Related Party Transaction (Detail) - Executive Vice President - USD ($)	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Related Party Transaction [Line Items]
Fees for performing duties	$ 46,000	$ 66,000
Related party transaction compensation for services on board	12,500	12,500
Payment of annual bonus compensation	$ 32,000	$ 85,000

Expenses recognized resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

Name:	us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration