4. Investments (Details Narrative)	6 Months Ended
	Jun. 30, 2018
Minimum | Commercial Paper [Member]
Schedule of Investments [Line Items]
Securities maturity length	6 days
Minimum | Corporate Bond Securities [Member]
Schedule of Investments [Line Items]
Securities maturity length	12 days
Maximum | Commercial Paper [Member]
Schedule of Investments [Line Items]
Securities maturity length	3 months 12 days
Maximum | Corporate Bond Securities [Member]
Schedule of Investments [Line Items]
Securities maturity length	53 months 15 days
Certificates of Deposits [Member]
Schedule of Investments [Line Items]
Securities maturity length	5 months 6 days