Leases (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Leases
Weighted average remaining lease term	62 months		62 months
ROU adjustment for lease incentives	$ 900		$ 900		$ 900
Right-of-use assets	2,100		2,100		2,200
Operating lease liabilities	$ 3,274		$ 3,274		$ 3,500
Operating Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:OtherAccruedLiabilitiesNoncurrent us-gaap:AccruedLiabilitiesCurrent		us-gaap:OtherAccruedLiabilitiesNoncurrent us-gaap:AccruedLiabilitiesCurrent		us-gaap:OtherAccruedLiabilitiesNoncurrent us-gaap:AccruedLiabilitiesCurrent
Total lease costs	$ 200	$ 300	$ 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 2020	$ 406		$ 406
2021	818		818
2022	807		807
2023	823		823
2024	840		840
Thereafter	642		642
Total lease payments	4,336		4,336
Less: imputed interest	(1,062)		(1,062)
Total lease liabilities	3,274		3,274		$ 3,500
Current operating lease liabilities	479		479
Non-current operating lease liabilities	$ 2,795		$ 2,795
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	$ 100	$ 100