Short Term Investments (Tables)
|6 Months Ended|
Jun. 30, 2018
|Investments, Debt and Equity Securities [Abstract]|
|Debt Securities, Available-for-sale [Table Text Block]||
The following table summarizes the available-for-sale investments heldas of
June 30, 2018. There were no available-for-sale investments in prior periods.
Tabular disclosure of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).
Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef