Leases (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Jan. 01, 2019
Leases
Weighted average remaining lease term	77 months	77 months
ROU adjustment for lease incentives	$ 900	$ 900	$ 900
Right-of-use assets	2,400	2,400	2,500
Operating lease liabilities	3,497	3,497	3,400
Total lease costs	$ 200	$ 400
Weighted-average incremental borrowing rate used to determine right-of-use assets and lease liabilities	11.00%	11.00%
Maturities of operating lease liabilities
Remaining six months of 2019	$ 206	$ 206
2020	807	807
2021	818	818
2022	807	807
2023	823	823
Thereafter	1,482	1,482
Total lease payments	4,943	4,943
Less: imputed interest	(1,446)	(1,446)
Total lease liabilities	3,497	3,497	$ 3,400
Current operating lease liabilities	321	321
Non-current operating lease liabilities	$ 3,176	$ 3,176
Minimum
Leases
Operating lease agreement term	36 months	36 months
Operating lease renewal term	24 months	24 months
Maximum
Leases
Operating lease agreement term	78 months	78 months
Operating lease renewal term	60 months	60 months
Short-term operating lease costs	$ 100	$ 100