Related-Party Transactions (Details)	12 Months Ended
Dec. 31, 2017 USD ($)
Affiliated entity
Related Party Transactions
Purchase from related party	$ 198,000

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_RelatedPartyTransactionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration