Leases - Lease costs and other lease information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Lease costs
Operating lease cost	$ 623	$ 572
Variable lease cost	197	199
Short-term lease cost	95	205
Finance lease cost
Interest on lease liabilities	12	15
Amortization of right-of-use assets	29	29
Sublease Income	(66)	(71)
Net lease cost	890	949
Operating cash flows from operating leases	618	$ 577
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 183
Minimum
Finance lease cost
Initial or remaining lease term under operating lease	1 year
Initial or remaining lease term under finance lease	1 year