Stockholders' Equity (Details) - USD ($)		6 Months Ended
	Jun. 06, 2017	Jun. 30, 2018	Jun. 30, 2017	May 12, 2017
Class of Stock [Line Items]
Net proceeds of public offering	$ 42,700,000	$ 382,000	$ 43,073,000
Public Offering [Member]
Class of Stock [Line Items]
Additional registration of shares of aggregate amount (up to)		$ 29,000,000		$ 75,000,000.0
Shares issued for public offering	2,139,534