Interim Financial Reporting (Details) - USD ($)	6 Months Ended
Jun. 30, 2018	Dec. 31, 2017
Deferred Revenue Arrangement [Line Items]
Contract retentions	$ 1,381,000	$ 1,065,000
Allowance for doubtful accounts	$ 211,000	$ 208,000
Licensing contract term	5 years
Minimum
Deferred Revenue Arrangement [Line Items]
Royalty percent earned on licensing agreement	4.00%
Maximum
Deferred Revenue Arrangement [Line Items]
Royalty percent earned on licensing agreement	6.00%

For an unclassified balance sheet, a valuation allowance for receivables due a company that are expected to be uncollectible.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5074-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.4)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_AllowanceForDoubtfulAccountsReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant