Leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Jan. 01, 2019
Leases
Weighted average remaining lease term	77 months
ROU adjustment for lease incentives	$ 900	$ 900
Right-of-use assets	2,400	2,500
Operating lease liabilities	3,413	3,400
Total lease costs	200
Operating lease costs for right-of-use assets	$ 200
Weighted-average incremental borrowing rate used to determine right-of-use assets and lease liabilities	11.00%
Operating Lease Liabilities, Payments, Due, Rolling Maturity [Abstract]
Remaining nine months of 2019	$ 213
2020	807
2021	818
2022	807
2023	823
Thereafter	1,482
Total lease payments	4,950
Less: imputed interest	(1,537)
Total lease liabilities	3,413	$ 3,400
Current operating lease liabilities	216
Non-current operating lease liabilities	$ 3,197
Minimum
Leases
Operating lease agreement term	36 months
Operating lease renewal term	24 months
Maximum
Leases
Operating lease agreement term	78 months
Operating lease renewal term	60 months
Short-term operating lease costs	$ 100