Investments (Details) - Money Market Funds [Member] - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Cash equivalents	$ 10,960	$ 10,949
Level 1 [Member]
Schedule of Equity Method Investments [Line Items]
Cash equivalents	10,960	10,949
Level 2 [Member]
Schedule of Equity Method Investments [Line Items]
Cash equivalents
Level 3 [Member]
Schedule of Equity Method Investments [Line Items]
Cash equivalents