Concentration of Credit Risk (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2016 USD ($) financial_institution	Dec. 31, 2015 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)
Risks and Uncertainties [Abstract]
Number of financial institutions with cash deposits held (more than 1) | financial_institution	1
Cash and cash equivalents held at one financial institution	$ 34,237
Cash and cash equivalents	$ 58,929	$ 76,217	$ 98,359	$ 93,452