Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Cash and cash equivalents	$ 58,757	$ 67,212	$ 93,493	$ 112,801
Going concern within next 12 months	false