Commitments and Contingencies - Leases and Contingencies (Details)	12 Months Ended
Dec. 31, 2019 USD ($) claim	Dec. 31, 2018 USD ($) claim
Commitments and Contingencies
Notice period for termination of lease	90 days
Rent expense \| $	$ 341,000	$ 314,000
Number of pending legal proceedings \| claim	0	0

Number of pending claims pertaining to a loss contingency.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118942415&loc=d3e14435-108349

Name:	us-gaap_LossContingencyPendingClaimsNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant