Leases - Summary of Components of the Leases and Supplemental Cash Flow Information (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)
Property, Plant and Equipment [Line Items]
Sublease income	$ (3)	$ (9)
Net lease expense	308	922
Office leases
Property, Plant and Equipment [Line Items]
Operating lease expense	$ 306	$ 916
Weighted-average remaining lease term	8 years 11 months 2 days	8 years 11 months 2 days
Weighted-average discount rate	2.64%	2.64%
Operating cash flows	$ 290	$ 808
Equipment leases
Property, Plant and Equipment [Line Items]
Operating lease expense	$ 5	$ 15
Weighted-average remaining lease term	8 months 2 days	8 months 2 days
Weighted-average discount rate	1.62%	1.62%
Operating cash flows	$ 5	$ 15