)
Adjustments to reconcile net loss to net cash used in operating activities:
Accounts receivable	859
Inventory	(1)
Shipping term reversal	$ 470

The increase (decrease) during the reporting period in customer liability.

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The increase (decrease) in shipping terms.

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The increase (decrease) during the reporting period in amount due within one year (or one business cycle) from customers for the credit sale of goods and services.

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The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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