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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The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

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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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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services 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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Property and equipment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
Property and equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Property and equipment
Less accumulated depreciation	$ (845)		$ (845)		$ (590)
Property and equipment, net	1,883		1,883		1,816
Depreciation and amortization	100	$ 100	216	$ 134
Computer software and equipment
Property and equipment
Property and equipment, gross	15		15		15
Office equipment and furniture
Property and equipment
Property and equipment, gross	160		160		92
Laboratory equipment
Property and equipment
Property and equipment, gross	1,560		1,560		1,529
Leasehold improvements
Property and equipment
Property and equipment, gross	$ 993		$ 993		748
Construction in progress
Property and equipment
Property and equipment, gross					$ 22