XML 37 R26.htm IDEA: XBRL DOCUMENT v3.7.0.1
Significant Accounting Policies, Trade Accounts Receivable and Allowance for Doubtful Accounts (Details) - USD ($)
Mar. 31, 2017
Dec. 31, 2016
Receivables [Abstract]    
Allowance for doubtful accounts $ 18,000 $ 19,000