Leases - Lease costs and other lease information (Details) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)
Lease costs
Operating lease cost	$ 602	$ 1,772
Variable lease cost	222	633
Short-term lease cost	122	416
Finance lease cost
Interest on lease liabilities	14	45
Amortization of right-of-use assets	29	87
Sublease Income	(65)	(202)
Net lease cost	924	2,751
Operating cash flows from operating leases	$ 600	$ 1,774
Minimum
Finance lease cost
Initial or remaining lease term under operating lease	1 year	1 year
Initial or remaining lease term under finance lease	1 year	1 year

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Amount of interest expense on finance lease liability.

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- Definition

Amount of amortization expense attributable to right-of-use asset from finance lease.

+ References

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- Definition

Amount of lease cost recognized by lessee for lease contract.

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Term of lessee's finance lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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- Definition

Amount of single lease cost, calculated by allocation of remaining cost of lease over remaining lease term. Includes, but is not limited to, single lease cost, after impairment of right-of-use asset, calculated by amortization of remaining right-of-use asset and accretion of lease liability.

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- Definition

Amount of cash outflow from operating lease, excluding payments to bring another asset to condition and location necessary for its intended use.

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- Definition

Amount of short-term lease cost, excluding expense for lease with term of one month or less.

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- Definition

Amount of sublease income excluding finance and operating lease expense.

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- Definition

Amount of variable lease cost, excluded from lease liability, recognized when obligation for payment is incurred for finance and operating leases.

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