Fair Value Measurements - Schedule of Financial Assets Measured at Fair Value on Recurring Basis (Details) - Fair Value Measurements Recurring - Money Market Funds - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Assets:
Money market funds	$ 6,969	$ 6,951
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Money market funds	$ 6,969	$ 6,951

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

Name:	us-gaap_AssetsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant