Leases (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Leases
Weighted average remaining lease term	65 months
ROU adjustment for lease incentives	$ 900	$ 900
Right-of-use assets	2,200	2,200
Operating lease liabilities	$ 3,383	$ 3,500
Operating Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:OtherAccruedLiabilitiesNoncurrent us-gaap:AccruedLiabilitiesCurrent	us-gaap:OtherAccruedLiabilitiesNoncurrent us-gaap:AccruedLiabilitiesCurrent
Total lease costs	$ 200	$ 700
Weighted-average incremental borrowing rate used to determine right-of-use assets and lease liabilities	11.00%
Maturities of operating lease liabilities
Remaining nine months of 2020	$ 608
2021	818
2022	807
2023	823
2024	840
Thereafter	641
Total lease payments	4,537
Less: imputed interest	(1,154)
Total lease liabilities	3,383	3,500
Current operating lease liabilities	462
Non-current operating lease liabilities	$ 2,921
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	$ 100