Subsequent Events (Details) - USD ($) $ in Thousands		12 Months Ended
	Feb. 20, 2018	Dec. 31, 2015
Subsequent Event [Line Items]
Proceeds from follow-on offering, net of costs		$ 61,397
Stifel, Nicolaus & Company, Incorporated
Subsequent Event [Line Items]
Commission percentage on gross prcoeeds	3.00%
Stifel, Nicolaus & Company, Incorporated | Maximum
Subsequent Event [Line Items]
Proceeds from follow-on offering, net of costs	$ 50,000