Fair Value Measurement (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Money Market Funds [Member]
Schedule of assets and liabilities measured at fair value on a recurring basis
Total assets at fair value on a recurring basis	$ 15,199	$ 5,103
Deferred payments [Member]
Liabilities:
Total liabilities at fair value on a recurring basis	4,424	11,741
Quoted Prices In Active Markets For Identical Assets/Liabilities (Level 1) [Member] | Money Market Funds [Member]
Schedule of assets and liabilities measured at fair value on a recurring basis
Total assets at fair value on a recurring basis	15,199	5,103
Significant Unobservable Inputs (Level 3) [Member] | Deferred payments [Member]
Liabilities:
Total liabilities at fair value on a recurring basis	$ 4,424	$ 11,741