Summary of Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Aug. 31, 2013	Dec. 31, 2016	Jun. 30, 2018	Dec. 31, 2017
Significant Accounting Policies [Line Items]
Impairment Of In-process Research and Development Expenses		$ 12,500
Finite-lived Intangible Assets Acquired	$ 27,500
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		$ 15,000	$ 15,000	$ 15,000